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Home >> FAQs/Tutorials >> SQL Server FAQ
SQL Server FAQ - Defragmenting Table Indexes
By: FYIcenter.com
(Continued from previous topic...)
How To Defragment Table Indexes?
When a table index is fragmented to a certain percentage,
you need to defragment the index to maintain its performance level.
There are 3 ways to defragment:
1. "ALTER INDEX index_name ON table_name REORGANIZE"
- Defragmenting the specified index performed in online mode.
No locks applied on affected table.
Used for indexes with a small fragmentation percentage.
2. "ALTER INDEX index_name ON table_name REBUILD"
- Defragmenting the specified index performed in offline mode by default.
It can be performed in online mode.
Used for indexes with a large fragmentation percentage.
3. "CREATE INDEX ... WITH (DROP_EXISTING = ON)"
- Re-creating the specified index. The definition of the index can be changed.
(Continued on next topic...)
- What Are Indexes?
- How To Create an Index on an Existing Table?
- How To View Existing Indexes on an Given Table using SP_HELP?
- How To View Existing Indexes on an Given Table using sys.indexes?
- How To Drop Existing Indexes?
- Is the PRIMARY KEY Column of a Table an Index?
- Does the UNIQUE Constraint Create an Index?
- What Is the Difference Between Clustered and Non-Clustered Indexes?
- How To Create a Clustered Index?
- How To Create an Index for Multiple Columns?
- How To Create a Large Table with Random Data for Index Testing?
- How To Measure Performance of INSERT Statements?
- Does Index Slows Down INSERT Statements?
- Does Index Speed Up SELECT Statements?
- What Happens If You Add a New Index to Large Table?
- What Is the Impact on Other User Sessions When Creating Indexes?
- What Is Index Fragmentation?
- What Causes Index Fragmentation?
- How To Defragment Table Indexes?
- How To Defragment Indexes with ALTER INDEX ... REORGANIZE?
- How To Rebuild Indexes with ALTER INDEX ... REBUILD?
- How To Rebuild All Indexes on a Single Table?
- How To Recreate an Existing Index?
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