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                              WORKLOG TASK
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TASK...........: Efficient group commit for binary log
CREATION DATE..: Mon, 26 Apr 2010, 13:28
SUPERVISOR.....: Knielsen
IMPLEMENTOR....: 
COPIES TO......: 
CATEGORY.......: Server-RawIdeaBin
TASK ID........: 116 (http://askmonty.org/worklog/?tid=116)
VERSION........: Server-9.x
STATUS.........: Un-Assigned
PRIORITY.......: 60
WORKED HOURS...: 0
ESTIMATE.......: 0 (hours remain)
ORIG. ESTIMATE.: 0

PROGRESS NOTES:



DESCRIPTION:

Currently, in order to ensure that the server can recover after a crash to a
state in which storage engines and binary log are consistent with each other,
it is necessary to use XA with durable commits for both storage engines
(innodb_flush_log_at_trx_commit=1) and binary log (sync_binlog=1).

This is _very_ expensive, since the server needs to do three fsync() operations
for every commit, as there is no working group commit when the binary log is
enabled.

The idea is to

 - Implement/fix group commit to work properly with the binary log enabled.

 - (Optionally) avoid the need to fsync() in the engine, and instead rely on
   replaying any lost transactions from the binary log against the engine
   during crash recovery.

For background see these articles:

    http://kristiannielsen.livejournal.com/12254.html
    http://kristiannielsen.livejournal.com/12408.html
    http://kristiannielsen.livejournal.com/12553.html


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