Usually, you should rebuild the index if it has a fragmentation greater than 30% and reorganize it if it has less than 30% fragmentation. This means that an index can be rebuilt without knowing the structure. Over time these modifications can cause the information in the index to become scattered in the database (fragmented). If you don’t spend much time with SQL Server and you. REORGANIZE, UPDATE STATISTICS and a simple SELECT statement. The indexes that cannot be rebuild online are: Disabled clustered index ; Disabled indexed view1. Under Select a page, select Options. The REORGANIZE modifier for ALTER INDEX is not currently supported by Azure SQL. The process uses the existing pages only and does not allocate new ones, but it does compact the index pages. SQL SERVER – Difference Between Index Rebuild and Index Reorganize Explained with T-SQL Script. It defragments the leaf level of clustered and nonclustered indexes on tables and views by physically reordering the leaf-level pages to match the logical, left to right, order of the leaf nodes. First, since you're literally rebuilding the index, it reorders the pages and the rows on those pages. ALTER INDEX . Since we are asking SQL Server to rebuild the clustered index on a quite large table twice, it will take a few. This removes fragmentation, reclaims disk space by compacting the pages based on the specified or existing fill factor setting. The. I'd just add that adding the line PRINT @sql after the SET @sql =. Rebuilding indexes only does the index itself so the column stats are stale unless they hit the "20% data change + 500 records" criteria to trigger the auto-update. #1637994. [FactInternetSales] REBUILD PARTITION = ALL WITH (PAD_INDEX = ON, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF,. The length of time the rebuild takes is related to the size of the index, not the amount of fragmentation in it. Check total_pages in sys. alter index all on table_name reorganize; But I only want to rebuild or reorganize if fragmentation percentage on each index is between a certain range. When you reorganize an index, SQL Server sorts the index pages and releases the unused space within the index pages. I have maintenance job on SQL Server 2012 Enterprise Edition that runs daily to check index fragmentation and reorganize or rebuild the index based on the percentage of fragmentation. is_ms_shipped = 0 --Excludes any objects created as a part of SQL Server installation AND ss. Give it a go with its fully functional 30-day free trial. dm_db_index_physical_stats (NULL, NULL, NULL, NULL, NULL); GO. As a result of rebuilding an index, SQL Server also updates the statistics for the indexes that were rebuilt. This happens approx. This has a benefit. The Reorganize Index task also includes an option to compact large object data. dm_db_index_physical_stats DMV to identify the fragmentation. @LeeWalters shrink is done, and yes, due to disk issues, not possible to add drives, that's why, in addition, db is populated with blob data, so the question is more from the index fragmentation side. We want to create an index. 35. Rebuild Index. From this tab, select a SQL Server instance in the server explorer on the left and choose database (s) as a target of index operation. I still see questions about SQL Server 2000/2005 pop up on Stack Exchange. REBUILD. If you want to fully automate your SQL Server Index maintenance then I seriously recommend that you check out Michelle Ufford's stored procedure for this. It defragments the leaf level of clustered and nonclustered indexes on tables and views by physically. . The first part of this tip focuses on SQL Server Enterprise Edition to reduce the duration for index maintenance for off-line rebuilds. The guidance from Microsoft is that indexes be rebuilt if the fragmentation is over 30% and reorganized if the fragmentation is between 5 and 30%. For example, the heaviest index (clustered index and also pk) is running reorg for around 4 hours 30 min even do the. UPDATEIn this article. SQL Server 2016 (13. Check the column, avg_fragmentation_in_percent and if its greater than. Applies to: SQL Server. The index uses the main filters on the sales table from the time dimension, i. It eventually makes a Job in your server agent and then you can set a schedule or run the job manually by running this script. Hi, We have SQL Server 2005 EE 62 bit with SP3. After it completes, we can see the job was successful. You can use Ola's Index maintenance solution or Michelle Ufford's - Index Defrag Script. Right-click on the index rebuild task and click on Edit…. Example #. Rename it to the Nightly Index Maintenance job. 2. DBCC DBREINDEX rebuilds an index for a table or all indexes defined for a table. 