SQL Server creates index statistics

Excerpt from: http://www.cnblogs.com/kerrycode/p/3337817.html

There are three parameters related to database statistics :

Automatically create statistics (auto create Statistics), auto UPDATE statistics (auto update Statistics), Automatic Update statistics automatically (auto update Statistics asynchronously), are database-level.

Recommendation : Automatically create statistics and auto update STATISTICS is set to True, automatic asynchronous update statistics is set to false.

You can see these three parameters by setting it in Enterprise Manager, selecting the database you want to modify, clicking the right-click option "Properties" and selecting "Options" on the left.

Reconstruction:

Index statistics need to be rebuilt periodically, in many ways, such as: DBCC DBREINDEX (' table name ')

The reconstructed effect can be viewed in the following ways: DBCC SHOWCONTIG (' table name ')

Before rebuilding:

A TABLE-level scan has been performed.

-Number of pages ...........: 24........ £ º
-Number of scan zones ............: 3.......
-Zone switching times ...........: 2....... £ º
-The average number of pages in each area ....: 8.0 ...... £ º..
-Scan density [best count: Actual Count] ...: 30%
-Logical scan fragment ....: 0%-----...
-area Scan fragment ....: 0%------
-The average number of bytes available per page .....: 649.7.... £ º
-Avg. page density (full) ..........: 91.97%.
DBCC execution is complete. If DBCC outputs an error message, contact your system administrator.

After rebuilding:

A TABLE-level scan has been performed.
-Number of pages ...........: 24........ £ º
-Number of scan zones ............: 3.......
-Zone switching times ...........: 2....... £ º
-The average number of pages in each area ....: 8.0 ...... £ º..
-Scan density [best count: Actual Count] ...: 100%
-Logical scan fragment ....: 0%-----...
-area Scan fragment ....: 0%------
-The average number of bytes available per page .....: 649.7.... £ º
-Avg. page density (full) ..........: 91.97%.
DBCC execution is complete. If DBCC outputs an error message, contact your system administrator.

Delete

When you delete an index, statistics are automatically deleted

SQL Server creates index statistics