So your db need to have: data space to accomodate your new index, data space to make a sort since you used SORT_IN_TEMPDB = OFF, and it needs log to be large. How Fragmentation Hurts SQL Server Performance. You can read more on rebuilding indexes here . Merging the full-text index fragments can improve performance and free up disk and memory resources. What works for me may not work for you. before i answer your question is the database on simple recovery. If you truly want to REBUILD, and you want to do it for ALL indexes on a given table, then the command would be (straight from the official docs that npe pointed you at): For more instructions see the official docs. 2. You can drop and create indexes at will. To update all statistics in a table. line is helpful to give the user some indication of what indexes it is rebuilding and how far it has progressed. To solve this, I want to use the REORGANIZE operation every time. I think there is another way to rebuild fragmented index, You can create an sp and scheduled it via SQL Server Agent or via task scheduler. 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. Use ALTER INDEX REORGANIZE, the replacement for DBCC INDEXDEFRAG, to reorder the leaf level pages of the index in a logical order. Scale back down once the index rebuild is complete. Improve this answer. Share. SQL Server doesn’t automatically correct index fragmentation problems. Monitor and track your index usage, or lack of index usage. Jan 11 at 14:24. Just go to the table, further expand the indexing folder and right after that you can right-click on it and select the option to rebuild all the indexes. Quick explanation: An online Rebuild, rebuilds the indexes on the tempDB making it available to the queries while it is being rebuilt. Hi @Devendra Kumar Sahu , You can perform a reorg or rebuild an index based on its fragmentation values. However, recently this approach has. Expand the Tables folder. An index reorganize holds an intent-exclusive table lock throughout the operation, which will only block shared, exclusive, and schema-modification table locks. SELECT a. . Yup, that is one perfectly valid way. Our Production instance is running SQL Server 2014. I suggest 50% for REORGANIZE, 80% or even 90% for REBUILD. Index maintenance usually starts 3 hours before the database full backup and ends before the full backup start. The T-SQL script in this article can be run by SQL Server administrators to reindex and defragment WSUS databases. So far, all good. @databaseToCheck (optional) Values: - NULL: It will scan all databases with compatibility level SQL Server 2005 (90) or later for fragmented indexes. We recently switched to Ola Hallengren's maintenance script and automated the deployment of MaintenanceSolution. First it’ll try an index reorganize, which is an online operation. Mohamad Mahmoud Darwish. The nonclustered B-tree index is updated as changes occur to the columnstore index. Feb 21, 2022, 8:01 AM. Feedback. Index automation Job script. Copy and paste the following example into the query window and click Execute. Here is the image for additional clarity. I have pasted the create syntax below for. And if it is a clustered index, the entire table is copied. Rebuild or reindex ?? good question ! Analysis indexes defragmentation RATIO and decide to REORGANIZE OR REBUILD. Sorted by: 1. index rebuild/reorganize frequency. This manual operation two-step. From all the research I've done, I can't really find any indication of why you would want page fullness to be low, and am anticipating that I'll want to do an index reorganize operation to set the value to. Right-click the table on which the full-text index is defined, select Full-Text index, and on the Full-Text index context menu, select Properties. Right-click on the index and select Rebuild. The first rebuilds a single index on a table and the second rebuilds all the indexes on the table. Under Select a page, select Options. 1. Start SSMS and connect to the SQL Server database engine. Index Rebuild operation first drops and then recreates the index. The query result is matched against the full-text index. The below T-SQL statement can be used to retrieve these wait types: 1. Veritas now uses the heavily debated command DBCC SHOWCONTIG WITH ALL_INDEXES,or DBCC SHOWCONTIG WITH ALL_INDEXES,tableresults (Table results will give you a table format to read) to. You can reorganize all indexes that are defined on a table by rebuilding the index data into unfragmented, physically contiguous pages. e. Default SQL Server value is 0 or 100%, which means that no free space should be left on each page. This issue can be solved by