Re: explain plan

From: Francisco Reyes <fran(at)reyes(dot)somos(dot)net>
To: rudy <rudy(at)heymax(dot)com>
Cc: <pgsql-novice(at)postgresql(dot)org>
Subject: Re: explain plan
Date: 2001-02-02 05:13:39
Message-ID: Pine.BSF.4.32.0102020007560.1877-100000@zoraida.reyes.somos.net
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> Seq Scan on article (cost=0.00..1.61 rows=1 width=8)

:-)
Replying to myself..

Notice the "cost" reported by the database. "0.00..1.61". That is fairly
low. Just to give you an example. I have a table with 259 rows. and I got:
-------
test=# explain select * from phones;
NOTICE: QUERY PLAN:

Seq Scan on phones (cost=0.00..20.00 rows=1000 width=36)

EXPLAIN
test=# vacuum analyze
test-# ;
VACUUM
test=# explain select * from phones;
NOTICE: QUERY PLAN:

Seq Scan on phones (cost=0.00..5.59 rows=259 width=36)
--------

0 to 5.59 for just 259 rows, yet yours is only 1.61. Possible the entire
table was in memory so there was no need to go to index.

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