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From:He Zhenxing Date:February 16 2009 9:03am
Subject:Re: bzr commit into mysql-6.0-rpl branch (alfranio.correia:2810)
Bug#40337
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Hi Alfranio,

Patch approved, I only have some one comment regarding the commit
message.

Alfranio Correia wrote:
> #At
> file:///home/acorreia/workspace.sun/repository.mysql/bzrwork/bug-40337/mysql-6.0-rpl/
> based on revid:luis.soares@stripped
> 
>  2810 Alfranio Correia	2009-02-13
>       BUG#40337  Fsyncing master and relay log to disk after every event is too slow
>             
>       The fix proposed in BUG#35542 and BUG#31665 introduces a performance issue
>       when fsyncing the master.info, relay.info and relay-log.bin* after #th events.
>       Although such solution has been proposed to reduce the probability of
> corrupted
>       files due to a slave-crash, the performance penalty introduced by it has
>       made the approach impractical for highly intensive workloads.
>             
>       In a nutshell, the option --syn-relay-log proposed in BUG#35542 and BUG#31665
>       simultaneously fsyncs master.info, relay-log.info and relay-log.bin* and
>       this is the main source of performance issues.
>             
>       This patch introduces new options that give more control to the user on
>       what should be fsynced and how often:
>         1) (--sync-master-info, integer) which syncs the master.info after #th
> event;
>         2) (--sync-relay-log, integer) which syncs the relay-log.bin* after #th
>       events.
>         3) (--sync-relay-log-info, integer) which syncs the relay.info after #th
>         transactions.
>             
>       To provide both performance and increased reliability, we recommend the
> following
>       setup:
>         1) --sync-master-info = 0 eventually the operating system will fsync it;
>         2) --sync-relay-log = 0 eventually the operating system will fsync it;
>         3) --sync-relay-log-info = 1 fsyncs it after every transaction;
>             
>         Notice, however, that the previous setup does not reduce the probability of
>       corrupted master.info and relay-log.bin*. To overcome the issue, this patch
> also 
>       introduces a recovery mechanism that right after restart throws away
> relay-log.bin* 
>       retrieved from a master and updates the master.info based on the relay.info:

I think it's better to state clear that the recovery mechanisam can only
recover the incorrect binlog file and position in master.info, if other
informations (host, port password, etc) are corrupted or incorrect, then
this recovery mechanism will fail to work.

>         4) (--relay-log-recovery, boolean) which enables a recovery mechanism that
>         throws away relay-log.bin* after a crash.
>             
>         So, it is advisable to setup: --syn-relay-log-info = 1.

[snip]


Thread
bzr commit into mysql-6.0-rpl branch (alfranio.correia:2810) Bug#40337Alfranio Correia13 Feb
  • Re: bzr commit into mysql-6.0-rpl branch (alfranio.correia:2810)Bug#40337He Zhenxing16 Feb
    • Re: bzr commit into mysql-6.0-rpl branch (alfranio.correia:2810)Bug#40337Alfranio Correia16 Feb
      • Re: bzr commit into mysql-6.0-rpl branch (alfranio.correia:2810)Bug#40337He Zhenxing16 Feb