include/master-slave.inc [connection master] include/stop_slave.inc RESET SLAVE ALL; include/start_slave.inc ==================================================================== Testing index for columns CHANNEL_NAME ==================================================================== ############ Explain for Query #################################### explain select HOST from performance_schema.replication_connection_configuration where CHANNEL_NAME = "impossible"; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table ############ Explain for Query #################################### explain select HOST from performance_schema.replication_connection_configuration where CHANNEL_NAME > "impossible"; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE replication_connection_configuration NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where ############ Explain for Query #################################### explain select HOST from performance_schema.replication_connection_configuration where CHANNEL_NAME < "2"; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE replication_connection_configuration NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where ############ Explain for Query #################################### explain select HOST from performance_schema.replication_connection_configuration where CHANNEL_NAME = "channel_1"; id select_type table partitions type possible_keys key key_len ref rows filtered Extra 1 SIMPLE replication_connection_configuration NULL const PRIMARY PRIMARY 256 const # 100.00 NULL ############# Explain End ######################################### flush status; select HOST from performance_schema.replication_connection_configuration where CHANNEL_NAME = "channel_1"; HOST # OK: handler_read_key incremented include/stop_slave.inc RESET SLAVE ALL; include/start_slave.inc include/rpl_end.inc