FreeTDS Development Group

[Medvidek Pu <Pu.Medvidek AT seznam.cz>]

Hi all,

I've just come accross a strange behavior of FreeTDS running on Core 2 Duo 
CPU. I'm using it from PHP. The pages with sql queries were generated much  
faster on my older machine than on my brand new Core 2 Duo PC. I've done a 
little investigation and I found that queries take an unreasonable amount of 
time. Looking more closely into the matter I found the following strange 
behavior:

1. I've created a script sql-test with the following content:

<code>
#!/bin/sh
for ((i=1; i<100; i++)); do sqsh -U sa -S my_server -D my_db -P my_passwd -i 
my_query.sql -p; done
</code>

It runs the same query repeatedly (100 times) and prints some statistcs (how 
much time it took).

2. While running the sql-test script above, the time a single query takes 
grows and grows. Sometimes it drops to reasonable time (0.1s) but then it 
grows upto several seconds.

3. But, running the sql-test script on two consoles concurrently, makes each 
single query complete in reasonable time. As the two sql-test processes take 
different time, one of them stops earlier then the other. After one of the 
two sql-test processes stops, the queries from the other sql-test process 
immediately start to run much slower.

4. Moreover, when I run the sql-test script while a PHP page with sql queries 
is being generated, then the PHP page is generated fast. When I do *not* run 
the sql-test script while a PHP page is being generated, then the PHP page is 
generated slowly.

5. When I generate two PHP pages with sql queries simultaneously, the pages 
are generated fast.

Summary: It is clearly not PHP-related thing, because the problem appears 
even in SQSH alone. It is clearly also not a SQSH-related thing, because 
PHP-SQSH is fast and PHP-PHP is fast. Therefore, I think it is a 
FreeTDS-related problem.

Is it a bug in FreeTDS? Is it a misconfiguration? Any ideas, solutions?

Thanks

Pavel

FreeTDS 0.64 and 0.63
SQSH 2.1.4
OpenSuSE Linux 10.2 x86
CPU: Core 2 Duo @ 2.4
RAM: 2GB