Re: parameter hints to the optimizer

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Oliver Jowett <oliver(at)opencloud(dot)com>
Cc: Merlin Moncure <merlin(dot)moncure(at)rcsonline(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: parameter hints to the optimizer
Date: 2004-08-08 00:10:07
Message-ID: 200408080010.i780A7l22395@candle.pha.pa.us
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Oliver Jowett wrote:
> Bruce Momjian wrote:
> > Oliver Jowett wrote:
> >
> >>Merlin Moncure wrote:
> >>
> >>
> >>>Another way to deal with the problem is to defer plan generation until
> >>>the first plan execution and use the parameters from that execution.
> >>
> >>When talking the V3 protocol, 7.5 defers plan generation for the unnamed
> >>statement until parameters are received in the Bind message (which is
> >>essentially the same as what you describe). There was some discussion at
> >>the time about making it more flexible so you could apply it to arbitary
> >>statements, but that needed a protocol change so it didn't happen.
> >
> >
> > What do you mean about arbitrary statements? Non-prepared ones, or
> > non-unnamed ones?
>
> Non-unnamed ones. Adding flag on the Parse message that says when to
> plan the statement (or maybe on each Bind message even).

OK, what are unnamed prepared statements? When are they used currently?
Only via the wire protocol? Who uses them now?

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