1 files changed, 91 insertions, 6 deletions

diff --git a/sql/field.cc b/sql/field.cc
index b70e2a92618..dbc8d2a49d7 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -67,6 +67,7 @@ inline int field_type2index (enum_field_types field_type)
           ((int)FIELDTYPE_TEAR_FROM) + (field_type - FIELDTYPE_TEAR_TO) - 1);
 }
 
+
 static enum_field_types field_types_merge_rules [FIELDTYPE_NUM][FIELDTYPE_NUM]=
 {
   /* MYSQL_TYPE_DECIMAL -> */
@@ -1233,6 +1234,7 @@ Field::Field(char *ptr_arg,uint32 length_arg,uchar *null_ptr_arg,
   flags=null_ptr ? 0: NOT_NULL_FLAG;
   comment.str= (char*) "";
   comment.length=0;
+  fieldnr= 0;
 }
 
 uint Field::offset()
@@ -2382,7 +2384,7 @@ bool Field_new_decimal::store_value(const my_decimal *decimal_value)
 #ifndef DBUG_OFF
   {
     char dbug_buff[DECIMAL_MAX_STR_LENGTH+1];
-    DBUG_PRINT("info", ("saving with precision %d, scale: %d, value %s",
+    DBUG_PRINT("info", ("saving with precision %d  scale: %d  value %s",
                         (int)precision, (int)dec,
                         dbug_decimal_as_string(dbug_buff, decimal_value)));
   }
@@ -2397,7 +2399,8 @@ bool Field_new_decimal::store_value(const my_decimal *decimal_value)
     my_decimal2binary(E_DEC_FATAL_ERROR, &buff, ptr, precision, dec);
     error= 1;
   }
-  DBUG_EXECUTE("info", print_decimal_buff(decimal_value, (byte *) ptr, bin_size););
+  DBUG_EXECUTE("info", print_decimal_buff(decimal_value, (byte *) ptr,
+                                          bin_size););
   DBUG_RETURN(error);
 }
 
@@ -5951,6 +5954,26 @@ int Field_str::store(double nr)
 }
 
 
+uint Field::is_equal(create_field *new_field)
+{
+  return (new_field->sql_type == type());
+}
+
+
+uint Field_str::is_equal(create_field *new_field)
+{
+  if (((new_field->flags & (BINCMP_FLAG | BINARY_FLAG)) &&
+       !(flags & (BINCMP_FLAG | BINARY_FLAG))) ||
+      (!(new_field->flags & (BINCMP_FLAG | BINARY_FLAG)) &&
+	(flags & (BINCMP_FLAG | BINARY_FLAG))))
+    return 0; /* One of the fields is binary and the other one isn't */
+
+  return ((new_field->sql_type == type()) &&
+	  new_field->charset == field_charset &&
+	  new_field->length == max_length());
+}
+
+
 int Field_string::store(longlong nr, bool unsigned_val)
 {
   char buff[64];
@@ -6342,7 +6365,8 @@ my_decimal *Field_varstring::val_decimal(my_decimal *decimal_value)
 }
 
 
-int Field_varstring::cmp(const char *a_ptr, const char *b_ptr)
+int Field_varstring::cmp_max(const char *a_ptr, const char *b_ptr,
+                             uint max_len)
 {
   uint a_length, b_length;
   int diff;
@@ -6357,6 +6381,8 @@ int Field_varstring::cmp(const char *a_ptr, const char *b_ptr)
     a_length= uint2korr(a_ptr);
     b_length= uint2korr(b_ptr);
   }
+  set_if_smaller(a_length, max_len);
+  set_if_smaller(b_length, max_len);
   diff= field_charset->coll->strnncollsp(field_charset,
                                          (const uchar*) a_ptr+
                                          length_bytes,
@@ -6731,6 +6757,22 @@ Field *Field_varstring::new_key_field(MEM_ROOT *root,
 }
 
 
+uint Field_varstring::is_equal(create_field *new_field)
+{
+  if (new_field->sql_type == type() &&
+      new_field->charset == field_charset)
+  {
+    if (new_field->length == max_length())
+      return IS_EQUAL_YES;
+    if (new_field->length > max_length() &&
+	((new_field->length <= 255 && max_length() <= 255) ||
+	 (new_field->length > 255 && max_length() > 255)))
+      return IS_EQUAL_PACK_LENGTH; // VARCHAR, longer variable length
+  }
+  return IS_EQUAL_NO;
+}
+
+
 /****************************************************************************
 ** blob type
 ** A blob is saved as a length and a pointer. The length is stored in the
@@ -7002,13 +7044,16 @@ int Field_blob::cmp(const char *a,uint32 a_length, const char *b,
 }
 
 
-int Field_blob::cmp(const char *a_ptr, const char *b_ptr)
+int Field_blob::cmp_max(const char *a_ptr, const char *b_ptr,
+                        uint max_length)
 {
   char *blob1,*blob2;
   memcpy_fixed(&blob1,a_ptr+packlength,sizeof(char*));
   memcpy_fixed(&blob2,b_ptr+packlength,sizeof(char*));
-  return Field_blob::cmp(blob1,get_length(a_ptr),
-			 blob2,get_length(b_ptr));
+  uint a_len= get_length(a_ptr), b_len= get_length(b_ptr);
+  set_if_smaller(a_len, max_length);
+  set_if_smaller(b_len, max_length);
+  return Field_blob::cmp(blob1,a_len,blob2,b_len);
 }
 
 
@@ -7871,6 +7916,17 @@ bool Field_num::eq_def(Field *field)
 }
 
 
+uint Field_num::is_equal(create_field *new_field)
+{
+  return ((new_field->sql_type == type()) &&
+	  ((new_field->flags & UNSIGNED_FLAG) == (uint) (flags &
+							 UNSIGNED_FLAG)) &&
+	  ((new_field->flags & AUTO_INCREMENT_FLAG) ==
+	   (uint) (flags & AUTO_INCREMENT_FLAG)) &&
+	  (new_field->length >= max_length()));
+}
+
+
 /*
   Bit field.
 
@@ -8058,6 +8114,35 @@ my_decimal *Field_bit::val_decimal(my_decimal *deciaml_value)
 }
 
 
+/*
+  Compare two bit fields using pointers within the record.
+  SYNOPSIS
+    cmp_max()
+    a                 Pointer to field->ptr in first record
+    b                 Pointer to field->ptr in second record
+    max_len           Maximum length used in index
+  DESCRIPTION
+    This method is used from key_rec_cmp used by merge sorts used
+    by partitioned index read and later other similar places.
+    The a and b pointer must be pointers to the field in a record
+    (not the table->record[0] necessarily)
+*/
+int Field_bit::cmp_max(const char *a, const char *b, uint max_len)
+{
+  my_ptrdiff_t a_diff= a - ptr;
+  my_ptrdiff_t b_diff= b - ptr;
+  if (bit_len)
+  {
+    int flag;
+    uchar bits_a= get_rec_bits(bit_ptr+a_diff, bit_ofs, bit_len);
+    uchar bits_b= get_rec_bits(bit_ptr+b_diff, bit_ofs, bit_len);
+    if ((flag= (int) (bits_a - bits_b)))
+      return flag;
+  }
+  return memcmp(a, b, field_length);
+}
+
+
 int Field_bit::key_cmp(const byte *str, uint length)
 {
   if (bit_len)