Thursday, March 27, 2014

Rebuild Index

-- Ensure a USE statement has been executed first.



-- define index defrag rate for this run
DECLARE @fragrate float;
SET @fragrate = 30.0; -- set to do something if defrag rate HIGH

DECLARE @rbrirate float;
SET @rbrirate = 50.0; -- set to rebuild if defrag rate EXTREME

-- define table holding index information
DECLARE @indexinfo TABLE(objectid int, indexid int, partitionnum bigint, frag float)

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);

-- Conditionally select tables and indexes from the sys.dm_db_index_physical_stats function
INSERT INTO @indexinfo
    object_id AS objectid,
    index_id AS indexid,
    partition_number AS partitionnum,
    avg_fragmentation_in_percent AS frag
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL , NULL, 'LIMITED')
WHERE avg_fragmentation_in_percent > @fragrate AND index_id > 0
--and object_id = object_id('mlsdata');

-- Declare the cursor for the list of partitions to be processed.
DECLARE partitions CURSOR FOR SELECT * FROM @indexinfo;
OPEN partitions;

-- Loop through the partitions.
FETCH NEXT FROM partitions
INTO @objectid, @indexid, @partitionnum, @frag;

WHILE (@@fetch_status <> -1)
        IF (@@fetch_status <> -2)

SELECT @objectname = QUOTENAME(, @schemaname = QUOTENAME(
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 < @rbrirate
SET @command = N'ALTER INDEX ' + @indexname + N' ON ' + @schemaname + N'.' + @objectname + N' REORGANIZE';
IF @frag >= @rbrirate
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));

EXEC (@command);
PRINT N'Executed (Defrag ' + CAST(@frag AS varchar(12)) + '): ' + @command;
--PRINT @command;
-- Get the next record to process
        FETCH NEXT FROM partitions
INTO @objectid, @indexid, @partitionnum, @frag;

-- Close and deallocate the cursor.
CLOSE partitions;
DEALLOCATE partitions;