| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Joachim Wieland <joe(at)mcknight(dot)de> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Listen / Notify - what to do when the queue is full |
| Date: | 2009-11-19 02:49:21 |
| Message-ID: | 3160.1258598961@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Joachim Wieland <joe(at)mcknight(dot)de> writes:
> The sequence in CommitTransaction() is like that:
> 1) add notifications to queue
> 2) commit to clog
> 3) signal backends
> Only those backends are signalled that listen to at least one channel,
> if the notify system isn't in use, then nobody will ever be signalled
> anyway.
> If a backend is reading a transaction id that has not yet committed,
> it will not deliver the notification.
But you were saying that this patch would enable sending more data than
would fit in the queue. How will that happen if the other backends
don't look at the queue until you signal them?
regards, tom lane
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