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: Andres Freund <andres@2ndquadrant.com>
Cc: Merlin Moncure <mmoncure@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2015-01-14T00:47:56Z
Lists: pgsql-hackers 
On Tue, Jan 13, 2015 at 3:54 PM, Andres Freund <andres@2ndquadrant.com> wrote:
>> I don't remember seeing _bt_moveright()  or _bt_compare() figuring so
>> prominently, where _bt_binsrch() is nowhere to be seen. I can't see a
>> reference to _bt_binsrch() in either profile.
>
> Well, we do a _bt_moveright pretty early on, so that actually might be
> cache misses we're primarily seing.

Still, I see zero references to _bt_binsrch(). Not one. Even if there
was only one non-meta page (i.e. pre-first-root-split), and regardless
of whether this was a read or a write to the B-Tree, there'd still be
some call there as the B-Tree was initially scanned (before _bt_next()
calls, of which I also see none).

-- 
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.