Re: planstats.sgml

On 16/02/16 20:01, Tatsuo Ishii wrote:
>>> 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.
>>
>> Oh, I see. I'm going to change "In this case" to "In the example above".
>
> Done.
>

Yeah, that is clearer.