1 files changed, 26 insertions, 7 deletions

diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 7e7bd7a21ae..7af39071561 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13066,7 +13066,8 @@ 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;
@@ -13182,7 +13183,7 @@ 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;
 
   /*
@@ -13228,7 +13229,7 @@ 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;
 }
 
 
@@ -13901,13 +13902,31 @@ calc_group_buffer(JOIN *join,ORDER *group)
                                                 group_item->decimals);
         break;
       case STRING_RESULT:
+      {
+        enum enum_field_types type= group_item->field_type();
         /*
-          Group strings are taken as varstrings and require an length field.
-          A field is not yet created by create_tmp_field()
-          and the sizes should match up.
+          As items represented as DATE/TIME fields in the group buffer
+          have STRING_RESULT result type, we increase the length 
+          by 8 as maximum pack length of such fields.
         */
-        key_length+= group_item->max_length + HA_KEY_BLOB_LENGTH;
+        if (type == MYSQL_TYPE_TIME ||
+            type == MYSQL_TYPE_DATE ||
+            type == MYSQL_TYPE_DATETIME ||
+            type == MYSQL_TYPE_TIMESTAMP)
+        {
+          key_length+= 8;
+        }
+        else
+        {
+          /*
+            Group strings are taken as varstrings and require an length field.
+            A field is not yet created by create_tmp_field()
+            and the sizes should match up.
+          */
+          key_length+= group_item->max_length + HA_KEY_BLOB_LENGTH;
+        }
         break;
+      }
       default:
         /* This case should never be choosen */
         DBUG_ASSERT(0);