* If the backend server has CLIENT_DEPRECATE_EOF enabled, and the cli…

…ent does not support CLIENT_DEPRECATE_EOF, warning_count will be '0' in intermediate EOF packet.

* Suppress the display of warning counts in the "SHOW WARNINGS" statement.

include/MySQL_Protocol.h

@@ -51,7 +51,7 @@ class MySQL_ResultSet {
 	unsigned int add_row(MYSQL_ROWS *rows);
 	unsigned int add_row(MYSQL_ROW row);
 	unsigned int add_row2(MYSQL_ROWS *row, unsigned char *offset);
-	void add_eof();
+	void add_eof(bool suppress_warning_count=false);
 	void remove_last_eof();
 	void add_err(MySQL_Data_Stream *_myds);
 	bool get_resultset(PtrSizeArray *PSarrayFinal);

lib/MySQL_Protocol.cpp

@@ -2726,7 +2726,9 @@ void MySQL_ResultSet::init(MySQL_Protocol *_myprot, MYSQL_RES *_res, MYSQL *_my,
 		// up to 2.2.0 we used to add an EOF here.
 		// due to bug #3547 we move the logic into add_eof() that can now handle also prepared statements
 		PROXY_TRACE2();
-		add_eof();
+		// if the backend server has CLIENT_DEPRECATE_EOF enabled, and the client does not support
+		// CLIENT_DEPRECATE_EOF, warning_count will be excluded from the intermediate EOF packet
+		add_eof((mysql->server_capabilities & CLIENT_DEPRECATE_EOF));
 	}
 }
 
@@ -2990,7 +2992,7 @@ unsigned int MySQL_ResultSet::add_row2(MYSQL_ROWS *row, unsigned char *offset) {
 	return length;
 }
 
-void MySQL_ResultSet::add_eof() {
+void MySQL_ResultSet::add_eof(bool suppress_warning_count) {
 	if (myprot) {
 		unsigned int nTrx=myds->sess->NumActiveTransactions();
 		uint16_t setStatus = (nTrx ? SERVER_STATUS_IN_TRANS : 0 );
@@ -3007,7 +3009,7 @@ void MySQL_ResultSet::add_eof() {
 		const MySQL_Data_Stream* _server_myds = (_mybe && _mybe->server_myds) ? _mybe->server_myds : nullptr;
 		const MySQL_Connection* _myconn = (_server_myds && _server_myds->myds_type == MYDS_BACKEND && _server_myds->myconn) ?
 			_server_myds->myconn : nullptr;
-		const unsigned int warning_count = (_myconn) ? _myconn->warning_count : 0;
+		const unsigned int warning_count = (_myconn && suppress_warning_count == false) ? _myconn->warning_count : 0;
 		if (deprecate_eof_active) {
 			PtrSize_t pkt;
 			buffer_to_PSarrayOut();

lib/MySQL_Session.cpp

@@ -8168,13 +8168,16 @@ void MySQL_Session::reset_warning_hostgroup_flag_and_release_connection()
 		// if we've reached this point, it means that warning was found in the previous query, but the
 		// current executed query is not 'SHOW WARNINGS' or 'SHOW COUNT(*) FROM WARNINGS', so we can safely reset warning_in_hg and 
 		// return connection back to the connection pool.
-		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();
+		MySQL_Backend* _mybe = find_backend(warning_in_hg);
+		if (_mybe) {
+			MySQL_Data_Stream* myds = _mybe->server_myds;
+			if (myds && myds->myconn) {
+				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();
+				}
+			}
 		}
 		warning_in_hg = -1;
 	}

lib/mysql_connection.cpp

@@ -1565,6 +1565,12 @@ MDB_ASYNC_ST MySQL_Connection::handler(short event) {
 				NEXT_IMMEDIATE(ASYNC_QUERY_END);
 			} else {
 				// since 'add_eof' utilizes 'warning_count,' we are setting the 'warning_count' here
+
+				// Note: There is a possibility of obtaining inaccurate warning_count and server_status at this point
+				// if the backend server has CLIENT_DEPRECATE_EOF enabled, and the client does not support CLIENT_DEPRECATE_EOF,
+				// especially when the query generates a warning. This information will be included in the intermediate EOF packet. 
+				// Correct information becomes available only after fetching all rows,
+				// and the warning_count and status flag details are extracted from the final OK packet.
 				update_warning_count_from_connection();
 				if (myds->sess->mirror==false) {
 					if (MyRS_reuse == NULL) {
@@ -1671,7 +1677,8 @@ MDB_ASYNC_ST MySQL_Connection::handler(short event) {
 					// since 'add_eof' utilizes 'warning_count,' we are setting the 'warning_count' here
 					update_warning_count_from_connection();
 					// we reach here if there was no error
-					MyRS->add_eof();
+					// exclude warning_count from the OK/EOF packet for the ‘SHOW WARNINGS’ statement
+					MyRS->add_eof(query.length == 13 && strncasecmp(query.ptr, "SHOW WARNINGS", 13) == 0);
 					NEXT_IMMEDIATE(ASYNC_QUERY_END);
 				}
 			}
@@ -2615,7 +2622,8 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 		if (warning_count > 0) {
 			// '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;
+			if (myds && myds->sess)
+				myds->sess->warning_in_hg = myds->sess->current_hostgroup;
 			// enabling multiplexing
 			set_status(true, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);
 		}
@@ -2627,7 +2635,8 @@ void MySQL_Connection::ProcessQueryAndSetStatusFlags(char *query_digest_text) {
 		// on backend.
 		if (!((dig_len == 22 && strncasecmp(dig, "SHOW COUNT(*) WARNINGS", 22) == 0) ||
 			(dig_len == 13 && strncasecmp(dig, "SHOW WARNINGS", 13) == 0))) {
-			myds->sess->warning_in_hg = -1;
+			if (myds && myds->sess)
+				myds->sess->warning_in_hg = -1;
 			warning_count = 0;
 			// disabling multiplexing
 			set_status(false, STATUS_MYSQL_CONNECTION_HAS_WARNINGS);