Add session command class

The class abstracts the session commands and the lists of session commands
using standard library containers.

server/modules/routing/schemarouter/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_library(schemarouter SHARED schemarouter.cc shard_map.cc)
+add_library(schemarouter SHARED schemarouter.cc shard_map.cc session_command.cc)
 target_link_libraries(schemarouter maxscale-common)
 add_dependencies(schemarouter pcre2)
 set_target_properties(schemarouter PROPERTIES VERSION "1.0.0")

server/modules/routing/schemarouter/schemarouter.cc

@@ -18,6 +18,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#include <string>
 
 #include <maxscale/alloc.h>
 #include <maxscale/buffer.h>
@@ -30,6 +31,8 @@
 #include <maxscale/secrets.h>
 #include <maxscale/spinlock.h>
 
+using std::string;
+
 #define DEFAULT_REFRESH_INTERVAL "300"
 
 /** Hashtable size for the per user shard maps */
@@ -569,9 +572,10 @@ static route_target_t get_shard_route_target(uint32_t qtype,
      * These queries are not affected by hints
      */
     if (qc_query_is_type(qtype, QUERY_TYPE_SESSION_WRITE) ||
+        qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_WRITE) ||
+        qc_query_is_type(qtype, QUERY_TYPE_USERVAR_WRITE) ||
         qc_query_is_type(qtype, QUERY_TYPE_PREPARE_STMT) ||
         qc_query_is_type(qtype, QUERY_TYPE_PREPARE_NAMED_STMT) ||
-        qc_query_is_type(qtype, QUERY_TYPE_GSYSVAR_WRITE) ||
         /** enable or disable autocommit are always routed to all */
         qc_query_is_type(qtype, QUERY_TYPE_ENABLE_AUTOCOMMIT) ||
         qc_query_is_type(qtype, QUERY_TYPE_DISABLE_AUTOCOMMIT))
@@ -1793,6 +1797,18 @@ static bool route_session_write(SCHEMAROUTER_SESSION* router_cli_ses,
     {
         if (BREF_IS_IN_USE((&backend_ref[i])))
         {
+            GWBUF *buffer = gwbuf_clone(querybuf);
+            backend_ref[i].session_commands.push_back(buffer);
+
+            for (SessionCommandList::iterator iter = backend_ref[i].session_commands.begin();
+                 iter != backend_ref[i].session_commands.end();
+                 iter++)
+            {
+                SessionCommand& scmd = *iter;
+                string str = scmd.to_string();
+                MXS_INFO("%s: %s", backend_ref[i].bref_backend->server->unique_name, str.c_str());
+            }
+
             sescmd_cursor_t* scur;
 
             if (MXS_LOG_PRIORITY_IS_ENABLED(LOG_INFO))

server/modules/routing/schemarouter/schemarouter.h

@@ -34,6 +34,7 @@
 #include <maxscale/pcre2.h>
 
 #include "shard_map.hh"
+#include "session_command.hh"
 
 MXS_BEGIN_DECLS
 
@@ -254,6 +255,9 @@ typedef struct backend_ref_st
     int             bref_num_result_wait; /*< Number of not yet received results */
     sescmd_cursor_t bref_sescmd_cur; /*< Session command cursor */
     GWBUF*          bref_pending_cmd; /*< For stmt which can't be routed due active sescmd execution */
+
+    SessionCommandList session_commands; /**< List of session commands that are
+                                          * to be executed on this backend server */
 #if defined(SS_DEBUG)
     skygw_chk_t     bref_chk_tail;
 #endif

server/modules/routing/schemarouter/session_command.cc

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include "session_command.hh"
+#include <maxscale/modutil.h>
+
+void SessionCommand::mark_reply_received()
+{
+    m_replySent = true;
+}
+
+bool SessionCommand::is_reply_received() const
+{
+    return m_replySent;
+}
+
+Buffer SessionCommand::copy_buffer() const
+{
+    return m_buffer;
+}
+
+SessionCommand::SessionCommand(GWBUF *buffer):
+    m_buffer(buffer),
+    m_replySent(false)
+{
+}
+
+SessionCommand::~SessionCommand()
+{
+}
+
+std::string SessionCommand::to_string()
+{
+    std::string str;
+    
+    GWBUF **buf = &m_buffer;
+    char *sql;
+    int sql_len;
+
+    if (modutil_extract_SQL(*buf, &sql, &sql_len))
+    {
+        str.append(sql, sql_len);
+    }
+
+    return str;
+}

server/modules/routing/schemarouter/session_command.hh

@@ -0,0 +1,69 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#pragma once
+
+#include <list>
+#include <string>
+
+#include <maxscale/buffer.hh>
+
+using namespace maxscale;
+
+class SessionCommand;
+typedef std::list<SessionCommand> SessionCommandList;
+
+class SessionCommand
+{
+public:
+    /**
+     * @brief Mark reply as received
+     */
+    void mark_reply_received();
+
+    /**
+     * @brief Check if the session command has received a reply
+     * @return True if the reply is already received
+     */
+    bool is_reply_received() const;
+
+    /**
+     * @brief Creates a copy of the internal buffer
+     * @return A copy of the internal buffer
+     */
+    Buffer copy_buffer() const;
+
+    /**
+     * @brief Create a new session command
+     *
+     * @param buffer The buffer containing the command. Note that the ownership
+     *               of @c buffer is transferred to this object.
+     */
+    SessionCommand(GWBUF *buffer);
+
+    ~SessionCommand();
+
+    /**
+     * @brief Debug function for printing session commands
+     *
+     * @return String representation of the object
+     */
+    std::string to_string();
+
+private:
+    Buffer m_buffer; /**< The buffer containing the command */
+    bool   m_replySent; /**< Whether the session command reply has been sent */
+
+    SessionCommand();
+    SessionCommand& operator = (const SessionCommand& command);
+};