Sql server database engine properties, File growth, Auto create statistics – HP ProLiant DL980 G7 Server User Manual

Page 36: Auto update statistics, Auto update statistics async, Analysis services properties, Data dir, Temp dir, Log dir, Backup dir

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SQL Server Database Engine properties

File Growth

The File Growth option specifies the method of incremental allocation applied when an operating
system file is extended. Possible values are OFF, MB, or % (Percent). SQL Server files can grow
automatically from their originally specified size. When you define a file, you can specify a specific
growth increment. Every time the file is filled, it increases its size by the growth increment. If there
are multiple files in a file group, they will not automatically grow until all the files are full. Growth
then occurs in a round-robin fashion. If necessary, the tool recommends allocation of larger space
in the file and turns off automatic file growth.

Auto Create Statistics

When you enable the AUTO_CREATE_STATISTICS option, the Query Optimizer creates statistics
on individual columns used in a predicate, if these statistics are not already available. These
statistics are necessary to generate the query plan. They are created on columns that do not have
a histogram in an existing statistics object.

Auto Update Statistics

Updates query optimization statistics on a table or indexed view. By default, the query optimizer
already updates statistics as necessary to improve the query plan; in some cases, you can improve
query performance by using UPDATE STATISTICS or the stored procedure sp_updatestats to update
statistics more frequently than the default updates.

Updating statistics ensures that queries compile with up-to-date statistics. However, updating statistics
causes queries to recompile. HP recommends that you avoid updating statistics too frequently:
there is a performance trade-off between improving query plans and the time it takes to recompile
queries. The specific trade-offs depend on your application. UPDATE STATISTICS can use tempdb
to sort the sample of rows for building statistics.

Auto Update Statistics Async

When this option is enabled, the SQL Server will start updating statistics asynchronously, using a
separate background thread. Client queries will not have to wait for the process to complete, and
they can continue using the current statistics while the update is processing in background. When
the update process completes, the Query Optimizer can start using the updated statistics. This
means that until the update process is complete, the Query Optimizer will produce execution plans
based on the current/old statistics.

Analysis Services properties

Data Dir

The Data Dir property specifies where Analysis Services data is stored per server instance.

Temp Dir

The Temp Dir property specifies where Analysis Services places temporary files that it uses during
processing operations.

Log Dir

The Log Dir property specifies where Analysis Services logs and traces are stored.

Backup Dir

The Backup Dir property specifies where Analysis Services backups are stored by default.

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Using HP ESO

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