Merge branch '2.3' into develop

Documentation/Tutorials/REST-API-Tutorial.md

@@ -53,7 +53,7 @@ now secure and can be used across networks.
 ## Requesting Data
 
 **Note:** For the sake of brevity, the rest of this tutorial will omit the
-TLS/SSL options for the `curl` command line. For more information, refer to the
+TLS/SSL options from the `curl` command line. For more information, refer to the
 `curl` manpage.
 
 The most basic task to do with the REST API is to see whether MaxScale is up and
@@ -272,8 +272,7 @@ execute the following command.
 curl -X PATCH -d @server1.txt 127.0.0.1:8989/v1/servers/server1
 ```
 
-To verify that the data was updated correctly, request the updated created
-object.
+To verify that the data was updated correctly, request the updated object.
 
 ```
 curl 127.0.0.1:8989/v1/servers/server1

include/maxscale/buffer.hh

@@ -45,6 +45,7 @@ enum gwbuf_type_t
     GWBUF_TYPE_RESULT         = (1 << 3),
     GWBUF_TYPE_REPLY_OK       = (1 << 4),
     GWBUF_TYPE_REPLAYED       = (1 << 5),
+    GWBUF_TYPE_TRACK_STATE    = (1 << 6),
 };
 
 #define GWBUF_IS_TYPE_UNDEFINED(b)     ((b)->gwbuf_type == 0)
@@ -56,6 +57,9 @@ enum gwbuf_type_t
 // True if the query is not initiated by the client but an internal replaying mechanism
 #define GWBUF_IS_REPLAYED(b)           ((b)->gwbuf_type & GWBUF_TYPE_REPLAYED)
 
+// Track session state change response
+#define GWBUF_SHOULD_TRACK_STATE(b) ((b)->gwbuf_type & GWBUF_TYPE_TRACK_STATE)
+
 enum  gwbuf_info_t
 {
     GWBUF_INFO_NONE   = 0x0,

include/maxscale/protocol/mysql.hh

@@ -336,6 +336,7 @@ typedef struct
     GWBUF*                 stored_query;                /*< Temporarily stored queries */
     bool                   collect_result;              /*< Collect the next result set as one buffer */
     bool                   changing_user;
+    bool                   track_state;     /*< Track session state */
     uint32_t               num_eof_packets; /*< Encountered eof packet number, used for check
                                              * packet type */
     bool large_query;                       /*< Whether to ignore the command byte of the next

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

@@ -17,6 +17,7 @@ user=maxskysql
 password=skysql
 auth_all_servers=1
 ignore_databases_regex=.*
+refresh_interval=5
 
 [Sharding-Listener]
 type=listener

maxscale-system-test/sharding.cpp

@@ -75,11 +75,11 @@ int main(int argc, char* argv[])
                                        "GRANT SELECT,USAGE,CREATE ON shard_db.* TO 'user%d'@'%%'",
                                        i),
                          "Query should succeed.");
+        execute_query(Test->repl->nodes[i], "FLUSH PRIVILEGES");
     }
 
     Test->repl->close_connections();
     Test->stop_timeout();
-    sleep(10);
 
     MYSQL* conn;
     for (i = 0; i < Test->repl->N; i++)
@@ -97,6 +97,7 @@ int main(int argc, char* argv[])
         Test->add_result(execute_query(conn, "CREATE TABLE table%d (x1 int, fl int);", i),
                          "Query should succeed.");
     }
+    sleep(6); // The router is configured to refresh the shard map if older than 5 seconds.
 
     for (i = 0; i < Test->repl->N; i++)
     {

server/core/service.cc

@@ -1439,7 +1439,7 @@ bool Service::dump_config(const char* filename) const
         for (const auto& f : m_filters)
         {
             dprintf(file, "%s%s", sep, f->name.c_str());
-            sep = ",";
+            sep = "|";
         }
 
         dprintf(file, "\n");

server/modules/protocol/MySQL/mariadbbackend/mysql_backend.cc

@@ -439,6 +439,8 @@ static inline void prepare_for_write(DCB* dcb, GWBUF* buffer)
     {
         proto->collect_result = true;
     }
+
+    proto->track_state = GWBUF_SHOULD_TRACK_STATE(buffer);
 }
 
 /*******************************************************************************
@@ -817,7 +819,8 @@ static int gw_read_and_write(DCB* dcb)
          * The OK packets sent in response to COM_STMT_PREPARE are of a different
          * format so we need to detect and skip them. */
         if (rcap_type_required(capabilities, RCAP_TYPE_SESSION_STATE_TRACKING)
-            && !expecting_ps_response(proto))
+            && !expecting_ps_response(proto)
+            && proto->track_state)
         {
             mxs_mysql_get_session_track_info(tmp, proto);
         }

server/modules/protocol/MySQL/mysql_common.cc

@@ -62,6 +62,7 @@ MySQLProtocol* mysql_protocol_init(DCB* dcb, int fd)
     p->changing_user = false;
     p->num_eof_packets = 0;
     p->large_query = false;
+    p->track_state = false;
     /*< Assign fd with protocol */
     p->fd = fd;
     p->owner_dcb = dcb;

