Bug #29419 "Specifying a join_buffer > 4GB on 64 bit machines not possible."

Use size_t instead of uint when calculating join buffer size, because uint can be overflown on 64-bit platforms and join_buffer_size > 4 GB.

The test case for this bug is a part of the test suite for bug #5731.

sql/sql_select.cc

@@ -13014,7 +13014,8 @@ static int
 join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
 {
   reg1 uint i;
-  uint length,blobs,size;
+  uint length, blobs;
+  size_t size;
   CACHE_FIELD *copy,**blob_ptr;
   JOIN_CACHE  *cache;
   JOIN_TAB *join_tab;
@@ -13130,7 +13131,7 @@ store_record_in_cache(JOIN_CACHE *cache)
   length=cache->length;
   if (cache->blobs)
     length+=used_blob_length(cache->blob_ptr);
-  if ((last_record=(length+cache->length > (uint) (cache->end - pos))))
+  if ((last_record= (length + cache->length > (size_t) (cache->end - pos))))
     cache->ptr_record=cache->records;
 
   /*
@@ -13176,7 +13177,7 @@ store_record_in_cache(JOIN_CACHE *cache)
     }
   }
   cache->pos=pos;
-  return last_record || (uint) (cache->end -pos) < cache->length;
+  return last_record || (size_t) (cache->end - pos) < cache->length;
 }