WL#2814: Query timeouts (SQL_TIMEOUT option)

Affects: Server-7.0   —   Status: Un-Assigned   —   Priority: Low

Using SQL_TIMEOUT option user will be able to specify maximum execution time for
query (by inserting proper option specification into the text of the query).

For example "SELECT SQL_TIMEOUT=30 * FROM foo.bar" will mean that query
execution should be aborted with proper error-message if it takes more than 30

Since this option could not be used in safe way with DML statements on
non-transactional tables (at least until support for statement rollbacks will be
implemented for them) it is intended only for SELECT statements.

We will also have "sql_select_timeout" session variable which will allow user to
specify default SQL_TIMEOUT value for all (SELECT) queries in this connection.

(Dmitri already has almost finished patch for this.)

Note added by Trudy Pelzer on 2005-10-05:
This task suggests SQL_TIMEOUT to implement the feature.
WL#1242 "Kill connections with disconnected clients" also 
suggests the use of SQL_TIMEOUT. So we need to be aware
of a possible conflict if both tasks are implemented.

See also thread "Re: Newly Added (by DmitriLenev): Query timeouts
(SQL_TIMEOUT option) (2814)"

See also
WL#1272 User timeouts on queries