From e0ce987d72e68f08a47db8d84e23a6d91fc4162a Mon Sep 17 00:00:00 2001
From: Markus Makela <markus.makela@mariadb.com>
Date: Sun, 22 Mar 2015 08:56:18 +0200
Subject: [PATCH] Mysql_backend now only sends complete packets from the
 backend servers.

---
 server/core/buffer.c  |  2 ++
 server/core/modutil.c | 24 +++++++++++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/server/core/buffer.c b/server/core/buffer.c
index fa2fa8d13..4c788cdd2 100644
--- a/server/core/buffer.c
+++ b/server/core/buffer.c
@@ -336,6 +336,8 @@ gwbuf_append(GWBUF *head, GWBUF *tail)
 {
 	if (!head)
 		return tail;
+	if(!tail)
+		return head;
         CHK_GWBUF(head);
 	head->tail->next = tail;
 	head->tail = tail->tail;
diff --git a/server/core/modutil.c b/server/core/modutil.c
index f4a0a4e4e..20e57a9e6 100644
--- a/server/core/modutil.c
+++ b/server/core/modutil.c
@@ -539,19 +539,29 @@ GWBUF* modutil_get_complete_packets(GWBUF** p_readbuf)
 {
     GWBUF *buff = NULL, *packet;
     uint8_t *ptr,*end;
-    unsigned int len,total = 0;
+    unsigned int len,blen,total = 0;
 
     if(p_readbuf == NULL || (*p_readbuf) == NULL ||
        gwbuf_length(*p_readbuf) < 3)
 	return NULL;
 
-    packet = *p_readbuf;
+    packet = gwbuf_make_contiguous(*p_readbuf);
     ptr = (uint8_t*)packet->start;
     end = (uint8_t*)packet->end;
     len = gw_mysql_get_byte3(ptr) + 4;
     
     if(ptr + len >= end)
-	return NULL;
+    {
+	if(len == gwbuf_length(*p_readbuf))
+	{
+	    *p_readbuf = NULL;
+	    return packet;
+	}
+	else
+	{
+	    return NULL;
+	}
+    }
 
     while(ptr + len < end)
     {
@@ -561,13 +571,17 @@ GWBUF* modutil_get_complete_packets(GWBUF** p_readbuf)
     }
 
     /** Full packets only, return original */
-    if(total == gwbuf_length(packet))
+
+    if(total + len == (blen = gwbuf_length(packet)))
+    {
+	*p_readbuf = NULL;
 	return packet;
+    }
 
     /** The next packet is a partial, split into complete and partial packets */
     total -= len;
 
-    if(buff = gwbuf_alloc(total))
+    if((buff = gwbuf_alloc(total)) == NULL)
     {
 	skygw_log_write(LOGFILE_ERROR,
 		 "Error: Failed to allocate new buffer "