Postmortem: MySQL Extractor errors


Original post

On May 11th 2020 10:12 UTC we have released a new version (5.5.1) of MySQL extractor in which a bug was present.
It caused errors in the UI:

Decoding JSON response from component failed: Syntax error

It also affected jobs of this extractor. Although the jobs seemed to finish successfully, they didn't process any data.
The flawed version was released at 10:12 UTC and reverted at 13:09 UTC.

Unfortunately another version (5.5.2) deployed on May 12th 7:25 UTC contained another bug, which affected certain queries, resulting in error message:
DB query failed: Trying to access array offset on value of type null

We have reverted this release on May 13th 11:26. It affected about 6% of all jobs of this component.
We sincerely apologize for the errors. 

What Happened?

The cause of the first problem was missing command in Dockerfile. This was fixed in release 5.5.2.

The second error was introduced with an update of PHP version. It was fixed in latest release (5.5.3).

What Are We Doing About This?

We have added tests to this component to cover these cases.