{"id":17114,"date":"2022-02-11T16:20:32","date_gmt":"2022-02-11T15:20:32","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/managing-refreshable-clone-pluggable-databases-with-oracle-21c\/"},"modified":"2022-02-11T16:20:32","modified_gmt":"2022-02-11T15:20:32","slug":"managing-refreshable-clone-pluggable-databases-with-oracle-21c","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/managing-refreshable-clone-pluggable-databases-with-oracle-21c\/","title":{"rendered":"Managing Refreshable Clone Pluggable Databases with Oracle 21c"},"content":{"rendered":"

By Mouhamadou Diaw<\/strong><\/p>\n

A refreshable clone PDB is a way to refresh a single PDB instead of refreshing all PDBs in a container as in a Data Guard environment. It consists to make a clone of a source PDB and the clone PDB is updated with redo accumulated since the last redo log apply
\nIn this blog I did some tests of this feature Refreshable pluggable databases.
\nI am doing my test with Oracle 21c but this feature exists since Oracle 12.2.<\/p>\n

The configuration I use in the following<\/p>\n

\"\"<\/a><\/p>\n

An Oracle 21c source CDB : DB21 with a source pluggable database PDB1
\nAn Oracle 21c target CDB : TEST21 which will contain the refreshable clone of PDB1. The clone will be named PDB1FRES<\/p>\n

Note that the refreshable clone can be created in the same container.<\/p>\n

The first step is to create a user in the source CDB DB21 for database link purpose<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>create<\/code> user<\/code> c##clone_user identified <\/code>by<\/code> rootroot2016 <\/code>temporary<\/code> tablespace <\/code>temp<\/code> container=<\/code>ALL<\/code>;<\/code><\/div>\n
<\/div>\n
User<\/code> created.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n
<\/div>\n
SQL> <\/code>grant<\/code> create<\/code> session, <\/code>create<\/code> pluggable <\/code>database<\/code>, sysoper <\/code>to<\/code> c##clone_user container=<\/code>ALL<\/code> ;<\/code><\/div>\n
<\/div>\n
Grant<\/code> succeeded.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

In the target CDB TEST21 let’s create a database link to the source CDB. We will use the user c##clone<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>create<\/code> database<\/code> link clonesource <\/code>connect<\/code> to<\/code> c##clone_user identified <\/code>by<\/code> rootroot2016 using <\/code>'DB21'<\/code>;<\/code><\/div>\n
<\/div>\n
Database<\/code> link created.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n
<\/div>\n
SQL> <\/code>select<\/code> * <\/code>from<\/code> dual@clonesource;<\/code><\/div>\n
<\/div>\n
D<\/code><\/div>\n
-<\/code><\/div>\n
X<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Now we can create a refreshable clone PDB1FRES of PDB1 in the database TEST21.<\/p>\n

First we will create a manual refreshable clone<\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n
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3<\/div>\n
4<\/div>\n
5<\/div>\n<\/td>\n
\n
\n
SQL> <\/code>create<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>from<\/code> PDB1@clonesource refresh mode manual;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> created.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

When created the new clone is mounted<\/p>\n

\n
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\n
\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MOUNTED<\/code><\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

We can see the refresh mode<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>select<\/code> PDB_NAME,REFRESH_MODE,REFRESH_INTERVAL,LAST_REFRESH_SCN <\/code>from<\/code> dba_pdbs <\/code>where<\/code> PDB_NAME=<\/code>'PDB1FRES'<\/code>;<\/code><\/div>\n
<\/div>\n
PDB_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 REFRES REFRESH_INTERVAL LAST_REFRESH_SCN<\/code><\/div>\n
--------------- ------ ---------------- ----------------<\/code><\/div>\n
PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MANUAL\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 39266271<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Ok now let’s do some change on PDB1 and let’s see how to propagate these changes on PDB1FRES<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> show con_name<\/code><\/div>\n
<\/div>\n
CON_NAME<\/code><\/div>\n
------------------------------<\/code><\/div>\n
PDB1<\/code><\/div>\n
<\/div>\n
<\/div>\n
SQL> <\/code>create<\/code> table<\/code> test(id number);<\/code><\/div>\n
<\/div>\n
Table<\/code> created.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>insert<\/code> into<\/code> test <\/code>values<\/code> (1);<\/code><\/div>\n
<\/div>\n
1 row created.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>commit<\/code>;<\/code><\/div>\n
<\/div>\n
Commit<\/code> complete.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

