From: | David Hartwig <daveh(at)insightdist(dot)com> |
---|---|
To: | Christian Steindl <e9425178(at)student(dot)tuwien(dot)ac(dot)at> |
Cc: | pgsql-interfaces(at)postgreSQL(dot)org |
Subject: | Re: [INTERFACES] scrollable cursor via odbc |
Date: | 1998-06-29 18:45:16 |
Message-ID: | 3597E0BB.DA0DF3DA@insightdist.com |
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Lists: | pgsql-interfaces |
Christian,
The problem is in the backend optimizer. If you turn on the commlog, you
will find that queries are being generated with lots of ORs. This is to get
a record set. If you run that query with EXPLAIN you will find that it is
doing a sequential scan. (Maybe several per page scroll.) Even worse, if
you have a multi-part key, the optimizer will spend (expend) much resource
CNFifying the where clause.
I am working on a patch to resolve this in the backend. I have a workable
solution, for queries with this particular signature, but I am trying to
make it more general purpose in nature.
Christian Steindl wrote:
> i use the odbc interface to the postgresql but it seems to be quite
> slowly.
> although it's a single table with about 20.000 rows.
> i set a link in an access-db and scrolling (next page, last row) is very
> slowly.
> is there a way to optimize the performance?
> can i use scrollable cursor via the odbc-drv?
>
> best regards
>
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