Horton

Re: hung backends stuck in spinlock heavy endless loop

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: Peter Geoghegan <pg@heroku.com>, Andres Freund <andres@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2015-01-14T15:13:32Z
Lists: pgsql-hackers 
Merlin Moncure <mmoncure@gmail.com> writes:
> Yes, it is pg_class is coming from  LockBufferForCleanup ().  As you
> can see above, it has a shorter runtime.   So it was killed off once
> about a half hour ago which did not free up the logjam.  However, AV
> spawned it again and now it does not respond to cancel.

Interesting.  That seems like there might be two separate issues at
play.  It's plausible that LockBufferForCleanup might be interfering
with other attempts to scan the index, but then why wouldn't killing
the AV have unstuck things?

Anyway it's now seeming that Peter may have the right idea about
where to look.

			regards, tom lane

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.