help with query speed

[Jason Tesser]

I have the below query written. I have removed a lot from the select
Statement for simplicity sake. The query takes way too long.
I am moving from an Access backend to a Postgres back with
Access in the front. The below query is taking like 14-20 seconds.
Is their a better way I can write the joins. I would think that
Postgres should be fast than Access. BTW I am writing these as
Pass through queries so it is not a problem with Access. I have
Even ran the query directly against Postgres.

SELECT
tblroster.transcriptlink
FROM
tblroster
FULL OUTER JOIN testclass ON (tblroster.classlink = testclass.classid)
FULL OUTER JOIN tblqualitypoint ON (tblroster.lettergrade =
tblqualitypoint.letter)
ORDER BY
tblroster.transcriptlink

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[scott.marlowe]

On Thu, 12 Feb 2004, Jason Tesser wrote:

I have the below query written. I have removed a lot from the select
Statement for simplicity sake. The query takes way too long.
I am moving from an Access backend to a Postgres back with
Access in the front. The below query is taking like 14-20 seconds.
Is their a better way I can write the joins. I would think that
Postgres should be fast than Access. BTW I am writing these as
Pass through queries so it is not a problem with Access. I have
Even ran the query directly against Postgres.

SELECT
tblroster.transcriptlink
FROM
tblroster
FULL OUTER JOIN testclass ON (tblroster.classlink = testclass.classid)
FULL OUTER JOIN tblqualitypoint ON (tblroster.lettergrade =
tblqualitypoint.letter)
ORDER BY
tblroster.transcriptlink

Are tblroster.classlink and testclass.classid the same type and indexed?

Same for tblroster.lettergrade and tblqualitypoint.letter

Also is tblroster.transcriptlink indexed? Is the query using indexes?
Check it with

explain analyze <query>

and see what it says, look for big differences between expected and actual
rows, width, and loops.
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