mysql5.6.38 High memory footprint problem resolution

I have a server memory of 1G, MySQL after the boot up memory of about 450M, memory ratio of about 46%. MySQL memory consumption is too large, resulting in server memory is very tight, and msyql and other processes in the running process often crashes. After finding the relevant data, the following three parameters were added to the my.cnf file:

performance_schema_max_table_instances=400
table_definition_cache=400
table_open_cache=256

After restarting MySQL, it was found that MySQL memory usage dropped to 10%.

As a comparison, record the default configuration of mysql5.6.38 for three parameters:

　　

The specific meanings of these three fields need to be supplemented and documented. At present, the results expressed satisfaction.

mysql5.6.38 High memory footprint problem resolution