Re: Improve ODBC Throughput ?

From: "Obe, Regina" <robe(dot)dnd(at)cityofboston(dot)gov>
To: "Arnaud Lesauvage" <thewild(at)freesurf(dot)fr>, <pgsql-odbc(at)postgresql(dot)org>
Subject: Re: Improve ODBC Throughput ?
Date: 2006-10-19 14:15:30
Message-ID: 53F9CF533E1AA14EA1F8C5C08ABC08D20107009A@ZDND.DND.boston.cob
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What kinds of indexes do you have on your tables? I think the way
Access works to limit transfer it first pulls the indexes and probably
the primary one first to determine how to fetch and how many to fetch.
I suspect if you have no indexes performance would be really bad.

Also which version of psqlODBC driver are you using?

-----Original Message-----
From: pgsql-odbc-owner(at)postgresql(dot)org
[mailto:pgsql-odbc-owner(at)postgresql(dot)org] On Behalf Of Arnaud Lesauvage
Sent: Thursday, October 19, 2006 8:55 AM
To: pgsql-odbc(at)postgresql(dot)org
Subject: [ODBC] Improve ODBC Throughput ?

Hi list !

I mostly use my PostgreSQL as a backend DB with Access2000 frontends.
The tables are linked via psqlODBC.
The problem I have is that even though queries / views run very fast,
the data take a long time to arrive to the client.
In the best situations, data is sent/received at ~500kB per second (for
instance, tables with only one column, which is a very large text field
>10.000 bytes per field).
In bad situations, I am at ~50kB per second.
If the queries / views return large resultsets, it can seconds for the
table to open., even though the query ran in milliseconds on the server
(explain analyze proves this).

What can I do to improve this throughput ? Either on the server side, or
on the ODBC client side ?

As a side note : network congestion, server acitvity is not a good
explanation. This server also is a file server, and I transfer files at
10MB per second all the time.

Thanks for your advices !
--
Arnaud

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