reorganizing or rebuilding the index. Depending on the type of index and database engine version, a rebuild operation can be done online or offline. Right-click Maintenance Plan and select Execute. در این مقاله روش بهینه سازی ایندکسها با استفاده از reorganize و rebuild کردن ایندکس تکه تکه شده (Fragmented Index) با استفاده از محیط SQL Server Management Studio و Transact-SQL شرح داده خواهد شد. SQL Server 2017 includes a new system view sys. The entire index has to be read to. Reorganize Index. The performance benefit may not be noticeable for indexes that are used primarily for seek operations. SQL Server development version and Enterprise version has option ONLINE, which can be turned on when Index is rebuilt. The equivalent statistics update can be achieved by: UPDATE STATISTICS . However, reorganizing can be a "more online" operation and is sometimes preferred, even for. 2. Select the Compact large object column data checkbox to specify that all pages that contain large object (LOB) data are also compacted. Summary: SharePoint Server uses SQL Server to store most of the content for the Web site and configuration settings. I have been advised by a contracted SQL Server expert that, after any change in # of CPUs and/or available memory, I should reorganize all indexes and then update all statistics or SQL Server will not make the full use of the new resources. The following index operations require no additional disk space: ALTER INDEX REORGANIZE; however, log space is required. Doing so will: Eliminate all data in the deltastore. Is this possible to do? In earlier versions of Microsoft SQL Server it could cause system slowdown to reorganize or rebuild a large index. 7. To create a new job, right click on SQL Server Agent, select New and then Job. However, sometimes you don't want this, say for read only tables or huge tables. 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. All indexes will be inserted to, updated to, or deleted from for every respective DML statement. (About 1 TB of data including myIndex (non. One common and widely used example is SQL Fool's scriptYes. Also, running UPDATE STATISTICS gets you both index and columns stats updates. dm_db_index_physical_stats fincation have index_id which display heap and index informatiob. Each night the maintenance plan is successful, but these commands take the longest to execute 3 hours, 3 hours and 5 hours respectivelly. Index Rebuild vs Index Reorganize. Microsoft's guidance on index reorganize and rebuild supports this: For example, if a given index is used mainly for scan operations, removing fragmentation can improve performance of these operations. Rebuild or Reorganize SQL Index. Someone else set it up. indexesのindex_id）または1、0、-1、-2のいずれか指定できます。 -1は、テーブルに関連するすべてのタイプのページ（行内データ、ローオーバーフローデータ、IAM、すべてのインデックス）についての完全な. Stack Exchange Network. Sorry No idea why this happened. The rebuild command will defragment all those intermediate pages. Please refer to SQL Server Maintenance Plan Reorganize Index and Update Statistics Tasks to get more information about how to design the maintenance plan. Defining "Index Stats Options" as well has become available in SSMS. ALTER INDEX [PK_SalesOrderDetailEnlarged_SalesOrderID_SalesOrderDetailID] ON [Sales]. This tool provides index analysis to manage index defragmentation, including rebuild and reorganize fragmented indexes . A more intelligent way is to check fragmentation first then rebuild or reorganise. After rebuilding all indexes, some queries seem to take forever for at least two queries/tables. Categorize fragmentation percentage – Microsoft suggests that we. Follow. Rebuild/Reorganize working fine. Check the column, avg_fragmentation_in_percent and if its greater than. An index rebuild will always build a new index, even if there’s no fragmentation. I suggest 50% for REORGANIZE, 80% or even 90% for REBUILD. dm_db_index_physical_stats DMV to identify the fragmentation. To create a new maintenance plan, right click on Maintenance Plan and select New Maintenance Plan and the following window will open. We need to set these parameters for the job IndexOptimize - USER_DATABASES: @UpdateStatistics = 'ALL'. Right-click the table on which you want to specify an index's fill factor and select Design. To add to this, you need to learn your system and how it's used. Create an agent WMI alert ('Reorganize Relief Valve') on a performance condition. Hi, Added an index maintenance job (Hallengren) to a database (SQL Server 2016) with a few large tables. name AS IndexName, indexstats. Locking. If the tables get more than 15% fragmented, performance is very negatively affected. When you reorganize an index, SQL Server physically reorders the leaf-level pages to match the logical order of the leaf nodes. #1258597. That can be found using the STATS_DATE function. August 21, 2010 at 11:54 pm. Copy and paste the following example into the query window and select Execute. If you want to know how far along it is, open up another instance of SSMS and connect to the server, then run a query against the sys. つまり、断片化率がある一定の閾値を超えた場合は再構築（REBUILD）、そうでない場合は再構成（REORGANIZE）を推奨する、というものです。 