Hemant K Chitale

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Updated: 9 hours 1 min ago

Testing RENAME LOB (Segment) in 23ai

Tue, 2024-05-21 09:46
Another new feature of 23ai is the ability to rename a LOB (Segment) in-place without having to use the MOVE clause.

A quick demo :


SQL> -- Version 23ai Free Edition
SQL> select banner from v$version;

BANNER
---------------------------------------------------------------------------------------------------------------------------------
Oracle Database 23ai Free Release 23.0.0.0.0 - Develop, Learn, and Run for Free

SQL>
SQL>
SQL> DROP TABLE my_lob_objects purge;

Table dropped.

SQL>
SQL> -- create the table with a LOB, column name "c",  lob segment name also "c"
SQL> CREATE TABLE my_lob_objects (object_id NUMBER primary key, c CLOB)
  2        lob (c) STORE AS SECUREFILE c
  3        ( TABLESPACE users
  4          DISABLE STORAGE IN ROW
  5          NOCACHE LOGGING
  6          RETENTION AUTO
  7          COMPRESS
  8        );

Table created.

SQL>
SQL> -- query the data dictionary
SQL> select table_name, column_name, segment_name, tablespace_name from user_lobs;

TABLE_NAME       COLUMN_NAME      SEGMENT_NAME         TABLESPACE_NAME
---------------- ---------------- -------------------- ----------------
MY_LOB_OBJECTS   C                C                    USERS

SQL>
SQL> -- insert three rows
SQL> insert into my_lob_objects values (1, dbms_random.string('X',100));

1 row created.

SQL> insert into my_lob_objects values (2, dbms_random.string('X',100));

1 row created.

SQL> insert into my_lob_objects values (3, dbms_random.string('X',100));

1 row created.

SQL>
SQL> -- verify the column name when querying the table
SQL> select * from my_lob_objects;

 OBJECT_ID C
---------- --------------------------------------------------------------------------------
         1 IBGOGKA9QKK56O746IJL3C56ZK9LEO0G1W4LWBN11T8EWCFTTLUW9TPIVQAU8BPSGPQ2ZV57BS0ZPK0S
         2 7K04DVVYDQB1URIQ1OQ2458M8ZOURHWW50XIZDMVGAZH6XVN2KKN4PIGKPY5CSVIQ9KU45LHZPJB33AA
         3 2G5194Z7TSR3XG0K698G587AOZOJ8VN6KFCTCH3074TNCOWCSMOPRJLRGTLIZMDD73XAY4KDD14IW4MG

SQL>
SQL> -- now rename the column
SQL> alter table my_lob_objects rename column c to clob_col;

Table altered.

SQL>
SQL> -- query the data dictionary
SQL> select table_name, column_name, segment_name, tablespace_name from user_lobs;

TABLE_NAME       COLUMN_NAME      SEGMENT_NAME         TABLESPACE_NAME
---------------- ---------------- -------------------- ----------------
MY_LOB_OBJECTS   CLOB_COL         C                    USERS

SQL>
SQL> -- now rename the lob segment
SQL> alter table my_lob_objects rename lob(clob_col) c to my_lob_objects_clob;

Table altered.

SQL>
SQL> -- query the data dictionary
SQL> select table_name, column_name, segment_name, tablespace_name from user_lobs;

TABLE_NAME       COLUMN_NAME      SEGMENT_NAME         TABLESPACE_NAME
---------------- ---------------- -------------------- ----------------
MY_LOB_OBJECTS   CLOB_COL         MY_LOB_OBJECTS_CLOB  USERS

SQL>
SQL> -- verify the column name when querying the table
SQL> select * from my_lob_objects;

 OBJECT_ID CLOB_COL
---------- --------------------------------------------------------------------------------
         1 IBGOGKA9QKK56O746IJL3C56ZK9LEO0G1W4LWBN11T8EWCFTTLUW9TPIVQAU8BPSGPQ2ZV57BS0ZPK0S
         2 7K04DVVYDQB1URIQ1OQ2458M8ZOURHWW50XIZDMVGAZH6XVN2KKN4PIGKPY5CSVIQ9KU45LHZPJB33AA
         3 2G5194Z7TSR3XG0K698G587AOZOJ8VN6KFCTCH3074TNCOWCSMOPRJLRGTLIZMDD73XAY4KDD14IW4MG

SQL>
SQL> -- identify the segment
SQL> select tablespace_name, segment_name, segment_type, bytes/1024 Size_KB
  2  from user_segments
  3  where segment_name = 'MY_LOB_OBJECTS_CLOB'
  4  /

TABLESPACE_NAME  SEGMENT_NAME         SEGMENT_TYPE         SIZE_KB
---------------- -------------------- ------------------ ---------
USERS            MY_LOB_OBJECTS_CLOB  LOBSEGMENT              2304

SQL>



First I create a Table where the Column and LOB (Segment) are both called "C".  In recent versions, SECUREFILE is the default and recommended for LOBs (e.g. with the COMPRESS, DEDUPLICATION and ENCRYPTION advantages).

Then I insert 3 rows.

I then rename the column "C" to "CLOB_COL".

Next, I rename the LOB (Segment) to "MY_LOB_OBJECTS_CLOB".  I include the Table Name because the LOB segment is an independent segment that I might query in USER_SEGMENTS (where Table Name) is not available.  This RENAME LOB clause is new in 23ai and does not require the use of MOVE LOB.


I then verify the new Segment Name for the LOB as well.

Yes, the 2,304KB "size" seems excessive but this will make sense (with the COMPRESS attribute) when the LOB grows much much larger as new rows with long Character-Strings are inserted.




Categories: DBA Blogs

Testing DEFAULT ON NULL FOR UPDATE in 23ai

Thu, 2024-05-09 10:25

 Testing  a new feature in 23ai that allows you to define a DEFAULT value for a column if a user/front-end/application sends a NULL :


[oracle@oel9 ~]$ sqlplus hemant/hemant@freepdb1

SQL*Plus: Release 23.0.0.0.0 - Production on Thu May 9 14:54:25 2024
Version 23.4.0.24.05

Copyright (c) 1982, 2024, Oracle.  All rights reserved.


Connected to:
Oracle Database 23ai Free Release 23.0.0.0.0 - Develop, Learn, and Run for Free
Version 23.4.0.24.05

SQL> create table my_new_employees(
  2  employee_id number(12) primary key,
  3  employee_name varchar2(48),
  4  department_id number(12)
  5  )
  6  /

Table created.

SQL>
SQL> insert into my_new_employees
  2  values (1,'Hemant',NULL)
  3  /

1 row created.

SQL>
SQL> select * from my_new_employees;

EMPLOYEE_ID EMPLOYEE_NAME                                    DEPARTMENT_ID
----------- ------------------------------------------------ -------------
          1 Hemant

SQL>
SQL> update my_new_employees
  2  set department_id=100  -- setting a non-NULL value
  3  where employee_id=1
  4  /

1 row updated.

SQL> select * from my_new_employees;

EMPLOYEE_ID EMPLOYEE_NAME                                    DEPARTMENT_ID
----------- ------------------------------------------------ -------------
          1 Hemant                                                     100

SQL>
SQL> alter table my_new_employees
  2  modify (department_id default on null for insert and update 512);

Table altered.

SQL> insert into my_new_employees
  2  values (2,'Larry');    -- I am not specifying a value for DEPARTMENT_ID 
insert into my_new_employees
            *
ERROR at line 1:
ORA-00947: not enough values
Help: https://docs.oracle.com/error-help/db/ora-00947/


SQL> insert into my_new_employees
  2  values(2,'Larry', NULL); -- I explicitly specify NULL for DEPARTMENT_ID

1 row created.

SQL> select * from my_new_employees order by 1;

EMPLOYEE_ID EMPLOYEE_NAME                                    DEPARTMENT_ID
----------- ------------------------------------------------ -------------
          1 Hemant                                                     100
          2 Larry                                                      512  -- it got set to 512 ON INSERT

SQL>
SQL> update my_new_employees
  2  set employee_name = 'Hemant Chitale', department_id=NULL -- I explicitly specify NULL for DEPARMTENT_ID
  3  where employee_id=1
  4  /

1 row updated.

SQL> select * from my_new_employees order by 1;

EMPLOYEE_ID EMPLOYEE_NAME                                    DEPARTMENT_ID
----------- ------------------------------------------------ -------------
          1 Hemant Chitale                                             512  -- it got set to 512 ON UPDATE
          2 Larry                                                      512

SQL>
SQL> commit;

Commit complete.

SQL> select * from my_new_employees order by 1;

EMPLOYEE_ID EMPLOYEE_NAME                                    DEPARTMENT_ID
----------- ------------------------------------------------ -------------
          1 Hemant Chitale                                             512
          2 Larry                                                      512

SQL>


So, now the column has a proper DEFAULT value when an UPDATE statement sends a NULL.  This allows the developer to avoid having to write a Front-End Value Check or a Database Table Trigger to convert an incoming NULL to a DEFAULT value.

Categories: DBA Blogs

Testing DB_FLASHBACK_LOG_DEST in 23ai

Mon, 2024-05-06 09:38

 Pre-23ai, Database Flashback Logs always were created in the DB_RECOVERY_FILE_DEST location (i.e.. the well-known "Fast Recovery Area" also known as "FRA").

However, these would share space with ArchiveLogs (if you've configured ArchiveLogs to the same location) and RMAN Backups (if you aren't specifically writing RMAN Backups to a different location).

23ai introduced the DB_FLASHBACK_LOG_DEST (and corresponding DB_FLASHBACK_LOG_DEST_SIZE) parameter to allow you to separate your Database Flashback Logs to a dedicated location.

The 23ai  New Features documentation has this to say :

In previous releases, you could store flashback database logs only in the fast recovery area. Now you can optionally designate a separate location for flashback logging. For example, if you have write-intensive database workloads, then flashback database logging can slow down the database if the fast recovery area is not fast enough. In this scenario, you can now choose to write the flashback logs to faster disks. Using a separate destination also eliminates the manual administration to manage the free space in the fast recovery area.

Managing flashback database logs outside the fast recovery area lowers the operational costs related to space management and guarantees the best performance for workloads that are typically impacted by flashback logging on traditional storage.


And it provides a link to the documentation on the parameter.


You might think that DB_FLASHBACK_LOG_DEST is now completely independent of DB_RECOVERY_FILE_DEST.


Here is my test run where I configured DB_FLASHBACK_LOG_DEST  without configuring DB_RECOVERY_FILE_DEST :




h-4.4$ cd /opt/oracle
sh-4.4$ mkdir FBL
sh-4.4$ mkdir FRA
sh-4.4$ sqlplus / as sysdba

SQL*Plus: Release 23.0.0.0.0 - Production on Sun May 5 10:26:26 2024
Version 23.4.0.24.05

Copyright (c) 1982, 2024, Oracle.  All rights reserved.


Connected to:
Oracle Database 23ai Free Release 23.0.0.0.0 - Develop, Learn, and Run for Free
Version 23.4.0.24.05

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.

Total System Global Area 1603726344 bytes
Fixed Size                  5360648 bytes
Variable Size             402653184 bytes
Database Buffers         1191182336 bytes
Redo Buffers                4530176 bytes
Database mounted.
SQL> show parameter spfile;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
spfile                               string      /opt/oracle/product/23ai/dbhom
                                                 eFree/dbs/spfileFREE.ora
SQL>
SQL> alter database archivelog;

Database altered.

SQL> alter database open;

Database altered.

SQL> show parameter db_flashback

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_flashback_log_dest                string
db_flashback_log_dest_size           big integer 0
SQL> alter system set db_flashback_log_dest_size=10G;

System altered.

SQL> alter system  set db_flashback_log_dest='/opt/oracle/FBL';

System altered.

SQL> create restore point MY_FIRST_RP ;

Restore point created.

SQL> alter system archive log current;

System altered.

SQL>
SQL> create table x as select * from cdb_objects;

Table created.

SQL> insert into x select * from x;

141420 rows created.

SQL> delete x;

282840 rows deleted.

SQL> commit;

Commit complete.

SQL> alter system archive log current;

System altered.

SQL>
SQL> alter database flashback on;  -- only here I enable Flashback

Database altered.

==============================================
alert log messages :
2024-05-05T10:38:35.262274+00:00
alter database flashback on
2024-05-05T10:38:35.423698+00:00
Allocating 8388608 bytes in shared pool for flashback generation buffer.
Allocated 8388608 bytes in shared pool for flashback generation buffer
Flashback Database Enabled at SCN 3124894
===============================================

SQL> create restore point MY_FIRST_RP;  -- testing if I can create another RP with the same name
create restore point MY_FIRST_RP
*
ERROR at line 1:
ORA-38778: Restore point 'MY_FIRST_RP' already exists.
Help: https://docs.oracle.com/error-help/db/ora-38778/


SQL> drop restore point MY_FIRST_RP;

Restore point dropped.

SQL> create restore point MY_FIRST_RP;

Restore point created.

SQL> drop table x;

Table dropped.

SQL> create table x as select * from cdb_objects;

Table created.

SQL>
SQL> alter system archive log current;

System altered.

SQL> delete x;

141420 rows deleted.

SQL> insert into x select * from cdb_objects;

141421 rows created.

SQL> commit;

Commit complete.

SQL> alter system archive log current;

System altered.

SQL>
SQL> select substr(name,1,32), scn, time from v$restore_point;  -- identify the RP that has been created

SUBSTR(NAME,1,32)
--------------------------------------------------------------------------------------------------------------------------------
       SCN TIME
---------- ---------------------------------------------------------------------------
MY_FIRST_RP
   3124955 05-MAY-24 10.39.30.000000000 AM


SQL> select * from v$flashback_database_log;  -- identify the FBDB Logs Size

OLDEST_FLASHBACK_SCN OLDEST_FL RETENTION_TARGET FLASHBACK_SIZE ESTIMATED_FLASHBACK_SIZE     CON_ID
-------------------- --------- ---------------- -------------- ------------------------ ----------
             3124893 05-MAY-24             1440      419430400                        0          0

SQL> select * from v$flashback_log_dest; -- identify the FB Log Dest (why isn't the view named V$FLASHBACK_DATABASE_LOG_DEST ?)

NAME
------------------------------------------------------------------------------------------------------------------------------------
SPACE_LIMIT SPACE_USED NUMBER_OF_FILES     CON_ID
----------- ---------- --------------- ----------
/opt/oracle/FBL
 1.0737E+10  419430400               2          0


SQL>
SQL> !sh
sh-4.4$ cd /opt/oracle/FBL
sh-4.4$ du -sh *
401M    FREE
sh-4.4$ cd FREE
sh-4.4$ ls
flashback
sh-4.4$ cd flashback
sh-4.4$ ls -l
total 409620
-rw-r----- 1 oracle oinstall 209723392 May  5 10:41 o1_mf_m3grfc8t_.flb
-rw-r----- 1 oracle oinstall 209723392 May  5 10:38 o1_mf_m3grfg1v_.flb
sh-4.4$
sh-4.4$ cd $ORACLE_HOME/dbs
sh-4.4$ ls -l arch1*
-rw-r----- 1 oracle oinstall  98164736 May  5 10:31 arch1_2_1167168121.dbf
-rw-r----- 1 oracle oinstall 106480640 May  5 10:33 arch1_3_1167168121.dbf
-rw-r----- 1 oracle oinstall  37506048 May  5 10:40 arch1_4_1167168121.dbf
-rw-r----- 1 oracle oinstall  52515840 May  5 10:40 arch1_5_1167168121.dbf
sh-4.4$
sh-4.4$ exit
exit

SQL> select count(*) from x;

  COUNT(*)
----------
    141421

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL>
SQL> startup mount;
ORACLE instance started.

