Upgrading MySQL to 5.7 on a previous working Piwik has broken it. Most of the dashboard widgets now error with:
Referrer Websites SQLSTATE[HY000]: General error: 2006 MySQL server has gone away - caused by plugin Actions Widget Overview SQLSTATE[HY000]: General error: 2006 MySQL server has gone away - caused by plugin Actions
As per the FAQ I have increased the following parameters:
wait_timeout=100000
max_allowed_packet=128M
Restarted and so on. Even tried re importing the database and removing the character sets as per another solution. Thanks for help.
This was resolved in my original github post https://github.com/piwik/piwik/issues/9419. I'm posting the answer here to help others: The solution ended up being an issue with the character sets and an issue with the file upload scripts.
MySQL 5.7.5+ has now become strict on this setting. By default this is a programdata windows directory but piwik requires the following (depending on your environment):
secure-file-priv="xxxxxxxxxxxxx/piwik/tmp/assets"
If this is not set - the real error is:
General error: 1290 The MySQL server is running with the --secure-file-priv option so it cannot execute this statement: LOAD DATA INFILE xxxxxxxxxxxx
But of course all we can see is the 2006 gone away error......
SQLSTATE[HY000]: General error: 1300 Invalid utf8 character string: '"x':
In Mysql I was able to change the default "schema" piwik database to "latin1" and like magic everything worked again. This leads me to assume that converting a latin1 db over to utf8 might encounter similar issues as I did. I know character sets are a mine field but I wouldn't expect to see issues going from a latin1 to utf8 dataset (as they in theory should be a subset but hey this is still possible) - the other way around yes of course there should be issues most certainly.