Shulou(Shulou.com)06/01 Report--

Snapshot Standby, this feature puts the standby library in a "read-write state" for things that are not convenient to test in the main library of the production environment, such as simulating online testing and other tasks. When the task is completed in the read and write state of the standby database, it is very easy to switch the Snapshot Standby database role back to the standby database role and restore data synchronization with the main database. In the state of Snapshot Standby database, the slave database can accept the logs passed by the main database, but the changes cannot be applied to the standby database.

Prerequisites for physical repository to be converted to Snapshot

Stop the log application on the repository.

Enable database flashback function for standby database

The following demonstration, if switched to snapshot.

1. Stop the log application on the repository.

DGMGRL > edit database 11gdg2 set state=APPLY-OFF;Succeeded.DGMGRL >

two。 Enable the flashback function of standby database

SQL > alter database flashback on;Database altered.

3. Convert repository to snapshot

DGMGRL > CONVERT DATABASE 11GDG2 TO SNAPSHOT STANDBY;Converting database "11gdg2" to a Snapshot Standby database, please wait...Database "11gdg2" converted successfully

4. At this point, we make some data modifications on the main library.

SQL > select count (*) from T1; COUNT (*)-56SQL > insert into T1 select * from T1 politics 56 rows created.SQL > commit;Commit complete.

5. Modify data in the repository

SQL > conn / as sysdbaConnected.SQL > select open_mode from vested database * select open_mode from vested database > conn scott/tigerConnected.SQL > create table T2 as select * from T1 lead Table created.SQL > select count (*) from T2; COUNT (*)-56SQL >

6. Convert snapshot to physical standby

DGMGRL > CONVERT DATABASE 11GDG2 TO PHYSICAL STANDBY Converting database "11gdg2" to a Physical Standby database Please wait...Operation requires shutdown of instance "dgtst" on database "11gdg2" Shutting down instance "dgtst"... Database closed.Database dismounted.ORACLE instance shut down.Operation requires startup of instance "dgtst" on database "11gdg2" Starting instance "dgtst"... ORACLE instance started.Database mounted.Continuing to convert database "11gdg2"... Operation requires shutdown of instance "dgtst" on database "11gdg2" Shutting down instance "dgtst"... ORA-01109: database not openDatabase dismounted.ORACLE instance shut down.Operation requires startup of instance "dgtst "on database" 11gdg2 "Starting instance" dgtst "... ORACLE instance started.Database mounted.Database" 11gdg2 "converted successfully"

Open the reserve library

SQL > alter database open read only;Database altered.

7. Check whether the T2 table still exists in the standby library.

SQL > conn scott/tigerConnected.SQL > select * from T2 * select * from T2 * ERROR at line 1:ORA-00942: table or view does not existSQL >

8. See if the changes made to the main library have been applied after the conversion to snapshot.

SQL > select count (*) from T1; COUNT (*)-112SQL >

The conclusion is the same as step 4.

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