a create index updates the statistics in pg_class,
this leads to substantial performance degradation compared to
6.4.2.

If you want to see what I mean simply run the performance test in
our test subdirectory.

I think the create index statement should not update this statistic.
(at least not in the newly created empty table case) 
This behavior would then be in sync with the create table behavior.

Andreas

Tue, 25 May 1999 17:04:17 +0200
ZEUGSWETTER Andreas IZ5 <Andreas.Zeugswetter@telecom.at>
create index updates nrows statistics
ZEUGSWETTER Andreas IZ5 <Andreas.Zeugswetter@telecom.at> writes:
> 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 think the create index statement should not update this statistic.
> (at least not in the newly created empty table case) 
> This behavior would then be in sync with the create table behavior.

Hmm, skip the update if size is found to be 0 you mean?  Might be
reasonable ... it would eliminate the problem that
	CREATE TABLE
	CREATE INDEX
	COPY ...
results in horrible plans compared to doing it in the "right" order.

			regards, tom lane

Tue, 25 May 1999 14:48:46 -0400
Tom Lane <tgl@sss.pgh.pa.us>
Re: [HACKERS] create index updates nrows statistics 