7.2b2 problem using like 'XXX%' sequential scan

Yes, I vacuumed/reindexed the db,
just tested the latest snapshot, same problem.

bye

Antonio Fiol Bonn�n wrote:

Did you VACUUM ANALYZE on your SMP machine?

Antonio

Giuseppe Tanzilli - CSF wrote:

Ciao,
I'm testing 7.2b2 and I see it is much slower when I use like on column
with indexes,
the explain sais it is a sequantial scan (same as 7.1.3), but the time
it get to complete is much longer.

I got the problem only on SMP machine:
explain on 7.1.3 say it is a seq scan with cost 18837
explain on 7.2b2 say it is a seq scan 22.5

on single cpu 7.2b2 says:
Index scan with cost 29 and it is very fast!!

All platform are linux/i386 using redhat 7.2 and latest libraries

I'm testing latest snapshot just now.

thanks

--
-------------------------------------------------------
Giuseppe Tanzilli g.tanzilli@gruppocsf.com
CSF Sistemi srl phone ++39 0775 7771
Via del Ciavattino
Anagni FR
Italy

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Giuseppe Tanzilli g.tanzilli@gruppocsf.com
CSF Sistemi srl phone ++39 0775 7771
Via del Ciavattino
Anagni FR
Italy

...

All platform are linux/i386 using redhat 7.2 and latest libraries

I'm guessing that one platform has "locale" enabled (or some combination
of multibyte parameters?), whereas the other does not. SMP will not make
a difference in configuration or optimizer choices.

The good news is that you have *one* machine which does what you want,
so we know that we can get the other one doing that too :)

- Thomas

(back on-list)

You got it, I have locale anebled on all platform,
but I see a different locale setting:

it is working where I have LC_* = it_IT
not working where I have LC_* = it_IT@euro
what I can do ?
I tried to start postgresql 7.2b2 with the working locale but nothing
appened, I must initdb ??

I would try that. If you stay on list, then someone who actually *knows*
is likely to answer. I'm just guessing ;)

- Thomas

I did a fresh initdb after setting LC_* to it_IT
but nothing seems to change

bye

Thomas Lockhart wrote:

(back on-list)

You got it, I have locale anebled on all platform,
but I see a different locale setting:

it is working where I have LC_* = it_IT
not working where I have LC_* = it_IT@euro
what I can do ?
I tried to start postgresql 7.2b2 with the working locale but nothing
appened, I must initdb ??

I would try that. If you stay on list, then someone who actually *knows*
is likely to answer. I'm just guessing ;)

- Thomas

--
-------------------------------------------------------
Giuseppe Tanzilli g.tanzilli@gruppocsf.com
CSF Sistemi srl phone ++39 0775 7771
Via del Ciavattino
Anagni FR
Italy

it is working where I have LC_* = it_IT
not working where I have LC_* = it_IT@euro
what I can do ?
I tried to start postgresql 7.2b2 with the working locale but nothing
appened, I must initdb ??

Yes. The database locale is determined at initdb time.

regards, tom lane