From: Tom Lane <tgl@sss.pgh.pa.us>
To: Noah Misch <noah@leadboat.com>
cc: Amit Khandekar <amitdkhan.pg@gmail.com>,
        Amit Kapila <amit.kapila16@gmail.com>,
        Alvaro Herrera from 2ndQuadrant <alvherre@alvh.no-ip.org>,
        Andres Freund <andres@anarazel.de>,
        Juan =?iso-8859-1?Q?Jos=E9_Santamar=EDa?= Flecha
 <juanjo.santamaria@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        Robert Haas <robertmhaas@gmail.com>,
        Thomas Munro <thomas.munro@gmail.com>,
        Tomas Vondra <tomas.vondra@2ndquadrant.com>
Subject: Re: logical decoding : exceeded maxAllocatedDescs for .spill files
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Comments: In-reply-to Noah Misch <noah@leadboat.com>
	message dated "Thu, 09 Jan 2020 17:57:36 -0800"
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Date: Fri, 10 Jan 2020 00:16:37 -0500
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Noah Misch <noah@leadboat.com> writes:
> On Thu, Jan 09, 2020 at 12:45:41AM -0500, Tom Lane wrote:
>> (1) Why did we get a crash and not some more-decipherable out-of-resour=
ces
>> error?  Can we improve that experience?

> By default, 32-bit AIX binaries have maxdata:0x00000000.  Specifying
> maxdata:0x10000000 provides the same 256M of RAM, yet it magically chang=
es the
> SIGSEGV to ENOMEM:
> ...
> We could add -Wl,-bmaxdata:0x10000000 (or a higher value) to LDFLAGS whe=
n
> building for 32-bit AIX.

+1, seems like that would improve matters considerably on that platform.

>> (2) Should we be dialing back the resource consumption of this test?
>> Even on machines where it doesn't fail outright, I'd imagine that it's
>> costing a lot of buildfarm cycles.  Is it actually worth that?

> The test's resource usage, being quite low, should not be a factor in th=
e
> test's fate.  On my usual development machine, the entire
> 006_logical_decoding.pl file takes just 3s and ~250 MiB of RAM.

Yeah, as I noted downthread, it appears that initdb itself can't
succeed with less than ~250MB these days.  My old-school self
feels like that's excessive, but I must admit I'm not motivated
to go reduce it right now.  But I think it's a clear win to fail
with "out of memory" rather than "SIGSEGV", so I think we ought
to adjust the AIX build options as you suggest.

			regards, tom lane