| From: | ZEUGSWETTER Andreas IZ5 <Andreas(dot)Zeugswetter(at)telecom(dot)at> |
|---|---|
| To: | "'tgl(at)sss(dot)pgh(dot)pa(dot)us'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | "'hackers(at)postgresql(dot)org'" <hackers(at)postgreSQL(dot)org> |
| Subject: | AW: [HACKERS] create index updates nrows statistics |
| Date: | 1999-05-26 07:28:07 |
| Message-ID: | 219F68D65015D011A8E000006F8590C60267B379@sdexcsrv1.f000.d0188.sd.spardat.at |
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| Lists: | pgsql-hackers |
> > a create index updates the statistics in pg_class,
> > this leads to substantial performance degradation compared to
> > 6.4.2.
>
> Create index did that in 6.4.2 as well --- how could it be making
> performance worse?
>
I am not sure why, but in 6.4.2 a create table, create index, insert,
select * from tab where indexedcol=5 did actually use the index path,
even if table reltuples and relpages was 0.
It currently uses a seq scan, which is exactly what we wanted to avoid
in the newly created table case, but do want on an actually small table.
Please apply the patch I previously sent.
Andreas
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| Next Message | Jan Wieck | 1999-05-26 07:43:29 | Re: AW: [HACKERS] create index updates nrows statistics |
| Previous Message | ZEUGSWETTER Andreas IZ5 | 1999-05-26 07:25:59 | Re: [HACKERS] strange behavior of UPDATE |