Hi,
We just upgraded from 2.6 to 2.7.1 and can now see lots of the following errors messages in the apache error log:
[Mon Jul 14 13:48:25.517768 2014] [:error] [pid 28003:tid 46985641113920] [client xxxxxxxx] PHP Warning: oci_new_connect(): ORA-12516: TNS:listener could not find available handler with matching protocol stack in /home/moodle/moodle-sbx/lib/dml/oci_native_moodle_database.php on line 175, referer: https://xxxxxxxx/moodle-sbx/
This was never the case before the upgrade and nothing on the DB side changed.
We are far away from hitting the max sessions or max processes specified on the DB server.
This only happens in MDL 2.7 and 2.7.1, but not in 2.6.
It also looks like this is breaking the site. When the error happens (it's not constantly), the site loads only partially. Looking at the console in Firefox or Chrome, the rest of the site is experiencing error 503 (Service unavailable). Not sure if there is a relation between this behavior and the log file entry above, but it looks like it.
Server
Apache/2.4.3
PHP 5.5.6
Oracle 11G
Thanks!