More metrics related to connectin pool #703

Metrics introduced:
* ConnPool_get_conn_failure : connection pool cannot provide any connection
* ConnPool_get_conn_immediate : connection is provided from per-thread cache
* ConnPool_get_conn_success : the session is able to get a connection, either from per-thread cache or connection pool

include/MySQL_Thread.h

@@ -171,6 +171,9 @@ class MySQL_Thread
 		unsigned long long mysql_backend_buffers_bytes;
 		unsigned long long mysql_frontend_buffers_bytes;
 		unsigned long long mysql_session_internal_bytes;
+		unsigned long long ConnPool_get_conn_immediate;
+		unsigned long long ConnPool_get_conn_success;
+		unsigned long long ConnPool_get_conn_failure;
 		unsigned int active_transactions;
 	} status_variables;
 
@@ -368,6 +371,9 @@ class MySQL_Threads_Handler
 	unsigned long long get_mysql_backend_buffers_bytes();
 	unsigned long long get_mysql_frontend_buffers_bytes();
 	unsigned long long get_mysql_session_internal_bytes();
+	unsigned long long get_ConnPool_get_conn_immediate();
+	unsigned long long get_ConnPool_get_conn_success();
+	unsigned long long get_ConnPool_get_conn_failure();
 	iface_info *MLM_find_iface_from_fd(int fd) {
 		return MLM->find_iface_from_fd(fd);
 	}

lib/MySQL_Session.cpp

@@ -2170,9 +2170,14 @@ void MySQL_Session::handler___client_DSS_QUERY_SENT___server_DSS_NOT_INITIALIZED
 		mc=thread->get_MyConn_local(mybe->hostgroup_id); // experimental , #644
 		if (mc==NULL) {
 			mc=MyHGM->get_MyConn_from_pool(mybe->hostgroup_id);
+		} else {
+			thread->status_variables.ConnPool_get_conn_immediate++;
 		}
 		if (mc) {
 			mybe->server_myds->attach_connection(mc);
+			thread->status_variables.ConnPool_get_conn_success++;
+		} else {
+			thread->status_variables.ConnPool_get_conn_failure++;
 		}
 //	}
 	proxy_debug(PROXY_DEBUG_MYSQL_CONNECTION, 5, "Sess=%p -- server_myds=%p -- MySQL_Connection %p\n", this, mybe->server_myds,  mybe->server_myds->myconn);

lib/MySQL_Thread.cpp

@@ -2178,6 +2178,9 @@ MySQL_Thread::MySQL_Thread() {
 	status_variables.mysql_backend_buffers_bytes=0;
 	status_variables.mysql_frontend_buffers_bytes=0;
 	status_variables.mysql_session_internal_bytes=0;
+	status_variables.ConnPool_get_conn_immediate=0;
+	status_variables.ConnPool_get_conn_success=0;
+	status_variables.ConnPool_get_conn_failure=0;
 	status_variables.active_transactions=0;
 }
 
@@ -2405,6 +2408,24 @@ SQLite3_result * MySQL_Threads_Handler::SQL3_GlobalStatus() {
 			result->add_row(pta);
 		}
 	}
+	{	// ConnPool_get_conn_immediate
+		pta[0]=(char *)"ConnPool_get_conn_immediate";
+		sprintf(buf,"%llu",get_ConnPool_get_conn_immediate());
+		pta[1]=buf;
+		result->add_row(pta);
+	}
+	{	// ConnPool_get_conn_success
+		pta[0]=(char *)"ConnPool_get_conn_success";
+		sprintf(buf,"%llu",get_ConnPool_get_conn_success());
+		pta[1]=buf;
+		result->add_row(pta);
+	}
+	{	// ConnPool_get_conn_failure
+		pta[0]=(char *)"ConnPool_get_conn_failure";
+		sprintf(buf,"%llu",get_ConnPool_get_conn_failure());
+		pta[1]=buf;
+		result->add_row(pta);
+	}
 	free(pta);
 	return result;
 }
@@ -2809,3 +2830,42 @@ void MySQL_Thread::return_local_connections() {
 	MyHGM->push_MyConn_to_pool_array(ca);
 	free(ca);
 }
+
+unsigned long long MySQL_Threads_Handler::get_ConnPool_get_conn_immediate() {
+	unsigned long long q=0;
+	unsigned int i;
+	for (i=0;i<num_threads;i++) {
+		if (mysql_threads) {
+			MySQL_Thread *thr=(MySQL_Thread *)mysql_threads[i].worker;
+			if (thr)
+				q+=__sync_fetch_and_add(&thr->status_variables.ConnPool_get_conn_immediate,0);
+		}
+	}
+	return q;
+}
+
+unsigned long long MySQL_Threads_Handler::get_ConnPool_get_conn_success() {
+	unsigned long long q=0;
+	unsigned int i;
+	for (i=0;i<num_threads;i++) {
+		if (mysql_threads) {
+			MySQL_Thread *thr=(MySQL_Thread *)mysql_threads[i].worker;
+			if (thr)
+				q+=__sync_fetch_and_add(&thr->status_variables.ConnPool_get_conn_success,0);
+		}
+	}
+	return q;
+}
+
+unsigned long long MySQL_Threads_Handler::get_ConnPool_get_conn_failure() {
+	unsigned long long q=0;
+	unsigned int i;
+	for (i=0;i<num_threads;i++) {
+		if (mysql_threads) {
+			MySQL_Thread *thr=(MySQL_Thread *)mysql_threads[i].worker;
+			if (thr)
+				q+=__sync_fetch_and_add(&thr->status_variables.ConnPool_get_conn_failure,0);
+		}
+	}
+	return q;
+}