As part of database maintenance, indexes on databases have to be rebuilt or reorganised depending on how fragmented the indexes are. From the article Reorganize and Rebuild Indexes, the advice is to reorganise index if avg_fragmentation_in_percent value is between 5 and 30 and to rebuild index if it is more than 30%.
The script below queries all fragmented indexes more than 5 percent and using a cursor a loop is performed on the results to rebuild or reorganise indexes depending on the percentage of fragmentation using dynamic SQL, i.e.
The script can be downloaded from technet gallery , i.e. if avg_fragmentation_in_percent value is between 5 and 30 then reorganise else rebuild.
declare @tableName nvarchar(500)
declare @indexName nvarchar(500)
declare @indexType nvarchar(55)
declare @percentFragment decimal(11,2)
declare FragmentedTableList cursor for
SELECT OBJECT_NAME(ind.OBJECT_ID) AS TableName,
ind.name AS IndexName, indexstats.index_type_desc AS IndexType,
indexstats.avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, NULL) indexstats
INNER JOIN sys.indexes ind ON ind.object_id = indexstats.object_id
AND ind.index_id = indexstats.index_id
WHERE
-- indexstats.avg_fragmentation_in_percent , e.g. >30, you can specify any number in percent
indexstats.avg_fragmentation_in_percent > 5
AND ind.Name is not null
ORDER BY indexstats.avg_fragmentation_in_percent DESC
OPEN FragmentedTableList
FETCH NEXT FROM FragmentedTableList
INTO @tableName, @indexName, @indexType, @percentFragment
WHILE @@FETCH_STATUS = 0
BEGIN
print 'Processing ' + @indexName + 'on table ' + @tableName + ' which is ' + cast(@percentFragment as nvarchar(50)) + ' fragmented'
if(@percentFragment<= 30)
BEGIN
EXEC( 'ALTER INDEX ' + @indexName + ' ON ' + @tableName + ' REBUILD; ')
print 'Finished reorganizing ' + @indexName + 'on table ' + @tableName
END
ELSE
BEGIN
EXEC( 'ALTER INDEX ' + @indexName + ' ON ' + @tableName + ' REORGANIZE;')
print 'Finished rebuilding ' + @indexName + 'on table ' + @tableName
END
FETCH NEXT FROM FragmentedTableList
INTO @tableName, @indexName, @indexType, @percentFragment
END
CLOSE FragmentedTableList
DEALLOCATE FragmentedTableList
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