Re: Repeated PredicateLockRelation calls during seqscan - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: Repeated PredicateLockRelation calls during seqscan
Date
Msg-id 4E022198020000250003EAC0@gw.wicourts.gov
Whole thread Raw
In response to Re: Repeated PredicateLockRelation calls during seqscan  (Dan Ports <drkp@csail.mit.edu>)
List pgsql-hackers
Dan Ports <drkp@csail.mit.edu> wrote:
> Note that this hadn't been a reasonable option until last week
> when we added the check for non-MVCC snapshots, since there are
> lots of things that use heap scans but SeqScan is the only
> (currently-existing) one we want to lock.
That is the sort of thing that I tended to notice going through the
backtraces from heap access I mentioned in another post, and is most
likely the reason the call landed where it did.  The MVCC snapshot
tests are then a game-changer.  It would be nice to find a way not
to acquire the relation lock if the node is never used, though.
> I am rather uneasy about making changes here unless we can be
> absolutely certain they're right...
Yeah....
-Kevin


pgsql-hackers by date:

Previous
From: Florian Pflug
Date:
Subject: Re: lazy vxid locks, v1
Next
From: Alvaro Herrera
Date:
Subject: Re: SYNONYMS (again)