Re: Replication stopping with exactly the same characteristics as [Jesse]

It can and does reuse a buffer assocated with each Binlog Dump thread if you use the MySQL patch at code.google.com. But that is a big patch and I understand why people can't use all of it. Hopefully, the MySQL replication team will incorporate it.

On 10/29/07, Rick James <rjames@yahoo-inc.com> wrote:
>
> The malloc/free seems like a recipe for memory fragmentation and
> sluggishness. Can't it at least reuse a static area for small pieces
> (say, < 1M)?
>
> > -----Original Message-----
> > From: Mark Callaghan [mailto:mcallaghan@google.com]
> > Sent: Monday, October 29, 2007 8:17 AM
> > To: Kieffer, Tom
> > Cc: replication@lists.mysql.com
> > Subject: Re: Replication stopping with exactly the same
> > characteristics as [Jesse]
> >
> > We had errors similar to this. They occurred because the
> > master got memory
> > allocation errors while trying to copy a large replication
> > event to the
> > slave. The master did not log an error for this, nor did it notice the
> > memory allocation error. The slave got the truncation error
> > and replication
> > stopped. The problems on the master have been fixed in recent
> > 5.0 branches.
> >
> > Large replication events are not streamed to slaves. They
> > require contiguous
> > memory allocation. Binlog dump threads on the master call
> > malloc/free for
> > every replication event copied to a slave.
> >
> > On 10/29/07, Kieffer, Tom <Tom.Kieffer@ds-plan.com> wrote:
> > >
> > > Hello,
> > >
> > >
> > >
> > > just came to the same problem than Jesse. Replication is
> > stopping without
> > > any
> > > visible reason. Slave stays at "Waiting for master to send
> > event". MySQL
> > > writes to the error log:
> > > Slave SQL thread exiting, replication stopped in log 'xxx'
> > at position
> > > yyy.
> > > I have the "Data truncated error" ignored. Never understood
> > why an entry
> > > is
> > > accepted on the master but throws a "Data truncated" error
> > on the slave.
> > > But
> > > if replication stopped even with ignore_error this parameter doesn't
> > > really
> > > make sense.
> > > Until now i couldn't figure out any solution whatsoever. I
> > just issue a
> > > "Start Slave" and replication continues where it stopped.
> > > The data is not yet critical but may become so in the near
> > future so i'm
> > > worrying somewhat about the replication behaviour.
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > Tom Kieffer
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> > --
> > Mark Callaghan
> > mcallaghan@google.com
> >
>

-- 
Mark Callaghan
mcallaghan@google.com