Tatsuo Ishii <ishii@postgresql.org> writes:
> While reading planstats.sgml, I encounted a sentence which I don't
> understand.
> These numbers are current as of the last <command>VACUUM</> or
> <command>ANALYZE</> on the table. The planner then fetches the
> actual current number of pages in the table (this is a cheap operation,
> not requiring a table scan). If that is different from
> <structfield>relpages</structfield> then
> <structfield>reltuples</structfield> is scaled accordingly to
> arrive at a current number-of-rows estimate. In this case the value of
> <structfield>relpages</structfield> is up-to-date so the rows estimate is
> the same as <structfield>reltuples</structfield>.
> I don't understand the last sentence (In this case...). For me it
> seems it is talking about the case when replages is not different from
> what the planner fetches from the table. If so, why "In this case"?
I think what it meant is "In the example above, ...". Feel free to
change it if you think that is clearer.
regards, tom lane