Error [hyt00] [microsoft][odbc sql server driver] query timeout expired

Question

I have the below network setup:-
1. Its a simple network at my father's office at a small town called Ichalkaranji (District - Kolhapur, Maharashtra).
2. We are using private network range 192.168.1.xxx with two Windows Server 2003 Enterprise Edition with SP2 licensed copies and 15 local Windows 7 clients who are only using Server A.
3. The network is having a TP-Link Braodband Router Connected to internet with the IP 192.168.1.1.
4. Both there Windows Server 2003 Enterprise Edition with SP2 are running separate SQL Server 2005 Express with Advanced Services, you can treat them as Server A (Problematic Server with IP of 192.168.1.2) 
and Server B (this is not having any issue with IP of 192.168.1.3).
5. Server A is also being used by 6 Remote users from our Kolkata office using DDNS facility through the NO IP client software which installed separately on both the servers. Kolkata remote users
do not use OR access the Server B.
6. Server B is being used by only 2 Remote users from our Erode office (Under Salem District, Tamilnadu) using DDNS facility through the NO IP client software which installed separately on both
the servers. Erode remote users do not use OR access the Server A.
7. The front end application which running separately on both the servers have been developed in VB by a local vendor at Ichalkaranji (District - Kolhapur, Maharashtra).
8. Both Servers are having the same database structure in terms of design and tables format. Only difference is that both the servers are being used separately.
9. This error OR problem is only related to Server A, where on the clients we get the message "error [hyt00] [microsoft][odbc sql server driver] query timeout expired" every now and then.
10. We have to frequently reboot the server whenever we get this message on the client machines. May be after rebooting every thing works perfectly for 2 hours / 5 Hours / may be one full day but
the the error will come back for sure.
11. Current Database back up size on Server A is around 35 GB and take around 1 hour 15 minutes daily to take the back up.
12. Current Database back up size on Server B is around 3 GB and take around 5 to 10 minutes daily to take the back up.
13. One thing I have noticed is that when ever we reboot Server A, for some time sqlsrvr.exe file will show memory usage of 200 to 300 MBs but it will start using slowly, what i understand is that
this is the way SQL Server works.
14. Both the Servers are also running Quick heal Antivirus Server Edition separate licensed copies also.
15. Server B is also running Tally ERP 9 Licenses copy which is being used locally by 15 users of Ichalkaranji (District - Kolhapur, Maharashtra) same users
Can any one help to resolve this issue. Any help will be highly appreciated.

Answer 1

The error message "query timeout expired" occurs, because by default many APIs, including ODBC only waits for 30 seconds for SQL Server to send any output. If no data has been seen for this period of time, they tell SQL Server to cancel execution
and return this error to the caller.
This timeout could be seen as a token that the query is taking too long time to execute and this needs to be fixed. But it can also be a pain in the rear parts, if you are content with a report taking five minutes, because you only run it once a day.
The simplest way to get rid of the error is to set the timeout to zero, which means "wait forever". This is something your vendor would have to do. This may, however, not resolve the problem, as the users may just find that the application is hanging.
To wit, there are two reasons why the query takes more than 30 seconds to complete. One is that there is simply that much work to do. This can be reduced by adding indexes or by doing other tuning, if the execution time is not acceptable. The other possibility
is blocking. That is, there is a process blocking this query from completing. This is much more likely to require attention.
It is not clear to me, whether the vendor has developed the database part as well. In this case, you should probably call the vendor's support desk to have them to sort this out.
Finally, I am little puzzled. You say that you are using Express Edition, but one of the databases is 35 GB in size. 35 GB is far above the limit for Express Edition.
Erland Sommarskog, SQL Server MVP, [email protected]