PDB1FRES must be closed (mounted) to be refreshed with changes in PDB1. As the clause REFRESH MANUAL was used during it’s creation, we have to manually do the refresh<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> show con_name<\/code><\/div>\n
<\/div>\n
CON_NAME<\/code><\/div>\n
------------------------------<\/code><\/div>\n
CDB$ROOT<\/code><\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES refresh;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Let’s now open PDB1FRES in Read Only mode to verify the refresh<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>open<\/code> read<\/code> only<\/code>;<\/code><\/div>\n
<\/div>\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MOUNTED<\/code><\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>open<\/code> read<\/code> only<\/code>;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
SQL> <\/code>alter<\/code> session <\/code>set<\/code> container=PDB1FRES;<\/code><\/div>\n
<\/div>\n
Session altered.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>select<\/code> * <\/code>from<\/code> test;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ID<\/code><\/div>\n
----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>1<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>close<\/code> immediate;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

As seen, the manual refresh works fine.<\/p>\n

Can we change the manual refresh mode to an automatic one?<\/p>\n

Let’s try<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode every 4 minutes;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>select<\/code> PDB_NAME,REFRESH_MODE,REFRESH_INTERVAL,LAST_REFRESH_SCN <\/code>from<\/code> dba_pdbs <\/code>where<\/code> PDB_NAME=<\/code>'PDB1FRES'<\/code>;<\/code><\/div>\n
<\/div>\n
PDB_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 REFRES REFRESH_INTERVAL LAST_REFRESH_SCN<\/code><\/div>\n
--------------- ------ ---------------- ----------------<\/code><\/div>\n
PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 AUTO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 39272240<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Now let’s again do some changes in PDB1<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>insert<\/code> into<\/code> test <\/code>values<\/code> (10);<\/code><\/div>\n
<\/div>\n
1 row created.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>insert<\/code> into<\/code> test <\/code>values<\/code> (20);<\/code><\/div>\n
<\/div>\n
1 row created.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>commit<\/code>;<\/code><\/div>\n
<\/div>\n
Commit<\/code> complete.<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

4 minutes after we can see the the last LAST_REFRESH_SCN has changed on PDB1FRES<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> <\/code>select<\/code> PDB_NAME,REFRESH_MODE,REFRESH_INTERVAL,LAST_REFRESH_SCN <\/code>from<\/code> dba_pdbs <\/code>where<\/code> PDB_NAME=<\/code>'PDB1FRES'<\/code>;<\/code><\/div>\n
<\/div>\n
PDB_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 REFRES REFRESH_INTERVAL LAST_REFRESH_SCN<\/code><\/div>\n
--------------- ------ ---------------- ----------------<\/code><\/div>\n
PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 AUTO\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 4\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 39272403<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Let’s open PDB1FRES on read only mode and let’s verify that the latest changes are replicated<\/p>\n

\n
\n\n\n\n
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\n
\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> session <\/code>set<\/code> container=PDB1FRES ;<\/code><\/div>\n
<\/div>\n
Session altered.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>select<\/code> * <\/code>from<\/code> test;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>ID<\/code><\/div>\n
----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>1<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>10<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>20<\/code><\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Note that the automatic refresh will success only if the PDB clone is mounted. Note also that a manual refresh can be done even if the auto refresh is configured.<\/p>\n

Another question may be if we can open PDB1FRES in read write mode.
\nLet’s try<\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n
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\n
\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>open<\/code> read<\/code> write;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

What? The command open read write returns SUCCESS but the database is real openend in read only mode.<\/p>\n

