Hardware and performance

OK, thanks.  I guess you mean http://docs.moodle.org/26/en/JMeter_test_plan_generator .  Which is great, but at the moment doesn't test anything related to quizzes, which is often an important part to test.

Hi Wen,

IMHO, having a huge mdl_log may affect mysql performance if your innodb buffer pool is too small or smaller than the actual database size. You can check your db size vs. memory and figure out an acceptable time frame to keep your log before purging it.

Hi Wen,

IMHO, having a huge mdl_log may affect mysql performance if your innodb buffer pool is too small or smaller than the actual database size. You can check your db size vs. memory and figure out an acceptable time frame to keep your log before purging it.

Here is a very quick summary. In our DB, mdl_log is a view defined like:

CREATE OR REPLACE VIEW mdl_log AS
        (         SELECT mdl_log_2014_02_12.id, mdl_log_2014_02_12."time", mdl_log_2014_02_12.userid, mdl_log_2014_02_12.ip, mdl_log_2014_02_12.course, mdl_log_2014_02_12.module, mdl_log_2014_02_12.cmid, mdl_log_2014_02_12.action, mdl_log_2014_02_12.url, mdl_log_2014_02_12.info
                   FROM mdl_log_2014_02_12
        UNION ALL
                 SELECT mdl_log_2014_02_05.id, mdl_log_2014_02_05."time", mdl_log_2014_02_05.userid, mdl_log_2014_02_05.ip, mdl_log_2014_02_05.course, mdl_log_2014_02_05.module, mdl_log_2014_02_05.cmid, mdl_log_2014_02_05.action, mdl_log_2014_02_05.url, mdl_log_2014_02_05.info
                   FROM mdl_log_2014_02_05)
UNION ALL
         SELECT mdl_log_2014_01_01.id, mdl_log_2014_01_01."time", mdl_log_2014_01_01.userid, mdl_log_2014_01_01.ip, mdl_log_2014_01_01.course, mdl_log_2014_01_01.module, mdl_log_2014_01_01.cmid, mdl_log_2014_01_01.action, mdl_log_2014_01_01.url, mdl_log_2014_01_01.info
           FROM mdl_log_2014_01_01;

CREATE OR REPLACE RULE mdl_log_delete AS
    ON DELETE TO mdl_log DO INSTEAD NOTHING;

CREATE OR REPLACE RULE mdl_log_insert AS
    ON INSERT TO mdl_log DO INSTEAD  INSERT INTO mdl_log_2014_02_12 ("time", userid, ip, course, module, cmid, action, url, info)
  VALUES (new."time", new.userid, new.ip, new.course, new.module, new.cmid, new.action, new.url, new.info);

Those definitions get modifed from time to time (new mdl_log_YYYY_MM_DD table created, and view changed to add the new one and no longer include the oldest one. The older mdl_log_YYYY_MM_DD tables are just left sitting around, making backups a pain, in case someone wants to use them for analytics some time in the future.

There is only one change in the code required to make this work. In get_columns in lib/dml/pgsql_native_moodle_database.php you need to change WHERE relkind = 'r' to WHERE relkind IN ('r', 'v').