3. Depending on how many rows actually fit on the page, your mileage may vary. The Reorganize Index task reorganizes all indexes, regardless of fragmentation level. Script to reorganize all indexes on all tables in user databases. To rebuild or reorganize indexes manually, head over to the Fragmentation tab. インデックスの断片化の状態がわかったら、それによってインデックス (index) を再構成 (Reorganize)するか、または再構築 (Rebuild) するか決定します。. Rebuilding basically creates an entirely new copy of the index, and is much more effective at reducing fragmentation - but this comes at a cost, both in terms of time and disk space. An index reorganize can be interrupted and the worst that will happen is that a single page move operation is rolled back. This is typically how indexes with page level locking disabled get created. This method can help when Change_tracking is Auto. TEST REORGANIZE We get our open delta store again, which will cause locking. Less than 10% - then do nothing; between 10% and 30% - then do a reorg; more than 30% - then rebuild them. New. Index rebuilds (not index reorganise) always do a fullscan update of the statistics. Recall the paper example from above: a rebuild would be like reprinting the document in the correct order and trashing the old ones. The performance benefit may not be noticeable for indexes that are used primarily for seek operations. SQL Server Rebuild. To fix the fragmentation either rebuild or reorganize the index on the table. The script for the index itself: ALTER TABLE [dbo]. MSDB is utilized by database mail, sql. I suspect the reorganize is compacting the index after the rebuild and thus moving quite a bit of data around. We use SQL Server Index Rebuild and Reorganize operation to remove fragmentation level of the indexes. Rebuilding your indexes will generate a lot of unused allocated space in the data file. This operation is always online, uses minimal system resources, honors the fill factor that has been used during the creation of the index (common misconception is that reorganize operation does not take into account. Unlike REORGANIZE on user tables, REORGANIZE on a queue is always performed as an offline operation because page level locks are explicitly disabled on queues. Obviously this isn't the same as index reorganize, so I'm still trying to think what does reorganize file technically mean. In this one case, it happens to make the query. Reorganizing the indexes will take less time, and less effort from the SQL server thus they can be done in a weeknight type of instances. Right-click the index that you want to rebuild online and select Properties. I'm able to rebuild all other indexes with online=on option and it won't affect performance. If an index contains less than 100 pages, I will perform no maintenance. line is helpful to give the user some indication of what indexes it is rebuilding and how far it has progressed. Sc (Comp Sci). Highly fragmented, the application performs well. if the index has: less than 5% logical fragmentation, don’t do anything. But the index is updating itself properly. Applies to: SQL Server SSIS Integration Runtime in Azure Data Factory The Rebuild Index task rebuilds indexes in SQL Server database tables and views. For a turnkey solution, you may refer to Microsoft MVP Ola Hallengren's SQL Server Index and Statistics Maintenance. As you've seen, shrinking your database causes high levels of index. The reason why too many page splits can decrease the performance of SQL Server is because of the large number of I/O operations. Select the Compact large object column data check box to specify that all pages that contain large object (LOB) data are also compacted. In this article. In this case you can perform index reorganize and index rebuild operations only on those partitions that really need it, thus making it more efficient by reducing the time and resources needed for this maintenance. 2) Extra disk space required during SQL Server online index rebuilds. Regards. You should REBUILD indexes every weekend, UPDATE STATISTICS every night. This will obviously alleviate both internal and external fragmentation but is a more heavy weight operation and by default causes the index to go offline, although it can be performed as an online operation, depending on your SQL. This script has been tested and will work with SQL Server 2005, SQL Server 2008, SQL Server 2008R2, SQL Server 2012, SQL Server 2014, SQL Server 2016, SQL Server 2017 and SQL Server 2019. May be index was not there, may be you were just rebuilding the index. The equivalent statistics update can be achieved by: UPDATE STATISTICS . Expand the Indexes folder. He has the best practices coded into his scripts, so it should serve you well. Reorganizing an index uses minimal system resources and is an online operation. This is larger than the minimum row size. It defragments the leaf level of clustered and nonclustered indexes on tables and views by physically reordering the leaf-level pages to match the logical, left to right, order of the leaf nodes. Which is the best method to reorganize sql server database. USE AdventureWorks; GO ALTER INDEX ALL ON Production. Solution. The first and most popular method is to rebuild indexes. Edit 2: Nikita added a good point on moving the data to a different filegroup as an option to exporting it outside SQL Server. The discussion of columnstore indexes thus far has focused on clustered columnstore indexes that target a primarily OLAP workload. No right from SQL Server 7. Bug in Rebuild on SQL Server 2016 and above? 