Re: Efficiency of timestamps

От: Martin Foster
Тема: Re: Efficiency of timestamps
Дата: ,
Msg-id: 3F0B98CA.90800@ethereal-realms.org
(см: обсуждение, исходный текст)
Ответ на: Re: Efficiency of timestamps  (Stephan Szabo)
Ответы: Re: Efficiency of timestamps  (Stephan Szabo)
Список: pgsql-performance

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Efficiency of timestamps  (Martin Foster, )
 Re: Efficiency of timestamps  (Stephan Szabo, )
  Re: Efficiency of timestamps  (Martin Foster, )
   Re: Efficiency of timestamps  (Stephan Szabo, )
    Re: Efficiency of timestamps  (Martin Foster, )
     Re: Efficiency of timestamps  (Stephan Szabo, )
      Re: Efficiency of timestamps  (Martin Foster, )

Stephan Szabo wrote:
>
>
> The row estimate is high. How many rows meet the various conditions and
> some of the combinations? And how many rows does it estimate if you do a
> simpler query on those with explain?
>
> I still think some variety of multi-column index to make the above index
> conditions would help, but you'd probably need to play with which ones
> help, and with the cost cut for the limit, I don't know if it'd actually
> get a better plan, but it may be worth trying a bunch and seeing which
> ones are useful and then dropping the rest.
>
>

At any given point in time you would not expect to see much more then 30
posts applying for a time based search.    That is primarily a result of
having more then one room for which posts are attached to, and then some
posts exist just to show people are there et cetera.

Simpler queries seem to do quiet well.   That view makes use of the same
table and seems to have no performance impact from doing as such, and
the position based search is considerably faster.

I can show EXPLAIN ANALYSE for all of those if you wish.

    Martin Foster
    Creator/Designer Ethereal Realms
    




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