Support min_gtid annotation

include/query_processor.h

@@ -152,6 +152,7 @@ class Query_Processor_Output {
 	int log;
 	int firewall_whitelist_mode;
 	char *comment; // #643
+	char *min_gtid;
 	std::string *new_query;
 	void * operator new(size_t size) {
 		return l_alloc(size);
@@ -188,6 +189,7 @@ class Query_Processor_Output {
 		error_msg=NULL;
 		OK_msg=NULL;
 		comment=NULL; // #643
+		min_gtid=NULL;
 		firewall_whitelist_mode = WUS_NOT_FOUND;
 	}
 	void destroy() {
@@ -199,6 +201,10 @@ class Query_Processor_Output {
 			free(OK_msg);
 			OK_msg=NULL;
 		}
+		if (min_gtid) {
+			free(min_gtid);
+			min_gtid = NULL;
+		}
 		if (comment) { // #643
 			free(comment);
 		}
@@ -305,7 +311,7 @@ class Query_Processor {
 	~Query_Processor();
 	void print_version();
 	void reset_all(bool lock=true);
-	void wrlock();		// explicit write lock, to be used in multi-isert 
+	void wrlock();		// explicit write lock, to be used in multi-insert
 	void wrunlock();	// explicit write unlock
 	bool insert(QP_rule_t *qr, bool lock=true);		// insert a new rule. Uses a generic void pointer to a structure that may vary depending from the Query Processor
 	QP_rule_t * new_query_rule(int rule_id, bool active, char *username, char *schemaname, int flagIN, char *client_addr, char *proxy_addr, int proxy_port, char *digest, char *match_digest, char *match_pattern, bool negate_match_pattern, char *re_modifiers, int flagOUT, char *replace_pattern, int destination_hostgroup, int cache_ttl, int cache_empty_result, int cache_timeout, int reconnect, int timeout, int retries, int delay, int next_query_flagIN, int mirror_hostgroup, int mirror_flagOUT, char *error_msg, char *OK_msg, int sticky_conn, int multiplex, int gtid_from_hostgroup, int log, bool apply, char *comment);	// to use a generic query rule struct, this is generated by this function and returned as generic void pointer
@@ -319,7 +325,7 @@ class Query_Processor {
 	void end_thread();
 	void commit();	// this applies all the changes in memory
 	SQLite3_result * get_current_query_rules();
-	SQLite3_result * get_stats_query_rules();	
+	SQLite3_result * get_stats_query_rules();
 
 	void update_query_processor_stats();
 
@@ -329,6 +335,7 @@ class Query_Processor {
 	void query_parser_free(SQP_par_t *qp);
 	char * get_digest_text(SQP_par_t *qp);
 	uint64_t get_digest(SQP_par_t *qp);
+	bool is_valid_gtid(char *gtid, size_t gtid_len);
 
 	void update_query_digest(SQP_par_t *qp, int hid, MySQL_Connection_userinfo *ui, unsigned long long t, unsigned long long n, MySQL_STMT_Global_info *_stmt_info, MySQL_Session *sess);
 

lib/MySQL_Session.cpp

@@ -6390,11 +6390,11 @@ void MySQL_Session::handler___status_WAITING_CLIENT_DATA___STATE_SLEEP___MYSQL_C
 
 void MySQL_Session::handler___client_DSS_QUERY_SENT___server_DSS_NOT_INITIALIZED__get_connection() {
 			// Get a MySQL Connection
-
-		with_gtid = false;
+
 		MySQL_Connection *mc=NULL;
 		MySQL_Backend * _gtid_from_backend = NULL;
 		char uuid[64];
+		char * gtid_uuid=NULL;
 		uint64_t trxid = 0;
 		unsigned long long now_us = 0;
 		if (qpo->max_lag_ms >= 0) {
@@ -6410,22 +6410,33 @@ void MySQL_Session::handler___client_DSS_QUERY_SENT___server_DSS_NOT_INITIALIZED
 			}
 		}
 		if (session_fast_forward == false) {
-			if (qpo->gtid_from_hostgroup >= 0) {
+			if (qpo->min_gtid) {
+				gtid_uuid = qpo->min_gtid;
+			} else if (qpo->gtid_from_hostgroup >= 0) {
 				_gtid_from_backend = find_backend(qpo->gtid_from_hostgroup);
 				if (_gtid_from_backend) {
 					if (_gtid_from_backend->gtid_uuid[0]) {
-						with_gtid = true;
+						gtid_uuid = _gtid_from_backend->gtid_uuid;
 					}
 				}
 			}
-			if (with_gtid) {
-				int l = index(_gtid_from_backend->gtid_uuid,':') - _gtid_from_backend->gtid_uuid;
-				trxid = strtoull(index(_gtid_from_backend->gtid_uuid,':')+1, NULL, 10);
+
+			char *sep_pos = NULL;
+			if (gtid_uuid != NULL) {
+				sep_pos = index(gtid_uuid,':');
+				if (sep_pos == NULL) {
+					gtid_uuid = NULL; // gtid is invalid
+				}
+			}
+
+			if (gtid_uuid != NULL) {
+				int l = sep_pos - gtid_uuid;
+				trxid = strtoull(sep_pos+1, NULL, 10);
 				int m;
 				int n=0;
 				for (m=0; m<l; m++) {
-					if (_gtid_from_backend->gtid_uuid[m] != '-') {
-						uuid[n]=_gtid_from_backend->gtid_uuid[m];
+					if (gtid_uuid[m] != '-') {
+						uuid[n]=gtid_uuid[m];
 						n++;
 					}
 				}

lib/Query_Processor.cpp

@@ -2779,6 +2779,17 @@ bool Query_Processor::query_parser_first_comment(Query_Processor_Output *qpo, ch
 					}
 				}
 			}
+			if (!strcasecmp(key,"min_gtid")) {
+				size_t l = strlen(value);
+				if (is_valid_gtid(value, l)) {
+					char *buf=(char*)malloc(l+1);
+					strncpy(buf, value, l);
+					buf[l+1] = '\0';
+					qpo->min_gtid = buf;
+				} else {
+					proxy_warning("Invalid gtid value=%s\n", value);
+				}
+			}
 		}
 
 		proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 5, "Variables in comment %s , key=%s , value=%s\n", token, key, value);
@@ -2789,6 +2800,24 @@ bool Query_Processor::query_parser_first_comment(Query_Processor_Output *qpo, ch
 	return ret;
 }
 
+bool Query_Processor::is_valid_gtid(char *gtid, size_t gtid_len) {
+	if (gtid_len < 3) {
+		return false;
+	}
+	char *sep_pos = index(gtid, ':');
+	if (sep_pos == NULL) {
+		return false;
+	}
+	size_t uuid_len = sep_pos - gtid;
+	if (uuid_len < 1) {
+		return false;
+	}
+	if (gtid_len < uuid_len + 2) {
+		return false;
+	}
+	return true;
+}
+
 void Query_Processor::query_parser_free(SQP_par_t *qp) {
 	if (qp->digest_text) {
 		if (qp->digest_text != qp->buf) {