server/modules/routing/readwritesplit/rwsplit_route_stmt.cc

@@ -277,6 +277,11 @@ bool RWSplitSession::route_single_stmt(GWBUF* querybuf)
         }
         else if (TARGET_IS_MASTER(route_target))
         {
+            if (m_config.causal_reads)
+            {
+                gwbuf_set_type(querybuf, GWBUF_TYPE_TRACK_STATE);
+            }
+
             succp = handle_master_is_target(&target);
 
             if (!succp && should_migrate_trx(target))

server/modules/routing/readwritesplit/rwsplit_select_backends.cc

@@ -22,6 +22,7 @@
 #include <functional>
 #include <random>
 #include <iostream>
+#include <array>
 
 #include <maxbase/stopwatch.hh>
 #include <maxscale/router.hh>
@@ -193,6 +194,11 @@ BackendSelectFunction get_backend_select_function(select_criteria_t sc)
     return backend_cmp_current_load;
 }
 
+namespace
+{
+// Buffers for sorting the servers, thread_local to avoid repeated memory allocations
+thread_local std::array<PRWBackends, 3> priority_map;
+}
 
 /**
  * @brief Find the best slave candidate for routing reads.
@@ -208,7 +214,6 @@ PRWBackends::iterator find_best_backend(PRWBackends& backends,
                                         bool masters_accepts_reads)
 {
     // Group backends by priority. The set of highest priority backends will then compete.
-    std::map<int, PRWBackends> priority_map;
     int best_priority {INT_MAX};    // low numbers are high priority
 
     for (auto& psBackend : backends)
@@ -222,16 +227,16 @@ PRWBackends::iterator find_best_backend(PRWBackends& backends,
         {
             if (!is_busy)
             {
-                priority = 1;   // highest priority, idle servers
+                priority = 0;   // highest priority, idle servers
             }
             else
             {
-                priority = 13;      // lowest priority, busy servers
+                priority = 2;       // lowest priority, busy servers
             }
         }
         else
         {
-            priority = 2;   // idle masters with masters_accept_reads==false
+            priority = 1;   // idle masters with masters_accept_reads==false
         }
 
         priority_map[priority].push_back(psBackend);
@@ -239,8 +244,14 @@ PRWBackends::iterator find_best_backend(PRWBackends& backends,
     }
 
     auto best = select(priority_map[best_priority]);
+    auto rval = std::find(backends.begin(), backends.end(), *best);
 
-    return std::find(backends.begin(), backends.end(), *best);
+    for (auto& a : priority_map)
+    {
+        a.clear();
+    }
+
+    return rval;
 }
 
 /**

server/modules/routing/readwritesplit/rwsplitsession.cc

@@ -563,6 +563,17 @@ static bool server_is_shutting_down(GWBUF* writebuf)
     return err == ER_SERVER_SHUTDOWN || err == ER_NORMAL_SHUTDOWN || err == ER_SHUTDOWN_COMPLETE;
 }
 
+void RWSplitSession::close_stale_connections()
+{
+    for (auto& backend : m_backends)
+    {
+        if (backend->in_use() && !backend->can_connect())
+        {
+            backend->close();
+        }
+    }
+}
+
 void RWSplitSession::clientReply(GWBUF* writebuf, DCB* backend_dcb)
 {
     DCB* client_dcb = backend_dcb->session->client_dcb;
@@ -719,6 +730,15 @@ void RWSplitSession::clientReply(GWBUF* writebuf, DCB* backend_dcb)
         m_can_replay_trx = true;
     }
 
+    if (m_expected_responses == 0)
+    {
+        /**
+         * Close stale connections to servers in maintenance. Done here to avoid closing the connections
+         * before all responses have been received.
+         */
+        close_stale_connections();
+    }
+
     if (backend->in_use() && backend->has_session_commands())
     {
         // Backend is still in use and has more session commands to execute

server/modules/routing/readwritesplit/rwsplitsession.hh

@@ -144,6 +144,7 @@ private:
     void continue_large_session_write(GWBUF* querybuf, uint32_t type);
     bool route_single_stmt(GWBUF* querybuf);
     bool route_stored_query();
+    void close_stale_connections();
 
     mxs::RWBackend* get_hinted_backend(char* name);
     mxs::RWBackend* get_slave_backend(int max_rlag);

server/modules/routing/schemarouter/schemaroutersession.cc

@@ -1592,8 +1592,17 @@ bool SchemaRouterSession::send_tables(GWBUF* pPacket)
 
     if (database.empty())
     {
-        MXS_FREE(query);
-        return false;
+        // Was not a "show tables from x". If a current database is selected, use that as target.
+        if (!m_current_db.empty())
+        {
+            database = m_current_db;
+        }
+        else
+        {
+            // No current db, route the query to a server, likely getting "No database selected"
+            MXS_FREE(query);
+            return false;
+        }
     }
 
     ServerMap tablelist;