[Users] lcr module stops rolling over...

As the subject sez., rollovers just stop working. Detailed scenario - We use the lcr module for outbound calls through our (multiple) gateway providers. For various reasons, the providers frequently reject the call, and we roll the call over to the next provider (next_gw(), etc., etc.) The lcr module, however, stop rolling the calls over after a couple of thousand rejections. As best as I can tell, next_gw() fails, and the rejection just gets passed back to the CPE. Any ideas? Is there some sort of counter? Some sort of memory limit that we are running into? For what it is worth, we process a couple of thousand calls an hour, and the box that OpenSER is running on is a dual Opteron with 3GB, etc., etc. Cheers p.s. One additional factoid. We log to acc/mysql, and query the acc table to get CDRs. The query runs once every 30 seconds or so. We can't turn this off for any extended period, but have done so once next_gw() starts failing. It doesn't seem to make a difference.