diff --git a/maxscale-system-test/CMakeLists.txt b/maxscale-system-test/CMakeLists.txt
index 7e4c19024..2dc71682e 100644
--- a/maxscale-system-test/CMakeLists.txt
+++ b/maxscale-system-test/CMakeLists.txt
@@ -20,7 +20,7 @@ set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING "Choose the type of
 build, options are: None(CMAKE_CXX_FLAGS or CMAKE_C_FLAGS used) Debug
 Release RelWithDebInfo MinSizeRel.")
 
-set(CMAKE_CXX_FLAGS "-std=c++11 -ggdb -Wall -Werror -Wno-format-overflow -Wno-unused-function")
+set(CMAKE_CXX_FLAGS "-std=c++11 -ggdb -Wall -Wextra -Werror -Wno-format-overflow -Wno-unused-function -Wno-unused-parameter -Werror=format-security")
 set(CMAKE_CXX_FLAGS_DEBUG "-std=c++11 -ggdb -Wall -Werror -Wno-format-overflow -Wno-unused-function")
 set(CMAKE_CXX_FLAGS_RELEASE "-std=c++11 -ggdb -Wall -Werror -Wno-format-overflow -Wno-unused-function")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-std=c++11 -ggdb -Wall -Werror -Wno-format-overflow -Wno-unused-function")
diff --git a/maxscale-system-test/big_load.cpp b/maxscale-system-test/big_load.cpp
index a6412750b..da3f2c245 100644
--- a/maxscale-system-test/big_load.cpp
+++ b/maxscale-system-test/big_load.cpp
@@ -48,7 +48,7 @@ void load(long int *new_inserts, long int *new_selects, long int *selects, long
         create_t1(Test->maxscales->conn_rwsplit[0]);
         create_insert_string(sql, sql_l, 1);
 
-        if ((execute_query(Test->maxscales->conn_rwsplit[0], sql) != 0) && (report_errors))
+        if ((execute_query(Test->maxscales->conn_rwsplit[0], "%s", sql) != 0) && (report_errors))
         {
             Test->add_result(1, "Query %s failed\n", sql);
         }
diff --git a/maxscale-system-test/big_transaction.cpp b/maxscale-system-test/big_transaction.cpp
index 2539aedb0..15305f84c 100644
--- a/maxscale-system-test/big_transaction.cpp
+++ b/maxscale-system-test/big_transaction.cpp
@@ -11,11 +11,11 @@ int big_transaction(MYSQL * conn, int N)
     for (int i = 0; i < N; i++)
     {
         create_insert_string(sql, 10000, i);
-        local_result += execute_query(conn, sql);
+        local_result += execute_query(conn, "%s", sql);
         local_result += execute_query(conn, "CREATE TABLE t2(id int);");
-        local_result += execute_query(conn, sql);
+        local_result += execute_query(conn, "%s", sql);
         local_result += execute_query(conn, "DROP TABLE t2;");
-        local_result += execute_query(conn, sql);
+        local_result += execute_query(conn, "%s", sql);
     }
 
     local_result += execute_query(conn, (char *) "COMMIT");
diff --git a/maxscale-system-test/binlog_big_transaction.cpp b/maxscale-system-test/binlog_big_transaction.cpp
index 72bc6dcda..aab774738 100644
--- a/maxscale-system-test/binlog_big_transaction.cpp
+++ b/maxscale-system-test/binlog_big_transaction.cpp
@@ -58,7 +58,7 @@ void *disconnect_thread( void *ptr )
     while (exit_flag == 0)
     {
         sprintf(cmd, "DISCONNECT SERVER %d", i);
-        execute_query(conn, cmd);
+        execute_query(conn, "%s", cmd);
         i++;
         if (i > Test->repl->N)
         {
diff --git a/maxscale-system-test/binlog_change_master.cpp b/maxscale-system-test/binlog_change_master.cpp
index 0a8632e08..8eb92bd73 100644
--- a/maxscale-system-test/binlog_change_master.cpp
+++ b/maxscale-system-test/binlog_change_master.cpp
@@ -87,7 +87,7 @@ int transaction(MYSQL * conn, int N)
     }
 
     create_insert_string(sql, N_INSERTS, N);
-    local_result += execute_query(conn, sql);
+    local_result += execute_query(conn, "%s", sql);
     if (local_result != 0)
     {
         Test->tprintf("Insert Failed\n");
@@ -308,7 +308,7 @@ void select_new_master(TestConnections * test)
         sprintf(str, setup_slave1, test->repl->IP[2], maxscale_log_file_new, "4", test->repl->port[2]);
     }
     test->tprintf("change master query: %s\n", str);
-    test->try_query(binlog, str);
+    test->try_query(binlog, "%s", str);
     test->tprintf("start slave\n");
     test->try_query(binlog, "start slave");
     test->tprintf("start slave one more\n");
@@ -331,7 +331,7 @@ void *disconnect_thread( void *ptr )
     while (exit_flag == 0)
     {
         sprintf(cmd, "DISCONNECT SERVER %d", i);
-        execute_query(conn, cmd);
+        execute_query(conn, "%s", cmd);
         i++;
         if (i > Test->repl->N)
         {
diff --git a/maxscale-system-test/blob_test.cpp b/maxscale-system-test/blob_test.cpp
index 6bb3f85a9..157149df9 100644
--- a/maxscale-system-test/blob_test.cpp
+++ b/maxscale-system-test/blob_test.cpp
@@ -17,7 +17,7 @@ int test_longblob(TestConnections* Test, MYSQL * conn, char * blob_name, unsigne
     Test->try_query(conn, (char *) "DROP TABLE IF EXISTS long_blob_table");
     sprintf(sql, "CREATE TABLE long_blob_table(id int NOT NULL AUTO_INCREMENT, x INT, b %s, PRIMARY KEY (id))",
             blob_name);
-    Test->try_query(conn, sql);
+    Test->try_query(conn, "%s", sql);
 
     for (int k = 0; k < rows; k++)
     {
diff --git a/maxscale-system-test/bug529.cpp b/maxscale-system-test/bug529.cpp
index 9b217b0c5..8a0cb4729 100644
--- a/maxscale-system-test/bug529.cpp
+++ b/maxscale-system-test/bug529.cpp
@@ -161,9 +161,9 @@ int main(int argc, char *argv[])
         master_conn[i] = Test->maxscales->open_readconn_master_connection(0);
         slave_conn[i] = Test->maxscales->open_readconn_slave_connection(0);
         sprintf(sql, "INSERT INTO t1 (x1, fl) VALUES(%d, 1);", i);
-        execute_query(rwsplit_conn[i], sql);
+        execute_query(rwsplit_conn[i], "%s", sql);
         sprintf(sql, "INSERT INTO t1 (x1, fl) VALUES(%d, 2);", i);
-        execute_query(master_conn[i], sql);
+        execute_query(master_conn[i], "%s", sql);
         fflush(stdout);
     }
 