Total System Global Area 1603726344 bytes
Fixed Size                  5360648 bytes
Variable Size             419430400 bytes
Database Buffers         1174405120 bytes
Redo Buffers                4530176 bytes
Database mounted.
SQL> flashback database to restore point MY_FIRST_RP;   -- try to Flashback the Database
flashback database to restore point MY_FIRST_RP
*
ERROR at line 1:
ORA-38760: This database instance failed to turn on flashback database
Help: https://docs.oracle.com/error-help/db/ora-38760/


============================================
alert log messages :
2024-05-05T10:45:28.380285+00:00
Successful mount of redo thread 1, with mount id 1440201864
2024-05-05T10:45:28.380506+00:00
Allocating 8388608 bytes in shared pool for flashback generation buffer.
Allocated 5807328 bytes in shared pool for flashback generation buffer
RVWR could not begin generation of flashback log data because
DB_RECOVERY_FILE_DEST is not set.
2024-05-05T10:45:28.392865+00:00
Errors in file /opt/oracle/diag/rdbms/free/FREE/trace/FREE_rvwr_2343.trc:
ORA-38776: cannot begin flashback generation - recovery area is disabled
2024-05-05T10:45:28.392899+00:00
WARNING: Cannot open the flashback thread for this instance due to the above error.
WARNING: Flashback thread open failed - to resolve this, either correct the reported error or turn off database flashbac
k.
2024-05-05T10:45:28.393060+00:00
Database mounted in Exclusive Mode
Lost write protection mode set to "auto"
Completed: ALTER DATABASE   MOUNT
2024-05-05T10:46:04.458087+00:00
flashback database to restore point MY_FIRST_RP
ORA-38760 signalled during: flashback database to restore point MY_FIRST_RP...
2024-05-05T10:50:43.887137+00:00
==============================================


Explanation of the Error :
===========================
38776, 00000, "cannot begin flashback generation - recovery area is disabled"
// *Cause: During a database mount, the RVWR process discovered that the
//         recovery area was disabled.  DB_RECOVERY_FILE_DEST must have
//         been set null or removed from the INIT.ORA file while the database
//         was unmounted.
// *Action: Flashback database requires the recovery area to be enabled.
//          Either enable the recovery area by setting the
//          DB_RECOVERY_FILE_DEST and DB_RECOVERY_FILE_DEST_SIZE initialization
//          parameters, or turn off flashback database with the
//          ALTER DATABASE FLASHBACK OFF command.



So, Oracle 
1.  allows me to create a Restore Point
2.  generates Flashback Log
3.  confirms that they exist
BUT DOES NOT ALLOW ME TO FLASHBACK THE DATABASE.

DB_RECOVERY_FILE_DEST is still mandatory (even if you have ArchiveLogs being written elsewhere -- my ArchiveLogs were going to the default location under $ORACLE_HOME/dbs).

If you look at the documentation (column "Required" in Table 5-4) it does say that DB__RECOVERY_FILE_DEST is a required parameter -- although it doesnt explicitly say that this is required for the FLASHBACK LOGS.  Also, my database was happy to generate ArchiveLogs in another, default, location ($ORACLE_HOME/dbs).

The CREATE RESTORE POINT command didn't give me any warning that the Restore Point would not be usable -- I would treat this as a Bug.

Categories: DBA Blogs

Video on monitoring (a single instance) DataGuard Standby for a RAC (2-node) Cluster

Wed, 2024-05-01 04:03

 I've just uploaded a new video on monitoring DataGuard where the Standby is a Single Instance environment for a 2-node RAC Cluster.


The script used in the demo are in this ZIP  (script files with extension TXT)

Categories: DBA Blogs

Video on Client Side Failover in RAC

Thu, 2024-04-11 01:54

 I've posted a new video demonstrating Client Side Failover defined by the tnsnames.ora file





Categories: DBA Blogs

Video on Host Names, SCAN and IP Addresses

Sat, 2024-03-30 04:31

 I've posted a new Video on Host Names, SCAN and Virtual IPs in RAC (using a 2-node 19c Cluster)



Categories: DBA Blogs

Grid Infrastructure --- OCR and Voting Disks Location at Installation

Sun, 2024-03-24 04:30

 In Oracle Grid Infrastructure, the OCR (Oracle Cluster Registry) and Voting "Disks" must be on Shared Storage accessible by all the nodes of the Cluster.  Typically, these are on ASM.

In ASM, a DiskGroup is created for the disks that hold the OCR.  

Normally, an ASM DiskGroup may use External Redundancy (Mirroring or other protection against Physical Disk or LUN failure is provided by the underlying Storage) or Normal Redundancy (Two-Way Mirroring, i.e. two Disks or LUN devices) or High Redundancy (Three-Way Mirroring with three Disks).

However, for the OCR and Voting "Disks" (i.e. Voting File), Normal Redundancy requires three Disks or LUN devices where three Voting Files and one OCR (Primary and Secondary copy) are created.  High Redundancy requires five Disks or LUN devices where five Voting Files and once OCR (with one Primary and two Secondary copies) are created.

In Test or Lab environments, you might have created your OCR/Vote DiskGroup on ASM storage with External Redundancy so as to not have to provision 3 or 5 disks.


However, in the 19c Lab environment with 2 Virtual Box VMs that I recently built on my Home PC, I created 5 ASM Disks of 2GB each (using ASMLib instead of udev persistent naming)  to hold the OCR + VOTE DiskGroup.  I then selected High Redundancy for the consequent DiskGroup.

This is the Installer Screen :



This is the subsequent output from running root.sh from the Grid ORACLE_HOME towards the end of the installation :

[datetime] CLSRSC-482: Running command: '/u01/app/grid/product/19.3/bin/ocrconfig -upgrade grid grid'

CRS-4256: Updating the profile

Successful addition of voting disk 6c3ea5fbf0254fd5bfd489fc5c674409.

Successful addition of voting disk ff3b9da031064fccbfab4b57933f12e1.

Successful addition of voting disk 44e50015bcf24f7cbfc1b9348fdbe568.

Successful addition of voting disk de64da366c164f5cbfba2761df5948d5.

Successful addition of voting disk 4485ff5940384f85bf524a81090c6bd8.

Successfully replaced voting disk group with +OCR_VOTE.

CRS-4256: Updating the profile

CRS-4266: Voting file(s) successfully replaced

##  STATE    File Universal Id                File Name Disk group

--  -----    -----------------                --------- ---------

 1. ONLINE   6c3ea5fbf0254fd5bfd489fc5c674409 (/dev/oracleasm/disks/OCR_VOTE_DISK_1) [OCR_VOTE]

 2. ONLINE   ff3b9da031064fccbfab4b57933f12e1 (/dev/oracleasm/disks/OCR_VOTE_DISK_2) [OCR_VOTE]

 3. ONLINE   44e50015bcf24f7cbfc1b9348fdbe568 (/dev/oracleasm/disks/OCR_VOTE_DISK_3) [OCR_VOTE]

 4. ONLINE   de64da366c164f5cbfba2761df5948d5 (/dev/oracleasm/disks/OCR_VOTE_DISK_4) [OCR_VOTE]

 5. ONLINE   4485ff5940384f85bf524a81090c6bd8 (/dev/oracleasm/disks/OCR_VOTE_DISK_5) [OCR_VOTE]

Located 5 voting disk(s).


Thus it did create 5 Voting "Disks" (Voting Files).

After the installation is completed, I verified this again  

from the first node "srv1":

[root@srv1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      84232
         Available space (kbytes) :     407452
         ID                       : 1183403784
         Device/File Name         :  +OCR_VOTE
                                    Device/File integrity check succeeded

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

         Cluster registry integrity check succeeded

         Logical corruption check succeeded

[root@srv1 ~]# crsctl query css votedisk
##  STATE    File Universal Id                File Name Disk group
--  -----    -----------------                --------- ---------
 1. ONLINE   6c3ea5fbf0254fd5bfd489fc5c674409 (/dev/oracleasm/disks/OCR_VOTE_DISK_1) [OCR_VOTE]
 2. ONLINE   ff3b9da031064fccbfab4b57933f12e1 (/dev/oracleasm/disks/OCR_VOTE_DISK_2) [OCR_VOTE]
 3. ONLINE   44e50015bcf24f7cbfc1b9348fdbe568 (/dev/oracleasm/disks/OCR_VOTE_DISK_3) [OCR_VOTE]
 4. ONLINE   de64da366c164f5cbfba2761df5948d5 (/dev/oracleasm/disks/OCR_VOTE_DISK_4) [OCR_VOTE]
 5. ONLINE   4485ff5940384f85bf524a81090c6bd8 (/dev/oracleasm/disks/OCR_VOTE_DISK_5) [OCR_VOTE]
Located 5 voting disk(s).
[root@srv1 ~]#


and from the second node "srv2" :


[root@srv2 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      84232
         Available space (kbytes) :     407452
         ID                       : 1183403784
         Device/File Name         :  +OCR_VOTE
                                    Device/File integrity check succeeded

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

         Cluster registry integrity check succeeded

         Logical corruption check succeeded

[root@srv2 ~]# crsctl query css votedisk
##  STATE    File Universal Id                File Name Disk group
--  -----    -----------------                --------- ---------
 1. ONLINE   6c3ea5fbf0254fd5bfd489fc5c674409 (/dev/oracleasm/disks/OCR_VOTE_DISK_1) [OCR_VOTE]
 2. ONLINE   ff3b9da031064fccbfab4b57933f12e1 (/dev/oracleasm/disks/OCR_VOTE_DISK_2) [OCR_VOTE]
 3. ONLINE   44e50015bcf24f7cbfc1b9348fdbe568 (/dev/oracleasm/disks/OCR_VOTE_DISK_3) [OCR_VOTE]
 4. ONLINE   de64da366c164f5cbfba2761df5948d5 (/dev/oracleasm/disks/OCR_VOTE_DISK_4) [OCR_VOTE]
 5. ONLINE   4485ff5940384f85bf524a81090c6bd8 (/dev/oracleasm/disks/OCR_VOTE_DISK_5) [OCR_VOTE]
Located 5 voting disk(s).
[root@srv2 ~]#



Note : Whether I create the DiskGroup with Normal or High Redundancy, it will still show only 1 OCR because there is only 1 Primary OCR location (Normal or High Redundancy will automatically create 1 or 2 Secondary OCR copy).


It is possible to add another location for OCR in this manner (where I add to the FRA DiskGroup):

[root@srv1 ~]# ocrconfig -add +FRA
[root@srv1 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      84232
         Available space (kbytes) :     407452
         ID                       : 1183403784
         Device/File Name         :  +OCR_VOTE
                                    Device/File integrity check succeeded
         Device/File Name         :       +FRA
                                    Device/File integrity check succeeded

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

         Cluster registry integrity check succeeded

         Logical corruption check succeeded

[root@srv1 ~]#

[root@srv2 ~]# ocrcheck
Status of Oracle Cluster Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      84232
         Available space (kbytes) :     407452
         ID                       : 1183403784
         Device/File Name         :  +OCR_VOTE
                                    Device/File integrity check succeeded
         Device/File Name         :       +FRA
                                    Device/File integrity check succeeded

                                    Device/File not configured

                                    Device/File not configured

                                    Device/File not configured

         Cluster registry integrity check succeeded

         Logical corruption check succeeded

[root@srv2 ~]#


Furthermore, each node of the Cluster has a Local Cluster Registry (that is called an OLR) :

[root@srv1 ~]# ocrcheck -local
Status of Oracle Local Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      83144
         Available space (kbytes) :     408540
         ID                       : 1343496565
         Device/File Name         : /u01/app/grid_base/crsdata/srv1/olr/srv1_19.olr
                                    Device/File integrity check succeeded

         Local registry integrity check succeeded

         Logical corruption check succeeded

[root@srv1 ~]#

[root@srv2 ~]# ocrcheck -local
Status of Oracle Local Registry is as follows :
         Version                  :          4
         Total space (kbytes)     :     491684
         Used space (kbytes)      :      83132
         Available space (kbytes) :     408552
         ID                       : 1914984123
         Device/File Name         : /u01/app/grid_base/crsdata/srv2/olr/srv2_19.olr
                                    Device/File integrity check succeeded

         Local registry integrity check succeeded

         Logical corruption check succeeded

[root@srv2 ~]#

If you are worried about Failure Groups for the OCR_VOTE DiskGroup, you can see that the FailureGroups are automatically created for this High Redundancy DiskGroup :

SQL> l
  1  select g.name, d.disk_number, d.label, d.failgroup
  2  from v$asm_diskgroup g right join v$asm_disk d
  3  on g.group_number = d.group_number
  4  where g.name = 'OCR_VOTE'
  5* order by 1,2
SQL> /

NAME         DISK_NUMBER LABEL              FAILGROUP
------------ ----------- ------------------ ----------------
OCR_VOTE               0 OCR_VOTE_DISK_1    OCR_VOTE_0000
OCR_VOTE               1 OCR_VOTE_DISK_2    OCR_VOTE_0001
OCR_VOTE               2 OCR_VOTE_DISK_3    OCR_VOTE_0002
OCR_VOTE               3 OCR_VOTE_DISK_4    OCR_VOTE_0003
OCR_VOTE               4 OCR_VOTE_DISK_5    OCR_VOTE_0004

SQL>





Categories: DBA Blogs

Installing and Running DBSAT on 21c

Tue, 2024-03-05 09:33

 DBSAT is Oracle's "Database Security Assessment Tool" that you can get from Oracle Support Document "Oracle Database Security Assessment Tool (DBSAT) (Doc ID 2138254.1)" .

This is the User Guide for the current release (3.1)

It does checks against "proven Oracle Database Security best practices, CIS benchmark recommendations and STIG rules". 

See Oracle Support Document "Does DBSAT Scan for all of the STIG And CIS Benchmark Controls? (Doc ID 2651827.1)" for a disclaimer.

Here I demonstrate quick installation :



[oracle@node2 ~]$ cd /u01/app/oracle
[oracle@node2 oracle]$ cd DB*
[oracle@node2 DBSAT_Installer]$ pwd
/u01/app/oracle/DBSAT_Installer
[oracle@node2 DBSAT_Installer]$ ls -l
total 45180
-rwxr-x---. 1 oracle dba 46264143 Mar  5 22:15 DBSAT.zip
[oracle@node2 DBSAT_Installer]$ which unzip
/bin/unzip
[oracle@node2 DBSAT_Installer]$
[oracle@node2 DBSAT_Installer]$ unzip DBSAT.zip
Archive:  DBSAT.zip
  inflating: dbsat
  inflating: dbsat.bat
  inflating: sat_collector.sql
  inflating: sa.jar
  inflating: jython-standalone-2.7.3.jar
  inflating: xlsxwriter/app.py
  inflating: xlsxwriter/chart_area.py
  inflating: xlsxwriter/chart_bar.py
  inflating: xlsxwriter/chart_column.py
....
....
deleted a few lines of output of the unzip command
  inflating: Discover/conf/sensitive_en.ini
  inflating: Discover/conf/sensitive_es.ini
  inflating: Discover/conf/sensitive_de.ini
  inflating: Discover/conf/sensitive_pt.ini
  inflating: Discover/conf/sensitive_it.ini
  inflating: Discover/conf/sensitive_fr.ini
  inflating: Discover/conf/sensitive_nl.ini
  inflating: Discover/conf/sensitive_el.ini
[oracle@node2 DBSAT_Installer]$

--- create the default script from the User Guide
[oracle@node2 DBSAT_Installer]$ cat > DBSAT_User.sql
create user dbsat_user identified by dbsat_user;
--If Database Vault is enabled, connect as DV_ACCTMGR to run this command
grant create session to dbsat_user;
grant select_catalog_role to dbsat_user;
grant select on sys.registry$history to dbsat_user;
grant read on sys.dba_audit_mgmt_config_params to dbsat_user;
grant select on sys.dba_users_with_defpwd to dbsat_user;
grant read on sys.dba_credentials to dbsat_user;
grant execute on sys.dbms_sql to dbsat_user;
grant audit_viewer to dbsat_user; // 12c and later
grant capture_admin to dbsat_user;// 12c and later covers sys.dba_priv_captures, sys.priv_capture$, sys.capture_run_log$
[oracle@node2 DBSAT_Installer]$

--- verify the script
[oracle@node2 DBSAT_Installer]$ cat DBSAT_User.sql
create user dbsat_user identified by dbsat_user;
--If Database Vault is enabled, connect as DV_ACCTMGR to run this command
grant create session to dbsat_user;
grant select_catalog_role to dbsat_user;
grant select on sys.registry$history to dbsat_user;
grant read on sys.dba_audit_mgmt_config_params to dbsat_user;
grant select on sys.dba_users_with_defpwd to dbsat_user;
grant read on sys.dba_credentials to dbsat_user;
grant execute on sys.dbms_sql to dbsat_user;
grant audit_viewer to dbsat_user; // 12c and later
grant capture_admin to dbsat_user;// 12c and later covers sys.dba_priv_captures, sys.priv_capture$, sys.capture_run_log$
[oracle@node2 DBSAT_Installer]$

-- I then create this user in my custom PDB

[oracle@node2 DBSAT_Installer]$ sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Tue Mar 5 22:30:29 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL> alter session set container=HEMANTPDB;

Session altered.

