Merge branch '2.3' into 2.4

system-test/stale_slaves.cpp

@@ -0,0 +1,79 @@
+/**
+ * @file stale_slaves.cpp Testing slaves who have lost their master and how MaxScale works with them
+ *
+ * When the master server is blocked and slaves lose their master, they should
+ * still be available for read queries. Once the master comes back, all slaves
+ * should get slave status if replication is running.
+ */
+
+#include <maxtest/testconnections.hh>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+using namespace std;
+
+int main(int argc, char** argv)
+{
+    TestConnections test(argc, argv);
+    vector<string> ids;
+
+    test.repl->connect();
+    for (int i = 0; i < test.repl->N; i++)
+    {
+        ids.push_back(test.repl->get_server_id_str(i));
+    }
+
+    auto get_id = [&]() {
+            Connection c = test.maxscales->readconn_slave();
+            test.expect(c.connect(), "Connection should be OK: %s", c.error());
+            string res = c.field("SELECT @@server_id");
+            test.expect(!res.empty(), "Field should not be empty: %s", c.error());
+            return res;
+        };
+
+    auto in_use = [&](string id) {
+            for (int i = 0; i < 2 * test.repl->N; i++)
+            {
+                if (get_id() == id)
+                {
+                    return true;
+                }
+            }
+
+            return false;
+        };
+
+    test.tprintf("Blocking the master and doing a read query");
+    test.repl->block_node(0);
+    test.maxscales->wait_for_monitor();
+
+    string first = get_id();
+    auto it = find(begin(ids), end(ids), first);
+    test.expect(it != end(ids), "ID should be found");
+    int node = distance(begin(ids), it);
+
+    test.tprintf("Blocking the slave that replied to us");
+    test.repl->block_node(node);
+    test.maxscales->wait_for_monitor();
+    test.expect(!in_use(first), "The first slave should not be in use");
+
+    test.tprintf("Unblocking all nodes");
+    test.repl->unblock_all_nodes();
+    test.maxscales->wait_for_monitor();
+    test.expect(in_use(first), "The first slave should be in use");
+
+    test.tprintf("Stopping replication on first slave");
+    execute_query(test.repl->nodes[node], "STOP SLAVE");
+    test.maxscales->wait_for_monitor();
+    test.expect(!in_use(first), "The first slave should not be in use");
+
+    test.tprintf("Starting replication on first slave");
+    execute_query(test.repl->nodes[node], "START SLAVE");
+    test.maxscales->wait_for_monitor();
+    test.expect(in_use(first), "The first slave should be in use");
+    test.repl->disconnect();
+
+    return test.global_result;
+}