The Moodle message 'Error reading database' was giving us a hard time. Turned out to be our Sonicwall 3600 firewall had downloaded new profiles for its Intrusion Detection and Prevention routines that mistook some of the more complex SQL queries (but not most of them) for a 'heartbeat' attack (a low risk info gathering exploit). The problem seemed to coincide with one of our Moodle updates, so we thought it was Moodle - but Moodle was fine. This happened in August-September 2015. The problem predictably showed up in several courses which had us looking for data corruption or problems with code associated with those courses. Once I caught the problem in our firewall log, I disabled 'prevention' in our firewall for the 'heartbeat' attack and the problem went away. Note: our Moodle configuration has the Web server in our DMZ and the SQL server in our protected internal network.
General help
error reading database message
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