@@ -248,7 +248,7 @@ int main(int argc, char *argv[])
         Test->set_timeout(60);
         slave_conn[i] = Test->maxscales->open_readconn_slave_connection(0);
         sprintf(sql, "SELECT * FROM t1");
-        execute_query(slave_conn[i], sql);
+        execute_query(slave_conn[i], "%s", sql);
         fflush(stdout);
     }
 
diff --git a/maxscale-system-test/cache_runtime.cpp b/maxscale-system-test/cache_runtime.cpp
index 7f5b775b3..dc954b27c 100644
--- a/maxscale-system-test/cache_runtime.cpp
+++ b/maxscale-system-test/cache_runtime.cpp
@@ -28,7 +28,7 @@ void drop(TestConnections& test)
     string stmt("DROP TABLE IF EXISTS cache_test");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void create(TestConnections& test)
@@ -40,7 +40,7 @@ void create(TestConnections& test)
     string stmt("CREATE TABLE cache_test (a INT)");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void insert(TestConnections& test)
@@ -50,7 +50,7 @@ void insert(TestConnections& test)
     string stmt("INSERT INTO cache_test VALUES (1)");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void update(TestConnections& test, int value)
@@ -61,7 +61,7 @@ void update(TestConnections& test, int value)
     stmt += std::to_string(value);
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void select(TestConnections& test, int* pValue)
@@ -118,7 +118,7 @@ void set(TestConnections& test, Cache::What what, bool value)
     stmt += (value ? "true" : "false");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 }
diff --git a/maxscale-system-test/cache_runtime_ttl.cpp b/maxscale-system-test/cache_runtime_ttl.cpp
index d1f7cc68d..bf3cd16c7 100644
--- a/maxscale-system-test/cache_runtime_ttl.cpp
+++ b/maxscale-system-test/cache_runtime_ttl.cpp
@@ -34,7 +34,7 @@ void drop(TestConnections& test)
     string stmt("DROP TABLE IF EXISTS cache_test");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void create(TestConnections& test)
@@ -46,7 +46,7 @@ void create(TestConnections& test)
     string stmt("CREATE TABLE cache_test (a INT, b INT)");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void insert(TestConnections& test)
@@ -56,7 +56,7 @@ void insert(TestConnections& test)
     string stmt("INSERT INTO cache_test VALUES (1, 1)");
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void update(TestConnections& test, Column column, int value)
@@ -68,7 +68,7 @@ void update(TestConnections& test, Column column, int value)
     stmt += std::to_string(value);
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 void select(TestConnections& test, Column column, int* pValue)
@@ -127,7 +127,7 @@ void set(TestConnections& test, Cache::What what, uint32_t value)
     stmt += std::to_string(value);
 
     cout << stmt << endl;
-    test.try_query(pMysql, stmt.c_str());
+    test.try_query(pMysql, "%s", stmt.c_str());
 }
 
 }
diff --git a/maxscale-system-test/cdc_client.cpp b/maxscale-system-test/cdc_client.cpp
index 034321264..6e68cb374 100644
--- a/maxscale-system-test/cdc_client.cpp
+++ b/maxscale-system-test/cdc_client.cpp
@@ -227,7 +227,7 @@ void *query_thread(void *ptr)
             char str[256];
             sprintf(str, "INSERT INTO t1 VALUES (%d, %d)", insert_val, insert_val + 100);
             insert_val = 0;
-            execute_query(Test->repl->nodes[0], str);
+            execute_query(Test->repl->nodes[0], "%s", str);
         }
     }
 
diff --git a/maxscale-system-test/cdc_datatypes/cdc_datatypes.cpp b/maxscale-system-test/cdc_datatypes/cdc_datatypes.cpp
index ec0044f28..49debf91a 100644
--- a/maxscale-system-test/cdc_datatypes/cdc_datatypes.cpp
+++ b/maxscale-system-test/cdc_datatypes/cdc_datatypes.cpp
@@ -156,7 +156,7 @@ struct
     { datetime_types, datetime_values },
     { date_types,     date_values     },
     { time_types,     time_values     },
-    { 0 }
+    { 0, 0 }
 };
 
 void insert_data(TestConnections& test, const char *table, const char* type, const char** values)
diff --git a/maxscale-system-test/change_master_during_session.cpp b/maxscale-system-test/change_master_during_session.cpp
index 1c53c07f1..e7e5949f8 100644
--- a/maxscale-system-test/change_master_during_session.cpp
+++ b/maxscale-system-test/change_master_during_session.cpp
@@ -35,7 +35,7 @@ int main(int argc, char *argv[])
         Test->set_timeout(60);
         sprintf(sql, "INSERT INTO t1 (x1, fl) VALUES(%d, 2);", i);
         Test->tprintf("Trying: %d\n", i);
-        execute_query(Test->maxscales->conn_rwsplit[0], sql);
+        execute_query(Test->maxscales->conn_rwsplit[0], "%s", sql);
     }
     Test->set_timeout(60);
     Test->tprintf("executing SELECT\n");
diff --git a/maxscale-system-test/compound_statement.cpp b/maxscale-system-test/compound_statement.cpp
index e2f0f24ba..1a37c51fc 100644
--- a/maxscale-system-test/compound_statement.cpp
+++ b/maxscale-system-test/compound_statement.cpp
@@ -24,7 +24,7 @@ int main(int argc, char** argv)
     test.maxscales->connect();
     test.try_query(test.maxscales->conn_rwsplit[0], "DROP TABLE IF EXISTS test.t1");
     test.try_query(test.maxscales->conn_rwsplit[0], "CREATE TABLE test.t1(id INT)");
-    test.try_query(test.maxscales->conn_rwsplit[0], sql);
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", sql);
 
