The join_buffer_size in 1.mysql is defined in the
classUchar in Join_cache (sql_join_buffer.h) *Buff;voidjoin_cache::set_constants () sets the size of the buffBOOLjoin_cache::alloc_buffer () Request buff-sized memoryvoidJoin_cache:: Free() When the join operation is complete, free the memory immediatelyvoidjoin::d Estroy () destroys the join class each join operation will call My_malloc, My_free function Request/frees the size of joib_buffer_size memory. The Join_buffer_size is applied and released joib_buffer_size according to the number of operations per operation of the join table. (GDB) join_cache::set_constantsundefined command:"Join_cache". Try" Help". (GDB) BR Join_cache::set_constantsbreakpoint1At0X9A8AC9: file/home/os1/open/mysql5616/sql/sql_join_buffer.cc, line432. (GDB) BR Join_cache::alloc_bufferbreakpoint2At0x9a8cb0: file/home/os1/open/mysql5616/sql/sql_join_buffer.cc, line468. (GDB) R (gdb) BR Join_cache:: Free(GDB) br JOIN::d Estroy
How to use Mysql join_buffer_size