SQL> @DBSAT_User.sql

User created.


Grant succeeded.


Grant succeeded.


Grant succeeded.


Grant succeeded.


Grant succeeded.


Grant succeeded.


Grant succeeded.

SQL>


I am now ready to run the Collector.



[oracle@node2 DBSAT_Installer]$ ./dbsat collect dbsat_user/dbsat_user@hemantpdb

Database Security Assessment Tool version 3.1 (Jan 2024)

This tool is intended to assist you in securing your Oracle database
system. You are solely responsible for your system and the effect and
results of the execution of this tool (including, without limitation,
any damage or data loss). Further, the output generated by this tool may
include potentially sensitive system configuration data and information
that could be used by a skilled attacker to penetrate your system. You
are solely responsible for ensuring that the output of this tool,
including any generated reports, is handled in accordance with your
company's policies.


    Usage: dbsat collect [ -n ] -lt database_connect_string > -lt output_file >
           dbsat report [ -a ] [ -n ] [ -g ] [ -x -lt section > ] [ -u -lt user > ] -lt input_file >
           dbsat discover [ -n ] -c -lt config_file > -lt output_file >

    Options:
       -a  Report with all user accounts, including locked and schema-only,
           Oracle-supplied users
       -n  No encryption for output
       -g  Show all grants including Common Grants in a Pluggable Database
       -x  Specify sections to exclude from report (may be repeated for
           multiple sections)
       -u  Specify users to exclude from report
       -c  Configuration file for discoverer



[oracle@node2 DBSAT_Installer]$  ./dbsat collect dbsat_user/dbsat_user@hemantpdb hemantpdb_DBSAT_Report

Database Security Assessment Tool version 3.1 (Jan 2024)

This tool is intended to assist you in securing your Oracle database
system. You are solely responsible for your system and the effect and
results of the execution of this tool (including, without limitation,
any damage or data loss). Further, the output generated by this tool may
include potentially sensitive system configuration data and information
that could be used by a skilled attacker to penetrate your system. You
are solely responsible for ensuring that the output of this tool,
including any generated reports, is handled in accordance with your
company's policies.

Connecting to the target Oracle database...


SQL*Plus: Release 21.0.0.0.0 - Production on Tue Mar 5 22:34:39 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

Setup complete.
SQL queries complete.
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/sqlnet.ora: No such file or directory
Warning: Exit status 256 from OS rule: sqlnet.ora
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/sqlnet.ora: No such file or directory
Warning: Exit status 512 from OS rule: ls_sqlnet.ora
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/listener.ora: No such file or directory
Warning: Exit status 256 from OS rule: listener.ora
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/listener.ora: No such file or directory
Warning: Exit status 512 from OS rule: ls_listener.ora
Warning: Exit status 256 from OS rule: dbcs_status
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/cman.ora: No such file or directory
Warning: Exit status 256 from OS rule: cman.ora
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/ldap/admin/fips.ora: No such file or directory
Warning: Exit status 256 from OS rule: fips1.ora
/bin/cat: /fips.ora: No such file or directory
Warning: Exit status 256 from OS rule: fips2.ora
/bin/ls: cannot access /diag: No such file or directory
Warning: Exit status 512 from OS rule: diag_dest_base
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/rdbms/log/diag: No such file or directory
Warning: Exit status 512 from OS rule: diag_dest_home
OS commands complete.
Disconnected from Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
DBSAT Collector completed successfully.

Calling /u01/app/oracle/product/21.3.0.0/dbhome_1/bin/zip to encrypt hemantpdb_DBSAT_Report.json...

Enter password:
Verify password:	
  adding: hemantpdb_DBSAT_Report.json (deflated 86%)
zip completed successfully.
[oracle@node2 DBSAT_Installer]$


So, apparently it assumes the old convention of the network folders being under ORACLE_HOME. 
Since this is a RAC install, the listener.ora is from the Grid Home and tnsnames.ora (in 19c) is not under $ORACLE_HOME.

I'll just re-run with ORACLE_BASE set for the diag_dest_base



[oracle@node2 DBSAT_Installer]$ rm hemantpdb_DBSAT_Report.json
[oracle@node2 DBSAT_Installer]$ ORACLE_BASE=/u01/app/oracle;export ORACLE_BASE
[oracle@node2 DBSAT_Installer]$ ./dbsat collect dbsat_user/dbsat_user@hemantpdb hemantpdb_DBSAT_Report

Database Security Assessment Tool version 3.1 (Jan 2024)

This tool is intended to assist you in securing your Oracle database
system. You are solely responsible for your system and the effect and
results of the execution of this tool (including, without limitation,
any damage or data loss). Further, the output generated by this tool may
include potentially sensitive system configuration data and information
that could be used by a skilled attacker to penetrate your system. You
are solely responsible for ensuring that the output of this tool,
including any generated reports, is handled in accordance with your
company's policies.

Connecting to the target Oracle database...


SQL*Plus: Release 21.0.0.0.0 - Production on Tue Mar 5 23:00:54 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.

Last Successful login time: Tue Mar 05 2024 23:00:00 +08:00

Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

Setup complete.
SQL queries complete.
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/sqlnet.ora: No such file or directory
Warning: Exit status 256 from OS rule: sqlnet.ora
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/sqlnet.ora: No such file or directory
Warning: Exit status 512 from OS rule: ls_sqlnet.ora
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/listener.ora: No such file or directory
Warning: Exit status 256 from OS rule: listener.ora
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/listener.ora: No such file or directory
Warning: Exit status 512 from OS rule: ls_listener.ora
Warning: Exit status 256 from OS rule: dbcs_status
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/network/admin/cman.ora: No such file or directory
Warning: Exit status 256 from OS rule: cman.ora
/bin/cat: /u01/app/oracle/product/21.3.0.0/dbhome_1/ldap/admin/fips.ora: No such file or directory
Warning: Exit status 256 from OS rule: fips1.ora
/bin/cat: /fips.ora: No such file or directory
Warning: Exit status 256 from OS rule: fips2.ora
/bin/ls: cannot access /u01/app/oracle/product/21.3.0.0/dbhome_1/rdbms/log/diag: No such file or directory
Warning: Exit status 512 from OS rule: diag_dest_home
OS commands complete.
Disconnected from Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
DBSAT Collector completed successfully.

Calling /u01/app/oracle/product/21.3.0.0/dbhome_1/bin/zip to encrypt hemantpdb_DBSAT_Report.json...

Enter password:
Verify password:
  adding: hemantpdb_DBSAT_Report.json (deflated 86%)
zip completed successfully.
[oracle@node2 DBSAT_Installer]$


I can afford to ignore the network/admin lookups under $ORACLE_HOME as they are not valid.  I might go back and check the "diag_dest_home" check (e.g. review "sat_collector.sql")


I need to add Java to my path. I know that I have it in the Grid installation so I can use that to generate the report.



[oracle@node2 DBSAT_Installer]$ PATH=/u01/app/21.3.0.0/grid/jdk/bin:$PATH;export PATH
[oracle@node2 DBSAT_Installer]$ java -version
java version "1.8.0_291"
Java(TM) SE Runtime Environment (build 1.8.0_291-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.291-b09, mixed mode)
[oracle@node2 DBSAT_Installer]$
[oracle@node2 DBSAT_Installer]$ JAVA_HOME=/u01/app/21.3.0.0/grid/jdk;export JAVA_HOME
[oracle@node2 DBSAT_Installer]$ ./dbsat report hemantpdb_DBSAT_Report

Database Security Assessment Tool version 3.1 (Jan 2024)

This tool is intended to assist you in securing your Oracle database
system. You are solely responsible for your system and the effect and
results of the execution of this tool (including, without limitation,
any damage or data loss). Further, the output generated by this tool may
include potentially sensitive system configuration data and information
that could be used by a skilled attacker to penetrate your system. You
are solely responsible for ensuring that the output of this tool,
including any generated reports, is handled in accordance with your
company's policies.

DBSAT Reporter ran successfully.

Calling /usr/bin/zip to encrypt the generated reports...

Enter password:
Verify password:
        zip warning: hemantpdb_DBSAT_Report_report.zip not found or empty
  adding: hemantpdb_DBSAT_Report_report.txt (deflated 76%)
  adding: hemantpdb_DBSAT_Report_report.html (deflated 83%)
  adding: hemantpdb_DBSAT_Report_report.xlsx (deflated 2%)
  adding: hemantpdb_DBSAT_Report_report.json (deflated 81%)
zip completed successfully.
[oracle@node2 DBSAT_Installer]$
[oracle@node2 DBSAT_Installer]$ unzip -l hemantpdb_DBSAT_Report_report.zip
Archive:  hemantpdb_DBSAT_Report_report.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
   161417  03-05-2024 23:09   hemantpdb_DBSAT_Report_report.txt
   261378  03-05-2024 23:09   hemantpdb_DBSAT_Report_report.html
    36732  03-05-2024 23:09   hemantpdb_DBSAT_Report_report.xlsx
   197620  03-05-2024 23:09   hemantpdb_DBSAT_Report_report.json
---------                     -------
   657147                     4 files
[oracle@node2 DBSAT_Installer]$
[oracle@node2 DBSAT_Installer]$ unzip hemantpdb_DBSAT_Report_report.zip hemantpdb_DBSAT_Report_report.txt
Archive:  hemantpdb_DBSAT_Report_report.zip
[hemantpdb_DBSAT_Report_report.zip] hemantpdb_DBSAT_Report_report.txt password:
  inflating: hemantpdb_DBSAT_Report_report.txt
[oracle@node2 DBSAT_Installer]$
[oracle@node2 DBSAT_Installer]$ more hemantpdb_DBSAT_Report_report.txt
### Oracle Database Security Assessment - Highly Sensitive ###

* Assessment Date & Time *
Date of Data Collection            Date of Report                     Reporter Version
---------------------------------- ---------------------------------- ---------------------
Tue Mar 05 2024 23:00:54 UTC+08:00 Tue Mar 05 2024 23:09:51 UTC+08:00 3.1 (Jan 2024) - b73a

* Database Identity *
Name     Container (Type:ID) Platform         Database Role Log Mode     Created
-------- ------------------- ---------------- ------------- ------------ ----------------------------------
DB21CRAC HEMANTPDB (PDB:3)   Linux x86 64-bit PRIMARY       NOARCHIVELOG Fri Jan 19 2024 15:12:46 UTC+08:00

### Summary ###

Section                     Pass Evaluate Advisory Low Risk Medium Risk High Risk Total Findings
--------------------------- ---- -------- -------- -------- ----------- --------- --------------
Basic Information              0        0        0        0           0         1              1
User Accounts                  7        8        1        3           2         1             22
Privileges and Roles           6       23        1        0           0         0             30
Authorization Control          0        3        1        0           0         0              4
Fine-Grained Access Control    0        0        5        0           0         0              5
Auditing                       0        2        9        3           0         0             14
Encryption                     0        3        1        0           0         0              4
Database Configuration         7        9        0        2           2         0             20
Network Configuration          0        0        0        0           0         1              1
Operating System               4        3        0        1           1         0              9
Total                         24       51       18        9           5         3            110

### Basic Information ###

* Database Version *
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production Version 21.3.0.0.0




The TXT format of the report is 161,417 bytes and the HTML format is 261,378 bytes.

The 3 "High Risk" entries (with corresponding CIS and STIG references) are :


* Patch Check *  -  The Oracle Database should be patched
Status: High Risk
Summary:
    Oracle Database version is supported but latest patch is missing.
    Latest comprehensive patch has not been applied.
Details:
    Latest patch not applied for a supported database version.
Remarks:
    Unsupported commercial and database systems should not be used because
    fixes to newly identified bugs will not be implemented by the vendor.
    The lack of support can result in potential vulnerabilities. Systems at
    unsupported servicing levels or releases will not receive security
    updates for new vulnerabilities, which leaves them subject to
    exploitation. When maintenance updates and patches are no longer
    available, the database software is no longer considered supported and
    should be upgraded or decommissioned.

    It is vital to keep the database software up-to-date with security
    fixes as they are released. Oracle issues comprehensive patches in the
    form of Release Updates on a regular quarterly schedule. These updates
    should be applied as soon as they are available.
References:
    Oracle Best Practice
    CIS Benchmark: Recommendation 1.1
    DISA STIG: V-237697, V-237748, V-251802



* Users with Default Passwords *  -  User accounts should not have default passwords
Status: High Risk
Summary:
    Found 1 unlocked user account with default password.
Details:
    Users with default password: HR
Remarks:
    Default passwords for predefined Oracle accounts are well known and
    provide a trivial means of entry for attackers. Database or account
    administrators should also change well-known passwords for locked
    accounts. Having default passwords can lead to unauthorized data
    manipulation and theft of confidential information.

    Note that if a script creates the database and the SYS or SYSTEM user
    password remains unchanged, these users are considered to possess a
    default password. Your database may be at risk due to the password
    presence within the script. Change the password to improve security.
References:
    Oracle Best Practice
    CIS Benchmark: Recommendation 4.1
    DISA STIG: V-237698



* Network Encryption *  -  Check configurations used for Native Network Encryption
Status: High Risk
Summary:
    Found unencrypted connections. Clients can connect to the database
        using unencrypted communication channels.
Details:
    Found 3 connections established over unencrypted channel.
Remarks:
    Network encryption is crucial for protecting the confidentiality and
    integrity of communication between a database server and its clients.
    Connections to a database instance must be established using the
    encrypted channels.
References:
    Oracle Best Practice
    CIS Benchmark: Recommendation 2.3.1, 2.3.2
    DISA STIG: V-219841, V-220263, V-220291, V-237699, V-237700, V-237723



Of course, the Report goes on to detail the 110 "findings".


And, of course, I DROP the user after I generate the report.


[oracle@node2 DBSAT_Installer]$ sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Tue Mar 5 23:18:49 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL> alter session set container=HEMANTPDB;

Session altered.

SQL> drop user dbsat_user;

User dropped.

SQL> quit
Disconnected from Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0
[oracle@node2 DBSAT_Installer]$


So, DBSAT does reference CIS and STIG in its report.








Categories: DBA Blogs

Installing and Running Oracle AHF ORACHK on a 12.2 DB Server

Tue, 2024-02-27 00:20

 The Oracle Autonomous Health Framework is described in Support Document "Autonomous Health Framework (AHF) - Including TFA and ORAchk/EXAchk (Doc ID 2550798.1)"

In a recent video I have demonstrated running 24.1 orachk (with "-b" for "Best Practices Check) against a 21.3 RAC Cluster.

Here I demonstrate the installation and execution against a 12.2 non-RAC database.

When you download the 24.1 release of AHF (AHF-LINUX_v24.1.0.zip, approximately 410MB), you have to unzip it and then run ahf_setup.  It is preferable to use the default location /opt/oracle.ahf  (and precreate a "data" subfolder if it doesn't exist).

If your first attempt at installation returns an error :

[ERROR] : AHF-00074: Required Perl Modules not found :  Data::Dumper

you can check the perl version and download and install this module (Note : In the listings below "AHF_Installer is the location where I have extracted the installation zip file).


[root@vbgeneric AHF_Installer]# /bin/perl -v

This is perl 5, version 16, subversion 3 (v5.16.3) built for x86_64-linux-thread-multi
(with 34 registered patches, see perl -V for more detail)

Copyright 1987-2012, Larry Wall

Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.

Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl".  If you have access to the
Internet, point your browser at http://www.perl.org/, the Perl Home Page.

[root@vbgeneric AHF_Installer]# yum install perl-Data-Dumper
Loaded plugins: langpacks, ulninfo
ol7_UEKR4                                                           | 3.0 kB  00:00:00     
ol7_latest                                                          | 3.6 kB  00:00:00     
(1/5): ol7_latest/x86_64/group_gz                                   | 136 kB  00:00:00     
(2/5): ol7_UEKR4/x86_64/updateinfo                                  | 130 kB  00:00:00     
(3/5): ol7_latest/x86_64/updateinfo                                 | 3.6 MB  00:00:00     
(4/5): ol7_latest/x86_64/primary_db                                 |  50 MB  00:00:02     
(5/5): ol7_UEKR4/x86_64/primary_db                                  |  37 MB  00:00:04     
Resolving Dependencies
--> Running transaction check
---> Package perl-Data-Dumper.x86_64 0:2.145-3.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===========================================================================================
 Package                   Arch            Version               Repository           Size
===========================================================================================
Installing:
 perl-Data-Dumper          x86_64          2.145-3.el7           ol7_latest           47 k

Transaction Summary
===========================================================================================
Install  1 Package

Total download size: 47 k
Installed size: 97 k
Is this ok [y/d/N]: y
Downloading packages:
perl-Data-Dumper-2.145-3.el7.x86_64.rpm                             |  47 kB  00:00:00     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
  Installing : perl-Data-Dumper-2.145-3.el7.x86_64                                     1/1 
  Verifying  : perl-Data-Dumper-2.145-3.el7.x86_64                                     1/1 

Installed:
  perl-Data-Dumper.x86_64 0:2.145-3.el7                                                    

Complete!
[root@vbgeneric AHF_Installer]#


Then resume the installation (precreate the "data" folder if it doesn't exist)

[root@vbgeneric AHF_Installer]# mkdir /opt/oracle.ahf/data
[root@vbgeneric AHF_Installer]# ./ahf_setup

AHF Installer for Platform Linux Architecture x86_64

AHF Installation Log : /tmp/ahf_install_241000_6588_2024_02_27-13_48_51.log

Starting Autonomous Health Framework (AHF) Installation

AHF Version: 24.1.0 Build Date: 202402051317

Default AHF Location : /opt/oracle.ahf

Do you want to install AHF at [/opt/oracle.ahf] ? [Y]|N : Y

AHF Location : /opt/oracle.ahf

AHF Data Directory stores diagnostic collections and metadata.
AHF Data Directory requires at least 5GB (Recommended 10GB) of free space.

Please Enter AHF Data Directory : /opt/oracle.ahf/data

AHF Data Directory : /opt/oracle.ahf/data

Do you want to add AHF Notification Email IDs ? [Y]|N : N

Extracting AHF to /opt/oracle.ahf

Setting up AHF CLI and SDK

Configuring TFA Services

Discovering Nodes and Oracle Resources

Successfully generated certificates.

Starting TFA Services
Created symlink from /etc/systemd/system/multi-user.target.wants/oracle-tfa.service to /etc/systemd/system/oracle-tfa.service.
Created symlink from /etc/systemd/system/graphical.target.wants/oracle-tfa.service to /etc/systemd/system/oracle-tfa.service.

.-------------------------------------------------------------------------------.
| Host      | Status of TFA | PID  | Port  | Version    | Build ID              |
+-----------+---------------+------+-------+------------+-----------------------+
| vbgeneric | RUNNING       | 8540 | 39049 | 24.1.0.0.0 | 240100020240205131724 |
'-----------+---------------+------+-------+------------+-----------------------'

Running TFA Inventory...

Adding default users to TFA Access list...

.-------------------------------------------------------.
|              Summary of AHF Configuration             |
+-----------------+-------------------------------------+
| Parameter       | Value                               |
+-----------------+-------------------------------------+
| AHF Location    | /opt/oracle.ahf                     |
| TFA Location    | /opt/oracle.ahf/tfa                 |
| Orachk Location | /opt/oracle.ahf/orachk              |
| Data Directory  | /opt/oracle.ahf/data                |
| Repository      | /opt/oracle.ahf/data/repository     |
| Diag Directory  | /opt/oracle.ahf/data/vbgeneric/diag |
'-----------------+-------------------------------------'

Starting ORAchk Scheduler from AHF

AHF binaries are available in /opt/oracle.ahf/bin

AHF is successfully Installed

Do you want AHF to store your My Oracle Support Credentials for Automatic Upload ? Y|[N] : N

Moving /tmp/ahf_install_241000_6588_2024_02_27-13_48_51.log to /opt/oracle.ahf/data/vbgeneric/diag/ahf/

[root@vbgeneric AHF_Installer]# 


orachk can then be executed.  This execution is to check against "Best Practices"  :



[root@vbgeneric AHF_Installer]# orachk -b

List of running databases

1. orcl12c
2. None of above

Select databases from list for checking best practices. For multiple databases, select 1 for All or comma separated number like 1,2 etc [1-2][1]. 1
.  .
.  .  

Checking Status of Oracle Software Stack - Clusterware, ASM, RDBMS

.  .  . . . .  
.  .  .  .  .  .  .  .  .  
-------------------------------------------------------------------------------------------------------
                                                 Oracle Stack Status                          
-------------------------------------------------------------------------------------------------------
  Host Name       CRS Installed       ASM HOME  RDBMS Installed    CRS UP    ASM UP  RDBMS UP    DB Instance Name
-------------------------------------------------------------------------------------------------------
  vbgeneric                  No           No          Yes           No       No      Yes             orcl12c
-------------------------------------------------------------------------------------------------------


Copying plug-ins

. .
.  .  .  .  .  .  

*** Checking Best Practice Recommendations ( Pass / Warning / Fail ) ***

.  

============================================================
              Node name - vbgeneric
============================================================
. . . . . . 
 Collecting - Database Parameters for orcl12c database
 Collecting - Database Undocumented Parameters for orcl12c database
 Collecting - List of active logon and logoff triggers for orcl12c database
 Collecting - CPU Information
 Collecting - Disk I/O Scheduler on Linux
 Collecting - DiskMount Information
 Collecting - Kernel parameters
 Collecting - Maximum number of semaphore sets on system
 Collecting - Maximum number of semaphores on system
 Collecting - Maximum number of semaphores per semaphore set
 Collecting - Memory Information
 Collecting - OS Packages
 Collecting - Operating system release information and kernel version
 Collecting - Patches for RDBMS Home
 Collecting - Patches xml for RDBMS Home
 Collecting - RDBMS patch inventory
 Collecting - Table of file system defaults
 Collecting - number of semaphore operations per semop system call
 Collecting - Database Server Infrastructure Software and Configuration
 Collecting - Disk Information
 Collecting - Root user limits
 Collecting - Verify ORAchk scheduler configuration
 Collecting - Verify TCP Selective Acknowledgement is enabled
 Collecting - Verify no database server kernel out of memory errors
 Collecting - Verify the vm.min_free_kbytes configuration

Data collections completed. Checking best practices on vbgeneric.
------------------------------------------------------------

 INFO =>     Traditional auditing is enabled in database for orcl12c
 WARNING =>  Linux swap configuration does not meet recommendation
 WARNING =>  Hidden database initialization parameters should not be set per best practice recommendations for orcl12c
 FAIL =>     loopback interface MTU value needs to be set to 16436
 INFO =>     Most recent ADR incidents for /u01/app/oracle/product/12.2/db_1
 FAIL =>     Verify Database Memory Allocation
 INFO =>     Oracle GoldenGate failure prevention best practices
 FAIL =>     The vm.min_free_kbytes configuration is not set as recommended
 INFO =>     user_dump_dest has trace files older than 30 days for orcl12c
 INFO =>     At some times checkpoints are not being completed for orcl12c
 WARNING =>  One or more redo log groups are not multiplexed for orcl12c
 WARNING =>  Primary database is not protected with Data Guard (standby database) for real-time data protection and availability for orcl12c
 INFO =>     Important Storage Minimum Requirements for Grid & Database Homes
 CRITICAL => Operating system hugepages count does not satisfy total SGA requirements
 FAIL =>     Table AUD$[FGA_LOG$] should use Automatic Segment Space Management for orcl12c
 FAIL =>     Database parameter DB_LOST_WRITE_PROTECT is not set to recommended value on orcl12c instance
 INFO =>     umask for RDBMS owner is not set to 0022
 FAIL =>     Database parameter DB_BLOCK_CHECKING on primary is not set to the recommended value. for orcl12c
 INFO =>     Operational Best Practices
 INFO =>     Database Consolidation Best Practices
 INFO =>     Computer failure prevention best practices
 INFO =>     Data corruption prevention best practices
 INFO =>     Logical corruption prevention best practices
 INFO =>     Database/Cluster/Site failure prevention best practices
 INFO =>     Client failover operational best practices
 WARNING =>  Oracle patch 30712670 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 29867728 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 31142749 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 26749785 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 29302565 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 29259068 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle clusterware is not being used
 WARNING =>  RAC Application Cluster is not being used for database high availability on orcl12c instance
 WARNING =>  DISK_ASYNCH_IO is NOT set to recommended value for orcl12c
 WARNING =>  Flashback on PRIMARY is not configured for orcl12c
 INFO =>     Database failure prevention best practices
 WARNING =>  fast_start_mttr_target has NOT been changed from default on orcl12c instance
 FAIL =>     Active Data Guard is not configured for orcl12c
 WARNING =>  Perl Patch 31858212 is not found in 12.2.0.1 RDBMS_HOME. /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 31602782 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 33121934 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 WARNING =>  Oracle patch 31211220 is not applied on RDBMS_HOME /u01/app/oracle/product/12.2/db_1
 INFO =>     Software maintenance best practices
 INFO =>     Oracle recovery manager(rman) best practices
 INFO =>     Database feature usage statistics for orcl12c
 WARNING =>  Consider investigating changes to the schema objects such as DDLs or new object creation for orcl12c
 WARNING =>  Consider investigating the frequency of SGA resize operations and take corrective action for orcl12c
------------------------------------------------------------

UPLOAD [if required] - /opt/oracle.ahf/data/vbgeneric/orachk/user_root/output/orachk_vbgeneric_orcl12c_022724_140315.zip

[root@vbgeneric AHF_Installer]# 


Thus, you can actually run the 24.1 orachk against even a 12.2 non-RAC (single instance) database.

The complete report is in HTML format in the final ZIP file.  

Here's the header :



Categories: DBA Blogs

A PDB as a Cluster Resource in RAC

Fri, 2024-02-23 03:40

 In my previous post, I have demonstrated how a new service can be created for a Pluggable Database (PDB) in Oracle RAC.  

Custom Services are configured as Resources.  Thus, in that post, I have demonstrated the custom service "newservice" for the PDB "hemantpdb" being configured in the Cluster.

However, PDBs can also be configured and managed as resources.   (see the reference in the Oracle Database Features documentation).

This is the current listing of resources in my 2-node 21c RAC Cluster :



[grid@node1 ~]$ crsctl status resource -t
--------------------------------------------------------------------------------
Name           Target  State        Server                   State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.LISTENER.lsnr
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.chad
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.net1.network
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.ons
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.DATA.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN2.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN3.lsnr
      1        ONLINE  ONLINE       node2                    STABLE
ora.RECO.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.asm(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    Started,STABLE
      2        ONLINE  ONLINE       node2                    Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.cdp1.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp2.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp3.cdp
      1        ONLINE  ONLINE       node2                    STABLE
ora.cvu
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.db
      1        ONLINE  ONLINE       node2                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
      2        ONLINE  ONLINE       node1                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
ora.db21crac.hemantpdb.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.newservice.svc
      1        ONLINE  ONLINE       node1                    STABLE
ora.node1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.node2.vip
      1        ONLINE  ONLINE       node2                    STABLE
ora.qosmserver
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan2.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan3.vip
      1        ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
[grid@node1 ~]$


Above, we can see 
the database resource "ora.db21crac.db"
the pdb resource "ora.db21crac.hemantpdb.pdb"
the service resource "ora.db21crac.newservice.svc"  (which I created in my previous post)

Now, I will add a new PDB "pdb2"


[oracle@node1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Fri Feb 23 17:04:31 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL> create pluggable database pdb2 admin user pdb2_admin identified by pdb2_admin;

Pluggable database created.

SQL>
SQL> col name format a30
SQL> select name, open_mode from v$pdbs;

NAME                           OPEN_MODE
------------------------------ ----------
PDB$SEED                       READ ONLY
HEMANTPDB                      READ WRITE
PDB2                           MOUNTED

SQL>

[grid@node1 ~]$ crsctl status resource -t
--------------------------------------------------------------------------------
Name           Target  State        Server                   State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.LISTENER.lsnr
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.chad
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.net1.network
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.ons
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.DATA.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN2.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN3.lsnr
      1        ONLINE  ONLINE       node2                    STABLE
ora.RECO.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.asm(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    Started,STABLE
      2        ONLINE  ONLINE       node2                    Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.cdp1.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp2.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp3.cdp
      1        ONLINE  ONLINE       node2                    STABLE
ora.cvu
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.db
      1        ONLINE  ONLINE       node2                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
      2        ONLINE  ONLINE       node1                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
ora.db21crac.hemantpdb.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.newservice.svc
      1        ONLINE  ONLINE       node1                    STABLE
ora.node1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.node2.vip
      1        ONLINE  ONLINE       node2                    STABLE
ora.qosmserver
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan2.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan3.vip
      1        ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
[grid@node1 ~]$


The new PDB, "pdb2" has been created but not opened yet (it is still only in the MOUNT state). However, if I try to manually add it, I get an error message that CARDINALITY wasn't specified for the first PDB that had been manually created from the SQL command line but not registered via srvctl. However, I *can* add the new PDB without having to specify CARDINALITY and then verify the status in the Cluster :

[oracle@node1 ~]$ srvctl add pdb -db DB21CRAC -pdb PDB2 -cardinality ALL -startoption open
PRCZ-4036 : failed to create pluggable database PDB2 with '-cardinality' option because this option was not specified for the previously created pluggable databases for database DB21CRAC

[oracle@node1 ~]$ srvctl config pdb -db DB21CRAC
Pluggable database name: HEMANTPDB
Application Root PDB:
Cardinality: %CRS_SERVER_POOL_SIZE%
Maximum CPU count (whole CPUs): 0
Minimum CPU count unit (1/100 CPU count): 0
Management policy: MANUAL
Rank value: 0
Start Option: open
Stop Option: immediate

[oracle@node1 ~]$ srvctl add pdb -db DB21CRAC -pdb PDB2  -startoption open

[oracle@node1 ~]$ srvctl config pdb -db DB21CRAC
Pluggable database name: HEMANTPDB
Application Root PDB:
Cardinality: %CRS_SERVER_POOL_SIZE%
Maximum CPU count (whole CPUs): 0
Minimum CPU count unit (1/100 CPU count): 0
Management policy: MANUAL
Rank value: 0
Start Option: open
Stop Option: immediate
Pluggable database name: PDB2
Application Root PDB:
Cardinality: %CRS_SERVER_POOL_SIZE%
Maximum CPU count (whole CPUs): 0
Minimum CPU count unit (1/100 CPU count): 0
Management policy: AUTOMATIC
Rank value: 0
Start Option: open
Stop Option: immediate

[grid@node1 ~]$ crsctl status resource -t
--------------------------------------------------------------------------------
Name           Target  State        Server                   State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.LISTENER.lsnr
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.chad
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.net1.network
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.ons
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.DATA.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN2.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN3.lsnr
      1        ONLINE  ONLINE       node2                    STABLE
ora.RECO.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.asm(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    Started,STABLE
      2        ONLINE  ONLINE       node2                    Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.cdp1.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp2.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp3.cdp
      1        ONLINE  ONLINE       node2                    STABLE
ora.cvu
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.db
      1        ONLINE  ONLINE       node2                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
      2        ONLINE  ONLINE       node1                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
ora.db21crac.hemantpdb.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.newservice.svc
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.pdb2.pdb
      1        OFFLINE OFFLINE                               STABLE
      2        OFFLINE OFFLINE                               STABLE
ora.node1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.node2.vip
      1        ONLINE  ONLINE       node2                    STABLE
ora.qosmserver
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan2.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan3.vip
      1        ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
[grid@node1 ~]$


If I then OPEN the new PDB on both instances, I can query the status again :

[oracle@node1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Fri Feb 23 17:19:20 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL> alter pluggable database pdb2 open;

Pluggable database altered.

