Re: bad JIT decision - Mailing list pgsql-general

From Scott Ribe
Subject Re: bad JIT decision
Date
Msg-id 559519F3-5285-4F2B-A88F-0067382761A7@elevated-dev.com
Whole thread Raw
In response to Re: bad JIT decision  (David Rowley <dgrowleyml@gmail.com>)
Responses Re: bad JIT decision
List pgsql-general
> On Jul 24, 2020, at 4:26 PM, David Rowley <dgrowleyml@gmail.com> wrote:
>
> It does not really take into account the cost of jitting.

That is what I was missing.

I read about JIT when 12 was pre-release; in re-reading after my post I see that it does not attempt to estimate JIT
cost.And in thinking about it, I realize that would be next to impossible to anticipate how expensive LLVM optimizstion
wasgoing to be. 

In the case where a set of functions is replicated across partitions, it would be possible to do them once, then
projectthe cost of the copies. Perhaps for PG 14 as better support for the combination of JIT optimization and
highly-partitioneddata ;-) 





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