ただし、再構築をオンラインで実行するためにはSQL ServerのエディションがEnterpriseでなければいけません。 Identify and remove index fragmentation – this is obviously what we have been talking until now and the biggest part of the SQL index maintenance. On large tables, that may be a while and not frequent enough. 2. Workaround. No – alter index rebuild or reorganize. Find and remove unused indexes – everything that is unused doesn’t do anything good. Reorganizing an index uses minimal system resources and is an online operation. Since you issued a REBUILD and not a REORG, cancelling the query will result in a rollback which will take even more time. Usually, you should rebuild the index if it has a fragmentation greater than 30% and reorganize it if it has less than 30% fragmentation. In SQL Server, when rebuilding an index which previously had statistics updated with PERSIST_SAMPLE_PERCENT, the persisted sample percent is reset back to default. There are two options to fix fragmentation. index optimization job failed from the last 4 days. 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. This caused the system to reorganize or rebuild some indexes even. Coming to update stats, I would prefer to do it with Full Scan depending on the size of the databases. To create SQL Server agent that will defragment specified indexes automatically, perform the following steps: Expand SQL Server Agent in Object explorer, right click on Jobs, and select New Job…: In General tab, specify the name and description for the job. There is all reason to only rebuild index that are fragmented, and a good maintenance. Reorganize or rebuild an index SQL Server Management Studio. Expand Databases, and then expand the database that contains the full-text index. 2. As with a B-tree index, the rebuild will create a brand new columnstore index from the underlying data. If you use Ola Hallegren's scripts then you can set the thresholds for a rebuild/reorganise (say over 50% fragmentation for a reorganise, over 80% for a rebuild) and this can run overnight out of hours. 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 ServerSQL Server 2016, that comes with many new features and enhancements to the existing features, bring new enhancements to a number of SQL Server Maintenance Plans tasks including the indexes Rebuilding and Reorganizing tasks, in addition to the Check Database Integrity tasks. In it, enter the Job name, owner, optionally Category. Expand the table on which you want to reorganize an index. deteriorating. I don't remember if IDENTITY INSERT ON will help. DROP INDEX when you are dropping a nonclustered index. And if the reorganize is a deadlock. For general guidance regarding index fragmentation, when fragmentation is between 5% and 30%, reorganize the index. Also, up to SQL Server 2008 R2, you could not perform online rebuild on Large Object (LOB) data: varchar(max), nvarchar(max), varbinary(max), or XML. table-name must be used. The log size shouldn't be unrestricted. Hallengren website has an option to reorganize indexes say with 5% Fragmentation, and rebuild for 30% Fragmentation. index_type_desc AS IndexType, indexstats. We are aware that we. 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. -- for SQL Server 2008 and up SELECT OBJECT_NAME([table_id]) AS TableName, COUNT([fragment_id]) AS Fragments FROM sys. Checking the reorganize files box and as a result, shrinking the database file(s) will only impact the database negatively. Otherwise you're holding an exclusive lock on the table/partition before you start the reorganize. Right-click the index for which you want to set the max degree of parallelism and select Properties. indexes ind ON ind. x) implemented major performance improvements for these index operations. 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%. When you rebuild indexes Offline, the operation acquires a Schema modification (Sch-M) lock on the table. 