I'd suspect the underlying query is poorly designed for the amount of data you have stored. If you have access to the mysql server you could connect to it using any mysql client and run 'show full processlist' to see the query as that page is trying to load. The query is probably in the 'sending data' state and gets killed at the limit of one of the timeout variables. This causes the application to throw that error you have.
Copy that query out, prefix it with explain and see if there are any tables in the query where an index could be added to optimize the database for the query. On Mon, Apr 3, 2017 at 6:09 AM, Ken D'Ambrosio <k...@jots.org> wrote: > Basically, it says that MySQL is not responding to queries. So it likely > has died, or perhaps is mis-configured. > > On April 3, 2017 7:07:25 AM EDT, Mahmood N <nt_mahm...@yahoo.com> wrote: > >Hi,I am using Moodle which itself uses SQL for the database. Problem is > >that, when I run the email plugin and execute the command, the refresh > >time of the page becomes high (in the order of 3-5 minutes) and at the > >end, I see this message > >Debug info: MySQL server has gone away > >SELECT id, sid, state, userid, lastip, timecreated, timemodified FROM > >mdl_sessions WHERE sid = ? > >[array ( > > 0 => 'jqfbgd5b0q6e2l81bb5gb87mn3', > >)] > >Error code: dmlreadexceptionStack trace: > > - line 479 of /lib/dml/moodle_database.php: dml_read_exception thrown > >- line 1175 of /lib/dml/mysqli_native_moodle_database.php: call to > >moodle_database->query_end() > >- line 1551 of /lib/dml/moodle_database.php: call to > >mysqli_native_moodle_database->get_records_sql() > >- line 1523 of /lib/dml/moodle_database.php: call to > >moodle_database->get_record_sql() > >- line 1502 of /lib/dml/moodle_database.php: call to > >moodle_database->get_record_select() > >- line 286 of /lib/classes/session/manager.php: call to > >moodle_database->get_record() > >- line 82 of /lib/classes/session/manager.php: call to > >core\session\manager::initialise_user_session() > > - line 785 of /lib/setup.php: call to core\session\manager::start() > > - line 27 of /config.php: call to require_once() > > - line 30 of /index.php: call to require_once() > > > > > >Although it looks like a bug in Moodle, but the guys said it is a MySQL > >issue. I am confused about that. If you have any idea please let me > >know. What does this error say exactly? > > > > Regards, > >Mahmood > > -- > Sent from my Android device with K-9 Mail. Please excuse my brevity. -- ----------------------------- Johnny Withers 601.209.4985 joh...@pixelated.net