Why is my Drupal site so slow?

There are a bazillion reasons why Drupal is slow, but the main one is because you weren't paying attention. You have to measure performance of your site every day during development so you can tell what made it slow, and undo it.

See also

The page "How I made a Drupal site fast enough, one problem at a time" is a more stripped-down writeup of this same info.

How I'm attacking the problem

Since I know next to nothing about Drupal, I started off small by writing a script to clone drupal from git, install it, populate a site with fake data, run a benchmark on it, back it up, restore it, or remove everything. You can see the draft script at busydrupal.sh.txt.

After two days writing and playing with that, I felt confident enough to bring up the site in question on my local workstation. Having a private version of the site gave me the freedom to try things.

While debugging "calendar event creation taking two minutes", here's what I tried:

Things I've run into and fixed

These need to be checked periodically, as the fixes don't always last.

Remaining problems

See also