From e1e01c029c20500e040e6ac257027db7f1a7a1b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20M=C3=A4kel=C3=A4?= <markus.makela@mariadb.com>
Date: Thu, 5 Apr 2018 14:46:08 +0300
Subject: [PATCH] MXS-1506: Allow immediate query re-routing

Now that the readwritesplit uses the same mechanism for both
retry_failed_reads and delayed query retries, the re-routing function
should accept a delay of 0 seconds. This makes the mechanism more suitable
for other uses e.g. delaying of queries in filters.
---
 include/maxscale/session.h                    |  2 +-
 server/core/session.cc                        | 19 +++++++++++++------
 .../routing/readwritesplit/rwsplitsession.cc  |  2 +-
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/maxscale/session.h b/include/maxscale/session.h
index cc8a8ff30..c401fe9d3 100644
--- a/include/maxscale/session.h
+++ b/include/maxscale/session.h
@@ -633,7 +633,7 @@ session_dump_statements_t session_get_dump_statements();
  * @param session The current Session
  * @param down    The downstream component, either a filter or a router
  * @param buffer  The buffer to route
- * @param seconds Number of seconds to wait before routing the query
+ * @param seconds Number of seconds to wait before routing the query. Use 0 for immediate re-routing.
  *
  * @return True if queuing of the query was successful
  */
diff --git a/server/core/session.cc b/server/core/session.cc
index 6e8038192..4cd016220 100644
--- a/server/core/session.cc
+++ b/server/core/session.cc
@@ -1394,16 +1394,23 @@ bool session_delay_routing(MXS_SESSION* session, MXS_DOWNSTREAM down, GWBUF* buf
 
     try
     {
-        std::stringstream name;
-        name << "Session_" << session->ses_id << "_retry";
-
         Worker* worker = Worker::get_current();
         ss_dassert(worker == Worker::get(session->client_dcb->poll.thread.id));
         std::auto_ptr<DelayedRoutingTask> task(new DelayedRoutingTask(session, down, buffer));
-        std::auto_ptr<TaskAssignment> job(new TaskAssignment(task, worker));
-        TaskAssignment* pJob = job.release();
 
-        hktask_add(name.str().c_str(), delayed_routing_cb, pJob, seconds);
+        if (seconds == 0)
+        {
+            // No actual delay, just re-route query
+            worker->post(task);
+        }
+        else
+        {
+            std::stringstream name;
+            name << "Session_" << session->ses_id << "_retry";
+            std::auto_ptr<TaskAssignment> job(new TaskAssignment(task, worker));
+            hktask_add(name.str().c_str(), delayed_routing_cb, job.release(), seconds);
+        }
+
         success = true;
     }
     catch (std::bad_alloc)
diff --git a/server/modules/routing/readwritesplit/rwsplitsession.cc b/server/modules/routing/readwritesplit/rwsplitsession.cc
index a6a094c32..cb744c27e 100644
--- a/server/modules/routing/readwritesplit/rwsplitsession.cc
+++ b/server/modules/routing/readwritesplit/rwsplitsession.cc
@@ -615,7 +615,7 @@ bool RWSplitSession::handle_error_new_connection(DCB *backend_dcb, GWBUF *errmsg
         {
             MXS_INFO("Re-routing failed read after server '%s' failed", backend->name());
             MXS_SESSION* session = m_client->session;
-            session_delay_routing(session, router_as_downstream(session), stored, 1);
+            session_delay_routing(session, router_as_downstream(session), stored, 0);
         }
         else
         {