18.1 Upgrade - Increased DB Connections

One thing I would suggest is to double check that all the databases you have configured are still reachable/active. It's very rare, but I have seen cases where a database was decommissioned or reconfigured, but not modified in the list of configured databases, and the connection pool became exhausted as a result. (Of course, we wouldn't normally expect this to happen, but there are some unusual edge cases that can result in threads not getting released back to the pool when a database can't be reached.)

One thing I would suggest is to double check that all the databases you have configured are still reachable/active. It's very rare, but I have seen cases where a database was decommissioned or reconfigured, but not modified in the list of configured databases, and the connection pool became exhausted as a result. (Of course, we wouldn't normally expect this to happen, but there are some unusual edge cases that can result in threads not getting released back to the pool when a database can't be reached.)

All databases are active and reachable. We upgraded our instances to MySQL 5.7.21, but did this a few weeks prior to upgrading to 18.1, and did not see the increase in connections until the upgrade. Another change we made was updating the RDBMS driver to 5.1.46

For anybody following along, I've not yet resolved this issue, however I just downgraded the mySQL connector from 5.1.46 to 5.1.44 in hopes to isolate the issue. I will post results to this thread. I should know by tomorrow if this resolves it.

Did downgrading the mySQL connector isolate the issue?

No it did not resolve the issue

Hi Josh Burwell by any chance, did you discuss about this issue with Appian product support team?

No I have not discussed this with them yet. I was hoping to find a resolution on Community before reaching out, but unfortunately have not been able to do so. Reaching out is my next step.