Great, I got reply from script author Mr. Ola Hallengren.

I have configured index rebuild on weekly basis at 3 AM..in production server,

I have checked at 9 AM there is no table locking and blocking that particular table which was made it rebuild the index.

As per your script rebuild index is online mode even though table is accessing through application even if locking that table.

Pl. confirms as blow parameters mention which is configured all production servers. also confirm updatestats for table index which is not rebuild the index.

DateTime: 2012-09-05 02:00:01

Server: servername

Version: 10.50.4000.0

Edition: Enterprise Edition (64-bit)

Procedure: [master].[dbo].[IndexOptimize]

Parameters:

@databases = 'USER_DATABASES', @FragmentationLow = NULL,

@FragmentationMedium = 'INDEX_REORGANIZE,INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE',

@FragmentationHigh = 'INDEX_REBUILD_ONLINE,INDEX_REBUILD_OFFLINE',

@FragmentationLevel1 = 5, @FragmentationLevel2 = 30, @PageCountLevel = 1000,

@SortInTempdb = 'N', @MaxDOP = NULL, @FillFactor = NULL, @PadIndex = NULL,

@LOBCompaction = 'Y', @UpdateStatistics = NULL, @OnlyModifiedStatistics = 'N',

@StatisticsSample = NULL, @StatisticsResample = 'N', @PartitionLevel = 'N',

@TimeLimit = NULL, @Indexes = NULL, @Delay = NULL, @LogToTable = 'Y',

@Execute = 'Y'

Source: http://ola.hallengren.com[/code%5D

thanks