Re: Dumb mistakes in WalSndWriteData()

From: Michael Paquier <michael(dot)paquier(at)gmail(dot)com>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>, Craig Ringer <craig(at)2ndquadrant(dot)com>
Subject: Re: Dumb mistakes in WalSndWriteData()
Date: 2016-11-09 05:01:07
Message-ID: CAB7nPqQmZkP_8Q7naosJf6Fe+dzgyK0j5wObV6ho5Ab6j-NkzQ@mail.gmail.com
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On Mon, Oct 31, 2016 at 10:54 PM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> On 2016-10-31 09:44:16 -0400, Robert Haas wrote:
>> On Mon, Oct 31, 2016 at 4:59 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> > I^Wsomebody appears to have made a number of dumb mistakes in
>> > WalSndWriteData(), namely:
>> > 1) The timestamp is set way too late, after
>> > pq_putmessage_noblock(). That'll sometimes work, sometimes not. I
>> > have no idea how that ended up happening. It's eye-wateringly dumb.
>> >
>> > 2) We only do WalSndKeepaliveIfNecessary() if we're blocked on socket
>> > IO. But on a long-lived connection that might be a lot of data, we
>> > should really do that once *before* trying to send the payload in the
>> > first place.
>> >
>> > 3) Similarly to 2) it might be worthwhile checking for interrupts
>> > everytime, not just when blocked on network IO.
>> >
>> > See also:
>> > http://archives.postgresql.org/message-id/CAMsr%2BYE2dSfHVr7iEv1GSPZihitWX-PMkD9QALEGcTYa%2Bsdsgg%40mail.gmail.com
>>
>> Do you intend to do something about these problems?
>
> At least 1) and 2), yes. I basically wrote this email to have something
> to reference in my todo list...

Just looking at this thread, 1) and 2) is actually something like the attached?
--
Michael

Attachment Content-Type Size
logidec-fixes.patch text/x-diff 1.8 KB

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