From 90ea9ea406f613de8af4182e6d981d2d5178e547 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Canna=C3=B2?= <rene.cannao@gmail.com>
Date: Fri, 17 Apr 2015 03:59:28 +0000
Subject: [PATCH] Allow admin module to wake up MySQL Threads #253

---
 include/mysql_thread.h          |  9 +++++++--
 lib/Standard_MySQL_Thread.cpp   | 23 ++++++++++++++++++++++-
 lib/Standard_ProxySQL_Admin.cpp | 12 ++++++++++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/include/mysql_thread.h b/include/mysql_thread.h
index d260f9896..35d74f8c0 100644
--- a/include/mysql_thread.h
+++ b/include/mysql_thread.h
@@ -177,12 +177,14 @@ class ProxySQL_Poll {
     if (len==size) {
       expand(1);
     }
-		_myds->mypolls=this;
     myds[len]=_myds;
     fds[len].fd=_fd;
     fds[len].events=_events;
     fds[len].revents=0;
-		_myds->poll_fds_idx=len;  // fix a serious bug
+		if (_myds) {
+			_myds->mypolls=this;
+			_myds->poll_fds_idx=len;  // fix a serious bug
+		}
     last_recv[len]=monotonic_time();
     last_sent[len]=sent_time;
     len++;
@@ -230,6 +232,7 @@ class MySQL_Thread
 	
 	public:
 
+	int pipefd[2];
 	unsigned long long curtime;
 
 	ProxySQL_Poll mypolls;
@@ -318,6 +321,7 @@ class MySQL_Threads_Handler
 	virtual int listener_del(const char *iface) {return -1;}
 	virtual int listener_del(const char *address, int port) {return -1;}
 	virtual void start_listeners() {};
+	virtual void signal_all_threads() {};
 };
 
 class Standard_MySQL_Threads_Handler: public MySQL_Threads_Handler
@@ -371,6 +375,7 @@ class Standard_MySQL_Threads_Handler: public MySQL_Threads_Handler
 	virtual int listener_add(const char *address, int port);
 	virtual int listener_del(const char *iface);
 	virtual void start_listeners();
+	virtual void signal_all_threads();
 //	virtual int listener_del(const char *address, int port);
 //	pthread_t connection_manager_thread_id;
 //	void connection_manager_thread();
diff --git a/lib/Standard_MySQL_Thread.cpp b/lib/Standard_MySQL_Thread.cpp
index 5681ac56e..a98b278a2 100644
--- a/lib/Standard_MySQL_Thread.cpp
+++ b/lib/Standard_MySQL_Thread.cpp
@@ -653,6 +653,9 @@ bool Standard_MySQL_Thread::init() {
 	memset(my_idle_myds,0,sizeof(MySQL_Data_Stream *)*SESSIONS_FOR_CONNECTIONS_HANDLER);
 	GloQPro->init_thread();
 	refresh_variables();
+	i=pipe(pipefd);
+	mypolls.add(POLLIN, pipefd[0], NULL, 0);
+	assert(i==0);
 	return true;
 }
 
@@ -767,7 +770,7 @@ void Standard_MySQL_Thread::run() {
 
 		for (n = 0; n < mypolls.len; n++) {
 			mypolls.fds[n].revents=0;
-			if (mypolls.myds[n]->myds_type!=MYDS_LISTENER && mypolls.myds[n]->myds_type!=MYDS_BACKEND_PAUSE_CONNECT) {
+			if (mypolls.myds[n] && mypolls.myds[n]->myds_type!=MYDS_LISTENER && mypolls.myds[n]->myds_type!=MYDS_BACKEND_PAUSE_CONNECT) {
 				mypolls.myds[n]->set_pollout();
 			}
 		}
@@ -831,6 +834,14 @@ void Standard_MySQL_Thread::run() {
 
 
 			MySQL_Data_Stream *myds=mypolls.myds[n];
+			if (myds==NULL) {
+				if (mypolls.fds[n].revents) {
+					char c;
+					read(mypolls.fds[n].fd, &c, 1);	// read just one byte , no need for error handling
+					fprintf(stderr,"Got signal from admin , done nothing\n"); // FIXME: this is just the scheleton for issue #253
+				}
+			continue;
+			}
 			if (mypolls.fds[n].revents==0) {
 
 				switch(myds->myds_type) {
@@ -1208,6 +1219,16 @@ SQLite3_result * Standard_MySQL_Threads_Handler::SQL3_Threads_status(MySQL_Sessi
 	return result;
 }
 
+void Standard_MySQL_Threads_Handler::signal_all_threads() {
+	unsigned int i;
+	char c;
+	for (i=0;i<num_threads;i++) {
+		Standard_MySQL_Thread *thr=(Standard_MySQL_Thread *)mysql_threads[i].worker;
+		int fd=thr->pipefd[1];
+		write(fd,&c,1);
+	}
+}
+
 extern "C" MySQL_Threads_Handler * create_MySQL_Threads_Handler_func() {
     return new Standard_MySQL_Threads_Handler();
 }
diff --git a/lib/Standard_ProxySQL_Admin.cpp b/lib/Standard_ProxySQL_Admin.cpp
index afcdfb5d8..7c69b2941 100644
--- a/lib/Standard_ProxySQL_Admin.cpp
+++ b/lib/Standard_ProxySQL_Admin.cpp
@@ -975,6 +975,18 @@ void admin_session_handler(MySQL_Session *sess, ProxySQL_Admin *pa, PtrSize_t *p
 		}
 	}
 
+	// FIXME: this should be removed, it is just a POC for issue #253 . What is important is the call to GloMTH->signal_all_threads();
+	if (!strncasecmp("SIGNAL MYSQL THREADS", query_no_space, strlen("SIGNAL MYSQL THREADS"))) {
+		GloMTH->signal_all_threads();
+		proxy_debug(PROXY_DEBUG_ADMIN, 4, "Received %s command\n", query_no_space);
+		Standard_ProxySQL_Admin *SPA=(Standard_ProxySQL_Admin *)pa;
+		SPA->save_admin_variables_from_runtime();
+		proxy_debug(PROXY_DEBUG_ADMIN, 4, "Sent signal to all mysql threads\n");
+		SPA->send_MySQL_OK(&sess->client_myds->myprot, NULL);
+		run_query=false;
+		goto __run_query;
+	}
+
 	if (strncasecmp("SHOW ", query_no_space, 5)) {
 		goto __end_show_commands; // in the next block there are only SHOW commands
 	}