Обсуждение: pg_dump on Postgres 9.1

Alanoly Andrews <alanolya@invera.com> writes:
> Is there any reported bug with pg_dump in Postgres 9.1, on AIX ? The following command hangs for "ever" and has to be
interrupted.It creates a zero-length file. 

We had a recent report of strange server-side behavior on AIX that went
away after rebuilding with a newer version of xlc, suggesting that the
code was getting bitten by an xlc optimization bug.  Perhaps this is the
same thing inside pg_dump.  If you're not using the latest xlc, try
updating.  If you are, does rebuilding with -O0 change the behavior?

            regards, tom lane

On this issue, instead of going for a newer version of xlc, as suggested, I opted to get a newer version of the
Postgressource code, 9.1.4. After compiling it with the same xlc version, I found that pg_dump works as expected. So,
theproblem appears to be somewhere in the 9.1 source code, at least for binaries created from it for AIX (6.1). 

Regards.

Alanoly.

-----Original Message-----
From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
Sent: Friday, July 27, 2012 12:13 PM
To: Alanoly Andrews
Cc: 'pgsql-admin@postgresql.org'
Subject: Re: [ADMIN] pg_dump on Postgres 9.1

Alanoly Andrews <alanolya@invera.com> writes:
> Is there any reported bug with pg_dump in Postgres 9.1, on AIX ? The following command hangs for "ever" and has to be
interrupted.It creates a zero-length file. 

We had a recent report of strange server-side behavior on AIX that went away after rebuilding with a newer version of
xlc,suggesting that the code was getting bitten by an xlc optimization bug.  Perhaps this is the same thing inside
pg_dump. If you're not using the latest xlc, try updating.  If you are, does rebuilding with -O0 change the behavior? 

            regards, tom lane
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Alanoly Andrews <alanolya@invera.com> writes:
> On this issue, instead of going for a newer version of xlc, as suggested, I opted to get a newer version of the
Postgressource code, 9.1.4. After compiling it with the same xlc version, I found that pg_dump works as expected. So,
theproblem appears to be somewhere in the 9.1 source code, at least for binaries created from it for AIX (6.1). 

Hm, maybe this 9.1.2 fix?

Author: Tom Lane <tgl@sss.pgh.pa.us>
Branch: master Release: REL9_2_BR [cf22e851b] 2011-11-10 16:09:01 -0500
Branch: REL9_1_STABLE Release: REL9_1_2 [febda37fd] 2011-11-10 16:09:16 -0500

    Avoid platform-dependent infinite loop in pg_dump.

    If malloc(0) returns NULL, the binary search in findSecLabels() will
    probably go into an infinite loop when there are no security labels,
    because NULL-1 is greater than NULL after wraparound.

    (We've seen this pathology before ... I wonder whether there's a way to
    detect the class of bugs automatically?)

    Diagnosis and patch by Steve Singer, cosmetic adjustments by me


            regards, tom lane