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




Wed, 14 Nov 2001 12:26:17 +0100
Giuseppe Tanzilli - CSF <g.tanzilli@gruppocsf.com>
7.2b2 problem using like 'XXX%' sequential scan 
Yes, I vacuumed/reindexed the db,
just tested the latest snapshot, same problem.

bye

Antonio Fiol Bonnï¿½n 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
>>
>>---------------------------(end of broadcast)---------------------------
>>TIP 5: Have you checked our extensive FAQ?
>>
>>http://www.postgresql.org/users-lounge/docs/faq.html
>>
>
>


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





Wed, 14 Nov 2001 12:59:28 +0100
Giuseppe Tanzilli - CSF <g.tanzilli@gruppocsf.com>
Re: 7.2b2 problem using like 'XXX%' sequential scan
...
> 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

Wed, 14 Nov 2001 14:00:35 +0000
Thomas Lockhart <lockhart@fourpalms.org>
Re: 7.2b2 problem using like 'XXX%' sequential scan
(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

Wed, 14 Nov 2001 16:27:32 +0000
Thomas Lockhart <lockhart@fourpalms.org>
Re: 7.2b2 problem using like 'XXX%' sequential scan

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





Wed, 14 Nov 2001 17:41:25 +0100
Giuseppe Tanzilli - CSF <g.tanzilli@gruppocsf.com>
Re: 7.2b2 problem using like 'XXX%' sequential scan
>> 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

Wed, 14 Nov 2001 11:59:58 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: 7.2b2 problem using like 'XXX%' sequential scan 