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PostgreSQL查看索引的使用情况

时间:2021-07-01 10:21:17 帮助过:176人阅读

--索引在重建或删除新建时sys.dm_db_index_usage_stats中相关的数据会被清除 --索引在重整是不会清除sys.dm_db_index_usage_stats的数据 SELECT DB_NAME(ixu.database_id) DataBase_Name , OBJECT_NAME(ixu.object_id) Table_Name , ix.name Index_Name , ( SELECT MAX(s.rows) FROM sysindexes s WHERE s.id = ixu.object_id ) AS Table_Rows , STATS_DATE(ixu.object_id, ixu.index_id) AS statistic_time , ixu.user_updates , ixu.last_user_update , ixu.last_user_seek , ixu.user_seeks , ixu.last_user_scan , ixu.user_scans , ixu.last_user_lookup , ixu.user_lookups , ixu.user_updates / ( ISNULL(ixu.user_seeks, 0) + ISNULL(ixu.user_scans, 0) + 1 ) AS UseRate FROM sys.dm_db_index_usage_stats ixu INNER JOIN sys.indexes ix ON ixu.object_id = ix.object_id AND ixu.index_id = ix.index_id INNER JOIN sys.objects ob ON ixu.object_id = ob.object_id WHERE ob.type = U AND ob.is_ms_shipped = 0 AND ixu.database_id = DB_ID() --AND ix.object_id=OBJECT_ID(TableName)

存放索引详细信息的表

data_name=# \d+ pg_stat_user_indexes;
           View "pg_catalog.pg_stat_user_indexes"
    Column     |  Type  | Modifiers | Storage | Description 
---------------+--------+-----------+---------+-------------
 relid         | oid |           | plain | 
 indexrelid    | oid |           | plain | 
 schemaname    | name |           | plain | 
 relname       | name |           | plain | 
 indexrelname  | name |           | plain | 
 idx_scan      | bigint |           | plain | 
 idx_tup_read  | bigint |           | plain | 
 idx_tup_fetch | bigint |           | plain | 
View definition:
 SELECT pg_stat_all_indexes.relid,
    pg_stat_all_indexes.indexrelid,
    pg_stat_all_indexes.schemaname,
    pg_stat_all_indexes.relname,
    pg_stat_all_indexes.indexrelname,
    pg_stat_all_indexes.idx_scan,
    pg_stat_all_indexes.idx_tup_read,
    pg_stat_all_indexes.idx_tup_fetch
   FROM pg_stat_all_indexes
  WHERE (pg_stat_all_indexes.schemaname <> ALL (ARRAY[pg_catalog::name, information_schema::name])) AND pg_stat_all_indexes.schemaname !~ ^pg_toast::text;

通过这个表查看某个表的索引使用情况易如反掌了。

示例一、查看所有表的索引的使用情况

select relname, indexrelname, idx_scan, idx_tup_read, idx_tup_fetch from pg_stat_user_indexes order by idx_scan asc, idx_tup_read asc, idx_tup_fetch asc;

 

示例二、查看某个表的索引使用情况

select relname, indexrelname, idx_scan, idx_tup_read, idx_tup_fetch from pg_stat_user_indexes where relname = table_name order by idx_scan asc, idx_tup_read asc, idx_tup_fetch asc;

 

PostgreSQL查看索引的使用情况

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