MXS-2300: Add history pruning test

The test checks that the session command history pruning works as
expected.

maxscale-system-test/CMakeLists.txt

@@ -918,6 +918,9 @@ add_test_executable(mxs2115_version_string.cpp mxs2115_version_string replicatio
 # MXS-2295: COM_CHANGE_USER does not clear out session command history
 add_test_executable(mxs2295_change_user_loop.cpp mxs2295_change_user_loop mxs2295_change_user_loop LABELS REPL_BACKEND)
 
+# MXS-2300: Prune session command history
+add_test_executable(mxs2300_history_pruning.cpp mxs2300_history_pruning mxs2300_history_pruning LABELS REPL_BACKEND)
+
 ############################################
 # BEGIN: binlogrouter and avrorouter tests #
 ############################################

maxscale-system-test/cnf/maxscale.cnf.template.mxs2300_history_pruning

@@ -0,0 +1,51 @@
+[maxscale]
+threads=###threads###
+log_info=1
+
+[server1]
+type=server
+address=###node_server_IP_1###
+port=###node_server_port_1###
+protocol=MySQLBackend
+
+[server2]
+type=server
+address=###node_server_IP_2###
+port=###node_server_port_2###
+protocol=MySQLBackend
+
+[server3]
+type=server
+address=###node_server_IP_3###
+port=###node_server_port_3###
+protocol=MySQLBackend
+
+[server4]
+type=server
+address=###node_server_IP_4###
+port=###node_server_port_4###
+protocol=MySQLBackend
+
+[MySQL Monitor]
+type=monitor
+module=mysqlmon
+servers=server1,server2,server3,server4
+user=maxskysql
+password=skysql
+monitor_interval=1000
+
+[RW Split Router]
+type=service
+router=readwritesplit
+servers=server1,server2,server3,server4
+user=maxskysql
+password=skysql
+max_sescmd_history=10
+prune_sescmd_history=true
+max_slave_connections=1
+
+[RW Split Listener]
+type=listener
+service=RW Split Router
+protocol=MySQLClient
+port=4006

maxscale-system-test/mariadb_nodes.cpp

@@ -936,6 +936,18 @@ std::string Mariadb_nodes::get_server_id_str(int index)
     return ss.str();
 }
 
+std::vector<int> Mariadb_nodes::get_all_server_ids()
+{
+    std::vector<int> rval;
+
+    for (int i = 0; i < N; i++)
+    {
+        rval.push_back(get_server_id(i));
+    }
+
+    return rval;
+}
+
 bool do_flush_hosts(MYSQL* conn)
 {
     int local_result = 0;

maxscale-system-test/mariadb_nodes.h

@@ -316,6 +316,13 @@ public:
     int         get_server_id(int index);
     std::string get_server_id_str(int index);
 
+    /**
+     * Get server IDs of all servers
+     *
+     * @return List of server IDs
+     */
+    std::vector<int> get_all_server_ids();
+
     /**
      * @brief Execute 'mysqladmin flush-hosts' on all nodes
      * @return 0 in case of success

maxscale-system-test/mxs2300_history_pruning.cpp

@@ -0,0 +1,109 @@
+/**
+ * MXS-2300: Session command history pruning
+ */
+
+#include "testconnections.h"
+#include <sstream>
+
+std::vector<int> ids;
+
+void block_by_id(TestConnections& test, int id)
+{
+    for (size_t i = 0; i < ids.size(); i++)
+    {
+        if (ids[i] == id)
+        {
+            test.repl->block_node(i);
+        }
+    }
+}
+
+void unblock_by_id(TestConnections& test, int id)
+{
+    for (size_t i = 0; i < ids.size(); i++)
+    {
+        if (ids[i] == id)
+        {
+            test.repl->unblock_node(i);
+        }
+    }
+}
+
+int main(int argc, char** argv)
+{
+    TestConnections test(argc, argv);
+
+    test.repl->connect();
+    ids = test.repl->get_all_server_ids();
+    test.repl->disconnect();
+
+    int master_id = test.get_master_server_id();
+    Connection conn = test.maxscales->rwsplit();
+    test.expect(conn.connect(), "Connection failed: %s", conn.error());
+
+    test.tprintf("Get the ID of the server we first start with");
+    int first_id = std::stoi(conn.field("SELECT @@server_id"));
+
+    test.tprintf("The history size is set to 10 commands, execute five and check that they are retained");
+    for (int i = 0; i < 5; i++)
+    {
+        std::stringstream query;
+        query << "SET @a" << i << " = " << i;
+        conn.query(query.str());
+    }
+
+    block_by_id(test, first_id);
+    test.maxscales->wait_for_monitor();
+
+    int second_id = std::stoi(conn.field("SELECT @@server_id"));
+
+    test.tprintf("Make sure that a reconnection actually took place");
+    test.expect(first_id != second_id && second_id > 0, "Invalid server ID: %d", second_id);
+    test.expect(master_id != second_id, "SELECT should not go to the master");
+
+    test.tprintf("Check that the values were correctly set");
+    for (int i = 0; i < 5; i++)
+    {
+        std::string value = std::to_string(i);
+        std::string query = "SELECT @a" + value;
+        test.expect(conn.check(query, value), "Invalid value for user variable @a%s", value.c_str());
+    }
+
+    unblock_by_id(test, first_id);
+
+    test.tprintf("Execute 15 commands and check that we lose the first five values");
+    for (int i = 0; i < 15; i++)
+    {
+        std::stringstream query;
+        query << "SET @b" << i << " =" << i;
+        conn.query(query.str());
+    }
+
+    block_by_id(test, second_id);
+    test.maxscales->wait_for_monitor();
+
+    int third_id = std::stoi(conn.field("SELECT @@server_id"));
+
+    test.expect(third_id != second_id && third_id > 0, "Invalid server ID: %d", third_id);
+    test.expect(master_id != third_id, "SELECT should not go to the master");
+
+    for (int i = 0; i < 5; i++)
+    {
+        std::string variable = "@b" + std::to_string(i);
+        std::string query = "SELECT IFNULL(" + variable + ", '" + variable + " is null')";
+        test.expect(conn.check(query, variable + " is null"), "%s should not be set", variable.c_str());
+    }
+
+    test.tprintf("Check that the remaining values were correctly set");
+    for (int i = 5; i < 15; i++)
+    {
+        std::string value = std::to_string(i);
+        std::string query = "SELECT @b" + value;
+        std::string f = conn.field(query);
+        test.expect(conn.check(query, value), "Invalid value for user variable @b%s: %s", value.c_str(), f.c_str());
+    }
+
+    unblock_by_id(test, second_id);
+
+    return test.global_result;
+}