Re: Sync Rep and shutdown Re: Sync Rep v19

On Wed, Mar 16, 2011 at 11:07 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> The problem is that there may be another backend B waiting on a lock
> held by A.  If backend A exits cleanly (without a PANIC), it will
> remove itself from the ProcArray and release locks.  That wakes up A,
> which can now go do its thing.  If the operating system is a bit on
> the slow side delivering the signal to B, then the client to which B
> is connected might manage to see a database state that shows the
> transaction previous running in A as committed, even though that
> transaction wasn't committed.  That would stink, because the whole
> point of having A hold onto locks until the standby ack'd the commit
> was that no other transaction would see it as committed until it was
> replicated.

The lock can be released also when the transaction running in A is
rollbacked. So I could not understand why the client wrongly always
see the transaction as commtted even though it's not committed.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center