Re: Optimizer showing wrong rows in plan

От: Matthew Wakeling
Тема: Re: Optimizer showing wrong rows in plan
Дата: ,
Msg-id: alpine.DEB.2.00.1003291210060.9798@aragorn.flymine.org
(см: обсуждение, исходный текст)
Ответ на: Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu)
Ответы: Re: Optimizer showing wrong rows in plan  (raghavendra t)
Список: pgsql-performance

Скрыть дерево обсуждения

Optimizer showing wrong rows in plan  (Tadipathri Raghu, )
 Re: Optimizer showing wrong rows in plan  (Szymon Guz, )
  Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu, )
   Re: Optimizer showing wrong rows in plan  (Szymon Guz, )
    Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu, )
     Re: Optimizer showing wrong rows in plan  (Tom Lane, )
      Re: Optimizer showing wrong rows in plan  (Jeremy Harris, )
       Re: Optimizer showing wrong rows in plan  (Tom Lane, )
        Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu, )
         Re: Optimizer showing wrong rows in plan  (Matthew Wakeling, )
          Re: Optimizer showing wrong rows in plan  (raghavendra t, )
           Re: Optimizer showing wrong rows in plan  (Nikolas Everett, )
 Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu, )
  Re: Optimizer showing wrong rows in plan  (Frank Heikens, )
  Re: Optimizer showing wrong rows in plan  (Gary Doades, )

On Mon, 29 Mar 2010, Tadipathri Raghu wrote:
> As per the documentation, one page is 8kb, when i create a table with int as
> one column its 4 bytes. If i insert 2000 rows, it should be in one page only
> as its 8kb, but its extending vastly as expected. Example shown below,
> taking the previous example table test with one column.

There is more to a row than just the single int column. The space used by
a column will include a column start marker (data length), transaction
ids, hint bits, an oid, a description of the types of the columns, and
finally your data columns. That takes a bit more space.

Matthew

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