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help / color / mirror / Atom feedFrom: Tom Lane <[email protected]>
To: Peter Geoghegan <[email protected]>
Cc: David Rowley <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Julien Rouhaud <[email protected]>
Cc: Magnus Hagander <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: Justin Pryzby <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Add parameter jit_warn_above_fraction
Date: Tue, 29 Mar 2022 18:04:32 -0400
Message-ID: <[email protected]> (raw)
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Peter Geoghegan <[email protected]> writes:
> On Tue, Mar 29, 2022 at 1:06 PM David Rowley <[email protected]> wrote:
>> That means that even if the total execution time of a plan was a true
>> reflection of the total estimated plan cost, then the fraction of time
>> spent (as is measured by jit_warn_above_fraction) doing JIT would
>> entirely depend on the number of expressions to compile. Of course,
>> the planner's not that good, but does that not indicate that the JIT
>> costing should really account for the number of expressions and not
>> just the total plan cost?
> That's a good point.
I think David's questions are sufficiently cogent and difficult
that we should not add jit_warn_above_fraction at this time.
Maybe we'll eventually decide it's the best we can do; but I do
not think we have a problem there that's so pressing that we need
to rush out a partially-baked bandaid. Especially not at the
tail end of the development cycle, with not much time to gain
experience with it before we ship.
regards, tom lane
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Subject: Re: Add parameter jit_warn_above_fraction
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