Why AcyMailing Causes Load Issues on the Server

A huge racing website that we manage sends out daily newsletters using AcyMailing (the famous newsletter extension for Joomla), and every time those newsletters are sent, the website slows down gradually and eventually crawls to a halt. The whole performance degradation time is typically only a few minutes, which has always been tolerable by the website administrators – until Sunday (a couple of days ago), when they had several newsletters to send because of a huge racing event. They just couldn’t tolerate 30 minutes of website unresponsiveness and so they asked us to investigate and fix the problem prior to sending out those newsletters.

Typically, we don’t recommend our large clients to use Joomla extensions that use the application’s mail server to send out newsletters, not because we think they’re unreliable (on the contrary – we think they are very reliable), but it’s because we think (for many reasons – including load issues, blacklisting, server management, etc…) that the server hosting the main website should not be used as a newsletter server. What we do recommend is using a 3rd party tool to send out emails (most of these tools have extensions which allow them to be used from within Joomla, but without using the Joomla server as a mail server), for example ConstantContact or MailChimp. But some clients send out many newsletters to many people every day, which makes using a 3rd party tool a non-viable alternative from a financial perspective.

Going back to our original client’s request, we started investigating the problem by checking the MySQL slow query log, and it didn’t take us long to discover the root cause: it was a myriad of slow INSERT queries to different tables in the eximstats database. Every time AcyMailing sent an email to one individual, several INSERT query statement were executed on different tables of the eximstats database. Since each table was fairly large, some of these statements were taking several seconds to execute.

Since our client was relying on AcyMailing‘s statistics (and not on Exim‘s), we decided to disable statistics on Exim (Exim is one of the most used mail servers out there). Here’s how we did it:

  • We logged in to WHM on the server hosting the Joomla website.
  • We clicked on Service Configuration.

  • We then clicked on Service Manager.

  • We unchecked the box next to Eximstats.

  • We clicked on Save at the bottom (you will have to wait for about half a minute when you click on that Save button).

  • We restarted the Exim mail server by going back to the Home page on WHM, and then clicking on Restart Services, and then clicking on Mail Server (Exim), and finally clicking on Yes.

Doing the above ensured that Exim no longer collected statistics about the sent emails, which resolved the problem as the website stopped having load issues during newsletter sending time.

If you are using AcyMailing and you are having load issues (or even downtime) during the sending process, then try disabling Exim‘s statistics. If that doesn’t fix the problem, then a good idea would be to contact us. Our fees are right, our work is super professional, we love what we do, and we are the friendliest developers on Planet Earth.

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