6. Compaction is based on the existing fill factor value. Since we are facing huge performance problem we have scheduled this Rebuild index task. If you prefer table lock, REBIULD is. Requires ALTER permission on the table or view. When you rebuild, SQL creates a new fresh index. Rebuild Indexes. This procedure automatically chooses whether to rebuild or reorganize an index according to its fragmentation level, amongst other parameters, and update statistics. On a small table just leave it alone. The default value for this parameter will be ‘CATALOG’. Enable Row Level and Page Level Locks. Sorted by: 1. One thing to ask! When I reorganize MSDB. The fi rst factor is whether you have SQL Server Standard Edition or SQL Server Enterprise Edition. dm_db_index_physical_stats in a script to rebuild or reorganize indexes). REORGANIZE, UPDATE STATISTICS and a simple SELECT statement. To reorganize index SQL Server, right-click it & choose Reorganize. I am a new DBA to a SQL 2005 production Report server. Shrinking is a wasteful operation. > 30% ALTER INDEX REBUILD WITH (ONLINE = ON)*. Also, in earlier versions the granularity of control was less refined. Sorry No idea why this happened. 1 Answer. Working this way is usually optimal, since SQL Server does not have to update the NCIs while the data is being imported. A table may only have one columnstore index on it at a time, regardless of whether it is clustered or nonclustered. Reorganize Index. #969726. dm_db_index_physical_stats system dynamic management function which returns a list of indexes created on SQL Server instance with enough information for a database admin to decide if the sql index is fragmented or not. Here’s how you can rebuild or reorganize fragmented indexes:-- Rebuild index to reduce fragmentation ALTER INDEX [YourIndexName] ON [YourTableName]. SQL Server index fragmentation is unavoidable, but you can minimize the negative effects of fragmentation on database performance. The index it is running against is 78% fragmented. This is because the Rebuild Index task will destroy all the indexes and build it again from scratch, without considering the fragmentation percentage. Large objects (LOBs) are stored in different "pages". dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, NULL) indexstats INNER JOIN sys. 2,057 11 22. Er…. It has an IF condition for the Reorganize but i don't need it, i need to modify the code so it queries indexes of a certain database and schema and rebuilds only if the fragmentation is bigger than 5%. Because of this, and also the fact that in such a small index that fragmentation is typically negligable, you really should only be rebuilding indexes with a certain page threshold. From sys. MS advises using Reorganize for 30% fragmentation or less. @LeeWalters shrink is done, and yes, due to disk issues, not possible to add drives, that's why, in addition, db is populated with blob data, so the question is more from the index fragmentation side. If we have 10-30% fragmentation a REORGANIZE is performed, and a REBUILD is performed when we have greater than 30% fragmentation. Exclusive page locks are taken on individual pages only while those pages are being manipulated. This topic describes how to reorganize or rebuild a fragmented index in SQL Server 2017 by using SQL Server Management Studio or Transact-SQL. Mohamad Mahmoud Darwish. – variable. It is used when the operation takes a. The rebuild can be resumed later after the previously completed partition number. DROP INDEX when. ”. The first rebuilds a single index on a table and the second rebuilds all the indexes on the table. One can also reorganize an index using. -Search all indexes of a table that have 5% or more of fragmentation and page_count >= 1000. Cancelling / Stopping ALTER INDEX REORGANIZE. To rebuild use: ALTER INDEX __NAME_OF_INDEX__ ON __NAME_OF_TABLE__ REBUILD. : 15% com. If you cancel a rebuild operation midway, it. There is all reason to only rebuild index that are fragmented, and a good maintenance. Index fragmentation problem after disabling page-level locking for an Index. configurations setting for fill factor. Does it mean reorganize the file contents maybe. Indexes are created on columns in tables or views and provide a quick way to look up data based on the values of those columns. From this tab, select a SQL Server instance in the server explorer on the left and choose database (s) as a target of index operation. . So I ran reorganize indexes and that took care of the fragmentation problem. This is a best practice for performance when you rebuild or reorganize indexes. x) and in Azure SQL Database, we recommend using ALTER. [Test] REBUILD WITH (ONLINE = ON); Additionally, I would only rebuild indexes which require it. You can query the sys. SQL Server ALTER INDEX Syntax. Expand the table on which you want to reorganize an index. Additionally, after reorganizing indexes it is reasonable to update the statistics as this operation does not update the statistics like the index rebuild operation. Sc (Comp Sci). Index rebuilding and reorganizing are the two methods to maintain indexes and improve database performance. Mohamad Mahmoud Darwish. Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance When you perform online index operations, the following guidelines apply: Clustered indexes must be created, rebuilt, or dropped offline when the underlying table contains the following large object (LOB) data types: image, ntext, and text. dm_db_index_physical_stats function is avg. When you reorganize the index, you go through the existing index, cleaning up blocks for deleted records etc. Right-click on Maintenance Plans and select New Maintenance Plan…. Index Rebuild : This process drops the existing Index and Recreates the index. So let’s take one thing at a time. It reorgs indexes when fragmentation is below 30% else it rebuild the index. Designing the SQL Server Reorganize Index Task. File type (Data), group (PRIMARY) Name () Shrink Action = reorganize pages (=move to front), Shrink File *. Index should be reorganized when index fragmentation is between 10% to 40%. SQL Server 2019 adds resumable online index creation, and it’s pretty spiffy: 1. ALTER INDEX index_name ON table_name REBUILD -- REORGANIZE. So, whenever I need to rebuild the indexes of my OrdersItemstable, with some millions of rows, my customers can't create/edit new orders for about 2-4 minutes. Both create/rebuild of columnstore index is an OFFLINE operation at this time but you can defragment columnstore index ONLINE. ALTER INDEX ALL ON Adventureworks. I am not sure I am picturing this correctly. Hallengren website has an option to reorganize indexes say with 5% Fragmentation, and rebuild for 30% Fragmentation. For example, the heaviest index (clustered index and also pk) is running reorg for around 4 hours 30 min even do the index was. This tool provides index analysis to manage index defragmentation, including rebuild and reorganize fragmented indexes . 3) SQL Server locks acquired with SQL Server online index rebuilds. A clustered index exists, along with 3 non-clustered indexes. Thanks, I will try this next time. This blog entry I came across a while back will explain it much better than I can. You could also refer another query which may be helpful to you. I used the sp_who2 procedure to see which queries were waiting, and which other query they were blocked by. To execute our task, we can right-click on the plan and choose Execute. Failing that (ie Standard Edition etc), look at re-organizing indexes - these will keep them online. Next the New Job window will open. If you're looking for whenif the index was ever rebuilt, the Ola sp does have the ability to log to a table and the previous DBA hopefully utilized this feature. I'm able to rebuild all other indexes with online=on option and it won't affect performance. e. We will use 3 statements in order to show the blocking: ALTER INDEX. 000 rows. Rebuilding your indexes will slow queries down. 5. Sumanta Roy (5/26/2011) Select Name as IndexName, STATS_DATE ( object_id , index_id ) as IndexCreatedDate. 1. Identify and remove index fragmentation – this is obviously what we have been talking until now and the biggest part of the SQL index maintenance. The best practice recommendation is to reorganize your index if you have 5-30% of fragmentation, and only rebuild it if it has more than 30% fragmentation. Add a comment. The possibility to. Use the ReorganizeIndex Task dialog to move index pages into a more efficient search order. Expand the Management folder. ALTER INDEX TableDetails_UK0 ON TableDetails REBUILD WITH ( PAD_INDEX=OFF, SORT_IN_TEMPDB=ON. Provide the appropriate name of the maintenance plan. If rate of Index fragmentation increased then index de-fragmentation is become required. . It is compatible with all versions of SQL Server 2005 , 2008 , 2012 , 2014 and 2016. Index rebuilding process uses more CPU and it locks the database resources. Applies to: SQL Server. Correct way of maintenance of SQLServer Cluster Columnstore Index. Reorganizing is designed to remove logical fragmentation from the leaf level of an index while keeping the index online and as available as possible. . Create an agent WMI alert ('Reorganize Relief Valve') on a performance condition. Yes it will - but only to a certain degree. Right-click the Indexes folder and select Reorganize All. The Microsoft Docs page for SQL Server statistics states: Operations such as rebuilding, defragmenting, or reorganizing an index do not change the distribution of data. If the older date partitions are pretty static , you might benefit from partition level index rebuild / reorganize, depending on sql server version. REORGANIZE seems to work as well as REBUILD all the time. Reorganize or rebuild an index SQL Server Management Studio. in this instance you can avoid re-inventing the wheel by making use of sql-server-index-and-statistics-maintenance – Stu. Starting with SQL Server 2016 (13. Particularly if you are in full recovery. Proceed to the Steps tab: Clicking on New. dm_os_performance_counters where counter_name = 'page splits/sec'. SQL Server Index Rebuild and Reorganize Script. You can slow down fragmentation by using a fill factor < 100. These scripts are widely tested in the community and are much flexible so that you can. Select the server connection to use when performing this task. Hi, The widely used thresholds are: Reorganize if fragmentation is between 10-30%. Bad internal fragmentation (having lots of free space on the pages) means the index is bigger than it needs to be. The MSDN page says this about reorganizing and rebuilding indexes: The SQL Server Database Engine automatically maintains indexes whenever insert, update, or delete operations are made to the underlying data. I am getting confused with choosing Index Reorganize/Rebuilding of indexes based on avg_fragmentation_in_percent returned by sys. Reorganizing or rebuilding a cluster index does not have any impact on the non-cluster indexes in SQL Server 2000 SP4 or above, or any version of SQL 2005 or. We need to set these parameters for the job IndexOptimize - USER_DATABASES: @UpdateStatistics = 'ALL'. This caused the system to reorganize or rebuild. This had a negligible impact. But commit your whole transaction before reorganize. By default, SQL Server uses a 100% fillfactor and tries to fill up all the pages in indexes as close to full as it can. It checks the SQL Server licences, if Enterprise it will rebuild the index online else it. The transaction log backup size spikes during index reorganize - exponentially bigger. Firstly you should take into account the page_count of the index. This to me would be a sign that constant rebuilds of that index actually aren't a good help. [MyHugeTable] ADD CONSTRAINT [MyHugeTable_pk] PRIMARY KEY. : 15% com. It will have a parameter called @MaintenanceMode that can be set to either ‘INDEX’ or ‘CATALOG’ in order to choose the way we want to maintain our Full-Text indexes. It gives you better advantage when tempdb is. A page is a small section of a database, typically an 8kb chunk. It drops index entirely and creates it from scratch. reorganize pages. 2) Extra disk space required during SQL Server online index rebuilds. REORGANIZE seems to work as well as REBUILD all the time. ApexSQL Defrag tool is a 3 rd party SQL index defragmentation tool that you can easily use to perform number of operations related to the SQL Server indexes. Online rebuilds are online available on the Enterprise version of SQL Server and your version probably isn't, so just set the operation not to be run "Online" on you Wizard. Right-click the Maintenance Plans folder and select New Maintenance Plan. If the command that's running is a reorg, you can just kill it. For now, I have just turned off the weekly index reorganize task which is not really a good long term solution. Click OK. Rebuild and Reorganize Index using SQL Server Management Studio (SSMS) Find and expand the table in Object Explorer >> Open Indexes >> Right-click on the target index >> Rebuild or Reorganize. ALTER INDEX ALL ON [dbo]. SELECT * FROM sys. A nonclustered columnstore. Create a execute sql task and schedule it through sql agent . This schema modification lock blocks all other concurrent access to the table, but it is only held for a very short period of time while the old index is dropped and the statistics updated. When you. Index should be rebuild when index fragmentation is great than 40%. Reorganize (SQL Server indexes, primary keys, and unique keys) The Reorganize Indexes dialog lets you reorganize an entire index, primary key, or unique key or a single partition of that object. Reorganizing an index uses minimal system resources. In this case Reorganize option is selected: DBCC DBREINDEX rebuilds an index for a table or all indexes defined for a table. The. These tables are updated daily. With the following command:. ". The scripts has some cool features like. This might be a good time to stop blindly rebuilding indexes. You can add a rebuild index task or reorganize index task into the maintenance plan, but the problem is that you can't really apply any logic to the plan. This allows you to interrupt the rebuild and preserve the work already done. The documentation is also indicating that: Online index operations are not available in every SQL Server edition. Therefore, you do not need to update statistics after performing ALTER INDEX REBUILD, DBCC DBREINDEX, DBCC INDEXDEFRAG, or ALTER INDEX REORGANIZE operations. dbForge Index Manager for SQL Server will. Which is the best method to reorganize sql server database. If the index is disabled, rebuilding brings it back to life. Expand Tables. Another possibly is that the index is being rebuilt and then re-fragmenting again. 1. 