Excerpts from Kevin Grittner's message of mié may 25 12:37:24 -0400 2011:
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> > I don't know what client-side code might be looking at
> > relpages/reltuples.
>
> I know that I find reltuples useful for getting an "accurate enough"
> sense of rows in a table (or set of tables) without resorting to
> count(*). I'd be OK with any two of pages, tuples, and density; but
> dropping to one would make databases harder to manage, IMV.
>
> Personally, I don't have much code that uses those columns;
> eliminating an existing column wouldn't involve much pain for me as
> long as it could still be derived.
Well, we only actually need to store one number, because you can figure
out a much more precise number-of-pages figure with pg_relation_size()
divided by configured page size.
(We feel free to hack around catalogs in other places, and we regularly
break pgAdmin and the like when we drop columns -- people just live with
it and update their tools. I don't think it's such a big deal in this
particular case.)
--
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
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