Re: LIMIT clause and long timings - Mailing list pgsql-novice

From Tom Lane
Subject Re: LIMIT clause and long timings
Date
Msg-id 2249.1143561086@sss.pgh.pa.us
Whole thread Raw
In response to LIMIT clause and long timings  (Andrea <andrea.b73@email.it>)
Responses Re: LIMIT clause and long timings  (Christoph Della Valle <christoph.dellavalle@goetheanum.ch>)
List pgsql-novice
Andrea <andrea.b73@email.it> writes:
> Then I have tried:
> SELECT * FROM banche ORDER BY banca LIMIT 10 OFFSET 34000;
> [....]
> (10 rows)

> Time: 2433,000 ms

> Why do I get this big timing???

Because the system has to scan through 34000 rows before it gets to the
ten you asked for.  OFFSET is not some bit of black magic, it just
causes the executor to discard the first N rows it's computed rather
than sending them over to the client.

            regards, tom lane

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