From: Silvio Macedo <smacedo@calmetric.pt>
To: pgsql-interfaces@postgresql.org
Subject: LabView and PostgreSQL ; and RecordSet GetString performance
Date: Thu, 25 Aug 2005 04:59:40 +0100
Message-ID: <000401c5a929$6c0cf930$0302a8c0@plexus> (raw)
Hi,
A week or two ago, Fisher Ulrich asked this list about interfaces from
LabView to PostgreSQL. (hope he's reading as I couldn't find his
original email in the list archive).
For LabView on Windows, you can use LabSQL, which is a simple, but
convenient, ADO wrapper to Postgres. You then can use native OLEDB
(undergoing development) or PostgreSQL OLE/ODBC driver.
LabSQL - google search it
OLEDB and ODBC come with standard dist (windows, of course)
To save you time, DSN-less connection strings are as follows:
For ODBC:
DRIVER={PostgreSQL};SERVER=127.0.0.1;port=5432;DATABASE=IT2CalMeter200
5;UID=IT2CalMeter;PWD=xxxxx;
For OLEDB:
Provider=PostgreSQL; Location=IT2CalMeter2005; User ID=IT2CalMeter;
Password=xxxxx;
change db, user and pass as needed, obviously.
Now, I'm having two issues with these:
- in native OLEDB, if an error happens when executing an SQL
statement, I cannot close the connection (ADO Connection.Close won't
actually close it) and the backend will start to have lots of zombie
connections (well, Idle at least).
- on the other hand, in OLE/ODBC, RecordSet.GetString is about 10
times slower than native OLEDB to get 20K records (tstamp,value).
Anybody had this sort of performance hit on GetString on PostgreSQL
ODBC?
Any tips? Any special connection string tuning?
Would GetRows be much better?
Thanks a lot
Silvio
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Cc: smacedo@calmetric.pt
Subject: Re: LabView and PostgreSQL ; and RecordSet GetString performance
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