Re: SSI patch version 14

From: Dan Ports <drkp(at)csail(dot)mit(dot)edu>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, simon(at)2ndQuadrant(dot)com, markus(at)bluegap(dot)ch, pgsql-hackers(at)postgresql(dot)org
Subject: Re: SSI patch version 14
Date: 2011-02-09 00:23:12
Message-ID: 20110209002312.GB9421@csail.mit.edu
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On Tue, Feb 08, 2011 at 04:04:39PM -0600, Kevin Grittner wrote:
> (2) The predicate lock and lock target initialization code was
> initially copied and modified from the code for heavyweight locks.
> The heavyweight lock code adds 10% to the calculated maximum size.
> So I wound up doing that for PredicateLockTargetHash and
> PredicateLockHash, but didn't do it for SerializableXidHassh.
> Should I eliminate this from the first two, add it to the third, or
> leave it alone?

Actually, I think for SerializableXidHash we should probably just
initially allocate it at its maximum size. Then it'll match the
PredXact list which is allocated in full upfront, and there's no risk
of being able to allocate a transaction but not register its xid. In
fact, I believe there would be no way for starting a new serializable
transaction to fail.

Dan

--
Dan R. K. Ports MIT CSAIL http://drkp.net/

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