From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: postgres_fdw bug in 9.6
Date: Thu, 08 Dec 2016 13:28:07 -0500
Message-ID: <7784.1481221687@sss.pgh.pa.us> (raw)
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Robert Haas <robertmhaas@gmail.com> writes:
> Maybe it would help for Jeff to use elog_node_display() to the nodes
> that are causing the problem - e.g. outerpathkeys and innerpathkeys
> and best_path->path_mergeclauses, or just best_path - at the point
> where the error is thrown. That might give us enough information to
> see what's broken.
I'll be astonished if that's sufficient evidence. We already know that
the problem is that the input path doesn't claim to be sorted in a way
that would match the merge clauses, but that doesn't tell us how such
a path came to be generated (or, if it wasn't intentionally done, where
the data structure got clobbered later).
It's possible that setting a breakpoint at create_mergejoin_path and
capturing stack traces for all calls would yield usable insight. But
there are likely to be lots of calls if this is an 8-way join query,
and probably only a few are wrong.
I'd much rather have a test case than try to debug this remotely.
Bandwidth too low.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, robertmhaas@gmail.com, jeff.janes@gmail.com
Subject: Re: postgres_fdw bug in 9.6
In-Reply-To: <7784.1481221687@sss.pgh.pa.us>
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