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| pthread_handler_t handle_one_connection(void *arg)
{
thread_scheduler.init_new_connection_thread(); // 初始化线程预处理操作
setup_connection_thread_globals(thd); //载入一些Session级变量
for (;;) {
lex_start(thd); //初始化LEX词法解析器
login_connection(thd); // 进行连接身份验证
prepare_new_connection_state(thd); // 初始化线程Status,即show status看到的
do_command(thd); // 处理命令
end_connection(thd); //没事做了关闭连接,丢入线程池
}
}
void do_handle_one_connection(THD *thd_arg)
{
THD *thd= thd_arg;
thd->thr_create_utime= my_micro_time(); // 更新thd 时间
//// 初始化线程预处理操作
if (MYSQL_CALLBACK_ELSE(thd->scheduler, init_new_connection_thread, (), 0))
{
close_connection(thd, ER_OUT_OF_RESOURCES);
statistic_increment(aborted_connects,&LOCK_status);
MYSQL_CALLBACK(thd->scheduler, end_thread, (thd, 0));
return;
}
/*
If a thread was created to handle this connection:
increment slow_launch_threads counter if it took more than
slow_launch_time seconds to create the thread.
*/
if (thd->prior_thr_create_utime)
{
ulong launch_time= (ulong) (thd->thr_create_utime -
thd->prior_thr_create_utime);
if (launch_time >= slow_launch_time*1000000L)
statistic_increment(slow_launch_threads, &LOCK_status);
thd->prior_thr_create_utime= 0;
}
/*
handle_one_connection() is normally the only way a thread would
start and would always be on the very high end of the stack ,
therefore, the thread stack always starts at the address of the
first local variable of handle_one_connection, which is thd. We
need to know the start of the stack so that we could check for
stack overruns.
*/
thd->thread_stack= (char*) &thd;
if (setup_connection_thread_globals(thd))
return;
for (;;)
{
bool rc;
thd->ppi_thread= PPI_THREAD_CALL(create_thread)();
thd->ppi_transaction=
PPI_THREAD_CALL(get_transaction_context)(thd->ppi_thread);
NET *net= &thd->net;
mysql_socket_set_thread_owner(net->vio->mysql_socket);
//// 准备connection
rc= thd_prepare_connection(thd);
if (rc)
goto end_thread;
while (thd_is_connection_alive(thd))
{
mysql_audit_release(thd);
if (do_command(thd))
break;
}
end_connection(thd);
end_thread:
close_connection(thd);
if (MYSQL_CALLBACK_ELSE(thd->scheduler, end_thread, (thd, 1), 0))
return; // Probably no-threads
/*
If end_thread() returns, we are either running with
thread-handler=no-threads or this thread has been schedule to
handle the next connection.
*/
thd= current_thd;
thd->thread_stack= (char*) &thd;
}
}
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