Re: parameter hints to the optimizer - Mailing list pgsql-hackers

From Oliver Jowett
Subject Re: parameter hints to the optimizer
Date
Msg-id 40FEDA30.2070401@opencloud.com
Whole thread Raw
In response to parameter hints to the optimizer  ("Merlin Moncure" <merlin.moncure@rcsonline.com>)
Responses Re: parameter hints to the optimizer  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
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.

So the guts of the work are done -- we'd just need a way to trigger the 
behaviour on demand. It sounds less painful to add something to PREPARE 
than to change the V3 protocol at this stage.

-O


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