SQL>

[oracle@node2 ~]$ sqlplus / as sysdba

SQL*Plus: Release 21.0.0.0.0 - Production on Fri Feb 23 17:19:36 2024
Version 21.3.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 21c Enterprise Edition Release 21.0.0.0.0 - Production
Version 21.3.0.0.0

SQL> alter pluggable database pdb2 open;

Pluggable database altered.

SQL>

[grid@node1 ~]$ crsctl status resource ora.db21crac.pdb2.pdb
NAME=ora.db21crac.pdb2.pdb
TYPE=ora.pdb.type
TARGET=ONLINE         , ONLINE
STATE=ONLINE on node1, ONLINE on node2

[grid@node1 ~]$ crsctl status resource -t
--------------------------------------------------------------------------------
Name           Target  State        Server                   State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.LISTENER.lsnr
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.chad
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.net1.network
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.ons
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.DATA.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN2.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN3.lsnr
      1        ONLINE  ONLINE       node2                    STABLE
ora.RECO.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.asm(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    Started,STABLE
      2        ONLINE  ONLINE       node2                    Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.cdp1.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp2.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp3.cdp
      1        ONLINE  ONLINE       node2                    STABLE
ora.cvu
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.db
      1        ONLINE  ONLINE       node2                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
      2        ONLINE  ONLINE       node1                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
ora.db21crac.hemantpdb.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.newservice.svc
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.pdb2.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.node1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.node2.vip
      1        ONLINE  ONLINE       node2                    STABLE
ora.qosmserver
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan2.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan3.vip
      1        ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
[grid@node1 ~]$


I can now add a custom service "pdb2service" for pdb2 to use DB21CRAC2 (instance 2, instead of instance 1) as preferred and with SESSION failover (and compare it with "newservice" for hemantpdb that I had added in the previous blogpost) :

[oracle@node1 ~]$ srvctl add service -db DB21CRAC  -service pdb2service -preferred DB21CRAC2 -available DB21CRAC1 \
> -tafpolicy BASIC -failovertype SESSION -pdb PDB2

[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service pdb2service
Service pdb2service is not running.

[oracle@node1 ~]$ srvctl config service -db DB21CRAC -service pdb2service
Service name: pdb2service
Server pool:
Cardinality: 1
Service role: PRIMARY
Management policy: AUTOMATIC
DTP transaction: false
AQ HA notifications: false
Global: false
Commit Outcome: false
Reset State: NONE
Failover type: SESSION
Failover method:
Failover retries:
Failover delay:
Failover restore: NONE
Connection Load Balancing Goal: LONG
Runtime Load Balancing Goal: NONE
TAF policy specification: BASIC
Edition:
Pluggable database name: PDB2
Hub service:
Maximum lag time: ANY
SQL Translation Profile:
Retention: 86400 seconds
Failback :  no
Replay Initiation Time: 300 seconds
Drain timeout:
Stop option:
Session State Consistency: DYNAMIC
GSM Flags: 0
Service is enabled
Preferred instances: DB21CRAC2
Available instances: DB21CRAC1
CSS critical: no
[oracle@node1 ~]$


[oracle@node1 ~]$ srvctl config service -db DB21CRAC -service newservice
Service name: newservice
Server pool:
Cardinality: 1
Service role: PRIMARY
Management policy: AUTOMATIC
DTP transaction: false
AQ HA notifications: false
Global: false
Commit Outcome: false
Reset State: NONE
Failover type: SELECT
Failover method:
Failover retries:
Failover delay:
Failover restore: NONE
Connection Load Balancing Goal: LONG
Runtime Load Balancing Goal: NONE
TAF policy specification: BASIC
Edition:
Pluggable database name: HEMANTPDB
Hub service:
Maximum lag time: ANY
SQL Translation Profile:
Retention: 86400 seconds
Failback :  no
Replay Initiation Time: 300 seconds
Drain timeout:
Stop option:
Session State Consistency: DYNAMIC
GSM Flags: 0
Service is enabled
Preferred instances: DB21CRAC1
Available instances: DB21CRAC2
CSS critical: no
Service uses Java: false
[oracle@node1 ~]$

[oracle@node1 ~]$ srvctl start service -db DB21CRAC -service pdb2service

[oracle@node1 ~]$ srvctl config service -db DB21CRAC -service pdb2service
Service name: pdb2service
Server pool:
Cardinality: 1
Service role: PRIMARY
Management policy: AUTOMATIC
DTP transaction: false
AQ HA notifications: false
Global: false
Commit Outcome: false
Reset State: NONE
Failover type: SESSION
Failover method:
Failover retries:
Failover delay:
Failover restore: NONE
Connection Load Balancing Goal: LONG
Runtime Load Balancing Goal: NONE
TAF policy specification: BASIC
Edition:
Pluggable database name: PDB2
Hub service:
Maximum lag time: ANY
SQL Translation Profile:
Retention: 86400 seconds
Failback :  no
Replay Initiation Time: 300 seconds
Drain timeout:
Stop option:
Session State Consistency: DYNAMIC
GSM Flags: 0
Service is enabled
Preferred instances: DB21CRAC2
Available instances: DB21CRAC1
CSS critical: no
Service uses Java: false
[oracle@node1 ~]$

[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service pdb2service
Service pdb2service is running on instance(s) DB21CRAC2

[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service newservice
Service newservice is running on instance(s) DB21CRAC1
[oracle@node1 ~]$


[grid@node1 ~]$ crsctl status resource -t
--------------------------------------------------------------------------------
Name           Target  State        Server                   State details
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.LISTENER.lsnr
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.chad
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.net1.network
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
ora.ons
               ONLINE  ONLINE       node1                    STABLE
               ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
Cluster Resources
--------------------------------------------------------------------------------
ora.ASMNET1LSNR_ASM.lsnr(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.DATA.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.LISTENER_SCAN1.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN2.lsnr
      1        ONLINE  ONLINE       node1                    STABLE
ora.LISTENER_SCAN3.lsnr
      1        ONLINE  ONLINE       node2                    STABLE
ora.RECO.dg(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.asm(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    Started,STABLE
      2        ONLINE  ONLINE       node2                    Started,STABLE
ora.asmnet1.asmnetwork(ora.asmgroup)
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.cdp1.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp2.cdp
      1        ONLINE  ONLINE       node1                    STABLE
ora.cdp3.cdp
      1        ONLINE  ONLINE       node2                    STABLE
ora.cvu
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.db
      1        ONLINE  ONLINE       node2                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
      2        ONLINE  ONLINE       node1                    Open,HOME=/u01/app/o
                                                             racle/product/21.3.0
                                                             .0/dbhome_1,STABLE
ora.db21crac.hemantpdb.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.newservice.svc
      1        ONLINE  ONLINE       node1                    STABLE
ora.db21crac.pdb2.pdb
      1        ONLINE  ONLINE       node1                    STABLE
      2        ONLINE  ONLINE       node2                    STABLE
ora.db21crac.pdb2service.svc
      1        ONLINE  ONLINE       node2                    STABLE
ora.node1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.node2.vip
      1        ONLINE  ONLINE       node2                    STABLE
ora.qosmserver
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan1.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan2.vip
      1        ONLINE  ONLINE       node1                    STABLE
ora.scan3.vip
      1        ONLINE  ONLINE       node2                    STABLE
--------------------------------------------------------------------------------
[grid@node1 ~]$




So, I have two PDBs "hemantpdb" and "pdb2" and their corresponding services ("newservice" and "pdb2service") using alternate database instances as Preferred Instances. "hemantpdb"'s service "newservices" runs on node1 (database instance DB21CRAC1) and "pdb2"'s service "pdb2service" runs on node2 (database instance DB21CRAC2) while both PDBs are actually OPEN on both nodes.

Categories: DBA Blogs

Adding a PDB (and Service) to a RAC database -- 1 - service running on only 1 Instance

Tue, 2024-02-13 02:10
On my existing, RAC database I have :

[oracle@node1 ~]$ srvctl status database -db DB21CRAC
Instance DB21CRAC1 is running on node node1
Instance DB21CRAC2 is running on node node2
[oracle@node1 ~]$
[oracle@node1 ~]$ srvctl status service -d DB21CRAC -s hemantpdb
PRKO-2017 : Service hemantpdb does not exist for database DB21CRAC.
[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service hemantpdb -pdb HEMANTPDB
PRKO-2017 : Service hemantpdb does not exist for database DB21CRAC.
[oracle@node1 ~]$
[grid@node1 ~]$ lsnrctl status LISTENER_SCAN1

LSNRCTL for Linux: Version 21.0.0.0.0 - Production on 13-FEB-2024 15:06:11

Copyright (c) 1991, 2021, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=IPC)(KEY=LISTENER_SCAN1)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER_SCAN1
Version                   TNSLSNR for Linux: Version 21.0.0.0.0 - Production
Start Date                13-FEB-2024 14:51:13
Uptime                    0 days 0 hr. 14 min. 57 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/21.3.0.0/grid/network/admin/listener.ora
Listener Log File         /u01/app/grid/diag/tnslsnr/node1/listener_scan1/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=LISTENER_SCAN1)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.56.115)(PORT=1521)))
Services Summary...
Service "0f488ad896262f80e0636f38a8c0fc18" has 2 instance(s).
  Instance "DB21CRAC1", status READY, has 1 handler(s) for this service...
  Instance "DB21CRAC2", status READY, has 1 handler(s) for this service...
Service "DB21CRAC" has 2 instance(s).
  Instance "DB21CRAC1", status READY, has 1 handler(s) for this service...
  Instance "DB21CRAC2", status READY, has 1 handler(s) for this service...
Service "DB21CRACXDB" has 2 instance(s).
  Instance "DB21CRAC1", status READY, has 1 handler(s) for this service...
  Instance "DB21CRAC2", status READY, has 1 handler(s) for this service...
Service "hemantpdb" has 2 instance(s).
  Instance "DB21CRAC1", status READY, has 1 handler(s) for this service...
  Instance "DB21CRAC2", status READY, has 1 handler(s) for this service...
The command completed successfully
[grid@node1 ~]$
[oracle@node1 ~]$SQL> select inst_id, name, network_name from gv$services order by 1;

   INST_ID NAME             NETWORK_NAME
---------- ---------------- ----------------
         1 hemantpdb        hemantpdb
         1 DB21CRAC         DB21CRAC
         1 SYS$BACKGROUND
         1 DB21CRACXDB      DB21CRACXDB
         1 SYS$USERS
         2 hemantpdb        hemantpdb
         2 DB21CRAC         DB21CRAC
         2 SYS$BACKGROUND
         2 DB21CRACXDB      DB21CRACXDB
         2 SYS$USERS

10 rows selected.

SQL>
SQL> select inst_id, con_id, name, open_mode from gv$pdbs order by 1,2;

   INST_ID     CON_ID NAME             OPEN_MODE
---------- ---------- ---------------- ----------
         1          2 PDB$SEED         READ ONLY
         1          3 HEMANTPDB        READ WRITE
         2          2 PDB$SEED         READ ONLY
         2          3 HEMANTPDB        READ WRITE

SQL>


Which means that I have created a custom PDB called "HEMANTPDB" and there is a default service called "hemantpdb" on each instance.  However, this services is NOT listed when I check via srvctl. 

This is because srvctl queries the cluster for information about services.  Service"hemantpdb" is created by default when I run CREATE PLUGGABLE DATABASE HEMANTPDB.


So, I can add a new service and configure Transparent Application Failover for SELECT failover but with only the first instance(DB21CRAC1) as the only one to start the service on initially{and the second instance (DB21CRAC2) as the alternate} :

[oracle@node1 ~]$ srvctl add service -db DB21CRAC  -service newservice -preferred DB21CRAC1 -available DB21CRAC2 -tafpolicy BASIC -failovertype SELECT -pdb HEMANTPDB
[oracle@node1 ~]$
[oracle@node1 ~]$ srvctl config service -db DB21CRAC  -service newservice
Service name: newservice
Server pool:
Cardinality: 1
Service role: PRIMARY
Management policy: AUTOMATIC
DTP transaction: false
AQ HA notifications: false
Global: false
Commit Outcome: false
Reset State: NONE
Failover type: SELECT
Failover method:
Failover retries:
Failover delay:
Failover restore: NONE
Connection Load Balancing Goal: LONG
Runtime Load Balancing Goal: NONE
TAF policy specification: BASIC
Edition:
Pluggable database name: HEMANTPDB
Hub service:
Maximum lag time: ANY
SQL Translation Profile:
Retention: 86400 seconds
Failback :  no
Replay Initiation Time: 300 seconds
Drain timeout:
Stop option:
Session State Consistency: DYNAMIC
GSM Flags: 0
Service is enabled
Preferred instances: DB21CRAC1
Available instances: DB21CRAC2
CSS critical: no
[oracle@node1 ~]$
[oracle@node1 ~]$ srvctl start service -db DB21CRAC -service newservice
[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service newservice
Service newservice is running on instance(s) DB21CRAC1
[oracle@node1 ~]$




If the database instance DB21CRAC1 fails (crashes), the ClusterWare starts the service on DB21CRAC2.  Here I kill the DB21CRAC process and then verify that the service has restarted on DB1CRAC2  :

[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service newservice
Service newservice is running on instance(s) DB21CRAC1
[oracle@node1 ~]$ ps -ef |grep smon
oracle    2951     1  0 16:05 ?        00:00:00 ora_smon_DB21CRAC1
root      3521     1  1 14:50 ?        00:00:48 /u01/app/21.3.0.0/grid/bin/osysmond.bin
grid      4068     1  0 14:50 ?        00:00:00 asm_smon_+ASM1
oracle    4146 25526  0 16:05 pts/0    00:00:00 grep --color=auto smon
[oracle@node1 ~]$ kill -9 2951
[oracle@node1 ~]$ srvctl status service -db DB21CRAC -service newservice
Service newservice is running on instance(s) DB21CRAC2
[oracle@node1 ~]$


In this case, connections using this service name ("newservice") will connect (failover) to the 2nd database instance running on node2 of the Cluster.

Categories: DBA Blogs

Playlist of Oracle RAC Videos

Sat, 2024-02-10 02:23

 This is a link to my YouTube playlist of demonstrations on Oracle RAC (12c and 21c)



Categories: DBA Blogs

Video demonstration of RAC Client Query Session and Query Failover

Sun, 2024-01-21 03:33

 I've put up a short video that shows a client session connected to a RAC SCAN IP address failing over to the surviving RAC instance when the database node goes down


Video demonstration of RAC Client Query Session and Query Failover

Categories: DBA Blogs

My Posts on Refreshable Clone PDBs

Sat, 2023-12-30 03:44

 Refreshable Clone PDBs have been available since Oracle 12.2


These are 4 blog posts I had made between Nov-21 and Jan-22 :

1.  Refreshable Clone PDB -- 1 Manual Refresh  (30-Nov-21)

2.  Refreshable Clone PDB -- 2 Datafile Names  (04-Dec-21)

3.  Refreshable Clone PDB -- 3 The ArchiveLog and ArchParLog files  (05-Dec-21)

4.  Refreshable Clone PDB -- 4 Converting it to a Read Write PDB  (23-Jan-22)


Additionally, here is a recent write-up Refreshable PDB Clones in Data Guard Environments On-premises and on Oracle Cloud  by Sinan Petrus Toma (@SinanPetrus)


Categories: DBA Blogs

Do DataFiles get updated when in BACKUP mode ?

Sun, 2023-10-15 05:33

 The Oracle feature allowing the DBA to put a database in "BACKUP" mode is useful for environments where non-RMAN methods / storage snapshots etc are used to make database backups.

