Help Center/ GaussDB(DWS)/ SQL Syntax Reference (8.1.3.x)/ DDL Syntax/ ALTER INDEX
Updated on 2024-09-30 GMT+08:00
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ALTER INDEX

Function

ALTER INDEX modifies the definition of an existing index.

There are several sub-forms:

  • 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. You might need to rebuild the index with REINDEX to get the desired effects depending on parameters.

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

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

  • COMMENT comment_text

    Adds, modifies, or deletes index comments.

Precautions

  • Only the owner of an index or a system administrator can run this statement.

Syntax

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

    The syntax cannot be used for column-store tables.

  • Rebuild a table index or index partition. 
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    ALTER INDEX index_name 
    REBUILD [ PARTITION index_partition_name ];
  • Rename an index partition. 
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    ALTER INDEX [ IF EXISTS ] index_name 
    RENAME PARTITION index_partition_name TO new_index_partition_name;

    PG_OBJECT does not support the record of the syntax when the last modification time of the index is recorded.

  • Add and modify the index comment. 
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    ALTER INDEX [ IF EXISTS ] index_name 
    COMMENT 'text';
  • Delete the index comment. 
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    ALTER INDEX [ IF EXISTS ] index_name 
    COMMENT '';
ALTER INDEX [ IF EXISTS ] index_name
    COMMENT NULL;

Parameter Description

  • index_name

    Specifies the index name to be modified.

  • new_name

    Specifies the new name for the index.

    Value range: a string that must comply with the identifier naming rules.

  • storage_parameter

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

  • value

    Specifies the 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

    Specifies the new name of the index partition.

  • index_partition_name

    Specifies the name of the index partition.

  • comment_text

    Comment of an index.

Examples

Rename the ds_ship_mode_t1_index1 index to ds_ship_mode_t1_index5:

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ALTER INDEX tpcds.ds_ship_mode_t1_index1 RENAME TO ds_ship_mode_t1_index5;

Set the ds_ship_mode_t1_index2 index as unusable:

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ALTER INDEX tpcds.ds_ship_mode_t1_index2 UNUSABLE;

Rebuild the ds_ship_mode_t1_index2 index:

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ALTER INDEX tpcds.ds_ship_mode_t1_index2 REBUILD;

Rename a partitioned table index:

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ALTER INDEX tpcds.ds_customer_address_p1_index2 RENAME PARTITION CA_ADDRESS_SK_index1 TO CA_ADDRESS_SK_index4;

Modify the index comment:

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ALTER INDEX tpcds.ds_customer_address_p1_index2 COMMENT 'comment_ds_customer_address_p1_index2';

Links

CREATE INDEX, DROP INDEX, REINDEX

Parent topic: DDL Syntax