I'm afraid there is still some cases would lead mistake if move cached_charset into rpl_group_info struct.

 

For a worker thread can keep a lot rpl_group_info structs in its rgi_free_list, and those rgis can be reused many times.

in this case:

a worker thread executes there transactions, which is trans1,trans2 and trans3

 

trans1's charset is utf8  and it use rgi1

trans2's charset is latin1  and it use rgi2

trans3's charset is utf8  and it use rgi1

 

so when worker thread start to execute trans3, rgi1->cached_charset == utf8. but thd->variables.character_set_* are latin1. and

them wouldn't be changed to utf8 for rgi->cached_charset_compare return 0.

 

Thanks