Until the logrotate hit in the middle of some significant processing and a client had a query. What we found was a 2 second gap in the logs. The end of the old log was the start of a transaction and the start of the new log was the end of a completely different transaction. So we have lost partial information from two transactions and it is possible that there was at least one transaction between these two that was lost completely. Each transaction takes around 1 second to process, sometimes less
Can you provide your logrotate configuration or an example of it? It's been a while since I messed with logrotate, but I seem to recall that there are cases when using compression where there could be gaps in the saved data. I also want to say that there's a workaround for that problem. In any case, seeing your configuration may help us all understand what's going on in your case.
-Jeremy