To open the database in a read write mode, we have to set the refresh mode to none<\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n
2<\/div>\n
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\n
\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode none;<\/code><\/div>\n
alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode none<\/code><\/div>\n
*<\/code><\/div>\n
ERROR <\/code>at<\/code> line 1:<\/code><\/div>\n
ORA-65025: Pluggable <\/code>database<\/code> PDB1FRES <\/code>is<\/code> not<\/code> closed <\/code>on<\/code> all<\/code> instances.<\/code><\/div>\n
<\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 <\/code>close<\/code> immediate;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode none;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> col pdb_name <\/code>for<\/code> a15<\/code><\/div>\n
SQL> <\/code>select<\/code> PDB_NAME,REFRESH_MODE,REFRESH_INTERVAL,LAST_REFRESH_SCN <\/code>from<\/code> dba_pdbs <\/code>where<\/code> PDB_NAME=<\/code>'PDB1FRES'<\/code>;<\/code><\/div>\n
<\/div>\n
PDB_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 REFRES REFRESH_INTERVAL LAST_REFRESH_SCN<\/code><\/div>\n
--------------- ------ ---------------- ----------------<\/code><\/div>\n
PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 NONE\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 39272683<\/code><\/div>\n
<\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>open<\/code> read<\/code> write;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> show pdbs;<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> WRITE <\/code>NO<\/code><\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

Now that PDB1FRES is opened in read write mode, let’s close it and let’s try to transform it again in refreshable clone<\/p>\n

\n
\n\n\n\n
\n
1<\/div>\n
2<\/div>\n
3<\/div>\n
4<\/div>\n
5<\/div>\n
6<\/div>\n
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\n
\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES <\/code>close<\/code> immediate;<\/code><\/div>\n
<\/div>\n
Pluggable <\/code>database<\/code> altered.<\/code><\/div>\n
<\/div>\n
SQL> show pdbs<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>CON_ID CON_NAME\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>OPEN<\/code> MODE\u00a0 RESTRICTED<\/code><\/div>\n
---------- ------------------------------ ---------- ----------<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>2 PDB$SEED\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/code>READ<\/code> ONLY<\/code>\u00a0 NO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>3 PDB1FRES\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MOUNTED<\/code><\/div>\n
SQL> <\/code>alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode manual;<\/code><\/div>\n
alter<\/code> pluggable <\/code>database<\/code> PDB1FRES\u00a0 refresh mode manual<\/code><\/div>\n
*<\/code><\/div>\n
ERROR <\/code>at<\/code> line 1:<\/code><\/div>\n
ORA-65261: pluggable <\/code>database<\/code> PDB1FRES <\/code>not<\/code> enabled <\/code>for<\/code> refresh<\/code><\/div>\n
<\/div>\n
<\/div>\n
SQL><\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

It’s not possible to convert back an opened R\/W PDB to a refreshable PDB. It’s clearly specified in the documentation
\nYou cannot change an ordinary PDB into a refreshable clone PDB. After a refreshable clone PDB is converted to an ordinary PDB, you cannot change it back into a refreshable clone PDB.<\/em><\/p>\n

Conclusion<\/h3>\n

One usage of refreshable PDB is that the clone can be used as a golden master for snapshots at PDB level. And these snapshots can be used for cloning environments for developers.<\/p>\n","protected":false},"excerpt":{"rendered":"

By Mouhamadou Diaw A refreshable clone PDB is a way to refresh a single PDB instead of refreshing all PDBs in a container as in a Data Guard environment. It consists to make a clone of a source PDB and the clone PDB is updated with redo accumulated since the last redo log apply In… <\/p>\n","protected":false},"author":27,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","neve_meta_reading_time":"","_themeisle_gutenberg_block_has_review":false,"footnotes":""},"categories":[4133,59],"tags":[137,2480],"class_list":["post-17114","post","type-post","status-publish","format-standard","hentry","category-database","category-oracle","tag-oracle-21c","tag-refreshable-clone-pdb"],"yoast_head":"\nManaging Refreshable Clone Pluggable Databases with Oracle 21c - dbi services | Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dbi-services.com\/blog\/managing-refreshable-clone-pluggable-databases-with-oracle-21c\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Managing Refreshable Clone Pluggable Databases with Oracle 21c\" \/>\n<meta property=\"og:description\" content=\"By Mouhamadou Diaw A refreshable clone PDB is a way to refresh a single PDB instead of refreshing all PDBs in a container as in a Data Guard environment. 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