000 rows. Create SQL Server Columnstore Non-Clustered Index. fulltext_index_fragments GROUP BY OBJECT_NAME([table_id]) HAVING COUNT([fragment_id]) >=30 Also,. When the catalog reorganize is occurring the users will still be able to query the full text data?. we have 5 databases in our instance, in that 2 databases are online and remaining are in offline. index_resumable_operations to monitor and check the current execution status for resumable index rebuilds. Select Maximum degree of parallelism, and then enter some value between 1 and 64. Well, I’d wager some of it is backwards compatibility. For now, I have just turned off the weekly index reorganize task which is not really a good long term solution. Microsoft recommends Index Rebuild operation to defrag indexes if the fragmentation level of your index is greater. x) および SQL Server 2014 (12. we are using Ola index job to rebuild and reorganize the index. Click the plus sign to expand the table on which you want to rebuild an index online. To reorganize index SQL Server, right-click it & choose Reorganize. SQL Agent doesn't connect as SA, and the rebuild index task generates a command that looks like ALTER INDEX [ci_FactInternetSales] ON [dbo]. Best regards, Carrin Cancelling / Stopping ALTER INDEX REORGANIZE. Create table and compressed index. e. 4. Many people (and even solutions) in the SQL Server community say you need to look at Index Fragmentation levels (e. All you might notice is a drop in performance executing queries while the indexes are gone but dropping and creating a (none-clustered) index has no impact whatsoever on the actual data stored in your tables (Creating a clustered index impacts the physical ordering of your data but again, no data. Dec 19, 2021, 9:55 PM. 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. You can read more on rebuilding indexes here . This index design guide contains information on index architecture, and best practices to help you design effective indexes to meet the needs of. Rebuilding an index drops and re-creates the index. Artemakis Artemiou. Index Rebuild vs Index Reorganize. If the index’s design doesn’t allow for that, IndexOptimize will try to rebuild the index online. Right-click Maintenance Plan and select Execute. You also can create a linked server to SQLAZURE and create a sql agent job. The REORGANIZE modifier for ALTER INDEX is not currently supported by Azure SQL. 1. Your could find your indexes are 95% plus fragmented, affecting query performance badly. Index should be rebuild when index fragmentation is great than 40%. This means that for a lightly fragmented index (e. Use Ola Hallengren ‘s IndexOptimize but don’t use his defaults. SQL Server Magazine just tweeted about their latest article, a. This procedure automatically chooses whether to rebuild or reorganize an index according to its fragmentation level, among other parameters, and update statistics with a linear threshold. I have tried reorganize, rebuild and even tried dropping them and creating again. If you read complete article it was trying to point out the commands or operations in SQL Server which would require additional disk space and others that would not. I have configured Ola Hallengren's backup and integrity check scripts. 4) Move database back to full recovery mode. 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. To create SQL database maintenance plan, launch SQL Server Management Studio > expand the database instance > Management > right-click on the maintenance plan > New Maintenance Plan. Here’s how: Download the MaintenanceSolution. SQL. Correct way of maintenance of SQLServer Cluster Columnstore Index. You can use sys. There needs to be an automated Index defragmentation job that will either reorganize or rebuild the indexes based on the fragmentation level for a specific table in a specific database. USE AdventureWorks; GO ALTER INDEX ALL ON Production. The Full-Text Engine compiles and executes full-text queries. The table can be in a local or a remote database. For a table with an ordered clustered columnstore index, ALTER. Too many full-text index fragments in the full-text index, can lead to substantial degradation in query performance. Click OK. If you what you are saying is true, even reorganizing the indexes that have never been, may cause a larger impact on the server as well. SQL Server ALTER INDEX Syntax. Disk space is an important consideration when you create, rebuild, or drop indexes. 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. The documentation is also indicating that: Online index operations are not available in every SQL Server edition. line is helpful to give the user some indication of what indexes it is rebuilding and how far it has progressed. I don't remember if IDENTITY INSERT ON will help. He has the best practices coded into his scripts, so it should serve you well. Under the very wrong assumption that it wouldn't take long, I've ran ALTER INDEX ALL ON OUR_BIGGEST_TABLE REORGANIZE;. [CCS-KIDS1] GO. 2. SQL Server Tools. 