-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Mark and Jerry,
On 1/20/20 5:50 AM, Mark Thomas wrote: > Can you share the configuration of the connection pool? Don't > forget to mask any passwords. Also the Tomcat version ;) Recent posts from you suggest that this is 8.5.x, which means you are using commons-dbcp 2.0 unless you have specifically configured tomcat-pool (which will be obvious from your configuration). But it's always good to be sure. - -chris > On 19/01/2020 05:43, Jerry Malcolm wrote: >> I have a web page that makes a couple of hundred ajax calls when >> it loads. But the calls are recursive. The response from one >> call generates a couple of more calls. The responses from those >> calls generate others, etc. So this is not a blast of 200 >> simultaneous calls to the server. In most cases the count of >> active database connections never gets over 10-15 at a time. I >> have the max count on the connection pool set to 125. >> >> The server has very low traffic averaging a few pages an hour. >> Yesterday, I was testing this one page described above and and I >> started getting errors that no connections were available in the >> pool. My connection abort timeouts are very short, about 5 >> seconds, and the wait time for a free connection is 60 seconds, I >> believe. So theoretically, even if there were connection leaks, >> they should be returned well before waiting connections timed >> out, right? I went to the AWS RDS console to look at the >> connections graph. It showed that in the previous couple of >> minutes the database went from 3 connections to the max of 125. >> The page had timeout errors. But it was done. There was no more >> activity on this webapp. Yet the database monitor continued to >> show 125 connections. I kept refreshing for about 10 minutes >> expecting the connection pool to finally drop all of the >> connections. Nothing. Finally after about 10 minutes it still >> showed 125 connections, I bounced tomcat and the connection count >> on the database immediately fell to zero. BTW, I have >> logAbandoned set to true, and I'm not getting any abandon log >> entries. >> >> The problem occurred twice requiring a reboot of TC each time. >> I enabled some jmx code in my web app that logs the connection >> count each time I request/return a connection. Of course, now >> that I've got logging on, I can't reproduce the problem. I can >> reload that page a hundred times now, and my AWS RDS monitor >> shows a bump up to 10-15 connections for a brief time, then >> returns, exactly like I believe it should be working. >> >> I'm not a big fan of problems that just go away. I really want >> to figure out what is happening here, even if it's random. I >> don't believe this is a problem in the mainline code. Otherwise >> I think it would be more consistent. And again, even if I was >> not returning connections, they should be timing out and being >> logged. Another option is that I have a rogue thread that is >> sucking up all of the connections and holding them. But this >> problem only starts when I load this page. And I'm not aware of >> code that starts new threads in that area. Is there anything I >> can be doing to the connection pool to make it not close >> connections and return them to the pool? Or is there anything >> the database could be doing that would cause closing a connection >> to fail? >> >> I guess I'm just grasping at straws. Is there any type of >> low-level logging that I can enable that will tell me each time a >> connection is requested and returned (and possibly the call stack >> each time)? >> >> I've got a feeling this one is going to bite me some time soon >> and take a client site down with it. I really need to understand >> this one. >> >> Thanks as always, >> >> Jerry >> >> >> --------------------------------------------------------------------- >> >> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org >> For additional commands, e-mail: users-h...@tomcat.apache.org >> > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIyBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl4nR8gACgkQHPApP6U8 pFjCvw/434FFGqDusIzEGtbo/DFwwSAzoi1mbkeZvZ1fui0A0/wU3CCLgvE9eBVc Y7GMIByTvNIEuDu3SpN+XLRdDvMcn+OJmlTnJmGiOMy2WZKr6lAL/U57YjUlpNgj BiTx2Y26ohbfmWBfy32x6Y3s5r4aszjyOMIoF3RNzgFa1YhvezNpyNxBqjoyxARi lU5djVbo8mdzZEORYifQdAZNqFviQLdRN+Dp6+j0+g8Y0xCIK9gJp3OtJxNL0Nbc FgGIIlO6V7uLgIXEPCnMkV4R5h6vrQ9feDjbxBhsafHfbqzHpCoWvWZyrYcyxC51 CimYxyenWUabh0TpGNxUovMgqEbdOrXQzQF/ALWBwyKtJevj4J/MuUNBFLluyt9K dW2CUtZrG+6eo0Ns65PAZ9jSPQNOJX0D8HYbCQj1QpRn6LMtfPmAMhveOjiZSDBu BXzRMPK9yqsJoJiziNNiFV2qF1h+MZQDwiIbUttWnm1bfnWGrBix/+wC+Kkr2rR/ ChzQFebHRdoxJGwqGZ8iaXBqlNYYIpp6OssCuRFEsDLBuPuDtupr48IstGsZm9Ni ZuRTEhD2Agv0yXS0uTyS4OK2cFuoOGCZ59QB7553dQngXDtCoGbdQ8Fi5iJ4oCpB 4jF9vTnOzOjtpqacN98EpDPMHOQ9H+RDNzluVL5haD0DTybmdg== =/J/H -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