However, there seems to be misconception that datafiles are not updated when the database is in BACKUP mode.

Here is a quick demonstration to disprove it.  I first place the database in BACKUP mode and then, from other sessions, start-off transactions and checkpoints and switch logfiles.  I then check if the datafile headers are updated and whether the datafiles themselves are updated.



17:55:28 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1240322

17:55:34 SQL> alter system checkpoint;

System altered.

17:55:42 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240326 15-OCT-23 17:55:42
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240326 15-OCT-23 17:55:42
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240326 15-OCT-23 17:55:42
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240326 15-OCT-23 17:55:42
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240326 15-OCT-23 17:55:42
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240326 15-OCT-23 17:55:42
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240326 15-OCT-23 17:55:42
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240326 15-OCT-23 17:55:42

8 rows selected.

17:56:01 SQL> alter database begin backup;

Database altered.

17:56:10 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

17:56:18 SQL>


The BEGIN BACKUP causes a Checkpoint.  Now I start off transactions and log file switches and checkpoints from other sessions and monitor the state here.



17:59:15 SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /opt/oracle/archivelog/HEMANT
Oldest online log sequence     118
Next log sequence to archive   120
Current log sequence           120
17:59:18 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

17:59:25 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 17:56 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 17:52 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 17:58 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 17:58 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 17:56 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 17:56 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 17:56 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 17:56 /opt/oracle/oradata/HEMANT/undotbs.dbf

17:59:38 SQL>
18:01:04 SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /opt/oracle/archivelog/HEMANT
Oldest online log sequence     119
Next log sequence to archive   121
Current log sequence           121
18:01:17 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

18:01:25 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 17:56 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 17:56 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:01 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 17:58 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:00 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 17:56 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 18:00 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 17:56 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 18:01 /opt/oracle/oradata/HEMANT/undotbs.dbf

18:01:34 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1240837

18:01:44 SQL>
18:01:44 SQL> !sleep 120

18:04:00 SQL>
18:04:04 SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /opt/oracle/archivelog/HEMANT
Oldest online log sequence     122
Next log sequence to archive   124
Current log sequence           124
18:04:10 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

18:04:16 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 18:03 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:03 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:03 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:03 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:03 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:03 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:03 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 18:03 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 18:03 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 18:03 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 18:03 /opt/oracle/oradata/HEMANT/undotbs.dbf

18:04:24 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1242436

18:04:34 SQL>
18:05:13 SQL> !sleep 120

18:07:15 SQL>
18:07:17 SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            /opt/oracle/archivelog/HEMANT
Oldest online log sequence     124
Next log sequence to archive   126
Current log sequence           126
18:07:20 SQL> alter system archive log current;

System altered.

18:07:30 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

18:07:36 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 18:07 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:07 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:07 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:07 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:07 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:06 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:07 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 18:07 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 18:07 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 18:07 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 18:07 /opt/oracle/oradata/HEMANT/undotbs.dbf

18:07:43 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1242872

18:07:50 SQL>
18:07:50 SQL> alter system checkpoint;

System altered.

18:08:23 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1243044

18:08:29 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1240339 15-OCT-23 17:56:10
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1240339 15-OCT-23 17:56:10
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1240339 15-OCT-23 17:56:10
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1240339 15-OCT-23 17:56:10
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1240339 15-OCT-23 17:56:10
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1240339 15-OCT-23 17:56:10
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1240339 15-OCT-23 17:56:10
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1240339 15-OCT-23 17:56:10

8 rows selected.

18:08:35 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 18:08 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:08 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:08 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:08 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:08 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:08 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:07 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 18:08 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 18:08 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 18:08 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 18:08 /opt/oracle/oradata/HEMANT/undotbs.dbf

18:08:41 SQL>


I now, finally, issue an END BACKUP and check the status.


18:09:45 SQL> alter database end backup;

Database altered.

18:09:51 SQL> select current_scn from v$database;

CURRENT_SCN
-----------
    1244942

18:09:58 SQL> @get_dbf_chk_scns

     FILE# NAME                                                     CHECKPOINT_CHANGE# CHECKPOINT_TIME
---------- -------------------------------------------------------- ------------------ ------------------
         1 /opt/oracle/oradata/HEMANT/system.dbf                               1243041 15-OCT-23 18:08:23
         2 /opt/oracle/oradata/HEMANT/sysaux.dbf                               1243041 15-OCT-23 18:08:23
         3 /opt/oracle/oradata/HEMANT/undotbs.dbf                              1243041 15-OCT-23 18:08:23
         4 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf             1243041 15-OCT-23 18:08:23
         5 /opt/oracle/oradata/HEMANT/indx01.dbf                               1243041 15-OCT-23 18:08:23
         6 /opt/oracle/oradata/HEMANT/HR_DATA.dbf                              1243041 15-OCT-23 18:08:23
        10 /opt/oracle/oradata/HEMANT/indx02.dbf                               1243041 15-OCT-23 18:08:23
        11 /opt/oracle/oradata/HEMANT/indx03.dbf                               1243041 15-OCT-23 18:08:23

8 rows selected.

18:10:05 SQL> !ls -l /opt/oracle/oradata/HEMANT/*dbf
-rw-r-----. 1 oracle oinstall   5251072 Oct 15 18:09 /opt/oracle/oradata/HEMANT/HR_DATA.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:09 /opt/oracle/oradata/HEMANT/indx01.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:09 /opt/oracle/oradata/HEMANT/indx02.dbf
-rw-r-----. 1 oracle oinstall  10493952 Oct 15 18:09 /opt/oracle/oradata/HEMANT/indx03.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:08 /opt/oracle/oradata/HEMANT/redo01.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:09 /opt/oracle/oradata/HEMANT/redo02.dbf
-rw-r-----. 1 oracle oinstall  10486272 Oct 15 18:09 /opt/oracle/oradata/HEMANT/redo03.dbf
-rw-r-----. 1 oracle oinstall 419438592 Oct 15 18:09 /opt/oracle/oradata/HEMANT/sysaux.dbf
-rw-r-----. 1 oracle oinstall 566239232 Oct 15 18:09 /opt/oracle/oradata/HEMANT/system.dbf
-rw-r-----. 1 oracle oinstall 104865792 Oct 15 18:09 /opt/oracle/oradata/HEMANT/TDE_TARGET_TBS_encrypted.dbf
-rw-r-----. 1 oracle oinstall 209723392 Oct 15 18:09 /opt/oracle/oradata/HEMANT/undotbs.dbf

18:10:10 SQL>


So, while the database was in BACKUP mode (from 17:56:10 to 18:09:45) the datafiles were being updated continuously, Log Switches were happening and ArchiveLogs were being generated.  I also had ALTER SYSTEM CHECKPOINT commands being issued.

The  last Checkpoint command issued from the same session that issued the BEGIN BACKUP  that was marked as completed (obviously, all previous Checkpoints where also completed) when the  END BACKUP command from the same session.

So a BEGIN BACKUP
a.  Issues a Checkpoint
b. Does *not* stop updates to datafiles
The last Checkpoint is marked as completed when an END BACKUP is issued -- but that doesn't mean that datafiles are not being updated.

Categories: DBA Blogs

Restoring a PDB from another CDB can increase your SCN

Sat, 2023-09-23 22:08

 I start with a 19c CDB called "ORCLCDB" and PDB "ORCLPDB1" that is present in it.


SQL> col name format a16
SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
2778483057 ORCLCDB             20906515

SQL> select dbid, guid, name, open_mode from v$pdbs;

      DBID GUID                             NAME             OPEN_MODE
---------- -------------------------------- ---------------- ----------
2054948555 88129263B99F4BBDE0530100007F7BDF PDB$SEED         READ ONLY
4057974068 8812E29864F47615E0530100007FA424 ORCLPDB1         READ WRITE
 181927604 C07D1F2BA98C23D0E0530100007F7D34 RMANCAT          MOUNTED

SQL>
SQL> alter pluggable database orclpdb1 close;

Pluggable database altered.

SQL> quit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0
oracle19c>rman target /

Recovery Manager: Release 19.0.0.0.0 - Production on Sun Sep 24 09:39:55 2023
Version 19.12.0.0.0

Copyright (c) 1982, 2019, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ORCLCDB (DBID=2778483057)

RMAN> backup pluggable database orclpdb1 tag for_migration;

Starting backup at 24-SEP-23
using channel ORA_DISK_1
using channel ORA_DISK_2
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00034 name=/opt/oracle/oradata/ORCLCDB/8812E29864F47615E0530100007FA424/datafile/o1_mf_tpcctab_jyl0mzsp_.dbf
input datafile file number=00009 name=/opt/oracle/oradata/ORCLCDB/ORCLPDB1/system01.dbf
input datafile file number=00026 name=/opt/oracle/oradata/ORCLCDB/8812E29864F47615E0530100007FA424/datafile/o1_mf_data_min_j2p8z0qn_.dbf
input datafile file number=00032 name=/opt/oracle/oradata/ORCLCDB/8812E29864F47615E0530100007FA424/datafile/o1_mf_hemant_d_jtkoojqn_.dbf
channel ORA_DISK_1: starting piece 1 at 24-SEP-23
channel ORA_DISK_2: starting full datafile backup set
channel ORA_DISK_2: specifying datafile(s) in backup set
input datafile file number=00011 name=/opt/oracle/oradata/ORCLCDB/ORCLPDB1/undotbs01.dbf
input datafile file number=00010 name=/opt/oracle/oradata/ORCLCDB/ORCLPDB1/sysaux01.dbf
input datafile file number=00012 name=/opt/oracle/oradata/ORCLCDB/ORCLPDB1/users01.dbf
input datafile file number=00031 name=/opt/oracle/oradata/ORCLCDB/8812E29864F47615E0530100007FA424/datafile/o1_mf_hemant_d_jtkoo5nr_.dbf
channel ORA_DISK_2: starting piece 1 at 24-SEP-23
channel ORA_DISK_1: finished piece 1 at 24-SEP-23
piece handle=/opt/oracle/FRA/ORCLCDB/ORCLCDB/8812E29864F47615E0530100007FA424/backupset/2023_09_24/o1_mf_nnndf_FOR_MIGRATION_ljz5825q_.bkp tag=FOR_MIGRATION comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
channel ORA_DISK_2: finished piece 1 at 24-SEP-23
piece handle=/opt/oracle/FRA/ORCLCDB/ORCLCDB/8812E29864F47615E0530100007FA424/backupset/2023_09_24/o1_mf_nnndf_FOR_MIGRATION_ljz5828m_.bkp tag=FOR_MIGRATION comment=NONE
channel ORA_DISK_2: backup set complete, elapsed time: 00:00:03
Finished backup at 24-SEP-23

Starting Control File and SPFILE Autobackup at 24-SEP-23
piece handle=/opt/oracle/FRA/ORCLCDB/ORCLCDB/autobackup/2023_09_24/o1_mf_s_1148377605_ljz585bw_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 24-SEP-23

RMAN>
RMAN> quit


Recovery Manager complete.
oracle19c>sqlplus / as sysdba

SQL*Plus: Release 19.0.0.0.0 - Production on Sun Sep 24 09:48:04 2023
Version 19.12.0.0.0

Copyright (c) 1982, 2021, Oracle.  All rights reserved.


Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0

SQL> alter pluggable database orclpdb1 unplug into '/opt/oracle/product/19c/dbhome_1/orclpdb1.xml';

Pluggable database altered.

SQL> !ls -l /opt/oracle/product/19c/dbhome_1/orclpdb1.xml
-rw-r--r--. 1 oracle oinstall 12583 Sep 24 09:50 /opt/oracle/product/19c/dbhome_1/orclpdb1.xml

SQL>
SQL> quit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0
oracle19c>


Now I go to the target CDB CDB2 and identify that there is no conflicting PDB.  I also find that it has a lower SCN.

SQL> col name format a16
SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
 837065713 CDB2                20664227

SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
 837065713 CDB2                20664231

SQL>
SQL> select * from v$pdbs
  2  /

    CON_ID       DBID    CON_UID GUID
---------- ---------- ---------- --------------------------------
NAME
--------------------------------------------------------------------------------------------------------------------------------
OPEN_MODE  RES OPEN_TIME                                                                   CREATE_SCN TOTAL_SIZE BLOCK_SIZE RECOVERY
---------- --- --------------------------------------------------------------------------- ---------- ---------- ---------- --------
SNAPSHOT_PARENT_CON_ID APP APP APP APPLICATION_ROOT_CON_ID APP PRO LOCAL_UNDO   UNDO_SCN UNDO_TIME CREATION_ DIAGNOSTICS_SIZE
---------------------- --- --- --- ----------------------- --- --- ---------- ---------- --------- --------- ----------------
 PDB_COUNT AUDIT_FILES_SIZE   MAX_SIZE MAX_DIAGNOSTICS_SIZE MAX_AUDIT_SIZE LAST_CHANGE TEM
---------- ---------------- ---------- -------------------- -------------- ----------- ---
TENANT_ID
------------------------------------------------------------------------------------------------------------------------------------
UPGRADE_LEVEL GUID_BASE64
------------- ------------------------------
         2 2054948555 2054948555 88129263B99F4BBDE0530100007F7BDF
PDB$SEED
READ ONLY  NO  24-SEP-23 09.26.31.678 AM +08:00                                               1997190  957349888       8192 ENABLED
                       NO  NO  NO                          NO  NO           1        280           04-MAY-19                0
         0                0          0                    0              0 COMMON USER NO

            1 iBKSY7mfS73gUwEAAH973wA=

         3 2205532678 2205532678 E6BD9C73839C10BEE0550A00275FC834
PDBTMP
MOUNTED                                                                                      17541716  999292928       8192 ENABLED
                       NO  NO  NO                          NO  NO           1        280           21-AUG-22                0
         0                0          0                    0              0 COMMON USER NO

            1 5r2cc4OcEL7gVQoAJ1/INAA=


I then have the backups and the "closed" datafiles from the source CDB copied over to the target.  (The CREATE PLUGGABLE DATABASE command will not be using the RMAN Backups but the PDB Describle XML file and the "closed" datafiles).

oracle19c>pwd
/tmp/From_Source
oracle19c>ls -l
total 1882384
-rw-r-----. 1 oracle oinstall 1146109952 Sep 24 09:56 o1_mf_nnndf_FOR_MIGRATION_ljz5825q_.bkp
-rw-r-----. 1 oracle oinstall  758202368 Sep 24 09:56 o1_mf_nnndf_FOR_MIGRATION_ljz5828m_.bkp
-rw-r-----. 1 oracle oinstall   23232512 Sep 24 09:55 o1_mf_s_1148377605_ljz585bw_.bkp
-rw-r--r--. 1 oracle oinstall      12583 Sep 24 09:59 orclpdb1.xml
oracle19c>


I now prepare to copy the PDB to the target CDB2.. First I check for compatibility.. And then I plug in the PDB with a new name "ORCLPDB1_NEW"

SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
 837065713 CDB2                20664231
SQL> set serveroutput on
SQL> declare
  2   compatible constant varchar2(3) :=
  3     case dbms_pdb.check_plug_compatibility(
  4       pdb_descr_file=>'/tmp/From_Source/orclpdb1.xml',
  5       pdb_name=>'ORCLPDB1')
  6     when true then 'YES'
  7     else 'NO'
  8  END;
  9  begin
 10    dbms_output.put_line(compatible);
 11  end;
 12  /
YES

PL/SQL procedure successfully completed.

SQL>
SQL> show parameter db_create

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_create_file_dest                  string      /opt/oracle/oradata

SQL>
SQL> create pluggable database orclpdb1_new
  2  using '/tmp/From_Source/orclpdb1.xml'
  3  copy;  --- copy will copy the datafiles to the location based on db_create_file_dest and CDB database name

Pluggable database created.

