| From: | Bruce Momjian <maillist(at)candle(dot)pha(dot)pa(dot)us> |
|---|---|
| To: | holston(at)itd(dot)nrl(dot)navy(dot)mil (Gregory Holston) |
| Cc: | pgsql-sql(at)hub(dot)org |
| Subject: | Re: [SQL] what is "cost"? |
| Date: | 1999-04-23 21:29:24 |
| Message-ID: | 199904232129.RAA14632@candle.pha.pa.us |
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| Lists: | pgsql-sql |
> > The cost value is only meaningful to the optimizer in comparing various
> > query plans.
> >
> I got the 72.98 on this table while doing a simple "select * from
> publication" meanwhile I got nothing higher than 4 on any other table. Is this
> indicative of a problem?
No. It means the optimizer thinks it is going to have to do more work
to complete the query. All other methods it used to complete the query
had a higher cost. It is related to the number of rows in the table,
the indexes available, sorts needed, joins, etc.
--
Bruce Momjian | http://www.op.net/~candle
maillist(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026
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