Re: Optimizer showing wrong rows in plan - Mailing list pgsql-performance

From Matthew Wakeling
Subject Re: Optimizer showing wrong rows in plan
Date
Msg-id alpine.DEB.2.00.1003291210060.9798@aragorn.flymine.org
Whole thread Raw
In response to Re: Optimizer showing wrong rows in plan  (Tadipathri Raghu <traghu.dba@gmail.com>)
Responses Re: Optimizer showing wrong rows in plan  (raghavendra t <raagavendra.rao@gmail.com>)
List pgsql-performance
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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