SQL>
SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
 837065713 CDB2                20910195

SQL>
SQL> select dbid, guid, name, open_mode from v$pdbs;

      DBID GUID                             NAME             OPEN_MODE
---------- -------------------------------- ---------------- ----------
2054948555 88129263B99F4BBDE0530100007F7BDF PDB$SEED         READ ONLY
2205532678 E6BD9C73839C10BEE0550A00275FC834 PDBTMP           MOUNTED
4057974068 8812E29864F47615E0530100007FA424 ORCLPDB1_NEW     READ WRITE

SQL>


The SCN of the target CDB2 has now been set to the much higher 20910195 (that was 20664231 before I "plugged in" ORCLDB1 as ORCLDB1_NEW).  This is because it "read" the SCN from the headers of the datafiles that were plugged in.


I can go back to the source and drop the PDB.

SQL> select dbid, name, current_scn from v$database;

      DBID NAME             CURRENT_SCN
---------- ---------------- -----------
2778483057 ORCLCDB             20910076

SQL> select dbid, guid, name, open_mode from v$pdbs;

      DBID GUID                             NAME             OPEN_MODE
---------- -------------------------------- ---------------- ----------
2054948555 88129263B99F4BBDE0530100007F7BDF PDB$SEED         READ ONLY
4057974068 8812E29864F47615E0530100007FA424 ORCLPDB1         MOUNTED
 181927604 C07D1F2BA98C23D0E0530100007F7D34 RMANCAT          MOUNTED

SQL> 
SQL> drop pluggable database orclpdb1 including datafiles;

Pluggable database dropped.

SQL> 
SQL> select dbid, guid, name, open_mode from v$pdbs;

      DBID GUID                             NAME             OPEN_MODE
---------- -------------------------------- ---------------- ----------
2054948555 88129263B99F4BBDE0530100007F7BDF PDB$SEED         READ ONLY
 181927604 C07D1F2BA98C23D0E0530100007F7D34 RMANCAT          MOUNTED

SQL>
SQL> quit
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0
oracle19c>


So, I have "migrated" ORCLPDB1 from ORCLCDB to CDB2 and, in the process, have found that the SCN in CDB2 got reset to a much higher value, because it "inherited" the higher Checkpoint SCN that was in the datafiles of ORCLPDB1.

I can verify that all the datafiles (that are OPEN) in CDB2 can get stamped with the new SCN.

SQL> select con_id, file#, plugin_change#, checkpoint_change#
  2  from v$datafile
  3  order by 1,2
  4  /

    CON_ID      FILE# PLUGIN_CHANGE# CHECKPOINT_CHANGE#
---------- ---------- -------------- ------------------
         1          1              0           20658011
         1          3              0           20658011
         1          4              0           20658011
         1          7              0           20658011
         2          5              0           13768423
         2          6              0           13768423
         2          8              0           13768423
         3         58              0           20657657
         3         59              0           20657657
         3         60              0           20657657
         4         69              0           20908595
         4         70              0           20908595
         4         71              0           20908595
         4         72              0           20908595
         4         73              0           20908595
         4         74              0           20908595
         4         75              0           20908595
         4         76              0           20908595

18 rows selected.

SQL> alter system checkpoint;

System altered.

SQL> select con_id, file#, plugin_change#, checkpoint_change#
  2  from v$datafile
  3  order by 1,2
  4  /

    CON_ID      FILE# PLUGIN_CHANGE# CHECKPOINT_CHANGE#
---------- ---------- -------------- ------------------
         1          1              0           20912767
         1          3              0           20912767
         1          4              0           20912767
         1          7              0           20912767
         2          5              0           13768423
         2          6              0           13768423
         2          8              0           13768423
         3         58              0           20657657
         3         59              0           20657657
         3         60              0           20657657
         4         69              0           20912767
         4         70              0           20912767
         4         71              0           20912767
         4         72              0           20912767
         4         73              0           20912767
         4         74              0           20912767
         4         75              0           20912767
         4         76              0           20912767

18 rows selected.

SQL> col name format a16
SQL> select con_id, name, open_mode from v$pdbs;

    CON_ID NAME             OPEN_MODE
---------- ---------------- ----------
         2 PDB$SEED         READ ONLY
         3 PDBTMP           MOUNTED
         4 ORCLPDB1_NEW     READ WRITE

SQL> alter pluggable database pdbtmp open;

Pluggable database altered.

SQL> select con_id, file#, plugin_change#, checkpoint_change#
  2  from v$datafile
  3  order by 1,2
  4  /

    CON_ID      FILE# PLUGIN_CHANGE# CHECKPOINT_CHANGE#
---------- ---------- -------------- ------------------
         1          1              0           20912767
         1          3              0           20912767
         1          4              0           20912767
         1          7              0           20912767
         2          5              0           13768423
         2          6              0           13768423
         2          8              0           13768423
         3         58              0           20912888
         3         59              0           20912888
         3         60              0           20912888
         4         69              0           20912767
         4         70              0           20912767
         4         71              0           20912767
         4         72              0           20912767
         4         73              0           20912767
         4         74              0           20912767
         4         75              0           20912767
         4         76              0           20912767

18 rows selected.

SQL> alter system checkpoint;

System altered.

SQL> select con_id, file#, plugin_change#, checkpoint_change#
  2  from v$datafile
  3  order by 1,2
  4  /

    CON_ID      FILE# PLUGIN_CHANGE# CHECKPOINT_CHANGE#
---------- ---------- -------------- ------------------
         1          1              0           20912967
         1          3              0           20912967
         1          4              0           20912967
         1          7              0           20912967
         2          5              0           13768423
         2          6              0           13768423
         2          8              0           13768423
         3         58              0           20912967
         3         59              0           20912967
         3         60              0           20912967
         4         69              0           20912967
         4         70              0           20912967
         4         71              0           20912967
         4         72              0           20912967
         4         73              0           20912967
         4         74              0           20912967
         4         75              0           20912967
         4         76              0           20912967

18 rows selected.

SQL>
SQL> alter session set container=ORCLPDB1_NEW;

Session altered.
SQL> col name format a54
SQL> select name from v$datafile;

NAME
------------------------------------------------------
/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_system_ljz7d02h_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_sysaux_ljz7d02l_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_undotbs1_ljz7d02m_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_users_ljz7d02o_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_data_min_ljz7d02p_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_hemant_d_ljz7d02r_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_hemant_d_ljz7d02s_.dbf

/opt/oracle/oradata/CDB2/8812E29864F47615E0530100007FA
424/datafile/o1_mf_tpcctab_ljz7d02t_.dbf


8 rows selected.

SQL>



CON_ID=1 is Root and the datafiles get the new SCN after a Checkpoint.   Note these datafiles still had the "older" SCN 20658011 before I issued the Checkpoint.
CON_ID=2  is the SEED PDB so it does not get updated.
CON_ID=3 is PDTMP  at 20657657 and is stamped to 2091288 after I OPEN it.
CON_ID=4 is the ORCLPDB1_NEW that I plugged in today.
All the non-SEED datafiles are stamped again (to 20912967) after another Checkpoint.

Categories: DBA Blogs

The FILTER operation for an EXISTS query

Wed, 2023-08-09 04:26

 Let's assume a business case where we want to track customers who have ever placed orders with us.

(The business case could be extended to identify customers who have registered with us at least 3 years ago but have not placed any order in the last 12months --- they could either be targets for an advertising or promotions/discount campaign or customers to be retired, depending on the nature of our business and products.  But I'll keep the query simple here).


Name              Null?       Type            
_________________ ___________ _______________ 
CUST_ID           NOT NULL    NUMBER(6)       
CUST_NAME         NOT NULL    VARCHAR2(56)    
CUST_REGN_DATE    NOT NULL    DATE                                                     
SQL> select count(*) from customers;
                                                                                                                     
   COUNT(*)                                                                                                                   
___________                                                                                                                            
        100                                                                                                                                   
                                                                                                                                                   
SQL> desc sales_orders;
                                                                                                                                                                    
Name          Null?       Type          
_____________ ___________ _____________ 
ORDER_ID      NOT NULL    NUMBER(12)    
SALE_DATE                 DATE          
CUST_ID                   NUMBER(6)     
PRODUCT_ID                NUMBER(6)     
QUANTITY                  NUMBER(12)    
SQL> 
SQL> select count(*) from sales_orders;

   COUNT(*) 
___________ 
    1979580 

SQL> select count(distinct(cust_id)) from sales_orders;

   COUNT(DISTINCT(CUST_ID)) 
___________________________ 
                         99 

SQL> 
SQL> create table sale_made_tracker (cust_id number(6,0), sales_made varchar2(3));

Table SALE_MADE_TRACKER created.

SQL> 

Given that we have 100 customers and 1.98million sales orders, we want to add an entry to the SALE_MADE_TRACKER for a customer with a sales order.  However, this is an "on-demand" query that an analyst runs from a front-end, customer-by-customer for specific customers.  Thus, it is not executed as a batch for all 100 customers and 1.98million sales orders.

The developer likes to use Bind Variables and comes up with a query like this :


insert into sale_made_tracker
select cust_id, 'YES'
from customers a
where a.cust_name = :bind_cust_name
and exists
(select '1'
 from customers c, sales_orders s
 where s.cust_id=c.cust_id
 and c.cust_id = a.cust_id)
 

This allows the user to specify a customer name without knowing the cust_id when executing the query.

When testing this in 23c, I've had to add the NO_UNNEST Hint so that I could see the FILTER operation (similar to what I saw in a current 12.1 database):


 SQL> explain plan for
  2  insert into sale_made_tracker
  3  select cust_id, 'YES'
  4  from customers a
  5  where a.cust_name = :bind_cust_name
  6  and exists
  7  (select  '1' 
  8   from customers c, sales_orders s
  9   where s.cust_id=c.cust_id
 10   and c.cust_id = a.cust_id) 
 11  /

Explained.

SQL> 
SQL> select * from table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                 
_________________________________________________________________________________________________ 
Plan hash value: 1657757803                                                                       
                                                                                                  
----------------------------------------------------------------------------------------------    
| Id  | Operation                | Name              | Rows  | Bytes | Cost (%CPU)| Time     |    
----------------------------------------------------------------------------------------------    
|   0 | INSERT STATEMENT         |                   |     1 |    45 |  2447   (1)| 00:00:01 |    
|   1 |  LOAD TABLE CONVENTIONAL | SALE_MADE_TRACKER |       |       |            |          |    
|   2 |   NESTED LOOPS SEMI      |                   |     1 |    45 |  2447   (1)| 00:00:01 |    
|*  3 |    TABLE ACCESS FULL     | CUSTOMERS         |     1 |    43 |     3   (0)| 00:00:01 |    
|   4 |    VIEW PUSHED PREDICATE | VW_SQ_1           |   208 |   416 |  2444   (1)| 00:00:01 |    
|   5 |     NESTED LOOPS         |                   | 20828 |   528K|  2444   (1)| 00:00:01 |    
|*  6 |      INDEX UNIQUE SCAN   | SYS_C0012587      |     1 |    13 |     1   (0)| 00:00:01 |    
|*  7 |      TABLE ACCESS FULL   | SALES_ORDERS      | 20828 |   264K|  2443   (1)| 00:00:01 |    
----------------------------------------------------------------------------------------------    
                                                                                                  
Predicate Information (identified by operation id):                                               
---------------------------------------------------                                               
                                                                                                  
   3 - filter("A"."CUST_NAME"=:BIND_CUST_NAME)                                                    
   6 - access("C"."CUST_ID"="A"."CUST_ID")                                                        
   7 - filter("S"."CUST_ID"="A"."CUST_ID")                                                        
                                                                                                  
Note                                                                                              
-----                                                                                             

PLAN_TABLE_OUTPUT                                           
___________________________________________________________ 
   - dynamic statistics used: dynamic sampling (level=2)    

25 rows selected. 

SQL> delete plan_table;

15 rows deleted.

SQL> 
SQL> explain plan for
  2  insert into sale_made_tracker
  3  select cust_id, 'YES'
  4  from customers a
  5  where a.cust_name = :bind_cust_name
  6  and exists
  7  (select /*+ NO_UNNEST */ '1' 
  8   from customers c, sales_orders s
  9   where s.cust_id=c.cust_id
 10   and c.cust_id = a.cust_id) 
 11  /

Explained.

SQL> 
SQL> select * from table(dbms_xplan.display);

PLAN_TABLE_OUTPUT                                                                                 
_________________________________________________________________________________________________ 
Plan hash value: 2963538242                                                                       
                                                                                                  
----------------------------------------------------------------------------------------------    
| Id  | Operation                | Name              | Rows  | Bytes | Cost (%CPU)| Time     |    
----------------------------------------------------------------------------------------------    
|   0 | INSERT STATEMENT         |                   |     1 |    43 |     6   (0)| 00:00:01 |    
|   1 |  LOAD TABLE CONVENTIONAL | SALE_MADE_TRACKER |       |       |            |          |    
|*  2 |   FILTER                 |                   |       |       |            |          |    
|*  3 |    TABLE ACCESS FULL     | CUSTOMERS         |     1 |    43 |     3   (0)| 00:00:01 |    
|   4 |    NESTED LOOPS          |                   |     1 |    26 |     3   (0)| 00:00:01 |    
|*  5 |     INDEX UNIQUE SCAN    | SYS_C0012587      |     1 |    13 |     1   (0)| 00:00:01 |    
|*  6 |     TABLE ACCESS FULL    | SALES_ORDERS      | 20828 |   264K|     2   (0)| 00:00:01 |    
----------------------------------------------------------------------------------------------    
                                                                                                  
Predicate Information (identified by operation id):                                               
---------------------------------------------------                                               
                                                                                                  
   2 - filter( EXISTS (SELECT /*+ NO_UNNEST */ 0 FROM "SALES_ORDERS" "S","CUSTOMERS"              
              "C" WHERE "C"."CUST_ID"=:B1 AND "S"."CUST_ID"=:B2))                                 
   3 - filter("A"."CUST_NAME"=:BIND_CUST_NAME)                                                    
   5 - access("C"."CUST_ID"=:B1)                                                                  
   6 - filter("S"."CUST_ID"=:B1)                                                                  
                                                                                                  
Note                                                                                              

PLAN_TABLE_OUTPUT                                           
___________________________________________________________ 
-----                                                       
   - dynamic statistics used: dynamic sampling (level=2)    

26 rows selected. 

SQL> delete plan_table;

7 rows deleted.

SQL> 

So, for the purpose of this demo of the FILTER operation for an EXISTS clause, I will use the second form of the query.



If I run the query for customer name "HEMANT" :

 SQL> exec :bind_cust_name := 'HEMANT'

PL/SQL procedure successfully completed.

SQL> 
SQL> insert /*+ gather_plan_statistics */ into sale_made_tracker
  2  select cust_id, 'YES'
  3  from customers a
  4  where a.cust_name = :bind_cust_name
  5  and exists
  6  (select /*+ NO_UNNEST */ '1' 
  7   from customers c, sales_orders s
  8   where s.cust_id=c.cust_id
  9   and c.cust_id = a.cust_id) 
 10  /

1 row inserted.

