Horton

Re: hung backends stuck in spinlock heavy endless loop

Merlin Moncure <mmoncure@gmail.com>

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From: Merlin Moncure <mmoncure@gmail.com>
To: Andres Freund <andres@2ndquadrant.com>
Cc: Peter Geoghegan <pg@heroku.com>, Heikki Linnakangas <hlinnakangas@vmware.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2015-01-16T14:38:56Z
Lists: pgsql-hackers 
On Fri, Jan 16, 2015 at 8:22 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> Is there any chance you can package this somehow so that others can run
> it locally? It looks hard to find the actual bug here without adding
> instrumentation to to postgres.

That's possible but involves a lot of complexity in the setup because
of the source database (SQL Server) dependency..

Thinking outside the box here I'm going to migrate the source to
postgres.   This will rule out pl/sh which is the only non-core
dependency but will take some setup work on my end first.  If I can
still reproduce the error at that point, maybe we can go in this
direction, and it it would make local reproduction easier anyways.

>> [cds2 21952 2015-01-15 22:54:51.833 CST 5502]WARNING:  page
>
> This was the first error? None of the 'could not find subXID' errors
> beforehand?

yep.  no caught exceptions or anything interesting in the log before that.

> Could you add a EmitErrorReport(); before the FlushErrorState() in
> pl_exec.c's exec_stmt_block()?

will do.

merlin

Commits

  1. Improve hash_create's API for selecting simple-binary-key hash functions.

  2. Fix WAL-logging of B-tree "unlink halfdead page" operation.

  3. Fix backup-block numbering in redo of b-tree split.

  4. Cleanup of new b-tree page deletion code.

  5. Fix bug in the new B-tree incomplete-split code.

  6. Fix bug in new B-tree page deletion code.

  7. Fix rm_desc routine of b-tree page delete records.

  8. Make the handling of interrupted B-tree page splits more robust.

  9. Fix race condition in B-tree page deletion.