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Re: RFC: Pausing a query thread
could you explain better what is very consuming a lot of resources? maybe a
consuming != locked
like sergei wrote, a lock may cause problems when you 'pause' a query
2013/6/24 Sergei Golubchik <serg@xxxxxxxxxxx>
> Hi, Marian!
> On Jun 24, Marian Marinov wrote:
> > Hi guys,
> > I work with hosting companies and all of my clients have the same
> > irritating problem, one query taking a lot of time to finish and
> > consuming a lot of resources.
> > So I have solved the same issue but with processes on the machine by
> > simply pausing(kill -STOP) these processes when the load is high and
> > continuing(kill -CONT) them when the server load goes down.
> > I want to implement the same logic within MariaDB, so I can STOP/CONT
> > the thread that is executing this query.
> > My idea is to implement this in the 'KILL query_id' function, so it
> > will accept one more argument, which will be either STOP or CONT. If
> > the parameter is not present, the default behavior should remain.
> > What do you think about my approach?
> That's surely possible. And it can be done with a relatively small patch.
> But note that if you "pause" a query that's holding locks, be it
> pthread mutexes, row locks, table locks, metadata locks, whatever, all
> other connections that might need them will "pause" too. They'll wait
> for the lock, and may eventually time out.
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