     // Do the select inside a transacttion so that it gets routed to the master
     test.try_query(test.maxscales->conn_rwsplit[0], "BEGIN");
diff --git a/maxscale-system-test/different_size.cpp b/maxscale-system-test/different_size.cpp
index ead4c9a79..09e7135db 100644
--- a/maxscale-system-test/different_size.cpp
+++ b/maxscale-system-test/different_size.cpp
@@ -47,13 +47,13 @@ void set_max_packet(TestConnections* Test, bool binlog, char * cmd)
     if (binlog)
     {
         Test->repl->connect();
-        Test->try_query(Test->repl->nodes[0], cmd);
+        Test->try_query(Test->repl->nodes[0], "%s", cmd);
         Test->repl->close_connections();
     }
     else
     {
         Test->maxscales->connect_maxscale(0);
-        Test->try_query(Test->maxscales->conn_rwsplit[0], cmd);
+        Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", cmd);
         Test->maxscales->close_maxscale_connections(0);
     }
     Test->tprintf(".. done\n");
diff --git a/maxscale-system-test/fwf.cpp b/maxscale-system-test/fwf.cpp
index 487bd80ca..eb40980a3 100644
--- a/maxscale-system-test/fwf.cpp
+++ b/maxscale-system-test/fwf.cpp
@@ -77,7 +77,7 @@ int main(int argc, char *argv[])
                     {
                         Test->tprintf("%s", sql);
                     }
-                    int rv = execute_query(Test->maxscales->conn_rwsplit[0], sql);
+                    int rv = execute_query(Test->maxscales->conn_rwsplit[0], "%s", sql);
                     Test->add_result(rv, "Query should succeed: %s", sql);
                     local_result += rv;
                 }
diff --git a/maxscale-system-test/fwf2.cpp b/maxscale-system-test/fwf2.cpp
index bd0e1dbd9..6967e079f 100644
--- a/maxscale-system-test/fwf2.cpp
+++ b/maxscale-system-test/fwf2.cpp
@@ -33,7 +33,7 @@ int read_and_execute_queries(TestConnections *Test, const char* filename, int ex
             if (strlen(sql) > 1)
             {
                 Test->tprintf("%s", sql);
-                if (execute_query(Test->maxscales->conn_rwsplit[0], sql) != expected &&
+                if (execute_query(Test->maxscales->conn_rwsplit[0], "%s", sql) != expected &&
                     (expected == 1 || mysql_errno(Test->maxscales->conn_rwsplit[0]) == 1141))
                 {
                     Test->tprintf("Query %s, but %s expected, MySQL error: %d, %s\n",
diff --git a/maxscale-system-test/local_address.cpp b/maxscale-system-test/local_address.cpp
index cceef3cc6..38e98de47 100644
--- a/maxscale-system-test/local_address.cpp
+++ b/maxscale-system-test/local_address.cpp
@@ -103,7 +103,7 @@ void drop_user(TestConnections& test, const string& user, const string& host)
     stmt += "'@'";
     stmt += host;
     stmt += "'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 }
 
 void create_user(TestConnections& test, const string& user, const string& password, const string& host)
@@ -119,7 +119,7 @@ void create_user(TestConnections& test, const string& user, const string& passwo
     stmt += "'";
     stmt += password;
     stmt += "'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 }
 
 void grant_access(TestConnections& test, const string& user, const string& host)
@@ -131,7 +131,7 @@ void grant_access(TestConnections& test, const string& user, const string& host)
     stmt += "'@'";
     stmt += host;
     stmt += "'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 
     test.try_query(test.maxscales->conn_rwsplit[0], "FLUSH PRIVILEGES");
 }
diff --git a/maxscale-system-test/lots_of_rows.cpp b/maxscale-system-test/lots_of_rows.cpp
index 0debd5384..19e270df3 100644
--- a/maxscale-system-test/lots_of_rows.cpp
+++ b/maxscale-system-test/lots_of_rows.cpp
@@ -24,7 +24,7 @@ int main(int argc, char *argv[])
     {
         Test->set_timeout(20);
         create_insert_string(sql, 100, i);
-        Test->try_query(Test->maxscales->conn_rwsplit[0], sql);
+        Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", sql);
     }
     Test->try_query(Test->maxscales->conn_rwsplit[0], "COMMIT");
 
diff --git a/maxscale-system-test/mariadb_nodes.cpp b/maxscale-system-test/mariadb_nodes.cpp
index 6a76b8ea0..df73d0b33 100644
--- a/maxscale-system-test/mariadb_nodes.cpp
+++ b/maxscale-system-test/mariadb_nodes.cpp
@@ -267,7 +267,7 @@ void Mariadb_nodes::change_master(int NewMaster, int OldMaster)
     }
 
     execute_query(nodes[NewMaster], "RESET SLAVE ALL");
-    execute_query(nodes[NewMaster], create_repl_user);
+    execute_query(nodes[NewMaster], "%s", create_repl_user);
 
     if (mysql_ping(nodes[OldMaster]) == 0)
     {
@@ -284,7 +284,7 @@ void Mariadb_nodes::change_master(int NewMaster, int OldMaster)
         {
             char str[1024];
             sprintf(str, setup_slave, IP[NewMaster], log_file, log_pos, port[NewMaster]);
-            execute_query(nodes[i], str);
+            execute_query(nodes[i], "%s", str);
         }
     }
 }
@@ -471,7 +471,7 @@ int Galera_nodes::start_galera()
     sleep(5);
 
