Oracle 18c-PDB Snapshot Carousel

Oracle 18c-PDB Snapshot Carousel

Description:-

• In this article we are going to see the oracle 18 new feature “PDB Snapshot Carousel”
• PDB Snapshot Carousel is a new feature of Oracle Database 18c
• We will configure the PDB snapshot carousel for a specified PDB,
• Create snapshots manually or automatically, and set the maximum number of snapshots.
• A PDB snapshot carousel is a useful way of maintaining a library of recent PDB copies for point-in-time recovery and cloning.
• This version allows us to maintain up to a maximum of 8 snapshots per PDB, once this number is reached,these will be overwritten as new instant copies are required. Snapshots can be configured automatically (executed from time to time) as a manual.
• A PDB snapshot carousel is a useful way of maintaining a library of recent PDB copies for point-in-time recovery and cloning.
• For example, while the production PDB named pdb1_prod is open and in use, you create a refreshable clone named pdb1_test_master.You then configure pdb1_test_master to create automatic snapshots every day. When you need new PDBs for testing, create a full clone of any snapshot, and then create sparse clones using CREATE PLUGGABLE DATABASE … SNAPSHOT COPY.

Oracle 18c-Creating a Point-in-Time Clone of a PDB Snapshot Here

• Setting the Maximum Number of Snapshots in a PDB Snapshot Carousel

Prerequisites
The PDB must be open in read/write mode.

SQL> show pdbs
CON_ID      CON_NAME    OPEN MODE RESTRICTED
———- ————- ———- ———-
2                PDB$SEED            READ ONLY         NO
4                PDB1                       READ WRITE        NO

SET LINESIZE 150
COL CON_ID FORMAT 99999
COL PROPERTY_NAME FORMAT a17
COL PDB_NAME FORMAT a9
COL VALUE FORMAT a3
COL DESCRIPTION FORMAT a43
SELECT r.CON_ID, p.PDB_NAME, PROPERTY_NAME,
PROPERTY_VALUE AS value, DESCRIPTION
FROM CDB_PROPERTIES r, CDB_PDBS p
WHERE r.CON_ID = p.CON_ID
AND PROPERTY_NAME LIKE ‘MAX_PDB%’
ORDER BY PROPERTY_NAME;

• SQL statement sets the maximum number of PDB snapshots for the current PDB to 7

SQL> ALTER PLUGGABLE DATABASE SET MAX_PDB_SNAPSHOTS=7;
Pluggable database altered.

• Dropping All Snapshots in a PDB Snapshot Carousel

ALTER PLUGGABLE DATABASE SET MAX_PDB_SNAPSHOTS=0;

• Configuring an Automatic Snapshot Every Day for an Existing PDB

Step:1

SQL> SELECT SNAPSHOT_MODE “S_MODE”, SNAPSHOT_INTERVAL/60 “SNAP_INT_HRS” FROM DBA_PDBS;

S_MODE SNAP_INT_HRS
—— ————
MANUAL

Step:2

SQL> ALTER PLUGGABLE DATABASE SNAPSHOT MODE EVERY 24 HOURS;

Pluggable database altered.

Step:3

SQL> SELECT SNAPSHOT_MODE “S_MODE”, SNAPSHOT_INTERVAL/60 “SNAP_INT_HRS” FROM DBA_PDBS;

S_MODE           SNAP_INT_HRS
——               ————
AUTO                            24

• Creating PDB Snapshots Manually

Creating a Snapshot with a System-Specified Name

ALTER PLUGGABLE DATABASE SNAPSHOT;
SET LINESIZE 150
COL CON_NAME FORMAT a10
COL SNAPSHOT_NAME FORMAT a25
COL SNAP_SCN FORMAT 9999999
COL FULL_SNAPSHOT_PATH FORMAT a45
SELECT CON_ID, CON_NAME, SNAPSHOT_NAME,SNAPSHOT_SCN AS snap_scn, FULL_SNAPSHOT_PATH
FROM DBA_PDB_SNAPSHOTS ORDER BY SNAP_SCN;

Creating a Snapshot with a User-Specified Name

ALTER PLUGGABLE DATABASE SNAPSHOT test_pdb2_wedload;

• Dropping a PDB Snapshot

ALTER PLUGGABLE DATABASE DROP SNAPSHOT test_pdb2_wedload;

Reference:-

https://docs.oracle.com/en/database/oracle/oracle-database/18/multi/administering-pdb-snapshots.html#GUID-FF6DF540-0C22-451C-80B3-1ACA8C8CB7D2

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