Snapshot of failure tolerance changes.

Added a lot of logging to error, trace and message logs which should help the user to handle errors which can't be automatically resolved, like attempt to use nonexisting database.

server/modules/include/mysql_client_server_protocol.h

@@ -88,7 +88,7 @@
 #define SMALL_CHUNK 1024
 #define MAX_CHUNK SMALL_CHUNK * 8 * 4
 #define ToHex(Y) (Y>='0'&&Y<='9'?Y-'0':Y-'A'+10)
-
+#define COM_QUIT_PACKET_SIZE (4+1)
 struct dcb;
 
 typedef enum {
@@ -104,7 +104,6 @@ typedef enum {
     MYSQL_SESSION_CHANGE
 } mysql_pstate_t;
 
-
 /*
  * MySQL Protocol specific state data
  */
@@ -257,6 +256,7 @@ int  gw_send_authentication_to_backend(
         MySQLProtocol *protocol);
 const char *gw_mysql_protocol_state2string(int state);
 int gw_do_connect_to_backend(char *host, int port, int* fd);
+int mysql_send_com_quit(DCB* dcb, int packet_number);
 int mysql_send_custom_error (
         DCB *dcb,
         int packet_number,

server/modules/include/readwritesplit.h

@@ -31,6 +31,12 @@
 
 #include <dcb.h>
 
+typedef enum bref_state {
+        BREF_NOT_USED,
+        BREF_IN_USE,
+        BREF_CLOSED
+} bref_state_t;
+
 typedef enum backend_type_t {
         BE_UNDEFINED=-1, 
         BE_MASTER, 
@@ -159,6 +165,7 @@ typedef struct backend_ref_st {
 #endif
         BACKEND*        bref_backend;
         DCB*            bref_dcb;
+        bref_state_t    bref_state;
         sescmd_cursor_t bref_sescmd_cur;
 #if defined(SS_DEBUG)
         skygw_chk_t     bref_chk_tail;