[Labs-l] Labs restart & mysql connections dropping?

[Russell Blau]

Sean Pringle <springle <at> wikimedia.org> writes:

> Which recent restart?  The GHOST restarts in late January, or the labsdb 
restarts last week? Something else?
> 
> 
> What error codes and messages are you seeing client side?
> 
> Is there any pattern? Eg, time of day, specific queries, etc
> What lead you to look at the problem? Is it definite that connections 
started dropping at a known point in time?
> 
I can give you some answers for a different project. Tool Labs project 
'dplbot' has a database job that runs twice a day. Starting after 18:00 
UTC on 8 Feb 2015, a particular PHP script that involves a lot of writes 
to a project database (p50380g50692__DPL_p) on enwiki.labsdb started to 
fail consistently with the error message "MySQL server has gone away." The 
script had not changed, and this error had not occurred before this time, 
but it now occurs every time we attempt to run this particular script.

Russ