From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Cygwin linking rules
Date: Sat, 29 Sep 2018 13:03:56 -0400
Message-ID: <f82cc25e-3404-33b1-3a7b-93e5130e188e@2ndQuadrant.com> (raw)
In-Reply-To: <86419508-9d36-36a9-93ff-2a051af7d2e4@2ndQuadrant.com>
References: <1056.1538235347@sss.pgh.pa.us>
<86419508-9d36-36a9-93ff-2a051af7d2e4@2ndQuadrant.com>
On 09/29/2018 12:09 PM, Andrew Dunstan wrote:
>
>
> On 09/29/2018 11:35 AM, Tom Lane wrote:
>> Most of the buildfarm is now happy with the changes I made to have
>> libpq + ecpg get src/port and src/common files via libraries ...
>> but lorikeet isn't. It gets through the core regression tests fine
>> (so libpq, per se, works), but contrib/dblink fails:
>>
>> ! ERROR: could not establish connection
>> ! DETAIL: libpq is incorrectly linked to backend functions
>>
>> What this means is that libpq is calling the backend version of
>> src/common/link-canary.c rather than the frontend version.
>> Why would it do the right thing normally and the wrong thing in dblink?
>>
>> I can think of a few theories but I lack the ability to investigate:
>>
>> 1. Maybe the dblink.dll build is pulling in libpq.a rather than
>> establishing a reference to libpq.dll. If so, the wrong things would
>> happen because libpq.a won't contain the src/common/ files that
>> libpq needs. (It seems like libpq.a is an active hazard given
>> this. Why are we building it at all?)
>>
>> 2. Maybe we need a --version-script option or something equivalent
>> to get libpq.dll's references to be preferentially resolved internally
>> rather than to the backend. But this doesn't really explain why it
>> worked properly before.
>>
>>
>
>
>
> I will see if I can determine if 1) is the cause. I don't know enough,
> or in fact anything, about 2), so don;t know that I can help there
> without advice.
>
>
It certainly looks like it's not linked to libpq.dll:
Microsoft (R) COFF/PE Dumper Version 14.15.26726.0
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file
\cygwin64\home\andrew\\bf64\root\HEAD\inst\lib\postgresql\dblink.dll
File Type: DLL
Image has the following dependencies:
postgres.exe
cygcrypto-1.0.0.dll
cygwin1.dll
cygssl-1.0.0.dll
KERNEL32.dll
I'll build an earlier version to do a comparison just to make sure we're
seeing the right thing.
cheers
andrew
--
Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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To: pgsql-hackers@postgresql.org
Cc: andrew.dunstan@2ndquadrant.com, tgl@sss.pgh.pa.us, pgsql-hackers@lists.postgresql.org
Subject: Re: Cygwin linking rules
In-Reply-To: <f82cc25e-3404-33b1-3a7b-93e5130e188e@2ndQuadrant.com>
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