How to Remove A Table From Cache In Oracle?

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To remove a table from the cache in Oracle, you can use the ALTER TABLE command with the NOCACHE option. By specifying this option, you are indicating that the table should not be cached in the buffer cache. This means that data from the table will not be stored in memory, but will be read and written directly to disk. This can be useful if you have tables that are large and infrequently accessed, as it can help to free up space in the buffer cache for more frequently accessed data. Remember that removing a table from the cache can affect performance, so it is important to consider the impact on your system before making this change.

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How to make sure the cache is refreshed after removing a table in Oracle?

To ensure that the cache is refreshed after removing a table in Oracle, you can follow these steps:

  1. Flush the shared pool: Executing the following command will remove all objects from the shared pool, causing Oracle to reacquire metadata and reparse any SQL statements that reference the removed table.
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ALTER SYSTEM FLUSH SHARED_POOL;


  1. Restart the database instance: Restarting the database instance will clear all cached data and force Oracle to rebuild the cache when the database is brought back online.
  2. Use the DBMS_SHARED_POOL package: You can use the DBMS_SHARED_POOL package to flush specific objects from the shared pool. This allows you to target only the cached objects related to the removed table without affecting other cached data.
  3. Analyze the shared pool: Use the DBMS_SHARED_POOL.ANALYZE_RE-PCACHE_CURSOR procedure to analyze the shared pool and identify any stale cached data related to the removed table. You can then use the DBMS_SHARED_POOL.PURGE procedure to remove these objects from the cache.


By following these steps, you can ensure that the cache is refreshed after removing a table in Oracle.


How to monitor cache usage for a specific table in Oracle?

To monitor cache usage for a specific table in Oracle, you can use the following methods:

  1. Query the V$BH (Buffer Headers) view: You can query the V$BH view to see the number of blocks in the buffer cache for a specific table. This view provides information about the buffer cache in the SGA (System Global Area). You can filter the results for a specific table by using SQL queries like the following:
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SELECT COUNT(*) "Number of Blocks in Cache"
FROM V$BH
WHERE objd = (SELECT data_object_id
              FROM dba_objects
              WHERE object_name = 'YOUR_TABLE_NAME');


This query will give you the number of blocks in the buffer cache for the specified table.

  1. Use Oracle Enterprise Manager: Oracle Enterprise Manager (EM) provides a graphical interface for monitoring and managing the database. You can use EM to monitor cache usage for a specific table by navigating to the Performance tab and looking at the buffer cache metrics. You can filter the results by specifying the table name you are interested in.
  2. Use AWR reports: You can generate an AWR (Automatic Workload Repository) report to analyze the performance of the database. The AWR report includes information about buffer cache usage, including statistics for specific tables. You can use this report to monitor cache usage for a specific table over a period of time.


By using these methods, you can monitor cache usage for a specific table in Oracle and analyze the performance of your database.


How to remove a table from cache in Oracle?

To remove a table from cache in Oracle, you can use the following steps:

  1. Connect to your Oracle database as a user with the necessary privileges.
  2. Identify the name of the table that you want to remove from the cache.
  3. Disable the cache for the table by executing the following SQL command: ALTER TABLE table_name NOCACHE; Replace table_name with the actual name of the table that you want to remove from the cache.
  4. Verify that the table is no longer cached by checking the V$CACHE view: SELECT table_name, cache FROM V$CACHE WHERE table_name = 'table_name'; If the table is no longer listed in the V$CACHE view, it has been successfully removed from the cache.


Note: Disabling the cache for a table may impact performance, especially for frequently accessed tables. It is recommended to carefully consider the implications of removing a table from the cache before executing the above steps.


What steps are involved in removing a table from cache in Oracle?

To remove a table from cache in Oracle, you can follow these steps:

  1. Identify the table that you want to remove from cache.
  2. Open SQL*Plus or any other SQL client.
  3. Log in to your Oracle database with appropriate privileges.
  4. Execute the following command to remove the table from cache: ALTER TABLE table_name CACHE NO; Replace table_name with the name of the table that you want to remove from cache.
  5. Verify the changes by checking the cache status of the table: SELECT table_name, CACHE FROM user_tables WHERE table_name = 'table_name'; Again, replace table_name with the name of the table you removed from cache.


By following these steps, you can successfully remove a table from cache in Oracle.

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