3. That can be found using the STATS_DATE function. Microsoft recommends Index Rebuild operation to defrag indexes if the fragmentation level of your index is greater. Reorganize a fragmented SQL Server index and optimize performance. Copied the LOB column to another table, dropped the column, re-created the column, and copied the data back (as outlined in this post: Freeing Unused Space SQL Server Table). Executing this query requires the VIEW SERVER STATE permission. REORGANIZE is an "online" operation, which means it doesn't take a big Sch-M lock at the beginning of the operation to have exclusive. dm_db_index_physical_stats DMV). The purpose is to reduce the size of database and increase the db performance. To create a new job, right click on SQL Server Agent, select New and then Job. A REORGANIZE physically reorders the leaf-level pages to match the logical order of the leaf nodes, whereas a REBUILD does just that, it rebuilds the index. Index Rebuild vs Index Reorganize. Larger indexes have more intermediate levels and pages. If you have a choice, then REBUILD. Update Statistics. When using columnstore indexes, the delta store may end up with multiple small row groups after inserting, updating, and. Reorgs defragment the leaf level of clustered and. Index Rebuild operation first drops and then recreates the index. An index can become fragmented over time as data is added, updated, or deleted, and this fragmentation can lead to longer query execution times and decreased performance. Expand the Tables folder. " But following the Russ's reply the REORGANIZE is a more time expensive operation the REBUILD one. The first steps of configuring the Reorganize Index task is quite similar to the Rebuild Index task. WITH (ONLINE=ON). You can apply a new fillfactor when you rebuild an index. ApexSQL Defrag is a powerful application used for scheduled analyzing and defragmenting of SQL Server database indexes. If your indexes are fragmented : If index has less than 1000 pages - do not perform any index maintenance operation. SQL Server NULL Index. We need to drag and drop tasks from the Toolbox (to open the toolbox use Ctrl + Alt + X) into the gray workspace area on the bottom as shown in the below screenshot. Updating statistics is important for query processing and optimization. In it, enter the Job name, owner, optionally Category. You can read more on rebuilding indexes here . This makes it more likely that some other session is blocked by your session, and that you may, in turn, become blocked by a lock held by that session. Less than 10% - then do nothing; between 10% and 30% - then do a reorg; more than 30% - then rebuild them. dm_db_index_physical_stats (NULL, NULL, NULL, NULL, NULL); GO. In the Rebuild Indexes dialog box, verify that the correct index is in the Indexes to be rebuilt grid and click OK. Dalam indeks rowstore, SQL Server mengimplementasikan pohon B+. T-SQL Alter Index. The second set of options, in figure 8-5, rebuilds only a single partition of a clustered columnstore index and optionally changes the compression type. Indexes play a vital role in the performance of SQL Server applications. To create a linked server to azure, you can see this SO link:I need to add a linked server to a MS Azure SQL ServerSelect “reorganize index” and “rebuild index. TRUNCATEONLY is applied which prevents the SQL server from performing any data reorganising. dm_tran_database_transactions DMV:This offline index rebuild could be done at the table or the partition level. Depending on the fragmentation level, you need to rebuild or reorganize the indexes. Similarly, removing. Object: SQLServer:Databases; Counter: Percent Log Used ; Instance: (your big database name) Alert if counter rises above: 80; Response: Execute job ('Reorganize Check') Create a job ('Reorganize Check')In this article. A few thing to consider: Can you insert the data in the order of the index? This will reduce fragmentation. You can also change this threshold via parameters. Right-click the Maintenance Plans folder and select Maintenance Plan Wizard. Select Maximum degree of parallelism, and then enter some value between 1. This blog entry I came across a while back will explain it much better than I can. Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) Poorly designed indexes and a lack of indexes are primary sources of database application bottlenecks. Select * from sys. Microsoft best practice says that you should generally not do a rebuild operation unless fragmentation is over 30%. On this MSDN Page it says if you should reorganize or rebuild based on the amount of fragmentation:. Yes, rebuilding indexes will take a toll on your transaction log file. The SQL Server Maintenance Plan reindex task is unintelligent, and will do a full rebuild on every index whether it needs it or not. It should be: TRUNCATE; Insert ; ALTER INDEX REBUILD; It might stil be slow, but at least you get sharp indexes. Basically, rebuilding is a total rebuild of an index - it will build a new index, then drop the existing one, whereas reorganising it will simply, well. Sc (Comp Sci) SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability. – The scripts has some cool features like.