Alex,
Alex Pilchin wrote:
> On Thu, 2007-07-05 at 16:06 +0200, Sergei Golubchik wrote:
>> Hi!
>>
>> On Jul 04, Alex Pilchin wrote:
>>> Hi,
>>> I need find a way to get notification that a checkpoint has occurred in
>>> MySql. Is this functionality available somewhere (eg. as a patch or
>>> somewhere in the MySql code)?
>> Checkpoint doesn't occur in MySQL, it occurs in the storage engine.
>> MySQL doesn't do checkpoints, it has no knowledge about checkpoints in
>> the storage engine, it does not know when they happen. Different storage
>> engines may do checkpoints in different moments of time, with different
>> frequency, or not at all.
>
> Sorry about that, all my questions are with regards to InnoDB but I'm
> also interested regarding BDB as well.
As Sergei clarified above, it's unpredictable (well for practical purposes
at least). InnoDB doesn't send any notification upstream when it does a
checkpoint and MySQL doesn't send it any message/command to initiate
checkpoint.
>>> Also, it would be nice to know which transactions have been executed
>>> after the last checkpoint. Is this at all possible w/o parsing and
>>> scanning the log at the moment?
Currently only scanning and parsing the log will do it for you.
>>> Is there any capability at the moment to support user triggered
>>> check-pointing?
Not without modifying MySQL syntax (which is unlikely). e.g adding
CHECKPOINT InnoDB; or some such.
Regards,
-sunny
Innobase/Oracle.
