Bug#11759519 - INFINITE HANG WITH 100% CPU USAGE WITH LOAD DATA

               LOCAL AND IMPORT ERRORS

Description:
-----------
This bug happens due to the fact that current algorithm is designed
that in the case of LOCAL load of data, in case of the error, the
remaining part of the file is read in order to return the proper
error message to the client side.

But, the problem with current implementation is that data stream
for the client side is cleared only in the case where line delimiters
exist, which is not a case with, for example fixed width
fields.

Fix:
----
Ported patch provided by Sinisa Milivojevic n bug report for this
issue to 5.5+ versions.

As part of this patch code is changed to clear the data stream
by calling new member function "READ_INFO::skip_data_till_eof".

1 files changed, 13 insertions, 6 deletions

diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index b593412c559..7f962520dd6 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -56,6 +56,9 @@ XML_TAG::XML_TAG(int l, String f, String v)
 }
 
 
+#define GET (stack_pos != stack ? *--stack_pos : my_b_get(&cache))
+#define PUSH(A) *(stack_pos++)=(A)
+
 class READ_INFO {
   File	file;
   uchar	*buffer,			/* Buffer for read text */
@@ -110,6 +113,15 @@ public:
     either the table or THD value
   */
   void set_io_cache_arg(void* arg) { cache.arg = arg; }
+
+  /**
+    skip all data till the eof.
+  */
+  void skip_data_till_eof()
+  {
+    while (GET != my_b_EOF)
+      ;
+  }
 };
 
 static int read_fixed_length(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
@@ -534,8 +546,7 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   if (error)
   {
     if (read_file_from_client)
-      while (!read_info.next_line())
-	;
+      read_info.skip_data_till_eof();
 
 #ifndef EMBEDDED_LIBRARY
     if (mysql_bin_log.is_open())
@@ -1392,10 +1403,6 @@ READ_INFO::~READ_INFO()
 }
 
 
-#define GET (stack_pos != stack ? *--stack_pos : my_b_get(&cache))
-#define PUSH(A) *(stack_pos++)=(A)
-
-
 inline int READ_INFO::terminator(char *ptr,uint length)
 {
   int chr=0;					// Keep gcc happy