query wait Option
Use the query wait option to specify the time in seconds (from 0 through 2147483647) that a query waits for resources before timing out. If the default value of -1 is used, or if –1 is specified, then the time-out is calculated as 25 times of the estimated query cost.
In Microsoft SQL Server, memory-intensive queries (such as those involving sorting and hashing) are queued when there is not enough memory available to run the query. The query times out after a set time calculated by SQL Server (25 times the estimated cost of the query) or the time specified by the nonnegative value of the query wait.
A transaction that contains the waiting query may hold locks while the query waits for memory. In rare situations, it is 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 may increase the amount of time for the query to be terminated. Changes to this option are not recommended.
The query wait option is an advanced option. If you are using the sp_configure system stored procedure to change the setting, you can change query wait only when show advanced options is set to 1. The setting takes effect immediately without a server restart.