10/28/2022. The database is using the Simple Recovery model. ALTER INDEX __NAME_OF_INDEX__ ON __NAME_OF_TABLE__ REBUILD. For more information, see CREATE INDEX (Transact-SQL). REORGANIZE INDEX blocks other queries. The performance of large WSUS deployments will degrade over time if the WSUS database isn't maintained properly. The only. Right-click the Maintenance Plans folder and select New Maintenance Plan. Applies to: SQL Server 2016 (13. REBUILD will not just rebuild index, but also force update of corresponding statistics. If the index’s design or your SQL Server edition doesn’t allow for that, it’ll perform the last resort – an offline index rebuild. Index Rebuild : This process drops the existing Index and Recreates the index. Here's another script to add to the list. I have many DBs that are currently used for insert and delete. May 5, 2010 at 8:00 am. Bad internal fragmentation (having lots of free space on the pages) means the index is bigger than it needs to be. All they do is waste space and resources. You can query the sys. ALTER INDEX index_name ON table_name REORGANIZE OR. All nonclustered indexes will include the clustered key by default, in order to perform lookups when necessary. To create a new job, right click on SQL Server Agent, select New and then Job. It drops index entirely and creates it from scratch. [Product] SET ( ALLOW_PAGE_LOCKS = ON ) ALTER INDEX [PK_Product] ON [Production]. Depending on database and indexes size it will grow. ". Reorganize the data on the data and index pages by rebuilding indexes with a new fill factor. Fragmentation. 1. It reorgs indexes when fragmentation is below 30% else it rebuild the index. This is a powerful feature that you can use to your advantage. Expand the Indexes folder. These are two different modes to remove index fragmentation. Default SQL Server value is 0 or 100%, which means that no free space should be left on each page. There needs to be an automated Index defragmentation job that will either reorganize or rebuild the indexes based on the fragmentation level for a specific table in a specific database. Here is a simple query to check fragmentation on your existing indexes:1 Answer. You can use WAIT_AT_LOW_PRIORITY time keyword along with online rebuild process and it will automatically abort the rebuilding process for. Resolution: Reorganize and rebuild indexes. in case you aren't on SQL enterprise edition, you cannot rebuild WITH ONLINE, hence you can cause additional blocking; ad. Reorganizing an index only deals with the fragmentation that exists, and the more fragmentation there is, the longer a reorganize will take. Large object data is data with the image, text, ntext, varchar (max), nvarchar (max), varbinary (max), or xml data type. Spatial Index. 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. On a data partitioned table, you can reorganize a specific nonpartitioned index on a partitioned table, or you can reorganize all the partitioned. Also, in earlier versions the granularity of control was less refined. If you what you are saying is true, even reorganizing the indexes that have never been, may. Are you seeing problems related to statistics? Or is this just. sql script from Ola’s website and open it up in a query window inside of SSMS. Product REBUILD GO Index Reorganize : This process physically reorganizes the leaf nodes of the index. EventID, MAX (b. Reorganizing also compacts the index pages. Instead of our phone book having 1,000 pages that are 100% full, we might have 1100 pages that are only 90% full. First, we will start the index reorganization in a session using the following T-SQL code. We are using clustered columnstore index in SqlServer 2016 for 400M rows. I'm just using the reorg index task that is in the maintenance plan designer GUI. In this article. When you reorganize the index, you go through the existing index, cleaning up blocks for deleted records etc. This index uses column-based data storage and query processing to achieve gains up to 10. And if it is a clustered index, the entire table is copied. The script uses the following parameters: @reportOnly (required) Values: - 0: The script will reorganize or rebuild the fragmented indexes. You need to do more research but basically, reorganize as often as needed to keep your fragmentation under 20-30% until you can rebuild it during off-hours. This means every time we need to scan the. Article. Applies to: SQL Server. For information about how to maintenance index, refer to MS document. m. You have to do some research and tailoring of how and when to do it