Horton

Re: hung backends stuck in spinlock heavy endless loop

Peter Geoghegan <pg@heroku.com>

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From: Peter Geoghegan <pg@heroku.com>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2015-01-13T23:17:15Z
Lists: pgsql-hackers 
On Tue, Jan 13, 2015 at 2:29 PM, Merlin Moncure <mmoncure@gmail.com> wrote:
> On my workstation today (running vanilla 9.4.0) I was testing some new
> code that does aggressive parallel loading to a couple of tables.

Could you give more details, please? For example, I'd like to see
representative data, or at least the table definitions involved. Do
you have any idea what index is involved with the _bt_compare() calls
above? I'm curious as to what its definition is.

You might also consider using my B-Tree verification tool on a
preserved data directory:
http://www.postgresql.org/message-id/CAM3SWZRK2YxKegj94_2wKs_vbEMJeHc1yE23ECsS01wRAKzkjg@mail.gmail.com

I'm inclined to think that this is a livelock, and so the problem
isn't evident from the structure of the B-Tree, but it can't hurt to
check. The tool is bleeding edge, so don't use it in production.

Thanks
-- 
Peter Geoghegan

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.