Code review comment for lp:~dingqi-lxb/percona-server/5.5_log_queries_in_memory

8.
+ ulonglong utime_of_query= thd->current_utime() - thd->utime_after_lock;
+ if (utime_of_query <= thd->variables.long_query_time)
+ return;

Please look into the slow_extended.patch:

static inline ulonglong get_query_exec_time(THD *thd, ulonglong cur_utime)
...
thd->server_status|= SERVER_QUERY_WAS_SLOW;

Please better use this status variable, instead of calculate query execution time directly.