Re: pgv18: simple table scan take more time than pgv14

install 18.beta1 from source ,remove enable_debug, much better now. it's
better than pgv14.11.

postgres=# select * from tt where b ~~ 'a%';
a | b
---+---
(0 rows)

Time: 67.545 ms
postgres=# select * from tt where b ~~ 'a%';
a | b
---+---
(0 rows)

Time: 50.945 ms
postgres=# select * from tt where b ~~ 'a%';
a | b
---+---
(0 rows)

Time: 48.176 ms
postgres=# select * from tt where b ~~ 'a%';
a | b
---+---
(0 rows)

Time: 49.919 ms

Thanks,

James

Devrim Gündüz <devrim(at)gunduz(dot)org> 於 2025年6月21日週六 下午7:13寫道：

> Hi,
>
> On Fri, 2025-06-20 at 09:46 +0800, James Pang wrote:
> > same OS RHEL8, install pgv14.11 and pgv18.beta1_3, both installation
> > by RPM from pgdg, and use similar postgresql.conf.
>
> <snip>
>
> > 18.beta1
> > postgres=# \timing on
> > Timing is on.
> > postgres=# select * from tt where b ~~ 'a%';
> > a | b
> > ---+---
> > (0 rows)
> >
> > Time: 78.532 ms
> > postgres=# select * from tt where b ~~ 'a%'
> > postgres-# ;
> > a | b
> > ---+---
> > (0 rows)
> >
> > Time: 83.516 ms
> > postgres=# select * from tt where b ~~ 'a%';
> > a | b
> > ---+---
> > (0 rows)
>
> It's likely because v18 beta RPMs are built with --enable-debug and
> --enable-cassert . See the note on yum.postgresql.org:
>
> https://yum.postgresql.org/rpmchart/#pg18
>
> Regards,
>
>
>
> --
> Devrim Gündüz
> Open Source Solution Architect, PostgreSQL Major Contributor
> BlueSky: @devrim.gunduz.org , @gunduz.org
>