Merge branch '2.3' into 2.4

Documentation/Routers/ReadWriteSplit.md

@@ -771,6 +771,19 @@ long-running sessions might cause MariaDB MaxScale to consume a growing amount
 of memory unless the sessions are closed. This can be solved by adjusting the
 value of `max_sescmd_history`.
 
+### Routing to previous target
+
+In the following cases, a query is routed to the same server where the previous
+query was executed. If no previous target is found, the query is routed to the
+current master.
+
+* If a query uses the `FOUND_ROWS()` function, it will be routed to the server
+  where the last query was executed. This is done with the assumption that a
+  query with `SQL_CALC_FOUND_ROWS` was previously executed.
+
+* COM_STMT_FETCH_ROWS will always be routed to the same server where the
+  COM_STMT_EXECUTE was routed.
+
 ## Limitations
 
 Read queries are routed to the master server in the following situations:

maxctrl/lib/show.js

@@ -208,6 +208,11 @@ const session_fields = [
         path: 'attributes.idle',
         description: 'How long the session has been idle, in seconds'
     },
+    {
+        name: 'Client TLS Cipher',
+        path: 'attributes.client.cipher',
+        description: 'Client TLS cipher'
+    },
     {
         name: 'Connections',
         path: 'attributes.connections[].server',

server/core/dcb.cc

@@ -3256,7 +3256,16 @@ json_t* dcb_to_json(DCB* dcb)
     char buf[25];
     snprintf(buf, sizeof(buf), "%p", dcb);
     json_object_set_new(obj, "id", json_string(buf));
-    json_object_set_new(obj, "server", json_string(dcb->server->name()));
+
+    if (dcb->server)
+    {
+        json_object_set_new(obj, "server", json_string(dcb->server->name()));
+    }
+
+    if (dcb->ssl)
+    {
+        json_object_set_new(obj, "cipher", json_string(SSL_get_cipher_name(dcb->ssl)));
+    }
 
     if (dcb->func.diagnostics_json)
     {

server/core/queryclassifier.cc

@@ -1108,6 +1108,21 @@ QueryClassifier::RouteInfo QueryClassifier::update_route_info(
 
         process_routing_hints(pBuffer->hint, &route_target);
 
+        if (route_target == TARGET_SLAVE)
+        {
+            const QC_FUNCTION_INFO* infos = nullptr;
+            size_t n_infos = 0;
+            qc_get_function_info(pBuffer, &infos, &n_infos);
+
+            for (size_t i = 0; i < n_infos; ++i)
+            {
+                if (strcasecmp(infos[i].name, "FOUND_ROWS") == 0)
+                {
+                    route_target = TARGET_LAST_USED;
+                }
+            }
+        }
+
         if (session_trx_is_ending(m_pSession)
             || qc_query_is_type(type_mask, QUERY_TYPE_BEGIN_TRX))
         {

server/core/session.cc

@@ -770,6 +770,7 @@ json_t* session_json_data(const Session* session, const char* host, bool rdns)
     }
 
     json_object_set_new(attr, "connections", dcb_arr);
+    json_object_set_new(attr, "client", dcb_to_json(session->client_dcb));
 
     json_t* queries = session->queries_as_json();
     json_object_set_new(attr, "queries", queries);