maria-developers team mailing list archive

[MARK CALLAGHAN <mdcallag@xxxxxxxxx>]

Maybe it has a confusing name, but EMPTY_QUERIES should count the number of
SELECT statements that return 0 rows. For me that has been a useful
indicator for inefficient applications.


On Fri, May 17, 2013 at 11:33 AM, Ian Gilfillan <launchpad@xxxxxxxxxxxxxx>wrote:

> I'm documenting the status variables at the moment, and have a question
> about Empty_queries vs Com_empty_queries.
>
> Com_empty_queries is not incremented when an empty result is returned, and
> appears to be incremented only when an empty query is sent to the server,
> eg:
>
> mysql --comments -e '-- sql comment'
>
> Empty_queries appears to match the empty queries returned with SHOW
> USER_STATISTICS. It increments each time a query is performed that returns
> an empty result.
>
> Currently the documentation on the user statistics page at
> https://kb.askmonty.org/en/**user-statistics/<https://kb.askmonty.org/en/user-statistics/>says that EMPTY_QUERIES (and therefore the Empty_queries status variable)
> is "The number of times this user's connections sent empty queries to the
> server", which would describe Com_empty_queries rather than Empty_queries,
> and would need to be corrected.
>
> The documentation on https://kb.askmonty.org/en/**server-status-variables/<https://kb.askmonty.org/en/server-status-variables/>is what I've just written based on the above.
>
> Have I understood this correctly, or is there something else to it?
>
> thanks,
> ian
>
>
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-- 
Mark Callaghan
mdcallag@xxxxxxxxx