AW: [HACKERS] create index updates nrows statistics

Zeugswetter Andreas <andreas.zeugswetter@telecom.at>

From: ZEUGSWETTER Andreas IZ5 <Andreas.Zeugswetter@telecom.at>
To: "'tgl@sss.pgh.pa.us'" <tgl@sss.pgh.pa.us>
Cc: "'hackers@postgresql.org'" <hackers@postgreSQL.org>
Date: 1999-05-26T07:28:07Z
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