Re: sequence scan on PK

От: Tom Lane
Тема: Re: sequence scan on PK
Дата: ,
Msg-id: 12303.1115570959@sss.pgh.pa.us
(см: обсуждение, исходный текст)
Ответ на: Re: sequence scan on PK  (Jeroen van Iddekinge)
Ответы: Re: sequence scan on PK  (Grega Bremec)
Список: pgsql-performance

Скрыть дерево обсуждения

sequence scan on PK  (Jeroen van Iddekinge, )
 Re: sequence scan on PK  (John A Meinel, )
  Re: sequence scan on PK  (Jeroen van Iddekinge, )
   Re: sequence scan on PK  (Matteo Beccati, )
    Re: sequence scan on PK  (Jeroen van Iddekinge, )
     Re: sequence scan on PK  (Matteo Beccati, )
      Re: sequence scan on PK  (Jeroen van Iddekinge, )
   Re: sequence scan on PK  (John A Meinel, )
   Re: sequence scan on PK  (Tom Lane, )
    Re: sequence scan on PK  (Grega Bremec, )

Jeroen van Iddekinge <> writes:
>> You could tweak with several settings to get it to do an index scan
>> earlier, but these would probably break other queries. You don't need to
>> tune for 100 rows, morelike 100k or 100M.

> Which settings shoud I change for this?

I'd agree with John's response: if you change any settings based on just
this one test case, you're a fool.  But usually random_page_cost is the
best knob to twiddle if you wish to encourage indexscans.

            regards, tom lane


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