Does max_connection=100 mean only 100 students simultaneously can attempt a quiz ?

Does max_connection=100 mean only 100 students simultaneously can attempt a quiz ?

by Mario Gharib -
Number of replies: 3

Dear Moodlers,

I would like to share with you a problem that we faced during an exam on Moodle

We are using the LMD

  • Moodle 3.1 (Postgresql 9.2.2; PHP Version 5.5.26) with
  • Server RedHatEnterpriseServer 5.3 Tikanga (Apache/2.2.4) RAM 8GB; CPU 3,07 GHz

We've faced a problem during the exam and in the log file we noticed that on

[Fri Jan 13 08:31:57 2017] [error] [client 172.17.34.16] PHP Warning: pg_connect(): Unable to connect to PostgreSQL server: FATAL: sorry, too many clients already in /usr/local/apache2/htdocs/moodle2.2/lib/dml/pgsql_native_moodle_database.php on line 159, referer: https://moodle.usj.edu.lb/mod/quiz/attempt.php?attempt=82596

The max_connection of PostgreSQL is set to 100,

Does it mean that I can only have a quiz of 100 students at the same time ?
If this is the case, what is the best number of max_connection with my server's specifications?

Many Thanks.

Mario.

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In reply to Mario Gharib

Re: Does max_connection=100 mean only 100 students simultaneously can attempt a quiz ?

by Tim Hunt -
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It does not mean that, because even when a student is attempting the quiz, most of the time they are just interacting with a page in their web browser, which does not involve the Moodle server. It is only when they submit a page of the quiz (or when autosave happens) that the server briefly has to do something. So, 100 DB connections should be enough for more than 100 users.

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In reply to Tim Hunt

Re: Does max_connection=100 mean only 100 students simultaneously can attempt a quiz ?

by Mario Gharib -

Dear Tim, thanks for your quick and helpful reply,

One more questions, what do they mean by shared_buffers = 32MB in the PostgreSQL configuration file ?

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