Re: performance...

You have weatherid indexed, right? If not, index it and run VACUUM
ANALYZE -- if so make then sure you've run VACUUM ANALYZE after you
created the index..

Also, you might want to EXPLAIN that query to get the query plan (just
type EXPLAIN <query>)if the above doesn't work. Post the ouput of
EXPLAIN along with the schema of your tables and perhaps someone can help
some more..

-Mitch

On Mon, 29 Jan 2001, chris markiewicz wrote:

> hello.
>
> this might be as much of a general database question as it is a postgres
> question...
>
> i have a table with 5 columns...a primary key (integer), three small (10
> character) text fields, and one semi-large (1400 characters) text field.
> note that only a small percentage (5% ?) of the rows contain 1400 characters
> in the 5th column...the other 95% have approx 10 characters. it has 1100
> rows.
>
> the problem is this - queries (command line) often take a very long time -
> anywhere from 5-15 seconds - to execute. the queries use only the primary
> key and nothing else in the where clause. no joins. a sample query is:
>
> select * from weather where weatherid = 12372;
>
> from the command line, it seems that the first query can take a very long
> time but subsequent queries happen quickly ( < 1 sec). i'm guessing that
> this is the result of caching or something.
>
> do the long times make sense? what can i do to shorten them? would a
> smaller text field help? i have no reason to think that this would be
> faster or slower in another db, so it might be unrelated to postgres itself.
>
> i greatly appreciate your help.
>
> chris
>
>