Re: Synchronization levels in SR

Fujii Masao írta:
> On Tue, Sep 7, 2010 at 6:02 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>
>> On Mon, 2010-09-06 at 22:32 +0200, Boszormenyi Zoltan wrote:
>>
>>> (in commit)
>>> write wal record
>>> release locks/etc <xact2 can proceed from here
>>> wait for sync ack
>>>
>>> In the first case, the contention is obviously increased.
>>> With this, we are creating more idle time in the server
>>> instead of letting other transactions do their jobs as soon
>>> as possible. The second method was implemented in my
>>> patch. Are there any drawbacks with this?
>>>
>> Then I respectfully suggest that you're releasing locks too early.
>>
>> Your proposal would allow a 2nd user to see the results of the 1st
>> user's transaction before the 1st user knew about whether it had
>> committed or not.
>>
>> I know why you want that, but I don't think its right.
>>
>
> Agreed. That's why I put the wait before ProcArrayEndTransaction()
> is called.
>

Then there is no use to implement individual sync/async
replicated transactions, period. An async replicated transaction
that waits for a sync replicated transaction because of locks
will become implicitely sync. It just waits for another transactions'
sync ack.

Best regards,
Zoltán Böszörményi

> Regards,
>
>

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Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
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