Few fixes

include/mysql_connection.h

@@ -129,6 +129,7 @@ class MySQL_Connection {
 	} statuses;
 
 	unsigned long largest_query_length;
+	unsigned int warning_count;
 	/**
 	 * @brief This represents the internal knowledge of ProxySQL about the connection. It keeps track of those
 	 *  states which *are not reflected* into 'server_status', but are relevant for connection handling.

lib/MySQL_Session.cpp

@@ -1250,6 +1250,7 @@ void MySQL_Session::generate_proxysql_internal_session_json(json &j) {
 				j["backends"][i]["conn"]["status"]["compression"] = _myconn->get_status(STATUS_MYSQL_CONNECTION_COMPRESSION);
 				j["backends"][i]["conn"]["status"]["prepared_statement"] = _myconn->get_status(STATUS_MYSQL_CONNECTION_PREPARED_STATEMENT);
 				j["backends"][i]["conn"]["status"]["has_warnings"] = _myconn->get_status(STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
+				j["backends"][i]["conn"]["warning_count"] = _myconn->warning_count;
 				j["backends"][i]["conn"]["MultiplexDisabled"] = _myconn->MultiplexDisabled();
 				j["backends"][i]["conn"]["ps"]["backend_stmt_to_global_ids"] = _myconn->local_stmts->backend_stmt_to_global_ids;
 				j["backends"][i]["conn"]["ps"]["global_stmt_to_backend_ids"] = _myconn->local_stmts->global_stmt_to_backend_ids;
@@ -6062,27 +6063,28 @@ bool MySQL_Session::handler___status_WAITING_CLIENT_DATA___STATE_SLEEP___MYSQL_C
 
 		if ((dig_len == 22) && (strncasecmp(dig, "SHOW COUNT(*) WARNINGS", 22) == 0)) {
 			proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "Intercepted '%s'\n", dig);
+			std::string warning_count = "0";
 			if (warning_in_hg > -1) {
 				proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "Changing current_hostgroup to '%d'\n", warning_in_hg);
-				current_hostgroup = warning_in_hg;
-				//warning_in_hg = -1;
-				return false;
+				current_hostgroup = warning_in_hg;	
+				assert(mybe && mybe->server_myds && mybe->server_myds->myconn && mybe->server_myds->myconn->mysql);
+				warning_count = std::to_string(mybe->server_myds->myconn->warning_count);
 			} else {
 				proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "No warnings were detected in the previous query. Sending an empty response.\n");
-				std::unique_ptr<SQLite3_result> resultset(new SQLite3_result(1));
-				resultset->add_column_definition(SQLITE_TEXT, "@@session.warning_count");
-				char* pta[1];
-				pta[0] = (char*)"0";
-				resultset->add_row(pta);
-				SQLite3_to_MySQL(resultset.get(), NULL, 0, &client_myds->myprot, false, (client_myds->myconn->options.client_flag & CLIENT_DEPRECATE_EOF));
-				client_myds->DSS = STATE_SLEEP;
-				status = WAITING_CLIENT_DATA;
-				if (mirror == false) {
-					RequestEnd(NULL);
-				}
-				l_free(pkt->size, pkt->ptr);
-				return true;
 			}
+			std::unique_ptr<SQLite3_result> resultset(new SQLite3_result(1));
+			resultset->add_column_definition(SQLITE_TEXT, "@@session.warning_count");
+			char* pta[1];
+			pta[0] = (char*)warning_count.c_str();
+			resultset->add_row(pta);
+			SQLite3_to_MySQL(resultset.get(), NULL, 0, &client_myds->myprot, false, (client_myds->myconn->options.client_flag & CLIENT_DEPRECATE_EOF));
+			client_myds->DSS = STATE_SLEEP;
+			status = WAITING_CLIENT_DATA;
+			if (mirror == false) {
+				RequestEnd(NULL);
+			}
+			l_free(pkt->size, pkt->ptr);
+			return true;
 		}
 
 		reset_warning_hostgroup_flag_and_release_connection();
@@ -8163,6 +8165,7 @@ void MySQL_Session::reset_warning_hostgroup_flag_and_release_connection()
 		MySQL_Backend* _mybe = NULL;
 		_mybe = find_backend(warning_in_hg);
 		MySQL_Data_Stream* myds = _mybe->server_myds;
+		myds->myconn->warning_count = 0;
 		myds->myconn->set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
 		if ((myds->myconn->reusable == true) && myds->myconn->IsActiveTransaction() == false && myds->myconn->MultiplexDisabled() == false) {
 			myds->return_MySQL_Connection_To_Pool();