based on your environment, though. Click the plus sign to expand the Tables folder. dm_exec_requests to see how much longer your query has to finish. SQL Server index fragmentation is unavoidable, but you can minimize the negative effects of fragmentation on database performance. It checks the SQL Server licences, if Enterprise it will rebuild the index online else it. The import process should be reworked to bulk-load one table at a time. There are two main ways to defragment a Heap Table: Create a Clustered Index and then drop it. To estimate the duration of the REORGANIZE DATABASE you can use the SQL statement from the "Step 1" section in the attached "REORGANIZE estimator" . dm_db_index_physical_stats DMV). My predecessor created a Maintenance Plan with 4 tasks: CHECKDB; SHRINKDATABASE (N'DB1',10,TRUNCATEONLY); it seems to be running a REORGANIZE on all Indexes for all Tables and Views and "Compact Large Objects" is checked; and then it UPDATE. To reorganize index SQL Server, right-click it & choose Reorganize. The default value for this parameter will be ‘CATALOG’. In the New Maintenance Plan dialog box, in the Name box, type a name for the plan and select OK. Rebuild if > 30%. The first and most popular method is to rebuild indexes. A probable cause is that the changed (presumably reduced) size of the structures after rebuilding means the optimizer is choosing a different plan. [myTable] REORGANIZE WITH ( LOB_COMPACTION = ON ) I have the above query running for 16 days (still running), the table is a dummy table used for benchmark tests, it has over 10 Billion rows. 2 contributors. We don't want to run index optimization on multiple databases at the same time The code uses stored procedure dbo. 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. In SQL Server, when rebuilding an index which previously had statistics updated with PERSIST_SAMPLE_PERCENT, the persisted sample percent is reset back to default. SSC Guru. I will let you know if it worked. Both versions allow you to specify the. This opens the Full-text. I'd just add that adding the line PRINT @sql after the SET @sql =. Reorganizing Indexes. Depending on INSERT, UPDATE and DELETE activity against your tables, your physical data can become very fragmented. Index Reorganize During Database Full Backup. dm_db_index_physical_stats(DB_ID(), NULL, NULL, NULL, NULL) indexstats INNER JOIN sys. Although this option increases the amount of temporary disk space that is used to create an index, the. The Reorganize Index task also includes an option to compact large object data. Reorganizing an index uses minimal system resources. The reason given is that the indexes and statistics are partly based on available CPU and memory resources. dm_db_index_physical_stats ‘ Dynamic Management View (DMV). You can safely stop it but you need to find out why your database became slow. less than 30% fragmentation), it’s generally faster to reorganize the index, but for a more heavily fragmented index, it’s generally faster to just. – As well as maintenance plans, SQL Server Agent jobs are also a handy way to automate and schedule index defragmentation jobs in SQL Server. You can apply a new fillfactor when you rebuild an index. 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. RESUMABLE = ON means you can pause. Maintain Index and Column StatisticsAs people have mentioned here, your indexes do not automatically rebuild. 1. Applies to: SQL Server. This procedure automatically chooses whether to rebuild or reorganize an index according to its fragmentation level, amongst other parameters, and update statistics. 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. the year and month columns. Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance Azure Synapse Analytics Analytics Platform System (PDW) Columnstore indexes are the standard for storing and querying large data warehousing fact tables. Beginning with SQL Server 2016 (13. We would like to show you a description here but the site won’t allow us. Reorganizing an index uses minimal system resources. @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. When you rebuild, SQL creates a new fresh index. Instead of our phone book having 1,000 pages that are 100% full, we might have 1100 pages that are only 90% full. Additionally, after reorganizing indexes it is reasonable to update the statistics as this operation does not update the statistics like the index rebuild operation. However, my SQL Server license is Standard and I can't rebuild indexes online. SELECT OBJECT_NAME(ind. Unlike DBCC INDEXDEFRAG, or ALTER INDEX with the REORGANIZE option, DBCC DBREINDEX is an offline operation.