Percona Server has implemented per-query variable statement support in version 5.6.14-62.0. This feature provides the ability to set variable values only for a certain query, after execution of which the previous values will be restored. Per-query variable values can be set up with the following command:
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mysql> SET STATEMENT <variable=value> FOR <statement>; |
Example:
If we want to increase the sort_buffer_size value just for one specific sort query we can do it like this:
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mysql> SET STATEMENT sort_buffer_size=100000 FOR SELECT name FROM name ORDER BY name; |
Percona Server has implemented a statement timeout feature (This feature with some changes was ported from Twitter MySQL patches). This feature can be used to limit the query execution time by specifying the timeout value in the max_statement_time variable. After the specified number of miliseconds is reached the server will attempt to abort the statement and return the following error to the client:
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ERROR 1877 (70101): Query execution was interrupted, max_statement_time exceeded |
Following example shows how to limit the execution time for a specific query by using per-query variable statements with Statement Timeout feature:
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mysql> SET STATEMENT max_statement_time=1000 FOR SELECT name FROM name ORDER BY name; |
This feature isn’t just limited to specifying one variable, we can provide more than one if we want to. Following example will both increase the sort_buffer_size value and limit the execution time:
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mysql> SET STATEMENT sort_buffer_size=100000, max_statement_time=1000 FOR SELECT name FROM name ORDER BY name; |
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