     local_result += connect();
-    local_result += execute_query(nodes[0], create_repl_user);
+    local_result += execute_query(nodes[0], "%s", create_repl_user);
 
     close_connections();
     return local_result;
@@ -940,7 +940,7 @@ int Mariadb_nodes::set_slave(MYSQL * conn, char master_host[], int master_port,
     {
         printf("Setup slave SQL: %s\n", str);
     }
-    return execute_query(conn, str);
+    return execute_query(conn, "%s", str);
 }
 
 int Mariadb_nodes::set_repl_user()
@@ -949,7 +949,7 @@ int Mariadb_nodes::set_repl_user()
     global_result += connect();
     for (int i = 0; i < N; i++)
     {
-        global_result += execute_query(nodes[i], create_repl_user);
+        global_result += execute_query(nodes[i], "%s", create_repl_user);
     }
     close_connections();
     return global_result;
@@ -1074,7 +1074,7 @@ int Mariadb_nodes::execute_query_all_nodes(const char* sql)
     connect();
     for (int i = 0; i < N; i++)
     {
-        local_result += execute_query(nodes[i], sql);
+        local_result += execute_query(nodes[i], "%s", sql);
     }
     close_connections();
     return local_result;
@@ -1505,6 +1505,6 @@ void Mariadb_nodes::replicate_from(int slave, int master, const char* type)
     }
 
     execute_query(nodes[slave], "STOP SLAVE;");
-    execute_query(nodes[slave], change_master.str().c_str());
+    execute_query(nodes[slave], "%s", change_master.str().c_str());
     execute_query(nodes[slave], "START SLAVE;");
 }
diff --git a/maxscale-system-test/mxs1071_maxrows.cpp b/maxscale-system-test/mxs1071_maxrows.cpp
index 7aaa84dc7..d96aaeadb 100644
--- a/maxscale-system-test/mxs1071_maxrows.cpp
+++ b/maxscale-system-test/mxs1071_maxrows.cpp
@@ -332,7 +332,7 @@ int main(int argc, char *argv[])
     exp_rows[0] = 2;
     exp_rows[1] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test03_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test03_sql);
     compare_expected(Test, "CALL multi()", 2, exp_rows);
 
     Test->tprintf("**** Test 4 ****\n");
@@ -341,7 +341,7 @@ int main(int argc, char *argv[])
     exp_rows[2] = 1;
     exp_rows[3] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test04_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test04_sql);
     compare_expected(Test, "CALL multi()", 4, exp_rows);
 
     Test->tprintf("**** Test 5 ****\n");
@@ -351,14 +351,14 @@ int main(int argc, char *argv[])
     exp_rows[3] = 1;
     exp_rows[4] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test05_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test05_sql);
     compare_expected(Test, "CALL multi()", 5, exp_rows);
 
     Test->tprintf("**** Test 6 ****\n");
     exp_rows[0] = 0;
 
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test06_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test06_sql);
     compare_expected(Test, "CALL multi()", 1, exp_rows);
 
 
@@ -382,14 +382,14 @@ int main(int argc, char *argv[])
     exp_rows[7] = 0;
 
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test07_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test07_sql);
     compare_expected(Test, "CALL multi()", 8, exp_rows);
 
     Test->tprintf("**** Test 8 ****\n");
     exp_rows[0] = 0;
 
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test08_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test08_sql);
     compare_expected(Test, "CALL multi()", 1, exp_rows);
 
     Test->tprintf("**** Test 9 ****\n");
@@ -403,7 +403,7 @@ int main(int argc, char *argv[])
     exp_rows[1] = 4;
 
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test10_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test10_sql);
     compare_expected(Test, "CALL multi()", 2, exp_rows);
 
     err_check(Test, 1096);
@@ -470,13 +470,13 @@ int main(int argc, char *argv[])
     exp_rows[2] = 1;
     exp_rows[3] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test14_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test14_sql);
     compare_expected(Test, "CALL multi()", 4, exp_rows);
 
     Test->tprintf("**** Test 15 ****\n");
     exp_rows[0] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test15_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test15_sql);
     compare_expected(Test, "CALL multi()", 1, exp_rows);
 
     Test->tprintf("**** Test 16 ****\n");
@@ -490,7 +490,7 @@ int main(int argc, char *argv[])
     exp_rows[2] = 1;
     exp_rows[3] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test17_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test17_sql);
     compare_expected(Test, "CALL multi()", 4, exp_rows);
 
     Test->tprintf("**** Test 18 ****\n");
@@ -516,14 +516,14 @@ int main(int argc, char *argv[])
     exp_rows[19] = 1;
     exp_rows[20] = 0;
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test18_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test18_sql);
     compare_expected(Test, "CALL multi()", 21, exp_rows);
 
     Test->tprintf("**** Test 19 ****\n");
     exp_rows[0] = 0;
 
     Test->try_query(Test->maxscales->conn_rwsplit[0], "DROP PROCEDURE IF EXISTS multi");
-    Test->try_query(Test->maxscales->conn_rwsplit[0], test19_sql);
+    Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", test19_sql);
     compare_expected(Test, "CALL multi()", 1, exp_rows);
 
     Test->tprintf("**** Test 20 ****\n");
diff --git a/maxscale-system-test/mxs127.cpp b/maxscale-system-test/mxs127.cpp
index 9ffe061ed..e8a206d7e 100644
--- a/maxscale-system-test/mxs127.cpp
+++ b/maxscale-system-test/mxs127.cpp
@@ -21,7 +21,7 @@ int main(int argc, char *argv[])
     {
         Test->set_timeout(5);
         sprintf(sql, "set @test=%d", i);
-        Test->try_query(Test->maxscales->conn_rwsplit[0], sql);
+        Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", sql);
     }
     Test->tprintf("done!\n");
 
@@ -30,7 +30,7 @@ int main(int argc, char *argv[])
     {
         Test->set_timeout(5);
         sprintf(sql, "set @test=%d", i);
-        Test->try_query(Test->maxscales->conn_master[0], sql);
+        Test->try_query(Test->maxscales->conn_master[0], "%s", sql);
     }
     Test->tprintf("done!\n");
 
