Statement Timeouts

The statement timeout feature allows execution of a statement to be stopped automatically when it has been running longer than a given timeout period.It gives the database administrator an instrument for limiting excessive resource consumption from heavy queries.

Statement timeouts can also be useful to application developers when creating and debugging complex queries without advance knowledge of execution time.Testers and others could find them handy for detecting long-running queries and establishing finite run times for test suites.

How the Statement Timeout Works

When the statement starts execution, or a cursor is opened, the engine starts a special timer.It is stopped when the statement completes execution, or the last record has been fetched by the cursor.

Note	A fetch does not reset this timer.

When the timeout point is reached:

if statement execution is active, it stops at closest possible moment
if statement is not active currently (between fetches, for example), it is marked as cancelled, and the next fetch will break execution and return an error

Note	Statement types excluded from timeouts Statement timeouts are not applicable to some types of statement and will be ignored: All DDL statements All internal queries issued by the engine itself