Validation queries run without any explicit timeout. If the validation query blocks (as it will with most drivers when a connection is invalid/stale), this can block the entire pool in certain cases (e.g. background-validation locks the pool during validation). Even with validate-on-match, the failure to enforce a short timeout can significantly impact time to get a connection if one or more failed connections are found in the pool. - Jira issue <https://issues.redhat.com/browse/WFLY-17180> - Feature proposal <https://github.com/wildfly/wildfly/pull/19641> Regards, Tomek