@@ -39,7 +39,7 @@ int main(int argc, char *argv[])
     {
         Test->set_timeout(5);
         sprintf(sql, "set @test=%d", i);
-        Test->try_query(Test->maxscales->conn_slave[0], sql);
+        Test->try_query(Test->maxscales->conn_slave[0], "%s", sql);
     }
     Test->tprintf("done!\n");
 
diff --git a/maxscale-system-test/mxs1323_stress.cpp b/maxscale-system-test/mxs1323_stress.cpp
index 8f62d13f8..cc3b76247 100644
--- a/maxscale-system-test/mxs1323_stress.cpp
+++ b/maxscale-system-test/mxs1323_stress.cpp
@@ -19,7 +19,7 @@ void* async_query(void* data)
         for (int i = 0; i < 50 && running && test->global_result == 0; i++)
         {
             const char* query = "SET @a = (SELECT SLEEP(1))";
-            test->try_query(conn, query);
+            test->try_query(conn, "%s", query);
         }
 
         mysql_close(conn);
@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
 
     ss << "CREATE OR REPLACE TABLE test.t1 (id INT)";
     test.maxscales->connect_maxscale(0);
-    test.try_query(test.maxscales->conn_rwsplit[0], ss.str().c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", ss.str().c_str());
 
     ss.str("");
     ss << "INSERT INTO test.t1 VALUES (0)";
@@ -46,7 +46,7 @@ int main(int argc, char *argv[])
     {
         ss << ",(" << i << ")";
     }
-    test.try_query(test.maxscales->conn_rwsplit[0], ss.str().c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", ss.str().c_str());
 
     test.maxscales->close_maxscale_connections(0);
 
diff --git a/maxscale-system-test/mxs1507_trx_replay.cpp b/maxscale-system-test/mxs1507_trx_replay.cpp
index 8abe2f2e0..8aefded32 100644
--- a/maxscale-system-test/mxs1507_trx_replay.cpp
+++ b/maxscale-system-test/mxs1507_trx_replay.cpp
@@ -43,9 +43,10 @@ int main(int argc, char** argv)
         vector<function<void ()>> pre;
         vector<function<void ()>> post;
         vector<function<void ()>> check;
-    }
-    tests[] =
-    {
+    };
+
+    std::vector<TrxTest> tests
+    ({
         {
             "Basic transaction",
             {
@@ -56,6 +57,8 @@ int main(int argc, char** argv)
                 bind(ok, "SELECT 2"),
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Transaction with a write",
@@ -81,6 +84,8 @@ int main(int argc, char** argv)
                 bind(ok, "SELECT 2"),
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Trx started, no queries",
@@ -91,6 +96,8 @@ int main(int argc, char** argv)
                 bind(ok, "SELECT 1"),
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Trx waiting on commit",
@@ -101,6 +108,8 @@ int main(int argc, char** argv)
             {
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Trx with NOW()",
@@ -111,6 +120,8 @@ int main(int argc, char** argv)
             {
                 bind(err, "SELECT 1"),
             },
+            {
+            }
         },
         {
             "Commit trx with NOW()",
@@ -121,6 +132,8 @@ int main(int argc, char** argv)
             {
                 bind(err, "COMMIT"),
             },
+            {
+            }
         },
         {
             "NOW() used after replay",
@@ -132,6 +145,8 @@ int main(int argc, char** argv)
                 bind(ok, "SELECT NOW()"),
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Exceed transaction length limit",
@@ -149,6 +164,8 @@ int main(int argc, char** argv)
                 bind(err, "SELECT 7"),
                 bind(err, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Normal trx after hitting limit",
@@ -183,6 +200,8 @@ int main(int argc, char** argv)
                 bind(check, "SELECT @a", "1"),
                 bind(ok, "COMMIT"),
             },
+            {
+            }
         },
         {
             "Empty transaction",
@@ -192,8 +211,10 @@ int main(int argc, char** argv)
             {
                 bind(ok, "COMMIT"),
             },
-        },
-    };
+            {
+            }
+        }
+    });
 
     // Create a table for testing
     test.maxscales->connect();
diff --git a/maxscale-system-test/mxs365.cpp b/maxscale-system-test/mxs365.cpp
index 162b4c149..46f4662a4 100644
--- a/maxscale-system-test/mxs365.cpp
+++ b/maxscale-system-test/mxs365.cpp
@@ -73,7 +73,7 @@ int main(int argc, char *argv[])
              filename);
     test->tprintf("Loading data\n");
     test->set_timeout(100);
-    test->add_result(execute_query(test->maxscales->conn_rwsplit[0], query), "Loading data failed.");
+    test->add_result(execute_query(test->maxscales->conn_rwsplit[0], "%s", query), "Loading data failed.");
     test->tprintf("Reading data\n");
     test->set_timeout(100);
     test->add_result(execute_query(test->maxscales->conn_rwsplit[0], "SELECT * FROM test.dump"),
diff --git a/maxscale-system-test/mxs421_events.cpp b/maxscale-system-test/mxs421_events.cpp
index ccd39b2b4..9cd64429c 100644
--- a/maxscale-system-test/mxs421_events.cpp
+++ b/maxscale-system-test/mxs421_events.cpp
@@ -63,7 +63,7 @@ bool found_in_file(TestConnections& test, const string& file, const string& patt
     command += " ";
     command += file;
 
-    return test.maxscales->ssh_node_f(0, true, command.c_str()) == 0;
+    return test.maxscales->ssh_node_f(0, true, "%s", command.c_str()) == 0;
 }
 
