Re: [HACKERS] create index updates nrows statistics

ZEUGSWETTER Andreas IZ5 <Andreas(dot)Zeugswetter(at)telecom(dot)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