Unusable indexes

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Unusable indexes

Oracle indexes can go into a UNUSABLE state after maintenance operation on the table or if the index is marked as 'unusable' with an ALTER INDEX command. A direct path load against a table or partition will also leave its indexes unusable.
Queries and other operations against a table with unusable indexes will generate errors:
ORA-01502: index ‘string.string’ or partition of such index is in unusable state
=== Detecting ===

The following SQL commands can be used to detect unusable indexes:
* Indexes:

SELECT owner, index_name, tablespace_name
FROM   dba_indexes
WHERE  status = 'UNUSABLE';

• Index partitions:

SELECT index_owner, index_name, partition_name, tablespace_name
FROM   dba_ind_PARTITIONS
WHERE  status = 'UNUSABLE';

• Index subpartitions:

SELECT index_owner, index_name, partition_name, subpartition_name, tablespace_name
FROM   dba_ind_SUBPARTITIONS
WHERE  status = 'UNUSABLE';

Fixing

The following SQL will print out a list of alter commands that can be executed to fix unusable indexes:
* Indexes:

SELECT 'alter index '||owner||'.'||index_name||' rebuild tablespace '||tablespace_name ||';' sql_to_rebuild_index
FROM   dba_indexes
WHERE  status = 'UNUSABLE';

• Index partitions:

SELECT 'alter index '||index_owner||'.'||index_name ||' rebuild partition '||PARTITION_NAME||' TABLESPACE '||tablespace_name ||';' sql_to_rebuild_index
FROM   dba_ind_partitions
WHERE  status = 'UNUSABLE';

• Index subpartitions:

SELECT 'alter index '||index_owner||'.'||index_name ||' rebuild subpartition '||SUBPARTITION_NAME||' TABLESPACE '||tablespace_name ||';' sql_to_rebuild_index
FROM   dba_ind_subpartitions
WHERE  status = 'UNUSABLE';

or if you prefer via single PLSQL anonymous block:

set serveroutput on size unlimited

BEGIN
    FOR x IN
    (
        SELECT 'ALTER INDEX '||OWNER||'.'||INDEX_NAME||' REBUILD ONLINE PARALLEL' comm
        FROM    dba_indexes
        WHERE   status = 'UNUSABLE'
        UNION ALL
        SELECT 'ALTER INDEX '||index_owner||'.'||index_name||' REBUILD PARTITION '||partition_name||' ONLINE PARALLEL'
        FROM    dba_ind_PARTITIONS
        WHERE   status = 'UNUSABLE'
        UNION ALL
        SELECT 'ALTER INDEX '||index_owner||'.'||index_name||' REBUILD SUBPARTITION '||subpartition_name||' ONLINE PARALLEL'
        FROM    dba_ind_SUBPARTITIONS
        WHERE   status = 'UNUSABLE'
    )
    LOOP
        dbms_output.put_line(x.comm);
        EXECUTE immediate x.comm;
    END LOOP;
END;
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