Merge branch '2.2' into develop

server/core/config.cc

@@ -80,6 +80,7 @@ const char CN_CONNECTION_TIMEOUT[]            = "connection_timeout";
 const char CN_DATA[]                          = "data";
 const char CN_DEFAULT[]                       = "default";
 const char CN_DESCRIPTION[]                   = "description";
+const char CN_DUMP_LAST_STATEMENTS[]          = "dump_last_statements";
 const char CN_ENABLE_ROOT_USER[]              = "enable_root_user";
 const char CN_FILTERS[]                       = "filters";
 const char CN_FILTER[]                        = "filter";
@@ -121,6 +122,7 @@ const char CN_RELATIONSHIPS[]                 = "relationships";
 const char CN_LINKS[]                         = "links";
 const char CN_LOCAL_ADDRESS[]                 = "local_address";
 const char CN_REQUIRED[]                      = "required";
+const char CN_RETAIN_LAST_STATEMENTS[]        = "retain_last_statements";
 const char CN_RETRY_ON_FAILURE[]              = "retry_on_failure";
 const char CN_ROUTER[]                        = "router";
 const char CN_ROUTER_DIAGNOSTICS[]            = "router_diagnostics";
@@ -1782,6 +1784,39 @@ handle_global_item(const char *name, const char *value)
             gateway.users_refresh_time = USERS_REFRESH_TIME_DEFAULT;
         }
     }
+    else if (strcmp(name, CN_RETAIN_LAST_STATEMENTS) == 0)
+    {
+        char* endptr;
+        int intval = strtol(value, &endptr, 0);
+        if (*endptr == '\0' && intval >= 0)
+        {
+            session_set_retain_last_statements(intval);
+        }
+        else
+        {
+            MXS_ERROR("Invalid value for '%s': %s", CN_RETAIN_LAST_STATEMENTS, value);
+        }
+    }
+    else if (strcmp(name, CN_DUMP_LAST_STATEMENTS) == 0)
+    {
+        if (strcmp(value, "on_close") == 0)
+        {
+            session_set_dump_statements(SESSION_DUMP_STATEMENTS_ON_CLOSE);
+        }
+        else if (strcmp(value, "on_error") == 0)
+        {
+            session_set_dump_statements(SESSION_DUMP_STATEMENTS_ON_ERROR);
+        }
+        else if (strcmp(value, "never") == 0)
+        {
+            session_set_dump_statements(SESSION_DUMP_STATEMENTS_NEVER);
+        }
+        else
+        {
+            MXS_ERROR("%s can have the values 'never', 'on_close' or 'on_error'.",
+                      CN_DUMP_LAST_STATEMENTS);
+        }
+    }
     else
     {
         for (i = 0; lognames[i].name; i++)

server/core/session.cc

@@ -37,6 +37,7 @@
 #include <maxscale/spinlock.h>
 #include <maxscale/utils.h>
 #include <maxscale/json_api.h>
+#include <maxscale/protocol/mysql.h>
 
 #include "internal/dcb.h"
 #include "internal/session.h"
@@ -52,6 +53,9 @@ using std::stringstream;
  */
 static uint64_t next_session_id = 1;
 
+static uint32_t retain_last_statements = 0;
+static session_dump_statements_t dump_statements = SESSION_DUMP_STATEMENTS_NEVER;
+
 static struct session session_dummy_struct;
 
 static void session_initialize(void *session);
@@ -88,6 +92,7 @@ session_initialize(MXS_SESSION *session)
 
     session->ses_chk_top = CHK_NUM_SESSION;
     session->state = SESSION_STATE_ALLOC;
+    session->last_statements = new SessionStmtQueue;
     session->ses_chk_tail = CHK_NUM_SESSION;
 }
 
@@ -388,8 +393,14 @@ static void session_free(MXS_SESSION *session)
 static void
 session_final_free(MXS_SESSION *session)
 {
+    if (dump_statements == SESSION_DUMP_STATEMENTS_ON_CLOSE)
+    {
+        session_dump_statements(session);
+    }
+
     gwbuf_free(session->stmt.buffer);
     delete session->variables;
+    delete session->last_statements;
     MXS_FREE(session);
 }
 
@@ -1276,3 +1287,94 @@ static void session_deliver_response(MXS_SESSION* session)
     ss_dassert(!session->response.up.error);
     ss_dassert(!session->response.buffer);
 }
+
+void session_set_retain_last_statements(uint32_t n)
+{
+    retain_last_statements = n;
+}
+
+void session_set_dump_statements(session_dump_statements_t value)
+{
+    dump_statements = value;
+}
+
+session_dump_statements_t session_get_dump_statements()
+{
+    return dump_statements;
+}
+
+void session_retain_statement(MXS_SESSION* pSession, GWBUF* pBuffer)
+{
+    if (retain_last_statements)
+    {
+        size_t len = gwbuf_length(pBuffer);
+
+        if (len > MYSQL_HEADER_LEN)
+        {
+            uint8_t header[MYSQL_HEADER_LEN + 1];
+            uint8_t* pHeader = NULL;
+
+            if (GWBUF_LENGTH(pBuffer) > MYSQL_HEADER_LEN)
+            {
+                pHeader = GWBUF_DATA(pBuffer);
+            }
+            else
+            {
+                gwbuf_copy_data(pBuffer, 0, MYSQL_HEADER_LEN + 1, header);
+                pHeader = header;
+            }
+
+            if (MYSQL_GET_COMMAND(pHeader) == MXS_COM_QUERY)
+            {
+                ss_dassert(pSession->last_statements->size() <= retain_last_statements);
+
+                if (pSession->last_statements->size() == retain_last_statements)
+                {
+                    pSession->last_statements->pop_back();
+                }
+
+                std::vector<uint8_t> stmt(len - MYSQL_HEADER_LEN - 1);
+                gwbuf_copy_data(pBuffer, MYSQL_HEADER_LEN + 1, len - (MYSQL_HEADER_LEN + 1), &stmt.front());
+
+                pSession->last_statements->push_front(stmt);
+            }
+        }
+    }
+}
+
+void session_dump_statements(MXS_SESSION* pSession)
+{
+    if (retain_last_statements)
+    {
+        int n = pSession->last_statements->size();
+
+        uint64_t id = session_get_current_id();
+
+        if ((id != 0) && (id != pSession->ses_id))
+        {
+            MXS_WARNING("Current session is %" PRIu64 ", yet statements are dumped for %" PRIu64 ". "
+                        "The session id in the subsequent dumped statements is the wrong one.",
+                        id, pSession->ses_id);
+        }
+
+        for (auto i = pSession->last_statements->rbegin(); i != pSession->last_statements->rend(); ++i)
+        {
+            int len = i->size();
+            const char* pStmt = (char*) &i->front();
+
+            if (id != 0)
+            {
+                MXS_NOTICE("Stmt %d: %.*s", n, len, pStmt);
+            }
+            else
+            {
+                // We are in a context where we do not have a current session, so we need to
+                // log the session id ourselves.
+
+                MXS_NOTICE("(%" PRIu64 ") Stmt %d: %.*s", pSession->ses_id, n, len, pStmt);
+            }
+
+            --n;
+        }
+    }
+}