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  6. ALTER INDEX

ALTER INDEX

Function

ALTER INDEX modifies the definition of an existing index. Only the owner of an index or a system administrator can execute this command. There are several subforms:

  • IF EXISTS

    If the specified index does not exist, a notice instead of an error is sent.

  • RENAME TO

    Changes only the name of the index. There is no effect on the stored data.

  • SET ( { STORAGE_PARAMETER = value } [, ...] )

    Change one or more index-method-specific storage parameters. Note that the index contents will not be modified immediately by this command. When you use certain parameters, you might need to rebuild the index with REINDEX to get the desired effects.

  • RESET ( { storage_parameter } [, ...] )

    Reset one or more index-method-specific storage parameters to the default value. Similar to the SET statement, the REINDEX may need to be used to completely update the index.

  • [ MODIFY PARTITION index_partition_name ] UNUSABLE

    Sets the index on a table or index partition to be unavailable.

  • REBUILD [ PARTITION index_partition_name ]

    Recreates the index on a table or index partition.

  • RENAME PARTITION

    Renames an index partition.

  • MOVE PARTITION

    Modifies the tablespace of an index partition.

Syntax

  • Rename a table index.
ALTER INDEX [ IF EXISTS ] index_name 
    RENAME TO new_name;
  • Modify the storage parameter of a table index.
ALTER INDEX [ IF EXISTS ] index_name 
    SET ( {storage_parameter = value} [, ... ] );
  • Reset the storage parameter of a table index.
ALTER INDEX [ IF EXISTS ] index_name 
    RESET ( storage_parameter [, ... ] ) ;
  • Set a table index or an index partition to be unavailable.
ALTER INDEX [ IF EXISTS ] index_name 
    [ MODIFY PARTITION index_partition_name ] UNUSABLE;
NOTE:

The syntax cannot be used for column-store tables.

  • Rebuild a table index or index partition.
ALTER INDEX index_name 
    REBUILD [ PARTITION index_partition_name ];
  • Modify the tablespace of an index partition.
    ALTER INDEX [ IF EXISTS ] index_name
        MOVE PARTITION index_partition_name TABLESPACE new_tablespace;
  • Rename an index partition.
ALTER INDEX [ IF EXISTS ] index_name 
    RENAME PARTITION index_partition_name TO new_index_partition_name;

  

Parameter Description

  • index_name

    Indicates the index name to be modified.

  • new_name

    New name for the index

    Value range: a string. It must comply with the naming rule.

  • storage_parameter

    Specifies the name of an index-method-specific parameter.

  • value

    New value for an index-method-specific storage parameter This might be a number or a word depending on the parameter.

  • new_index_partition_name

    New name of the index partition

  • index_partition_name

    Name of the index partition

Example

See Example in CREATE INDEX.

Helpful Links

CREATE INDEX, DROP INDEX, REINDEX