 }
diff --git a/maxscale-system-test/mxs47.cpp b/maxscale-system-test/mxs47.cpp
index 7878205ba..8c89e3a9a 100644
--- a/maxscale-system-test/mxs47.cpp
+++ b/maxscale-system-test/mxs47.cpp
@@ -21,7 +21,7 @@ int main(int argc, char *argv[])
         sprintf(str, "SELECT REPEAT('a',%d)", i);
 
         test.set_timeout(15);
-        test.try_query(test.maxscales->conn_rwsplit[0], str);
+        test.try_query(test.maxscales->conn_rwsplit[0], "%s", str);
     }
 
     test.maxscales->close_maxscale_connections(0);
diff --git a/maxscale-system-test/mxs548_short_session_change_user.cpp b/maxscale-system-test/mxs548_short_session_change_user.cpp
index 208575fcc..421193cff 100644
--- a/maxscale-system-test/mxs548_short_session_change_user.cpp
+++ b/maxscale-system-test/mxs548_short_session_change_user.cpp
@@ -255,7 +255,7 @@ void *query_thread_master(void *ptr)
     {
         while (data->exit_flag == 0)
         {
-            data->Test->try_query(data->conn1, sql);
+            data->Test->try_query(data->conn1, "%s", sql);
             data->i++;
         }
     }
diff --git a/maxscale-system-test/mxs564_big_dump.cpp b/maxscale-system-test/mxs564_big_dump.cpp
index f7e3a087c..657650c34 100644
--- a/maxscale-system-test/mxs564_big_dump.cpp
+++ b/maxscale-system-test/mxs564_big_dump.cpp
@@ -206,14 +206,14 @@ void *query_thread1( void *ptr )
 
     while (data->exit_flag == 0)
     {
-        if (data->Test->try_query(data->conn1, sql))
+        if (data->Test->try_query(data->conn1, "%s", sql))
         {
             data->Test->add_result(1, "Query to ReadConn Master failed\n");
             return NULL;
         }
         if (data->rwsplit_only == 0)
         {
-            if (data->Test->try_query(data->conn2, sql))
+            if (data->Test->try_query(data->conn2, "%s", sql))
             {
                 data->Test->add_result(1, "Query to RWSplit failed\n");
                 return NULL;
diff --git a/maxscale-system-test/mxs682_cyrillic.cpp b/maxscale-system-test/mxs682_cyrillic.cpp
index f0ae95c33..326907c00 100644
--- a/maxscale-system-test/mxs682_cyrillic.cpp
+++ b/maxscale-system-test/mxs682_cyrillic.cpp
@@ -52,7 +52,7 @@ int main(int argc, char *argv[])
     Test->try_query(conn, (char *) "CREATE TABLE t2 (x varchar(10));");
     char sql[256];
     sprintf(sql, "INSERT INTO t2 VALUES (\"Кот\");");
-    Test->try_query(conn, sql);
+    Test->try_query(conn, "%s", sql);
     Test->stop_timeout();
     sleep(5);
 
diff --git a/maxscale-system-test/mxs781_binlog_wrong_passwrd.cpp b/maxscale-system-test/mxs781_binlog_wrong_passwrd.cpp
index 95a77c18a..db71988cd 100644
--- a/maxscale-system-test/mxs781_binlog_wrong_passwrd.cpp
+++ b/maxscale-system-test/mxs781_binlog_wrong_passwrd.cpp
@@ -49,7 +49,7 @@ int main(int argc, char *argv[])
     sprintf(str, setup_binlog_wrong_passwrd, Test->repl->IP[0], Test->repl->port[0]);
     Test->tprintf("binlog setup sql: %s\n", str);
     Test->set_timeout(10);
-    execute_query(binlog, str);
+    execute_query(binlog, "%s", str);
     Test->tprintf("Error: %s\n", mysql_error(binlog));
 
     Test->tprintf("'start slave' to binlog\n");
diff --git a/maxscale-system-test/mxs957.cpp b/maxscale-system-test/mxs957.cpp
index b9f6b40af..28a9cf231 100644
--- a/maxscale-system-test/mxs957.cpp
+++ b/maxscale-system-test/mxs957.cpp
@@ -48,7 +48,7 @@ int main(int argc, char *argv[])
     for (int i = 0; queries[i]; i++)
     {
         Test->set_timeout(30);
-        Test->try_query(Test->maxscales->conn_rwsplit[0], queries[i]);
+        Test->try_query(Test->maxscales->conn_rwsplit[0], "%s", queries[i]);
     }
     int rval = Test->global_result;
     delete Test;
diff --git a/maxscale-system-test/mysqlmon_detect_standalone_master.cpp b/maxscale-system-test/mysqlmon_detect_standalone_master.cpp
index a7927b2f1..0307cbf74 100644
--- a/maxscale-system-test/mysqlmon_detect_standalone_master.cpp
+++ b/maxscale-system-test/mysqlmon_detect_standalone_master.cpp
@@ -41,7 +41,7 @@ void replicate_from(TestConnections& test, int server_ind, int target_ind)
        cout << "Query is '" << change_master.str() << "'" << endl;
     }
     test.try_query(test.repl->nodes[server_ind], "STOP SLAVE;");
-    test.try_query(test.repl->nodes[server_ind], change_master.str().c_str());
+    test.try_query(test.repl->nodes[server_ind], "%s", change_master.str().c_str());
     test.try_query(test.repl->nodes[server_ind], "START SLAVE;");
 }
 
diff --git a/maxscale-system-test/mysqlmon_failover_manual2.cpp b/maxscale-system-test/mysqlmon_failover_manual2.cpp
index 702c2f9a7..6d2fbd509 100644
--- a/maxscale-system-test/mysqlmon_failover_manual2.cpp
+++ b/maxscale-system-test/mysqlmon_failover_manual2.cpp
@@ -55,7 +55,7 @@ void connect_maxscale(TestConnections& test)
 
 void try_query(TestConnections& test, const char* zQuery)
 {
-    if (test.try_query(test.maxscales->conn_rwsplit[0], zQuery) != 0)
+    if (test.try_query(test.maxscales->conn_rwsplit[0], "%s", zQuery) != 0)
     {
         string s("Could not execute query: ");
         s += zQuery;
diff --git a/maxscale-system-test/mysqlmon_failover_rejoin_old_slave.cpp b/maxscale-system-test/mysqlmon_failover_rejoin_old_slave.cpp
index e9ba67a92..806dbfb81 100644
--- a/maxscale-system-test/mysqlmon_failover_rejoin_old_slave.cpp
+++ b/maxscale-system-test/mysqlmon_failover_rejoin_old_slave.cpp
@@ -51,7 +51,7 @@ void insert_data(TestConnections& test)
     {
         stringstream ss;
         ss << "INSERT INTO test.t1 VALUES (" << i << ")";
-        test.try_query(pConn, ss.str().c_str());
+        test.try_query(pConn, "%s", ss.str().c_str());
     }
 
