Add get_current_query_rules_fast_routing_count()

Query_Processor::get_current_query_rules_fast_routing_count() now allows to
quickly execute this query is ran on Admin:
SELECT COUNT(*) FROM runtime_mysql_query_rules_fast_routing

include/query_processor.h

@@ -335,6 +335,7 @@ class Query_Processor {
 	SQLite3_result * fast_routing_resultset;
 	void load_fast_routing(SQLite3_result *resultset);
 	SQLite3_result * get_current_query_rules_fast_routing();
+	int get_current_query_rules_fast_routing_count();
 	int testing___find_HG_in_mysql_query_rules_fast_routing(char *username, char *schemaname, int flagIN);
 	int testing___find_HG_in_mysql_query_rules_fast_routing_dual(char *username, char *schemaname, int flagIN);
 

lib/ProxySQL_Admin.cpp

@@ -3621,6 +3621,20 @@ void admin_session_handler(MySQL_Session *sess, void *_pa, PtrSize_t *pkt) {
 			}
 		}
 	}
+
+	// if the client simply executes:
+	// SELECT COUNT(*) FROM runtime_mysql_query_rules_fast_routing
+	// we just return the count
+	if (strcmp("SELECT COUNT(*) FROM runtime_mysql_query_rules_fast_routing", query_no_space)==0) {
+		int cnt = GloQPro->get_current_query_rules_fast_routing_count();
+		l_free(query_length,query);
+		char buf[256];
+		sprintf(buf,"SELECT %d AS 'COUNT(*)'", cnt);
+		query=l_strdup(buf);
+		query_length=strlen(query)+1;
+		goto __run_query;
+	}
+
 	if (!strncasecmp("TRUNCATE ", query_no_space, strlen("TRUNCATE "))) {
 		if (sess->session_type == PROXYSQL_SESSION_ADMIN) { // no stats
 			if (strstr(query_no_space,"stats_mysql_query_digest")) {

lib/Query_Processor.cpp

@@ -840,6 +840,14 @@ SQLite3_result * Query_Processor::get_current_query_rules() {
 	return result;
 }
 
+int Query_Processor::get_current_query_rules_fast_routing_count() {
+	int result = 0;
+	pthread_rwlock_rdlock(&rwlock);
+	result = fast_routing_resultset->rows_count;
+	pthread_rwlock_unlock(&rwlock);
+	return result;
+}
+
 SQLite3_result * Query_Processor::get_current_query_rules_fast_routing() {
 	proxy_debug(PROXY_DEBUG_MYSQL_QUERY_PROCESSOR, 4, "Dumping current query rules fast_routing, using Global version %d\n", version);
 	SQLite3_result *result=new SQLite3_result(5);