We recently experienced several random server crash events when the server was under load (circa 10,000 API calls per second). Initially, we thought we may have had some form of RACE event, but we narrowed the issue to several boolean fields that we were setting with a default value of false (n.b. a default value of true is ok).
We have not yet investigated why this field setting is an issue - this post is for community information - we will update as we learn more.
What affected this? workflows?
The default value for booleans is nothing (NULL in db).
You can set the default in the module field config
We had the default value box checked in the field settings. We have a beforeCreateUpdate workflow that sets some boolean values to true or false, but we found no causal relationship that the workflow was causing the issue. Simply unchecking the default value box on the fields prevented crashes from occurring. Crashes did not happen with low-volume, so it was hard to replicate.