SQLServer表的索引碎片查询和处理
目录
1.查看索引的碎片率
2.reorganize索引
3.rebuild索引
4.rebuild表上所有的索引
5.rebuild数据库中所有的索引
1.查看索引的碎片率SELECT object_name(ips.object_id) AS TableName, ips.index_id, name AS IndexName,
avg_fragmentation_in_percent,db_name(ips.database_id) AS DatabaseName
FROM sys.dm_db_index_physical_stats
(Db_id(DB_NAME())
, NULL
, NULL
, NULL
, NULL) AS ips
INNER JOIN sys.indexes AS SI ON ips.object_id = SI.object_id AND ips.index_id = SI.index_id
WHERE ips.avg_fragmentation_in_percent > 5 AND SI.index_id <> 0
索引的碎片率低于5%或者，索引的页数少于1000，可以忽略；
索引碎片率在5%-30%之间的，建议reorganize；
索引碎片率大于30%的，建议rebuild。
alter index [索引名] on [dbo].[表名] reorganize;
3.rebuild索引
alter index [索引名] on [dbo].[表名] rebuild;
4.rebuild表上所有的索引
alter index all on [dbo].[表名] rebuild;
5.rebuild数据库中所有的索引
USE [数据库名]
GO
DECLARE @NoOfPartitions BIGINT;
DECLARE @objectid INT;
DECLARE @indexid INT;
DECLARE @idxname NVARCHAR(255);
DECLARE @objname NVARCHAR(255);
DECLARE @partitionnum BIGINT;
DECLARE @schemaname NVARCHAR(255);
DECLARE @partitions BIGINT;
DECLARE @frag FLOAT;
DECLARE @statement VARCHAR(8000);
-- checking existance of the table that we create for temporary purpose
IF OBJECT_ID('defrag_work', 'U') IS NOT NULL
DROP TABLE defrag_work;
-- Copy the fragmented indexes data into defrag_work table
-- All the indexes that has fragmentation < 5 are getting stored into our work table
SELECT [object_id] AS objectid ,
index_id AS indexid ,
partition_number AS partition_no ,
avg_fragmentation_in_percent AS frag
INTO defrag_work
FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, 'LIMITED')
WHERE avg_fragmentation_in_percent >5.0 and index_id > 0;
-- cursor to process the list of partitions
DECLARE partitions CURSOR
FOR
SELECT *
FROM defrag_work;
-- Open the cursor.
OPEN partitions;
-- Looping through the partitions
FETCH NEXT
FROM partitions
INTO @objectid, @indexid, @partitionnum, @frag;
WHILE @@FETCH_STATUS = 0
BEGIN;
SELECT @objname= QUOTENAME(so.name) ,
@schemaname = QUOTENAME(ss.name)
FROM sys.objects AS so
JOIN sys.schemas AS ss ON ss.schema_id = so.schema_id
WHERE so.object_id = @objectid;
SELECT @idxname = QUOTENAME(name)
FROM sys.indexes
WHERE object_id = @objectid
AND index_id = @indexid;
SELECT @NoOfPartitions = COUNT(*)
FROM sys.partitions
WHERE object_id = @objectid
AND index_id = @indexid;
/*
Let's say N = fragmentation percentage
N <= 5 = IGNORE
5 < N < 30 = REORGANIZE
N > 30 = REBUILD
*/
IF (@frag < 30.0) -- @frag > 5 is already filtered in our first query, so we need that condition here
BEGIN;
SELECT @statement = 'ALTER INDEX ' + @idxname + ' ON '
+ @schemaname + '.' + @objname + ' REORGANIZE';
IF @NoOfPartitions > 1
SELECT @statement = @statement + ' PARTITION='
+ CONVERT (CHAR, @partitionnum);
EXEC (@statement);
END;
IF @frag >= 30.0
BEGIN;
SELECT @statement = 'ALTER INDEX ' + @idxname + ' ON '
+ @schemaname + '.' + @objname + ' REBUILD';
IF @NoOfPartitions > 1
SELECT @statement = @statement + ' PARTITION='
+ CONVERT (CHAR, @partitionnum);
EXEC (@statement);
END;
PRINT 'Executed ' + @statement;
FETCH NEXT FROM partitions INTO @objectid, @indexid, @partitionnum,
@frag;
END;
-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;
-- drop the table
IF OBJECT_ID('defrag_work', 'U') IS NOT NULL
DROP TABLE defrag_work;
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