Re: [HACKERS] create index updates nrows statistics - Mailing list pgsql-hackers

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 thatCREATE TABLECREATE INDEXCOPY ...
results in horrible plans compared to doing it in the "right" order.
        regards, tom lane