Re: [INTERFACES] scrollable cursor via odbc - Mailing list pgsql-interfaces

From David Hartwig
Subject Re: [INTERFACES] scrollable cursor via odbc
Date
Msg-id 3597E0BB.DA0DF3DA@insightdist.com
Whole thread Raw
In response to scrollable cursor via odbc  (Christian Steindl <e9425178@student.tuwien.ac.at>)
List 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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