Re: [HACKERS] Neverending query on 6.5.2 over Solaris 2.5.1

From: Fernando Schapachnik <fpscha(at)ns1(dot)via-net-works(dot)net(dot)ar>
To: tgl(at)sss(dot)pgh(dot)pa(dot)us (Tom Lane)
Cc: fpscha(at)via-net-works(dot)net(dot)ar, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Neverending query on 6.5.2 over Solaris 2.5.1
Date: 1999-10-26 12:47:11
Message-ID: 199910261247.JAA06204@ns1.via-net-works.net.ar
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En un mensaje anterior, Tom Lane escribió:
> Well, it's sure confused about the selectivity of WHERE activa,
> all right.
>
> I tried to duplicate this here, by duplicating the table definition you
> sent and filling it with some junk data --- about 1800 rows, 1500 of
> which had activa = 't'. I found that after loading the table and
> running a plain "vacuum", the system indeed estimated one row out, just
> as you show above. But after "vacuum analyze", it estimated 1360 rows
> out, which is a lot closer to reality (and would make a big difference
> in the plan selected for a join).
>
> Now I know you said you did a "vacuum analyze" on the table, but
> I am wondering if maybe you got confused about what you did.
> Please try it again just to make sure.

I tried again and now it's working better. I think the first problem
was due to low shared memory available and a special factor between my
keyboard and my chair ;-)

Thanks for all you help!

Fernando P. Schapachnik
Administración de la red
VIA Net Works Argentina SA
Diagonal Roque Sáenz Peña 971, 4º y 5º piso.
1035 - Capital Federal, Argentina.
(54-11) 4323-3333
http://www.via-net-works.net.ar

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