SQL> 
SQL> select * from table(dbms_xplan.display_cursor(format=>'ALLSTATS LAST'));

PLAN_TABLE_OUTPUT                                                                                           
___________________________________________________________________________________________________________ 
SQL_ID  1j3jggfsurwg4, child number 0                                                                       
-------------------------------------                                                                       
insert /*+ gather_plan_statistics */ into sale_made_tracker select                                          
cust_id, 'YES' from customers a where a.cust_name = :bind_cust_name and                                     
exists (select /*+ NO_UNNEST */ '1'   from customers c, sales_orders s                                      
where s.cust_id=c.cust_id  and c.cust_id = a.cust_id)                                                       
                                                                                                            
Plan hash value: 2963538242                                                                                 
                                                                                                            
--------------------------------------------------------------------------------------------------------    
| Id  | Operation                | Name              | Starts | E-Rows | A-Rows |   A-Time   | Buffers |    
--------------------------------------------------------------------------------------------------------    
|   0 | INSERT STATEMENT         |                   |      1 |        |      0 |00:00:00.01 |     195 |    
|   1 |  LOAD TABLE CONVENTIONAL | SALE_MADE_TRACKER |      1 |        |      0 |00:00:00.01 |     195 |    
|*  2 |   FILTER                 |                   |      1 |        |      1 |00:00:00.01 |     193 |    
|*  3 |    TABLE ACCESS FULL     | CUSTOMERS         |      1 |      1 |      1 |00:00:00.01 |       7 |    
|   4 |    NESTED LOOPS          |                   |      1 |      1 |      1 |00:00:00.01 |     186 |    
|*  5 |     INDEX UNIQUE SCAN    | SYS_C0012587      |      1 |      1 |      1 |00:00:00.01 |       1 |    
|*  6 |     TABLE ACCESS FULL    | SALES_ORDERS      |      1 |  20828 |      1 |00:00:00.01 |     185 |    
--------------------------------------------------------------------------------------------------------    
                                                                                                            
Predicate Information (identified by operation id):                                                         
---------------------------------------------------                                                         
                                                                                                            

PLAN_TABLE_OUTPUT                                           
___________________________________________________________ 
   2 - filter( IS NOT NULL)                                 
   3 - filter("A"."CUST_NAME"=:BIND_CUST_NAME)              
   5 - access("C"."CUST_ID"=:B1)                            
   6 - filter("S"."CUST_ID"=:B1)                            
                                                            
Note                                                        
-----                                                       
   - dynamic statistics used: dynamic sampling (level=2)    
                                                            

33 rows selected. 

SQL> 
Which shows that a total of 185 blocks were read from the SALES_ORDERS table for "HEMANT"'s orders.  Plus 1 block for the Index Unique Scan and 7 blocks for the Full Table Scan of CUSOMERS (totally 193 blocks for the SELECT) {Ignore the A-Rows being 0 for the actual INSERT in the Plan output, the execution shows that 1 row was inserted)



But if I run the query for  customer name "LARRY" :
SQL> exec :bind_cust_name := 'LARRY'

PL/SQL procedure successfully completed.

SQL> 
SQL> insert /*+ gather_plan_statistics */ into sale_made_tracker
  2  select cust_id, 'YES'
  3  from customers a
  4  where a.cust_name = :bind_cust_name
  5  and exists
  6  (select /*+ NO_UNNEST */ '1' 
  7   from customers c, sales_orders s
  8   where s.cust_id=c.cust_id
  9   and c.cust_id = a.cust_id) 
 10  /

0 rows inserted.

SQL> 
SQL> select * from table(dbms_xplan.display_cursor(format=>'ALLSTATS LAST'));

PLAN_TABLE_OUTPUT                                                                                           
___________________________________________________________________________________________________________ 
SQL_ID  1j3jggfsurwg4, child number 0                                                                       
-------------------------------------                                                                       
insert /*+ gather_plan_statistics */ into sale_made_tracker select                                          
cust_id, 'YES' from customers a where a.cust_name = :bind_cust_name and                                     
exists (select /*+ NO_UNNEST */ '1'   from customers c, sales_orders s                                      
where s.cust_id=c.cust_id  and c.cust_id = a.cust_id)                                                       
                                                                                                            
Plan hash value: 2963538242                                                                                 
                                                                                                            
--------------------------------------------------------------------------------------------------------    
| Id  | Operation                | Name              | Starts | E-Rows | A-Rows |   A-Time   | Buffers |    
--------------------------------------------------------------------------------------------------------    
|   0 | INSERT STATEMENT         |                   |      1 |        |      0 |00:00:00.06 |    8723 |    
|   1 |  LOAD TABLE CONVENTIONAL | SALE_MADE_TRACKER |      1 |        |      0 |00:00:00.06 |    8723 |    
|*  2 |   FILTER                 |                   |      1 |        |      0 |00:00:00.06 |    8723 |    
|*  3 |    TABLE ACCESS FULL     | CUSTOMERS         |      1 |      1 |      1 |00:00:00.01 |       7 |    
|   4 |    NESTED LOOPS          |                   |      1 |      1 |      0 |00:00:00.06 |    8716 |    
|*  5 |     INDEX UNIQUE SCAN    | SYS_C0012587      |      1 |      1 |      1 |00:00:00.01 |       1 |    
|*  6 |     TABLE ACCESS FULL    | SALES_ORDERS      |      1 |  20828 |      0 |00:00:00.06 |    8715 |    
--------------------------------------------------------------------------------------------------------    
                                                                                                            
Predicate Information (identified by operation id):                                                         
---------------------------------------------------                                                         
                                                                                                            

PLAN_TABLE_OUTPUT                                           
___________________________________________________________ 
   2 - filter( IS NOT NULL)                                 
   3 - filter("A"."CUST_NAME"=:BIND_CUST_NAME)              
   5 - access("C"."CUST_ID"=:B1)                            
   6 - filter("S"."CUST_ID"=:B1)                            
                                                            
Note                                                        
-----                                                       
   - dynamic statistics used: dynamic sampling (level=2)    
                                                            

33 rows selected. 

SQL>

Which shows that a total of 8,715 blocks were read for "LARRY"'s orders from the SALES_ORDERS table alone but actual rows returned was 0 -- so no rows were inserted into SALE_MADE_TRACKER.

Both "HEMANT" and "LARRY" exist in the CUSTOMERS table.


SQL> select cust_id, cust_name 
  2  from customers
  3  where cust_id in (1,2)
  4* /

   CUST_ID CUST_NAME    
__________ ____________ 
         1 HEMANT       
         2 LARRY        

SQL>
SQL> select cust_id, count(*)
  2   from sales_orders
  3  where cust_id in (1,2)
  4  group by cust_id
  5  order by 1
  6* /

   CUST_ID    COUNT(*) 
__________ ___________ 
         1       20502 

SQL> 
SQL> select /*+ gather_plan_statistics FULL (s) */ count(*)
  2  from sales_orders s
  3* /

   COUNT(*) 
___________ 
    1979580 

SQL> select * from table(dbms_xplan.display_cursor(format=>'ALLSTATS LAST'));

PLAN_TABLE_OUTPUT                                                                                
________________________________________________________________________________________________ 
SQL_ID  042jxgv8y5xny, child number 0                                                            
-------------------------------------                                                            
select /*+ gather_plan_statistics FULL (s) */ count(*) from                                      
sales_orders s                                                                                   
                                                                                                 
Plan hash value: 1409771706                                                                      
                                                                                                 
---------------------------------------------------------------------------------------------    
| Id  | Operation          | Name         | Starts | E-Rows | A-Rows |   A-Time   | Buffers |    
---------------------------------------------------------------------------------------------    
|   0 | SELECT STATEMENT   |              |      1 |        |      1 |00:00:00.03 |    8715 |    
|   1 |  SORT AGGREGATE    |              |      1 |      1 |      1 |00:00:00.03 |    8715 |    
|   2 |   TABLE ACCESS FULL| SALES_ORDERS |      1 |   2082K|   1979K|00:00:00.02 |    8715 |    
---------------------------------------------------------------------------------------------    
                                                                                                 
Note                                                                                             
-----                                                                                            
   - dynamic statistics used: dynamic sampling (level=2)                                         
                                                                                                 

19 rows selected. 

SQL> 

While "HEMANT" has 20,502 sales orders, "LARRY", despite being a registered customer, has not issued any order.

The EXISTS query for "HEMANT" had to read only 185 blocks from the SALES_ORDERS table until it was *stopped* by the FILTER operation because the FILTER here stops the subquery as soon as the first row is returned (which you can also see as actual rows being "1" from the SALES_ORDERS table) -- as soon as the subquery returns TRUE.

"LARRY" has no orders so the EXISTS query ran through the whole SALES_ORDERS table to read 8,715 blocks.


Side note on the use of the Bind Variable here :  The fact that the developer used Bind Variables means that the Estimated Rows from the SALES_ORDERS table  in the Execution Plan was always going to be the same -- no matter which customer name was queried for -- because it prevents the use of Histograms (if they existed) on the tale.

Categories: DBA Blogs

Recent Video PlayLists

Mon, 2023-01-09 08:19

 I've added a few videos to my YouTube Channel in the past two years.


Oracle MultiTenant Database Configurations


Oracle DataGuard


Categories: DBA Blogs

Instance Parameters for Pluggable Databases

Sun, 2022-10-30 09:38
Since 12c Oracle has permitted Pluggable Databases with the MultiTenant Architecture. Normally, instance parameters (those in the init<SID>.ora or spfile<SID>.ora) apply to the whole Instance -- thus to all the Pluggable Databases.

However, certain parameters can be changed at the PDB (Pluggable Database) level.

Oracle stores the values for these changed parameters in the PDB_SPFILE$ table in the Root Container.

Here is a simple demonstration (in 19c) :


-- connect to the root and check certain parameter
SQL> connect / as sysdba
Connected.
SQL> show parameter optimizer_features_enable

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
optimizer_features_enable string 19.1.0
SQL> show parameter sort_area_size

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sort_area_size integer 65536
SQL> show parameter workarea_size_policy

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
workarea_size_policy string AUTO
SQL>


-- override them at the PDB level for ORCLPDB1
SQL> alter session set container=ORCLPDB1;

Session altered.

SQL> alter system set optimizer_features_enable='12.2.0.1';

System altered.

SQL> alter system set sort_area_size=10485760;
alter system set sort_area_size=10485760
*
ERROR at line 1:
ORA-02096: specified initialization parameter is not modifiable with this option

SQL> -- note that changing S_A_S has to be done as "DEFERRED" to apply to subsequent sessions
SQL> alter system set sort_area_size=10485760 deferred;

System altered.

SQL> alter system set workarea_size_policy='MANUAL';

System altered.

SQL>
SQL> show parameter optimizer_features_enable;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
optimizer_features_enable string 12.2.0.1
SQL> show parameter workarea_size_policy;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
workarea_size_policy string MANUAL
SQL>

-- connect to the PDB and verify that they have changed for the user session
SQL> connect hemant/hemant@orclpdb1
ERROR:
ORA-28002: the password will expire within 7 days


Connected.
SQL> show parameter optimizer_features_enable

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
optimizer_features_enable string 12.2.0.1
SQL> show parameter sort_area_size

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sort_area_size integer 10485760
SQL> show parameter workarea_size_policy

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
workarea_size_policy string MANUAL
SQL>


-- return to the root CDB and check that it retains the old (default) values
SQL> connect / as sysdba
Connected.
SQL> show parameter optimizer_features_enable

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
optimizer_features_enable string 19.1.0
SQL> show parameter sort_area_size

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sort_area_size integer 65536
SQL> show parameter workarea_size_policy

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
workarea_size_policy string AUTO
SQL>


-- identify from the CDB where the overriding values are
SQL> connect / as sysdba
Connected.
SQL> get show_orclpdb1_params.sql
1 select pdb.dbid, pdb.con_uid, sp.name, sp.value$
2 from v$pdbs pdb, pdb_spfile$ sp
3 where pdb.name = 'ORCLPDB1'
4 and pdb.con_uid=sp.pdb_uid
5* order by sp.name
SQL> /

DBID CON_UID NAME VALUE$
---------- ---------- ---------------------------------------- ----------------------------------------
4057974068 4057974068 deferred_segment_creation FALSE
4057974068 4057974068 nls_date_format ''
4057974068 4057974068 optimizer_features_enable '12.2.0.1'
4057974068 4057974068 sort_area_size 10485760
4057974068 4057974068 workarea_size_policy 'MANUAL'

SQL>


(The two parameters "deferred_segment_creation" and "nls_date_format") are in my YouTube demonstration).

Thus, we can see that Oracle stores PDB parameters in a table called PDB_SPFILE$ in the Root Container.
These will apply whenever the Pluggable Database is re-opened -- and thus override the parameters for the Root that are from the Server Parameter File (spfile<SID>.ora)

I have presented a short Video Demonstration as well on YouTube.

 


Categories: DBA Blogs

SCN Synchronization when using a Database Link

Wed, 2022-09-07 09:36

 In my previous blog post about querying across a Database Link, I had stated "when running a query (just a SELECT statement) requires the two databases to synchronise SCN.  Whichever is the database with the lower SCN has to increment its SCN to the other database's (higher) SCN "


Here is a quick demonstration :


-- First I verify the current SCN in two databases "ORCLCDB" and "CDB2"
ORCLCDB SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
ORCLCDB 07-SEP-22 10.10.49.643026 PM +08:00 19617903

ORCLCDB SQL>

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
CDB2 07-SEP-22 10.10.52.378969 PM +08:00 18562711

CDB2 SQL>
-- there is a wide gap between the two -- with ORCLCDB being ahead by approximately 1million
============================================================================================



-- now I connect a client to a PDB in ORCLCDB
-- and run a SELECT query that queries across a DBLink a table in a PDB in CDB2
-- this query is NOT a user transaction, only a SELECT statement
SQL> connect hemant/hemant@orclpdb1
Connected.
SQL> set time on
22:11:33 SQL>
22:11:48 SQL> select count(*) from tmp_data@pdbtmp_data;

COUNT(*)
----------
73181

22:12:05 SQL>


-- Now I check the SCNs in the two databases
ORCLCDB SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
ORCLCDB 07-SEP-22 10.12.19.955477 PM +08:00 19620089

ORCLCDB SQL>

CDB2 SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
CDB2 07-SEP-22 10.12.23.499409 PM +08:00 19620089

CDB2 SQL>
-- I can see that CDB2's SCN has "mysteriously" caught up with ORCLCDB
-- in fact they are exactly the same
-- in the real world there would still be some difference by the time I query again
-- because other transactions in either or both the databases would have incremented the SCN(s)
================================================================================================



-- now I disconnect from the client
-- this *closes* the database link
22:12:58 SQL> disconnect
Disconnected from Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0

-- and reconnect to the client
22:13:04 SQL> connect hemant/hemant@orclpdb1
Connected.
22:13:14 SQL>

-- I compare the SCNs in the two databases
ORCLCDB SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
ORCLCDB 07-SEP-22 10.13.22.738662 PM +08:00 19620223

ORCLCDB SQL>

CDB2 SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
CDB2 07-SEP-22 10.13.30.874874 PM +08:00 19620229

CDB2 SQL>
-- the gap is very small
-- in fact some internal operations in CDB2 have slightly incremented it ahead
===============================================================================



-- I run a PLSQL procedure in my client that does 1million COMMITs in the PDB
-- to increase the SCN only in ORCLCDB
22:14:06 SQL> execute onemillioncommits;

PL/SQL procedure successfully completed.

22:15:03 SQL>
22:15:07 SQL>


-- I now compare the two SCNs
ORCLCDB SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
ORCLCDB 07-SEP-22 10.15.21.713518 PM +08:00 20654338

ORCLCDB SQL>
CDB2 SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
CDB2 07-SEP-22 10.15.23.779855 PM +08:00 19620296

CDB2 SQL>
-- and find that there is again a huge gap between the two databases, with ORCLCDB ahead again
==============================================================================================



-- I query across the Database Link again from my client session
22:15:46 SQL> select count(*) from tmp_data@pdbtmp_data;

COUNT(*)
----------
73181

22:15:50 SQL>


-- and now compare the two SCNs
ORCLCDB SQL>select name, systimestamp, current_scn from v$database;
NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
ORCLCDB 07-SEP-22 10.16.02.362146 PM +08:00 20654373

ORCLCDB SQL>
CDB2 SQL>select name, systimestamp, current_scn from v$database;

NAME SYSTIMESTAMP CURRENT_SCN
--------- ------------------------------------ -----------
CDB2 07-SEP-22 10.16.14.122201 PM +08:00 20654453

CDB2 SQL>
-- now the gap is very small
-- some other operations in ORCLCDB have already incremented the SCN after the query
====================================================================================


So, simply running a SELECT statement (not even a User-Initiated COMMIT causes the two databases to synchronise SCNs.  The database with the lower SCN "inherits" the higher SCN.

So, the next time you see database SCNs mysteriously jump (e.g. in V$DATABASE.CURRENT_SCN  or in V$ARCHIVED_LOG.FIRST_CHANGE#  or in V$DATAFILE.CHECKPOINT_SCN) very significantly, check to see if you have queries to/from the database that use one or more Database Links.

Categories: DBA Blogs

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