| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
| Cc: | Marko Tiikkaja <marko(at)joh(dot)to>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-bugs(at)postgresql(dot)org> |
| Subject: | Re: BUG #14830: Missed NOTIFications, PostgreSQL 9.1.24 |
| Date: | 2017-10-10 18:07:36 |
| Message-ID: | 7833.1507658856@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-bugs |
I wrote:
> Wait, I have an idea. Let's fetch a snapshot at the top of
> ProcessIncomingNotify, and then use the snapshot to decide whether
> xids are running, instead of calling TransactionIdIsInProgress.
Concretely, I suggest the attached patch. I tried Marko's testbed
against this, and it seems indeed a bit faster than before ---
running it for 100000 notifies takes about 19.25 seconds, rather than
19.5 seconds with HEAD. But the testbed is probably about the best
case because it has a bunch of threads sending notifies to one
receiver, so that the receiver is quite likely to have multiple
messages to read at a time. OTOH, in a situation where the NOTIFY
traffic isn't so high, it probably hardly matters anyway.
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| fix-notify-xact-testing.patch | text/x-diff | 6.5 KB |
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