Forum OpenACS Q&A: Response to What are all the fields that Aolserver includes in the log?

AOLserver maintains a pool of threads that handle each incoming connection, by amongst other things, allocating a Tcl interpreter, running your various filters, running the page itself, and running the trace filters.

The connection number is not the nth request that has been made to your server, but the nth thread started to handle the connections. Connection threads have an maximuum idle. If they are idle too long, they exit.

So amusingly, if you have a busy server in which connections threads are rarely idle and never exit, the connection numbers are very small. But if you have an idle server, which is rarely used, and in which connections threads usually timeout, the connection numbers grow large.