Re: TB-sized databases

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От Ron Mayer
Тема Re: TB-sized databases
Дата
Msg-id 4759B11D.1030201@cheapcomplexdevices.com
обсуждение исходный текст
Ответ на Re: TB-sized databases  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> Ron Mayer <rm_pg@cheapcomplexdevices.com> writes:
>> Tom Lane wrote:
>>> There's something fishy about this --- given that that plan has a lower
>>> cost estimate, it should've picked it without any artificial
>>> constraints.

One final thing I find curious about this is that the estimated
number of rows is much closer in the "offset 0" form of the query.

Since the logic itself is identical, I would have expected the
estimated total number of rows for both forms of this query to
be identical.

Any reason the two plans estimate a different total number of rows?



(explain statements for the two forms of the same query
from earlier in the thread here:
http://archives.postgresql.org/pgsql-performance/2007-12/msg00088.php )

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