How to check index usage in Oracle 11g?

How to check index usage in Oracle 11g?

If you suspect or want to verify the usage of an index, simply issue the following ALTER INDEX command to start monitoring that index: SQL> ALTER INDEX pk_emp MONITORING USAGE; Index altered. SQL> ALTER INDEX ix_emp_sal MONITORING USAGE; Index altered.

How do you check if an index is being used in Oracle?

In Oracle SQL Developer, when you have SQL in the worksheet, there is a button “Explain Plan”, you can also hit F10. After you execute Explain plan, it will show in the bottom view of SQL Developer. There is a column “OBJECT_NAME”, it will tell you what index is being used.

Is it possible to turn on index monitoring in Oracle 10g?

Since Oracle 10g, you can monitor indexes to see if they are being used or not. It recommended to enable index monitoring for an appropriate period that is representative of your full workload cycle. For example if you run a report every week, month or even year, just to catch all those activities.

What is Dba_indexes?

DBA_INDEXES describes all indexes in the database. This view supports parallel partitioned index scans. Its columns are the same as those in “ALL_INDEXES”.

What is index monitoring in Oracle?

Index monitoring allows unused indexes to be identified accurately, removing the risks associated with dropping useful indexes. It is important to make sure that index monitoring is performed over a representative time period.

How do I enable and disable indexes in Oracle?

To disable an index, you run an ALTER INDEX command: ALTER INDEX index_name ON table_name DISABLE; You can replace the index_name with the name of your index, and the table_name with the name of the table that the index is created on.

How do you know if an index is being used?

To check whether an index is being used, proceed as follows:

1. Open a second session and choose System Utilities Performance Trace there.
2. Select SQL Trace and choose Trace on.
3. In the first window, carry out the action for which you want the system to use the desired index.
4. Choose Trace off and then Trace list .

How can I tell which index a table is using?

On Oracle:

1. Determine all indexes on table: SELECT index_name FROM user_indexes WHERE table_name = :table.
2. Determine columns indexes and columns on index: SELECT index_name , column_position , column_name FROM user_ind_columns WHERE table_name = :table ORDER BY index_name, column_order.

What is Oracle index status na?

N/A indicates that index is a partitioned index.This is explicitly enforced by catalog.sql.To get the status of the partitioned index query DBA_IND_PARTITIONS: select table_name,INDEX_TYPE,PARTITIONED,status from dba_indexes where status !=’USABLE’;

What are the DBA tables in Oracle?

DBA_TABLES describes all relational tables in the database. Its columns are the same as those in ALL_TABLES .

How do I make an index usable?

Altering Indexes

1. Rebuild or coalesce an existing index.
2. Deallocate unused space or allocate a new extent.
3. Specify parallel execution (or not) and alter the degree of parallelism.
4. Alter storage parameters or physical attributes.
5. Specify LOGGING or NOLOGGING.
6. Enable or disable key compression.
7. Mark the index unusable.

How do I enable indexing?

To enable a disabled index Click the plus sign to expand the Tables folder. Click the plus sign to expand the table on which you want to enable an index. Click the plus sign to expand the Indexes folder. Right-click the index you want to enable and select Rebuild.

How to enable monitoring for the index?

Lets enable monitoring for the index. SQL> SQL> alter index IND_EMP monitoring usage; Index altered.

What is indexindex usage tracking in Oracle 12c?

Index usage tracking in Oracle 12.2 replaces the old index monitoring functionality of previous versions. This article is essentially a rewrite of the previous Index Monitoring article, bringing it in line with Oracle Database 12c Release 2 (12.2). The database maintains all indexes defined against a table regardless of their usage.

What is index usage tracking and why is it important?

Index usage tracking allows unused indexes to be identified, helping to removing the risks associated with dropping useful indexes. It is important to make sure that index usage tracking is performed over a representative time period.

What is the difference between monitoring usage and nomonitoring usage?

Each time the MONITORING USAGE clause is a specified, the V$OBJECT_USAGE view is reset for the specified index. The previous usage information is cleared or reset, and a new start time is recorded. When you specify NOMONITORING USAGE, no further monitoring is performed, and the end time is recorded for the monitoring period.