From: Jocelyn Fournier
Date: August 31 2002 4:45pm
Subject: Re: Problem with insert delayed thread. Perhaps a linuxthread  problem ?
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Hi,

In fact I'm not using delay_key_write, but I tested it one time, and when I
did the flush table I understood my pain :)
And yes, it's for the Hardware.fr forum :)

Regards,
  Jocelyn

----- Original Message -----
From: "Antoine" <antoine@stripped>
To: <internals@stripped>
Sent: Saturday, August 31, 2002 5:33 PM
Subject: Re: Problem with insert delayed thread. Perhaps a linuxthread
problem ?


>
> Hi,
>
> > As my use of MySQL (in terms of queries per second) has increased over
> > the years, I'm come to find all sorts of issues with insert delayed.
> > Including this one you mention (which is a variation of other
> > incarnations) which was in 3.23.x. Eventually we rewrote things to not
> > use or need it and haven't looked back.
> >
> > Debugging will not be fun. As I remember, it only occurred over a
> > certain QPS threshold, which means full debugging will slow the server
> > to a point that it won't happen. Yuck!
>
> I had the same problem (with 3.23.x source distribution under Linux 2.4.x)
> and finally gave up using INSERT DELAYED under high pressure. It's really
> a QPS-related problem because my application doesn't have much concurrency
> in itself (only one writing client and very few reading clients - but the
> writing client sometimes keeps sending queries to MySQL as it receives
lots
> of data to process & store).
>
> The shame is, DELAYED INSERTs are really only useful under high load
> (because then inserts are batched together). Well....
>
> Jocelyn, if you already use DELAY_KEY_WRITE, maybe DELAYED isn't much
> useful after all ? With an async filesystem (default under Linux) and
> noatime set on the partition, it may get together quite well...
> (as I've seen in your query results, is it for the well-known web site
> hardware.fr ?)
>
> Regards
>
> Antoine.
>
>
>
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