     test.try_query(pConn, "COMMIT");
diff --git a/maxscale-system-test/mysqlmon_failover_rolling_restart_slaves.cpp b/maxscale-system-test/mysqlmon_failover_rolling_restart_slaves.cpp
index b404a60d3..6ef0c61ea 100644
--- a/maxscale-system-test/mysqlmon_failover_rolling_restart_slaves.cpp
+++ b/maxscale-system-test/mysqlmon_failover_rolling_restart_slaves.cpp
@@ -70,7 +70,7 @@ void insert_data(TestConnections& test)
     {
         stringstream ss;
         ss << "INSERT INTO test.t1 VALUES (" << i << ")";
-        test.try_query(pConn, ss.str().c_str());
+        test.try_query(pConn, "%s", ss.str().c_str());
     }
 
     test.try_query(pConn, "COMMIT");
diff --git a/maxscale-system-test/mysqlmon_failover_stress.cpp b/maxscale-system-test/mysqlmon_failover_stress.cpp
index 20a180fa6..0c3c8ec73 100755
--- a/maxscale-system-test/mysqlmon_failover_stress.cpp
+++ b/maxscale-system-test/mysqlmon_failover_stress.cpp
@@ -327,10 +327,10 @@ private:
         for (size_t i = 0; i < s_nClients; ++i)
         {
             string drop = drop_head + std::to_string(i);
-            test.try_query(pConn, drop.c_str());
+            test.try_query(pConn, "%s", drop.c_str());
 
             string create = create_head + std::to_string(i) + create_tail;
-            test.try_query(pConn, create.c_str());
+            test.try_query(pConn, "%s", create.c_str());
         }
 
         return test.ok();
@@ -360,7 +360,7 @@ private:
                 }
             }
 
-            test.try_query(pConn, insert.c_str());
+            test.try_query(pConn, "%s", insert.c_str());
         }
 
         return test.ok();
diff --git a/maxscale-system-test/mysqlmon_switchover.cpp b/maxscale-system-test/mysqlmon_switchover.cpp
index 17ffba528..b193b9a60 100644
--- a/maxscale-system-test/mysqlmon_switchover.cpp
+++ b/maxscale-system-test/mysqlmon_switchover.cpp
@@ -70,7 +70,7 @@ void insert_data(TestConnections& test)
     {
         stringstream ss;
         ss << "INSERT INTO test.t1 VALUES (" << i << ")";
-        test.try_query(pConn, ss.str().c_str());
+        test.try_query(pConn, "%s", ss.str().c_str());
     }
 
     test.try_query(pConn, "COMMIT");
diff --git a/maxscale-system-test/mysqlmon_switchover_bad_master.cpp b/maxscale-system-test/mysqlmon_switchover_bad_master.cpp
index 9d8c46451..d4c3b054a 100644
--- a/maxscale-system-test/mysqlmon_switchover_bad_master.cpp
+++ b/maxscale-system-test/mysqlmon_switchover_bad_master.cpp
@@ -70,7 +70,7 @@ void insert_data(TestConnections& test)
     {
         stringstream ss;
         ss << "INSERT INTO test.t1 VALUES (" << i << ")";
-        test.try_query(pConn, ss.str().c_str());
+        test.try_query(pConn, "%s", ss.str().c_str());
     }
 
     test.try_query(pConn, "COMMIT");
diff --git a/maxscale-system-test/mysqlmon_switchover_stress.cpp b/maxscale-system-test/mysqlmon_switchover_stress.cpp
index 1f65bf0e5..10919987c 100644
--- a/maxscale-system-test/mysqlmon_switchover_stress.cpp
+++ b/maxscale-system-test/mysqlmon_switchover_stress.cpp
@@ -330,10 +330,10 @@ private:
         for (size_t i = 0; i < s_nClients; ++i)
         {
             string drop = drop_head + std::to_string(i);
-            test.try_query(pConn, drop.c_str());
+            test.try_query(pConn, "%s", drop.c_str());
 
             string create = create_head + std::to_string(i) + create_tail;
-            test.try_query(pConn, create.c_str());
+            test.try_query(pConn, "%s", create.c_str());
         }
 
         return test.ok();
@@ -363,7 +363,7 @@ private:
                 }
             }
 
-            test.try_query(pConn, insert.c_str());
+            test.try_query(pConn, "%s", insert.c_str());
         }
 
         return test.ok();
@@ -514,7 +514,7 @@ void create_client_user(TestConnections& test)
     stmt += "'";
     stmt += CLIENT_USER;
     stmt += "'@'%%'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 
     // Create user
     stmt = "CREATE USER ";
@@ -525,14 +525,14 @@ void create_client_user(TestConnections& test)
     stmt += "'";
     stmt += CLIENT_PASSWORD;
     stmt += "'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 
     // Grant access
     stmt = "GRANT SELECT, INSERT, UPDATE ON *.* TO ";
     stmt += "'";
     stmt += CLIENT_USER;
     stmt += "'@'%%'";
-    test.try_query(test.maxscales->conn_rwsplit[0], stmt.c_str());
+    test.try_query(test.maxscales->conn_rwsplit[0], "%s", stmt.c_str());
 
     test.try_query(test.maxscales->conn_rwsplit[0], "FLUSH PRIVILEGES");
 }
diff --git a/maxscale-system-test/session_limits.cpp b/maxscale-system-test/session_limits.cpp
index 84c75972a..1cfe0ab5b 100644
--- a/maxscale-system-test/session_limits.cpp
+++ b/maxscale-system-test/session_limits.cpp
@@ -40,7 +40,7 @@ int main(int argc, char *argv[])
     test.maxscales->connect_maxscale(0);
     for (int i = 0; i < 10; i++)
     {
-        test.try_query(test.maxscales->conn_rwsplit[0], std::string("set @test=" + std::to_string(i)).c_str());
+        test.try_query(test.maxscales->conn_rwsplit[0], "%s", std::string("set @test=" + std::to_string(i)).c_str());
     }
 
