Added regression test for #3327 to check that 'ProcessQueryAndSetStatusFlags' is properly call after a failed query

test/tap/tests/reg_test_3327-process_query_set_status_flags-t.cpp

@@ -0,0 +1,77 @@
+/**
+ * @file reg_test_3327-process_query_set_status_flags-t.cpp
+ * @brief This test is a regression test for issue #3327.
+ * @details The test performs a invalid query that according to the new introduced behavior in
+ *   ProxySQL #3327 should be processed by 'ProcessQueryAndSetStatusFlags' and disable multiplexing.
+ * @date 2021-03-01
+ */
+
+#include <vector>
+#include <string>
+#include <stdio.h>
+#include <mysql.h>
+
+#include "tap.h"
+#include "command_line.h"
+#include "utils.h"
+#include "json.hpp"
+
+using std::string;
+using namespace nlohmann;
+
+void parse_result_json_column(MYSQL_RES *result, json& j) {
+	if(!result) return;
+	MYSQL_ROW row;
+
+	while ((row = mysql_fetch_row(result))) {
+		j = json::parse(row[0]);
+	}
+}
+
+int main(int argc, char** argv) {
+	CommandLine cl;
+
+	if (cl.getEnv()) {
+		diag("Failed to get the required environmental variables.");
+		return -1;
+	}
+
+	MYSQL* proxysql_mysql = mysql_init(NULL);
+
+	if (!mysql_real_connect(proxysql_mysql, cl.host, cl.username, cl.password, NULL, cl.port, NULL, 0)) {
+		fprintf(stderr, "File %s, line %d, Error: %s\n", __FILE__, __LINE__, mysql_error(proxysql_mysql));
+		return -1;
+	}
+
+	int query_err = mysql_query(proxysql_mysql, "SELECT SQL_CALC_FOUND_ROWS * FROM reg_test_3327_non_exist_table");
+	ok (query_err != 0, "Initial query failed as intended.");
+
+	MYSQL_QUERY(proxysql_mysql, "PROXYSQL INTERNAL SESSION");
+	json j_status {};
+	MYSQL_RES* int_session_res = mysql_store_result(proxysql_mysql);
+	parse_result_json_column(int_session_res, j_status);
+	mysql_free_result(int_session_res);
+
+	if (j_status.contains("backends")) {
+		bool found_backend = false;
+		for (auto& backend : j_status["backends"]) {
+			if (backend != nullptr && backend.contains("conn") && backend["conn"].contains("status")) {
+				found_backend = true;
+				bool multiplex_disabled = backend["conn"]["MultiplexDisabled"];
+				ok(
+					multiplex_disabled == true,
+					"Connection status should reflect that 'MultiplexDisabled' is enabled due to the invalid 'SELECT SQL_CALC_FOUND_ROWS'."
+				);
+			}
+		}
+		if (found_backend == false) {
+			ok(false, "'backends' doens't contains 'conn' objects with the relevant session information");
+		}
+	} else {
+		ok(false, "No backends detected for the current connection.");
+	}
+
+	mysql_close(proxysql_mysql);
+
+	return exit_status();
+}