lib/mysql_connection.cpp

@@ -434,6 +434,7 @@ MySQL_Connection::MySQL_Connection() {
 	query.stmt_meta=NULL;
 	query.stmt_result=NULL;
 	largest_query_length=0;
+	warning_count=0;
 	multiplex_delayed=false;
 	MyRS=NULL;
 	MyRS_reuse=NULL;
@@ -2575,11 +2576,12 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 	// checking warnings and disabling multiplexing will be effective only when the mysql-query_digests is enabled
 	if (myds->sess->CurrentQuery.QueryParserArgs.digest_text) {
 		if (get_status(STATUS_MYSQL_CONNECTION_HAS_WARNINGS) == false) {
-			if (mysql_warning_count(this->mysql) > 0) {
+			if (this->mysql && mysql_warning_count(this->mysql) > 0) {
 				if (myds && myds->sess) {
 					// 'warning_in_hg' will be used if the next query is 'SHOW WARNINGS' or
 					// 'SHOW COUNT(*) WARNINGS'
 					myds->sess->warning_in_hg = myds->sess->current_hostgroup;
+					warning_count = mysql_warning_count(this->mysql);
 					// enabling multiplexing
 					set_status(true, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
 				}
@@ -2595,6 +2597,7 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 				if (myds && myds->sess) {
 					myds->sess->warning_in_hg = -1;
 				}
+				warning_count = 0;
 				// disabling multiplexing
 				set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
 			}
@@ -2828,7 +2831,7 @@ void MySQL_Connection::reset() {
 	set_status(old_compress,STATUS_MYSQL_CONNECTION_COMPRESSION);
 	reusable=true;
 	options.last_set_autocommit=-1; // never sent
-
+	warning_count=0;
 	delete local_stmts;
 	local_stmts=new MySQL_STMTs_local_v14(false);
 	creation_time = monotonic_time();

test/tap/tests/test_warnings-t.cpp

@@ -31,11 +31,7 @@ using MESSAGE = std::string;
 		} \
 	} while(0)
 
-#define MYSQL_CLEAR_RESULT(mysql) do { MYSQL_RES* mysql_result = mysql_use_result(mysql); \
-									 while (MYSQL_ROW row = mysql_fetch_row(mysql_result)) {} \
-									 mysql_free_result(mysql_result); \
-								  } while(0)
-
+#define MYSQL_CLEAR_RESULT(mysql)	 mysql_free_result(mysql_store_result(mysql));
 
 enum MultiplexStatus {
 	kNotApplicable = 0,
@@ -150,15 +146,17 @@ int check_proxysql_internal_session(MYSQL* proxysql, int exp_status) {
 			if (backend != nullptr && backend.contains("conn")) {
 				found_backend = true;
 
-				if (backend["conn"]["MultiplexDisabled"]) {
+				if (backend["conn"]["MultiplexDisabled"] == true) {
 					status |= MultiplexStatus::kMultiplexingEnabled;
 				}
 
-				if (backend["conn"]["status"]["has_warnings"] && j_status["warning_in_hg"] != -1) {
+				if (backend["conn"]["status"]["has_warnings"] == true && 
+					backend["conn"]["warning_count"] > 0 &&
+					j_status["warning_in_hg"] != -1) {
 					status |= MultiplexStatus::kHasWarnings;
 				}
 
-				if (backend["conn"]["status"]["user_variable"]) {
+				if (backend["conn"]["status"]["user_variable"] == true) {
 					status |= MultiplexStatus::kUserVariables;
 				}
 			}
@@ -233,8 +231,6 @@ const std::vector<TestInfo> multiplexing_test = {
 													{ ConnectionType::kMySQL, {"SELECT 1", true}, {WarningCheckType::kAll, 0}, (MultiplexStatus::kMultiplexingEnabled | MultiplexStatus::kUserVariables) }
 };
 
-
-
 #define IS_BIT_MASK_SET(variable,flag) ((variable & static_cast<int>(flag)) == static_cast<int>(flag))
 
 int main(int argc, char** argv) {
@@ -246,7 +242,12 @@ int main(int argc, char** argv) {
 		return -1;
 	}
 
-	plan(9+13+4+23+9+10);
+	plan((7+2) +   // select test: 7 warning checks, 2 multiplex status checks
+		 (9+4) +   // insert test: 9 warning checks, 4 multiplex status checks
+		 (3+1) +   // query digest test: 3 warning checks, 1 multiplex status checks
+		 (18+5) + // query cache test: 18 warning checks, 5 multiplex status checks
+		 (7+2) +   // warning log test: 7 warning checks, 2 multiplex status checks
+		 (7+3));   // multiplexing test: 7 warning checks, 3 multiplex status checks
 
 	// Initialize Admin connection
 	MYSQL* proxysql_admin = mysql_init(NULL);