Slow log configuration

±-----------------±------+
| Variable_name | Value |
±-----------------±------+
| slow_launch_time | 2 |
±-----------------±------+

Above configuration mean that any query run with duration 2 miliseconds will be show up on the memsql.log file ?

Can I change this values ? And Does it need to change in all the nodes ?

No, that variable doesn’t do anything in MemSQL.

Because MemSQL attempts to be MySQL compat. it also allows you to set/query many MySQL variables that MySQL client drivers or MySQL tools may query so those drivers and tools continue to function. Those variables are no-ops in MemSQL though.

MemSQL doesn’t have a slow query log like MySQL does. It instead has a much more detailed information. The place to start looking for slow queries is the plancache (https://docs.memsql.com/tutorials/v6.8/query-tuning/). If you want more detailed information you can use workload profiling (https://docs.memsql.com/concepts/v6.8/workload-profiling-overview/)