Muokkaa

Jaa

Server configuration: query wait

  • Artikkeli

Applies to: SQL Server

This article describes how to configure the query wait server configuration option in SQL Server by using SQL Server Management Studio or Transact-SQL. Memory-intensive queries (such as those involving sorting and hashing) are queued when there isn't enough memory available to run the query. The query wait option specifies the time, in seconds (from 0 through 2,147,483,647), that a query waits for resources before it times out. The default value for this option is -1. This means the time-out is calculated as 25 times the estimated query cost.

Important

A transaction that contains the waiting query might hold locks while the query waits for memory. In rare situations, it's possible for an undetectable deadlock to occur. Decreasing the query wait time lowers the probability of such deadlocks. Eventually, a waiting query will be terminated and the transaction locks released. However, increasing the maximum wait time might increase the amount of time for the query to be terminated. Changes to this option aren't recommended.

Recommendations

This option is an advanced option and should be changed only by an experienced database administrator or certified SQL Server professional.

Permissions

Execute permissions on sp_configure with no parameters or with only the first parameter are granted to all users by default. To execute sp_configure with both parameters to change a configuration option or to run the RECONFIGURE statement, a user must be granted the ALTER SETTINGS server-level permission. The ALTER SETTINGS permission is implicitly held by the sysadmin and serveradmin fixed server roles.

Use SQL Server Management Studio

  1. In Object Explorer, right-click a server and select Properties.

  2. Select the Advanced node.

  3. Under Parallelism, type the desired value for the query wait option.

Use Transact-SQL

  1. Connect to the Database Engine.

  2. From the Standard bar, select New Query.

  3. Copy and paste the following example into the query window and select Execute. This example shows how to use sp_configure to set the value of the query wait option to 7500 seconds.

    USE master;
GO

EXECUTE sp_configure 'show advanced options', 1;
GO

RECONFIGURE;
GO

EXECUTE sp_configure 'query wait', 7500;
GO

RECONFIGURE;
GO

EXECUTE sp_configure 'show advanced options', 0;
GO

RECONFIGURE;
GO

For more information, see Server configuration options.

Follow up: After you configure the query wait option

The setting takes effect immediately without restarting the server.

Related content