Verifying the True Cache Configuration

2.5.1 Verifying That True Cache Is Working as Expected

To verify that True Cache is applying redo and making progress, check the following queries on True Cache.

Run SQL*Plus on the True Cache.
```
sqlplus / as SYSDBA
```
Enter the following query:
```
SELECT database_role, open_mode FROM v$database;
```
The output should look like this:
```
DATABASE_ROLE    OPEN_MODE
---------------- --------------------
TRUE CACHE       READ ONLY WITH APPLY
```
If OPEN_MODE is READ ONLY WITH APPLY, it means that the True Cache redo apply is actively working.
Enter the following query multiple times:
```
SELECT current_scn FROM v$database;
```
If CURRENT_SCN is advancing over time, it means that True Cache is moving forward as expected.
To find the size of each log file, enter the following query:
```
SELECT THREAD#, SEQUENCE#, BYTES FROM v$standby_log;
```

2.5.2 Verifying the Remote Listener Configuration

After the database application service starts on True Cache, use the lsnrctl command to validate the remote listener services for the True Cache service registration.

Note:

For Oracle RAC primary databases, before using the lsnrctl command, set your $ORACLE_HOME environment variable to the path for the Oracle Grid Infrastructure home (Grid home).

The following example shows two True Caches registered with the SCAN listener for an Oracle RAC primary database:

lsnrctl services LISTENER_SCAN1

Service "sales_tc" has 2 instance(s).
    Instance "tcdb1", status READY, has 1 handler(s) for this service...
        Handler(s):
            "DEDICATED" established:0 refused:0 state:ready
                REMOTE SERVER       
                (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=tc1.example.com)(PORT=1521)))
    Instance "tcdb2", status READY, has 1 handler(s) for this service...
        Handler(s):
            "DEDICATED" established:0 refused:0 state:ready
                REMOTE SERVER       
                (ADDRESS=(PROTOCOL=TCP)(HOST=tc2.example.com)(PORT=1521))

Note:

If the True Cache service is not registered with the remote listener, validate the remote listener invited nodes and the True Cache initialization parameters for REMOTE_LISTENER or LISTENER_NETWORKS.

2.5.3 Verifying the True Cache and Primary Database Application Services

Verify that all database application services are active on both the primary database and True Cache.

True Cache

Run SQL*Plus on True Cache.
```
sqlplus / as SYSDBA
```

Enter the following query:

SELECT service_id, name FROM v$active_services WHERE name='true_cache_service_name';

For example:

SELECT service_id, name FROM v$active_services WHERE name='SALES_TC';

SERVICE_ID  NAME
----------  ---------
        28  SALES_TC

Primary Database

Run SQL*Plus on the primary database.
```
sqlplus / as SYSDBA
```

Enter the following query:

SELECT service_id, name, true_cache_service FROM v$active_services WHERE name='primary_db_service_name';

For example:

SELECT service_id, name, true_cache_service FROM v$active_services WHERE name='SALES';

SERVICE_ID   NAME    TRUE_CACHE_SERVICE
----------   ------  ----------------
        29   SALES   SALES_TC

Related Topics

2.5 Verifying the True Cache Configuration

2.5.1 Verifying That True Cache Is Working as Expected

2.5.2 Verifying the Remote Listener Configuration

2.5.3 Verifying the True Cache and Primary Database Application Services