Horton

Re: [HACKERS] eval_const_expresisions and ScalarArrayOpExpr

Dmitry Dolgov <9erthalion6@gmail.com>

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From: Dmitry Dolgov <9erthalion6@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Michael Paquier <michael.paquier@gmail.com>, Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2018-01-03T11:40:35Z
Lists: pgsql-hackers 
> On 2 January 2018 at 20:52, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> I did find one case where the patch makes things significantly slower:
>
> select * from test where true is true
>  and true is true
>  and true is true
>  and true is true
>  ... (100 times altogether)

Yes, indeed, I never tested this kind of conditions. I can confirm, this
query
is significantly slower with the previous version of the patch, but the
current
version solves this.

> I'm disinclined to change the usage of "saop" here --- that's already
> in use in lots of code touching ScalarArrayOp

Oh, ok - I see now, thank you. So, I think no one would object if I'll mark
this patch as ready for committer.

Commits

  1. Teach eval_const_expressions() to handle some more cases.