Index Maintenance

SET NOCOUNT ON;

DECLARE @objectid int;

DECLARE @indexid int;

DECLARE @partitioncount bigint;

DECLARE @schemaname nvarchar(130);

DECLARE @objectname nvarchar(130);

DECLARE @indexname nvarchar(130);

DECLARE @partitionnum bigint;

DECLARE @partitions bigint;

DECLARE @frag float;

DECLARE @command nvarchar(4000);

DECLARE @dbid smallint;

— Conditionally select tables and indexes from the sys.dm_db_index_physical_stats function

— and convert object and index IDs to names.

SET @dbid = DB_ID();

SELECT

    [object_id] AS objectid,

    index_id AS indexid,

    partition_number AS partitionnum,

    avg_fragmentation_in_percent AS frag, page_count

INTO #work_to_do

FROM sys.dm_db_index_physical_stats (@dbid, NULL, NULL , NULL, N’LIMITED’)

WHERE avg_fragmentation_in_percent > 10.0  — Allow limited fragmentation

AND index_id > 0 — Ignore heaps

AND page_count > 25; — Ignore small tables

— Declare the cursor for the list of partitions to be processed.

DECLARE partitions CURSOR FOR SELECT objectid,indexid, partitionnum,frag FROM #work_to_do;

— Open the cursor.

OPEN partitions;

— Loop through the partitions.

WHILE (1=1)

BEGIN

FETCH NEXT

FROM partitions

INTO @objectid, @indexid, @partitionnum, @frag;

IF @@FETCH_STATUS < 0 BREAK;

SELECT @objectname = QUOTENAME(o.name), @schemaname = QUOTENAME(s.name)

FROM sys.objects AS o

JOIN sys.schemas as s ON s.schema_id = o.schema_id

WHERE o.object_id = @objectid;

SELECT @indexname = QUOTENAME(name)

FROM sys.indexes

WHERE object_id = @objectid AND index_id = @indexid;

SELECT @partitioncount = count (*)

FROM sys.partitions

WHERE object_id = @objectid AND index_id = @indexid;

— 30 is an arbitrary decision point at which to switch between reorganizing and rebuilding.

IF @frag < 30.0

SET @command = N’ALTER INDEX ‘ + @indexname + N’ ON ‘ + @schemaname + N’.’ + @objectname + N’ REORGANIZE’;

IF @frag >= 30.0

SET @command = N’ALTER INDEX ‘ + @indexname + N’ ON ‘ + @schemaname + N’.’ + @objectname + N’ REBUILD’;

IF @partitioncount > 1

SET @command = @command + N’ PARTITION=’ + CAST(@partitionnum AS nvarchar(10));

EXECUTE(@command);

PRINT N’Executed: ‘ + @command;

END

— Close and deallocate the cursor.

CLOSE partitions;

DEALLOCATE partitions;

— Drop the temporary table.

DROP TABLE #work_to_do;

GO