That's very odd. Even for a timeout you should get back a page that says timeout (unless you've set your script timeout to -1 or some huge number and it's the web client or server that's timing out). Check your vortex.log and webserver error log for corresponding events.
You can eliminate the webserver from the equation by performing SQL on the command line with texis.
texis -d /path/to/your/database -s "select ..."
Please also summarize the actual sql statement and queries you're using and what kind(s) of indices are on the fields being queried.
You can eliminate the webserver from the equation by performing SQL on the command line with texis.
texis -d /path/to/your/database -s "select ..."
Please also summarize the actual sql statement and queries you're using and what kind(s) of indices are on the fields being queried.