From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Subject: Re: [COMMITTERS] pgsql: Use asynchronous connect API in
 libpqwalreceiver
To: Tom Lane <tgl@sss.pgh.pa.us>,
 Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
References: <E1cjo1g-0000mr-ST@gemulon.postgresql.org>
 <19403.1488586564@sss.pgh.pa.us>
 <34d98fbf-9195-04d2-b85a-634d6952ffdf@2ndquadrant.com>
 <19815.1488600693@sss.pgh.pa.us>
Cc: pgsql-hackers@postgreSQL.org
Message-ID: <091deea0-75f2-cfda-ee8c-424162852084@2ndQuadrant.com>
Date: Tue, 14 Mar 2017 20:29:04 -0400
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On 03/03/2017 11:11 PM, Tom Lane wrote:
> Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
>> On 3/3/17 19:16, Tom Lane wrote:
>>> Peter Eisentraut <peter_e@gmx.net> writes:
>>>> Use asynchronous connect API in libpqwalreceiver
>>> Buildfarm member bowerbird has been failing in the pg_rewind test since
>>> this patch went in.  It looks like it's failing to complete connections
>>> from the standby; which suggests that something platform-specific is
>>> missing from this commit, but I dunno what.
>> Hmm, I wonder how widely tested the async connection API is on Windows
>> at all.  I only see bowerbird and jacana running bin-check on Windows.
> Yeah, I was wondering if this is just exposing a pre-existing bug.
> However, the "normal" path operates by repeatedly invoking PQconnectPoll
> (cf. connectDBComplete) so it's not immediately obvious how such a bug
> would've escaped detection.
>
>=20=09=09=09

(After a long period of fruitless empirical testing I turned to the code)


Maybe I'm missing something, but connectDBComplete() handles a return of
PGRESS_POLLING_OK as a success while connectDBStart() seems not to. I
don't find anywhere in our code other than libpqwalreceiver that
actually uses that interface, so it's not surprising if it's now
failing. So my bet is it is indeed a long-standing bug.

cheers

andr4ew

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Andrew Dunstan                https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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