maria-developers team mailing list archive
Mailing list archive
Re: a Query_log_event charset bug in parallel replication
Hi nanyi607rao, sorry for the delayed response, in part due to the Easter holidays.
"nanyi607rao" <nanyi607rao@xxxxxxxxx> writes:
> If character_set in different Query_log_events changed, worker threads may apply them with wrong character_set. the codes leading this problem is in Query_log_event::do_apply_event, that is:
> if (charset_inited)
> if (rli->cached_charset_compare(charset))
> /* Verify that we support the charsets found in the event. */
> if (!(thd->variables.character_set_client=
> get_charset(uint2korr(charset), MYF(MY_WME))) ||
> get_charset(uint2korr(charset+2), MYF(MY_WME))) ||
> get_charset(uint2korr(charset+4), MYF(MY_WME))))
> There is a charset in rli, which cached last Query_log_event's charset in serial replication. But in parallel replication it would lead mistake, because every worker thread can read and set rli->charset, so rli->charset isn't any worker threads' last Query_log_event charset. but rli->charset can affect every worker threads' thd->variables.character_set_* setting.
Right, I see. Probably the cached_charset just needs to be moved into the
I have filed a bug for this that I will fix:
Thanks a lot for finding this, as usual your input on parallel replication is
most useful, keep it coming!