Re: [GENERAL] Creation of tsearch2 index is very slow

От: Steinar H. Gunderson
Тема: Re: [GENERAL] Creation of tsearch2 index is very slow
Дата: ,
Msg-id: 20060121003646.GA31406@uio.no
(см: обсуждение, исходный текст)
Ответ на: Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane)
Список: pgsql-performance

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Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
 Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
  Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
   Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
    Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
     Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
      Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
      Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
       Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
        Re: [GENERAL] Creation of tsearch2 index is very slow  (Ron, )
         Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
       Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
       Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
      Re: [GENERAL] Creation of tsearch2 index is very slow  (Ron, )
       Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
       Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
        Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
         Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
          Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
           Re: [GENERAL] Creation of tsearch2 index is very slow  (Tom Lane, )
            Re: [GENERAL] Creation of tsearch2 index is very slow  ("Steinar H. Gunderson", )
            Re: [GENERAL] Creation of tsearch2 index is very slow  ("Craig A. James", )
            Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
             Re: [GENERAL] Creation of tsearch2 index is very  (Oleg Bartunov, )
              Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
             Re: [GENERAL] Creation of tsearch2 index is very  (Tom Lane, )
              Re: [GENERAL] Creation of tsearch2 index is very  (David Lang, )
               Re: [GENERAL] Creation of tsearch2 index is very  (Tom Lane, )
              Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
               Re: [GENERAL] Creation of tsearch2 index is very  (Alvaro Herrera <-ip.org>, )
                Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
                 Re: [GENERAL] Creation of tsearch2 index is very  ("Craig A. James", )
                  Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
        Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
         Re: [GENERAL] Creation of tsearch2 index is very slow  (Oleg Bartunov, )
          Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
           Re: [GENERAL] Creation of tsearch2 index is very slow  (Oleg Bartunov, )
            Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
           Re: [GENERAL] Creation of tsearch2 index is very slow  (Oleg Bartunov, )
       Re: [GENERAL] Creation of tsearch2 index is very slow  (Martijn van Oosterhout, )
      Re: [GENERAL] Creation of tsearch2 index is very  (Ron, )
 Re: [GENERAL] Creation of tsearch2 index is very  (Oleg Bartunov, )

On Fri, Jan 20, 2006 at 07:23:10PM -0500, Tom Lane wrote:
> I'm not very clear on what tsearch2 is doing with these bitmaps, but it
> looks like an upper page's downlink has the union (bitwise OR) of the
> one-bits in the values on the lower page, and you have to visit the lower
> page if this union has a nonempty intersection with the set you are looking
> for.  If that's correct, what you really want is to divide the values so
> that the unions of the two sets have minimal overlap ... which seems to me
> to have little to do with what the code does at present.

Sort of like the vertex-cover problem? That's probably a lot harder than
finding the two farthest points...

/* Steinar */
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Homepage: http://www.sesse.net/


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