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: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Merlin Moncure <mmoncure@gmail.com>, Andres Freund <andres@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2015-01-14T00:23:09Z
Lists: pgsql-hackers 
On Tue, Jan 13, 2015 at 4:05 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I'm not convinced that Peter is barking up the right tree.  I'm noticing
> that the profiles seem rather skewed towards parser/planner work; so I
> suspect the contention is probably on access to system catalogs.  No
> idea exactly why though.

I see no int4cmp() calls at all, but plenty of _bt_compare(), and some
FunctionCall2Coll(). And yet, no _bt_binsrch(). I can see btoidcmp(),
so if I'm right then I guess it's a system catalog index.

I too would like to see a stack trace.

Trivia: pg_attribute_relid_attnam_index has deleted B-Tree pages after
a fresh initdb.
-- 
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.