Thread: Bad performance using ODBC
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I have a performance problem using postgresql when the connection is made via ODBC with a windows machine using the latests ODBC drivers (Windows) and PostgreSQL 7.3.3 (Linux). The queries made by my Visual Basic program are very very simple. It queries with as Select if a record exists and if so, it reduces stock with an Update. For the benchmarks I do it 200 times. If I test it against an Access database (located in a SMB server) it spends 3 seconds but against PostgreSQL 17 !! Exactly the same test programmed in C (with pgsql libraries) and run within the same machine or another Linux spends less than a second!! So the problem seems to be whether with the ODBC drivers or with Windows ODBC itself. Are there any parameters in the ODBC drivers that might help reducing that big overhead added or do you have any suggestions to speed it up? Thanks in advance! -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQE/FV3pTK7ZP4pDOHcRAmVWAJ9KF/YyKmuBZcidV3FK2gESaX25NwCgjABx 6WhA0HgC7oxF7VFJeczIrgE= =3H+u -----END PGP SIGNATURE-----
Albert Cervera Areny <albertca@jazzfree.com> writes:
> I have a performance problem using postgresql when the connection is made
> via ODBC with a windows machine using the latests ODBC drivers (Windows) and
> PostgreSQL 7.3.3 (Linux).
Do you have logging turned on in the ODBC driver? I recall hearing that
that adds a heck of a lot of overhead...
regards, tom lane
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 A Dimecres 16 Juliol 2003 16:38, Tom Lane va escriure: > Albert Cervera Areny <albertca@jazzfree.com> writes: > > I have a performance problem using postgresql when the connection is > > made via ODBC with a windows machine using the latests ODBC drivers > > (Windows) and PostgreSQL 7.3.3 (Linux). > > Do you have logging turned on in the ODBC driver? I recall hearing that > that adds a heck of a lot of overhead... After trying too many things I've finally been able to make it run in just 1 or 2 seconds. I simply had to change the recordset type and set it to dbOpenSnapshot (This one doesn't show changes made to the database once it's been open) instead of the default dbDynaset (much more powerful but unnecessary in this application). Take note that though it might seem obvious the performance loss against Access isn't that much and thus VB users aren't probably used to change the recordset type. I think It would be nice a note with this performance benchmarks (2 seconds against 15) in the Mini-Howto on Accessing PostgreSQL from Visual Basic. I'll contact Dave Page directly in case he finds it interesting. I haven't seen any speed improvements desabling logging but thanks for your suggestion anyway! > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) iD8DBQE/FstfTK7ZP4pDOHcRArepAJ9rIhOKtztuPORbGkrVTOfC4UmUOQCeJ00u UxJegkvrs4TL3QVXNun3iFs= =itG7 -----END PGP SIGNATURE-----