How can I change MySQL server variables in Vitess? #

In general, if you want to apply global variables at the MySQL level, you have to do it through VTTablet. There are a few ways to do that in the operator, but we recommend that you use vtctldclient ExecuteFetchAsDba.

For example if you want to temporarily switch sync_binlog off on the MySQL that is being managed by a tablet with alias zone1-0000000100 you would perform the following:

$ vtctldclient -server localhost:15999 ExecuteFetchAsDba zone1-0000000100 "set global sync_binlog=0"

This would show the following result after checking the variable:

$ vtctldclient -server localhost:15999 ExecuteFetchAsDba zone1-0000000100 "show variables like 'sync_binlog'"+---------------+-------+| Variable_name | Value |+---------------+-------+| sync_binlog   |     0 |+---------------+-------+