     test.tprintf("Execute one more session command and expect message in error log");
diff --git a/maxscale-system-test/short_sessions.cpp b/maxscale-system-test/short_sessions.cpp
index cf698899c..8f59960cd 100644
--- a/maxscale-system-test/short_sessions.cpp
+++ b/maxscale-system-test/short_sessions.cpp
@@ -37,7 +37,7 @@ int main(int argc, char *argv[])
 
         test.set_timeout(15);
         conn = test.maxscales->open_rwsplit_connection(0);
-        execute_query(conn, sql);
+        execute_query(conn, "%s", sql);
         mysql_close(conn);
     }
 
diff --git a/maxscale-system-test/sql_t1.cpp b/maxscale-system-test/sql_t1.cpp
index 6bfe3cec0..a1bae7ff3 100644
--- a/maxscale-system-test/sql_t1.cpp
+++ b/maxscale-system-test/sql_t1.cpp
@@ -183,7 +183,7 @@ int insert_into_t1(MYSQL *conn, int N)
         printf("INSERT: rwsplitter\n");
         printf("Trying INSERT, len=%d\n", x);
         fflush(stdout);
-        result += execute_query(conn,  sqlstr);
+        result += execute_query(conn, "%s", sqlstr);
         fflush(stdout);
         x *= 16;
     }
diff --git a/maxscale-system-test/testconnections.cpp b/maxscale-system-test/testconnections.cpp
index b69371831..6ef5948ed 100644
--- a/maxscale-system-test/testconnections.cpp
+++ b/maxscale-system-test/testconnections.cpp
@@ -619,7 +619,7 @@ void TestConnections::process_template(int m, const char *template_name, const c
         }
 
         mdn[j]->connect();
-        execute_query(mdn[j]->nodes[0], (char *) "CREATE DATABASE IF NOT EXISTS test");
+        execute_query(mdn[j]->nodes[0], "CREATE DATABASE IF NOT EXISTS test");
         mdn[j]->close_connections();
     }
 
@@ -889,8 +889,8 @@ int TestConnections::start_binlog(int m)
     repl->stop_nodes();
 
     binlog = open_conn_no_db(maxscales->binlog_port[m], maxscales->IP[m], repl->user_name, repl->password, ssl);
-    execute_query(binlog, (char *) "stop slave");
-    execute_query(binlog, (char *) "reset slave all");
+    execute_query(binlog, "stop slave");
+    execute_query(binlog, "reset slave all");
     mysql_close(binlog);
 
     tprintf("Stopping maxscale\n");
@@ -1068,7 +1068,7 @@ bool TestConnections::replicate_from_master(int m)
     return rval;
 }
 
-void TestConnections::revert_replicate_from_master(int m)
+void TestConnections::revert_replicate_from_master()
 {
     char log_file[256] = "";
 
@@ -1106,11 +1106,11 @@ int TestConnections::start_mm(int m)
     repl->connect();
     for (i = 0; i < 2; i++)
     {
-        execute_query(repl->nodes[i], (char *) "stop slave");
-        execute_query(repl->nodes[i], (char *) "reset master");
+        execute_query(repl->nodes[i], "stop slave");
+        execute_query(repl->nodes[i], "reset master");
     }
 
-    execute_query(repl->nodes[0], (char *) "SET GLOBAL READ_ONLY=ON");
+    execute_query(repl->nodes[0], "SET GLOBAL READ_ONLY=ON");
 
     find_field(repl->nodes[0], (char *) "show master status", (char *) "File", log_file1);
     find_field(repl->nodes[0], (char *) "show master status", (char *) "Position", log_pos1);
@@ -1573,7 +1573,7 @@ int TestConnections::get_client_ip(int m, char * ip)
 
     maxscales->connect_rwsplit(m);
     if (execute_query(maxscales->conn_rwsplit[m],
-                      (char *) "CREATE DATABASE IF NOT EXISTS db_to_check_client_ip") != 0 )
+                      "CREATE DATABASE IF NOT EXISTS db_to_check_client_ip") != 0 )
     {
         return ret;
     }
@@ -1746,15 +1746,15 @@ int TestConnections::use_db(int m, char * db)
     sprintf(sql, "USE %s;", db);
     set_timeout(20);
     tprintf("selecting DB '%s' for rwsplit\n", db);
-    local_result += execute_query(maxscales->conn_rwsplit[m], sql);
+    local_result += execute_query(maxscales->conn_rwsplit[m], "%s", sql);
     tprintf("selecting DB '%s' for readconn master\n", db);
-    local_result += execute_query(maxscales->conn_slave[m], sql);
+    local_result += execute_query(maxscales->conn_slave[m], "%s", sql);
     tprintf("selecting DB '%s' for readconn slave\n", db);
-    local_result += execute_query(maxscales->conn_master[m], sql);
+    local_result += execute_query(maxscales->conn_master[m], "%s", sql);
     for (int i = 0; i < repl->N; i++)
     {
         tprintf("selecting DB '%s' for direct connection to node %d\n", db, i);
-        local_result += execute_query(repl->nodes[i], sql);
+        local_result += execute_query(repl->nodes[i], "%s", sql);
     }
     return local_result;
 }
diff --git a/maxscale-system-test/testconnections.h b/maxscale-system-test/testconnections.h
index 807bc3f92..d571272da 100644
--- a/maxscale-system-test/testconnections.h
+++ b/maxscale-system-test/testconnections.h
@@ -293,7 +293,7 @@ public:
     /**
      * @brief Stop binlogrouter replication from master
      */
-    void revert_replicate_from_master(int m = 0);
+    void revert_replicate_from_master();
 
     /**
      * @brief prepare_binlog clean up binlog directory, set proper access rights to it