Re: gincostestimate

Itagaki Takahiro <itagaki(dot)takahiro(at)gmail(dot)com> writes:
> On Wed, Sep 8, 2010 at 1:02 AM, Teodor Sigaev <teodor(at)sigaev(dot)ru> wrote:
>> Fixed, and slightly reworked to be more clear.
>> Attached patch is based on your patch.

> The stats page is updated only in VACUUM. ANALYZE doesn't update
> the information at all.

ANALYZE doesn't scan indexes, so it's not realistic to expect ANALYZE to
update these numbers.

In addition, REINDEX, VACUUM FULL, and
> CLUSTER reset the information to zero, but the reset is not preferable.
> Is it possible to fill the statistic fields at bulk index-build?

I fixed that and committed it. It probably wouldn't be a bad idea for
Teodor or Oleg to double-check where I put in the counter increments;
although I did test that they matched the results of VACUUM for a
reasonably large GIN index.

> We don't have any methods to dump the meta information at all.
> They might be internal information, but some developers and
> debuggers might want such kinds of tools. Contrib/pageinspect
> might be a good location to have such function; it has bt_metap().

That seems like a good idea, but I haven't done it.

regards, tom lane