Error Code: 2013. Lost connection to MySQL server during query

Question

I got the Error Code: 2013. Lost connection to MySQL server during query error when I tried to add an index to a table using MySQL Workbench. I noticed als

Answer 1

If all the other solutions here fail - check your syslog (/var/log/syslog or similar) to see if your server is running out of memory during the query.

Had this issue when innodb_buffer_pool_size was set too close to physical memory without a swapfile configured. MySQL recommends for a database specific server setting innodb_buffer_pool_size at a max of around 80% of physical memory, I had it set to around 90%, the kernel was killing the mysql process. Moved innodb_buffer_pool_size back down to around 80% and that fixed the issue.