Re: pgstattuple extension for indexes

Bruce,

Attached patch has been cleaned up,
and modified to be able to work with CVS HEAD.

Thanks.

Satoshi Nagayasu wrote:
> Alvaro,
>
> Alvaro Herrera wrote:
>> Huh, I bet it works with 8.1.4, but it doesn't work on CVS HEAD:
>>
>> /pgsql/source/00orig/contrib/pgstattuple/pgstatindex.c: In function 'GetBTPageStatistics':
>> /pgsql/source/00orig/contrib/pgstattuple/pgstatindex.c:182: error: 'BTItem' undeclared (first use in this function)
>>
>>
>> While you're at it, please consider removing C++ style comments and
>> unused code.
>>
>> Formatting is way off as well, but I guess that is easily fixed with
>> pgindent.
>
> Thanks for comments. I'm going to fix my patch from now.
>
>> Regarding the pg_relpages function, why do you think it's necessary?
>> (It returns the true number of blocks of a given relation). It may
>> belong into core given a reasonable use case, but otherwise it doesn't
>> seem to belong into pgstatindex (or pgstattuple for that matter).
>
> I wanted to sample some pages from the table/index, and get their statistics
> to know table/index conditions. I know pgstattuple() reports table
> statistics, however, pgstattuple() generates heavy CPU and I/O load.
>
> When we need to sample some pages from table/index, we need to know
> true number of blocks.
>
> I have another function, called pgstatpage(), to get information inside
> a single block/page statistics of the table. pg_relpages() will be used
> with this.
>
> Sorry for not mentioned in previous post about pgstatpage(),
> but I've remembered about it just now.
>
> Many memories in my brain have already `paged-out` (too busy in last few months),
> and some of them got `out-of-memory`. :^)
>
> Thanks.

--
NAGAYASU Satoshi <nagayasus(at)nttdata(dot)co(dot)jp>
Phone: +81-3-3523-8122