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From:Sergei Golubchik Date:October 12 2007 8:37am
Subject:Re: bk commit into 5.0 tree (thek:1.2480) BUG#21074
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Hi!

On Oct 11, He Zhenxing wrote:
> Hi,
> 
> Why is this patch for 5.0 only?

Because 5.1 has a different more complex fix -

ChangeSet@stripped, 2007-07-02 19:14:48+02:00, thek@adventure.(none) +10 -0
  Bug#21074 Large query_cache freezes mysql server sporadically under heavy load
  
  Invaldating a subset of a sufficiently large query cache can take a long time.
  During this time the server is efficiently frozen and no other operation can
  be executed. This patch addresses this problem by moving the locks which cause
  the freezing and also by temporarily disable the query cache while the 
  invalidation takes place.

Regards / Mit vielen Grüssen,
Sergei

> On 2007-08-29 18:30 +0400, Konstantin Osipov Wrote???
> > * kpettersson@stripped <kpettersson@stripped> [07/08/14 18:00]:
> > > 
> > > ChangeSet@stripped, 2007-08-14 15:52:46+02:00, thek@adventure.(none) +1 -0
> > >   Bug #21074 Large query_cache freezes mysql server sporadically under
> heavy load
> > >   
> > >   Invaldating a subset of a sufficiently large query cache can take a long
> time.
> > >   During this time the server is efficiently frozen and no other operation
> can
> > >   be executed. This patch addresses this problem by setting a time limit
> on
> > >   how long time a dictionary access request can take before giving up on
> the 
> > >   attempt. This patch does not work for query cache invalidations issued
> by
> > >   DROP, ALTER or RENAME TABLE operations.
> > > 
> > >   sql/sql_cache.cc@stripped, 2007-08-14 15:52:44+02:00, thek@adventure.(none)
> +27 -1
> > >     Changed mutex locking to a timed spinn lock. If access to query cache
> dictionary
> > >     takes "a long time" (currently more than 0.1 seconds) the system fall
> backs on
> > >     ordinary statement execution.
> > 
> > As discussed on IRC:
> > since this patch is for  5.0 only, Shane/Sinisa should perform acceptance
> > tests.
> > 
> > After that, the patch is OK to push into 5.0 and null-merge into
> > 5.1.
 
-- 
   __  ___     ___ ____  __
  /  |/  /_ __/ __/ __ \/ /   Sergei Golubchik <serg@stripped>
 / /|_/ / // /\ \/ /_/ / /__  Principal Software Developer
/_/  /_/\_, /___/\___\_\___/  MySQL GmbH, Dachauer Str. 37, D-80335 München
       <___/                  Geschäftsführer: Kaj Arnö - HRB
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Thread
bk commit into 5.0 tree (thek:1.2480) BUG#21074kpettersson14 Aug
  • Re: bk commit into 5.0 tree (thek:1.2480) BUG#21074Konstantin Osipov29 Aug
    • Re: bk commit into 5.0 tree (thek:1.2480) BUG#21074He Zhenxing11 Oct
      • Re: bk commit into 5.0 tree (thek:1.2480) BUG#21074Sergei Golubchik12 Oct