diff --git a/server/modules/routing/schemarouter/schemaroutersession.cc b/server/modules/routing/schemarouter/schemaroutersession.cc
index e7a3ee00a..57a479d4f 100644
--- a/server/modules/routing/schemarouter/schemaroutersession.cc
+++ b/server/modules/routing/schemarouter/schemaroutersession.cc
@@ -101,6 +101,11 @@ void SchemaRouterSession::close()
     {
         m_closed = true;
 
+        if (m_dcid)
+        {
+            mxb::Worker::get_current()->cancel_delayed_call(m_dcid);
+        }
+
         for (SSRBackendList::iterator it = m_backends.begin(); it != m_backends.end(); it++)
         {
             SSRBackend& bref = *it;
@@ -287,7 +292,7 @@ int32_t SchemaRouterSession::routeQuery(GWBUF* pPacket)
         return 0;
     }
 
-    if (m_shard.empty())
+    if (m_shard.empty() && (m_state & INIT_MAPPING) == 0)
     {
         // Check if another session has managed to update the shard cache
         m_shard = m_router->m_shard_manager.get_shard(m_key, m_config->refresh_min_interval);
@@ -303,10 +308,17 @@ int32_t SchemaRouterSession::routeQuery(GWBUF* pPacket)
             else
             {
                 // Too many concurrent updates
+                m_queue.push_back(pPacket);
 
-                // TODO: Queue this session instead of killing it
-                m_pSession->kill(modutil_create_mysql_err_msg(1, 0, 1096, "HY000", "Too many updates"));
-                return 0;
+                if (m_dcid == 0)
+                {
+                    // Wait for the other session to finish its update
+                    auto worker = mxs::RoutingWorker::get_current();
+                    m_dcid = worker->delayed_call(1000, &SchemaRouterSession::delay_routing, this);
+                    MXS_INFO("Waiting for the database mapping to be completed by another session");
+                }
+
+                return 1;
             }
         }
     }
@@ -1105,6 +1117,37 @@ void SchemaRouterSession::route_queued_query()
     session_delay_routing(m_pSession, router_as_downstream(m_pSession), tmp, 0);
 }
 
+bool SchemaRouterSession::delay_routing(mxb::Worker::Call::action_t action)
+{
+    bool rv = false;
+
+    if (action == mxb::Worker::Call::EXECUTE)
+    {
+        mxb_assert(m_shard.empty());
+        m_shard = m_router->m_shard_manager.get_shard(m_key, m_config->refresh_min_interval);
+
+        if (!m_shard.empty())
+        {
+            MXS_INFO("Another session updated the shard information, reusing the result");
+            route_queued_query();
+            m_dcid = 0;
+        }
+        else if (m_router->m_shard_manager.start_update(m_key))
+        {
+            // No other sessions are doing an update, start our own update
+            query_databases();
+            m_dcid = 0;
+        }
+        else
+        {
+            // We're still waiting for an update from another session
+            rv = true;
+        }
+    }
+
+    return rv;
+}
+
 /**
  *
  * @param router_cli_ses Router client session
@@ -1477,6 +1520,7 @@ enum showdb_response SchemaRouterSession::parse_mapping_response(SSRBackend& bre
  */
 void SchemaRouterSession::query_databases()
 {
+    MXS_INFO("Mapping databases");
 
     for (SSRBackendList::iterator it = m_backends.begin(); it != m_backends.end(); it++)
     {
diff --git a/server/modules/routing/schemarouter/schemaroutersession.hh b/server/modules/routing/schemarouter/schemaroutersession.hh
index 902b123f6..9ec3f8bf7 100644
--- a/server/modules/routing/schemarouter/schemaroutersession.hh
+++ b/server/modules/routing/schemarouter/schemaroutersession.hh
@@ -148,6 +148,7 @@ private:
     int                  inspect_mapping_states(SSRBackend& bref, GWBUF** wbuf);
     enum showdb_response parse_mapping_response(SSRBackend& bref, GWBUF** buffer);
     void                 route_queued_query();
+    bool                 delay_routing(mxb::Worker::Call::action_t action);
     void                 synchronize_shards();
     void                 handle_mapping_reply(SSRBackend& bref, GWBUF** pPacket);
     bool                 handle_statement(GWBUF* querybuf, SSRBackend& bref, uint8_t command, uint32_t type);
@@ -170,5 +171,6 @@ private:
     uint64_t               m_sent_sescmd;   /**< The latest session command being executed */
     uint64_t               m_replied_sescmd;/**< The last session command reply that was sent to the client */
     SERVER*                m_load_target;   /**< Target for LOAD DATA LOCAL INFILE */
+    uint32_t               m_dcid {0};
 };
 }