[freetds] ODBC.ini parameter in FreeTDS

Frediano Ziglio freddy77 at gmail.com
Fri May 2 03:16:03 EDT 2008


Il giorno ven, 02/05/2008 alle 11.35 +0530, Rajesh Akolu ha scritto:
> Hi,
> 
> 
> 
> We are using FreeTDS 0.64 (TDS version 8.0) and unixODBC 2.2.12 on RH Linux 3.4.6 and connecting to Microsoft SQL Server 2000 from Linux. We are using C++ on Linux. 
> 
> 
> 
> We are looking for parameters which can increase the performance, so we used "Packetsize" parameter in odbc.ini and set it with different values and monitored our application performance. We found no difference.
> 
> 
> 
> We have done following tests:
> 
> 
> 
> Case 1:
> 
> ODBCConfig --> User DSN --> Configure --> "We entered 512 against PacketSize"
> 
> 
> 
> Case 2:
> 
> We used following connecting string in our code (here we did not specify PacketSize using ODBCConfig since we are using the same in connection string): "DRIVER=FreeTDS; SERVER=<server name>; DATABASE=pubs; UID=<user name>; PWD=<password>; PacketSize=512"
> 
> 
> 
> In both the above cases we did not see any performance difference. 
> 
> 
> 
> Please suggest thanks in advance.
> 
> 
> 
> 
> 
> Thanks & best regards,
> 
> Rajesh Akolu
> 

It's normal. TDS 7+ use a default of 4096, setting packet size to 512
don't change that much. Also under Linux there is an optimization that
use the bandwidth very efficiently so you wouldn't see much difference
increasing packet size.
I think that one of the greatest optimization that can be done is
binding BEFORE preparing. You'll remove an extra round-trip with the
server. Also don't prepare if you don't reuse the statement.

freddy77





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