show variables like 'max_%';

 

max_heap_table_size	16777216
max_tmp_tables	32

show variables like 'tmp_%';

tmp_table_size

1048576000

 

set tmp_table_size=1048576000

set max_heap_table_size=10240000000;

需要重启mysql服务才生效

 

 

set global read_buffer_size = 10240000;