Merge of the patch introducing virtual columns into maria-5.2

1 files changed, 182 insertions, 71 deletions

diff --git a/sql/field.cc b/sql/field.cc
index 5bce6a412fc..591a2bcbbb9 100644
--- a/sql/field.cc
+++ b/sql/field.cc
@@ -57,7 +57,7 @@ const char field_separator=',';
 ((ulong) ((LL(1) << min(arg, 4) * 8) - LL(1)))
 
 #define ASSERT_COLUMN_MARKED_FOR_READ DBUG_ASSERT(!table || (!table->read_set || bitmap_is_set(table->read_set, field_index)))
-#define ASSERT_COLUMN_MARKED_FOR_WRITE DBUG_ASSERT(!table || (!table->write_set || bitmap_is_set(table->write_set, field_index)))
+#define ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED DBUG_ASSERT(!table || (!table->write_set || bitmap_is_set(table->write_set, field_index) || bitmap_is_set(&table->vcol_set, field_index)))
 
 /*
   Rules for merging different types of fields in UNION
@@ -1312,7 +1312,8 @@ Field::Field(uchar *ptr_arg,uint32 length_arg,uchar *null_ptr_arg,
    key_start(0), part_of_key(0), part_of_key_not_clustered(0),
    part_of_sortkey(0), unireg_check(unireg_check_arg),
    field_length(length_arg), null_bit(null_bit_arg), 
-   is_created_from_null_item(FALSE)
+   is_created_from_null_item(FALSE),
+   vcol_info(0), stored_in_db(TRUE)
 {
   flags=null_ptr ? 0: NOT_NULL_FLAG;
   comment.str= (char*) "";
@@ -1611,7 +1612,7 @@ longlong Field::convert_decimal2longlong(const my_decimal *val,
 
 int Field_num::store_decimal(const my_decimal *val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int err= 0;
   longlong i= convert_decimal2longlong(val, unsigned_flag, &err);
   return test(err | store(i, unsigned_flag));
@@ -1683,7 +1684,7 @@ void Field_num::make_field(Send_field *field)
 
 int Field_str::store_decimal(const my_decimal *d)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   double val;
   /* TODO: use decimal2string? */
   int err= warn_if_overflow(my_decimal2double(E_DEC_FATAL_ERROR &
@@ -1760,7 +1761,7 @@ bool Field::get_time(MYSQL_TIME *ltime)
 
 int Field::store_time(MYSQL_TIME *ltime, timestamp_type type_arg)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   char buff[MAX_DATE_STRING_REP_LENGTH];
   uint length= (uint) my_TIME_to_str(ltime, buff);
   return store(buff, length, &my_charset_bin);
@@ -1887,7 +1888,7 @@ void Field_decimal::overflow(bool negative)
 
 int Field_decimal::store(const char *from_arg, uint len, CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   char buff[STRING_BUFFER_USUAL_SIZE];
   String tmp(buff,sizeof(buff), &my_charset_bin);
   const uchar *from= (uchar*) from_arg;
@@ -1923,16 +1924,16 @@ int Field_decimal::store(const char *from_arg, uint len, CHARSET_INFO *cs)
     Pointers used when digits move from the left of the '.' to the
     right of the '.' (explained below)
   */
-  const uchar *int_digits_tail_from;
+  const uchar *UNINIT_VAR(int_digits_tail_from);
   /* Number of 0 that need to be added at the left of the '.' (1E3: 3 zeros) */
-  uint int_digits_added_zeros;
+  uint UNINIT_VAR(int_digits_added_zeros);
   /*
     Pointer used when digits move from the right of the '.' to the left
     of the '.'
   */
-  const uchar *frac_digits_head_end;
+  const uchar *UNINIT_VAR(frac_digits_head_end);
   /* Number of 0 that need to be added at the right of the '.' (for 1E-3) */
-  uint frac_digits_added_zeros;
+  uint UNINIT_VAR(frac_digits_added_zeros);
   uchar *pos,*tmp_left_pos,*tmp_right_pos;
   /* Pointers that are used as limits (begin and end of the field buffer) */
   uchar *left_wall,*right_wall;
@@ -1943,11 +1944,6 @@ int Field_decimal::store(const char *from_arg, uint len, CHARSET_INFO *cs)
   */
   bool is_cuted_fields_incr=0;
 
-  LINT_INIT(int_digits_tail_from);
-  LINT_INIT(int_digits_added_zeros);
-  LINT_INIT(frac_digits_head_end);
-  LINT_INIT(frac_digits_added_zeros);
-
   /*
     There are three steps in this function :
     - parse the input string
@@ -2258,7 +2254,7 @@ int Field_decimal::store(const char *from_arg, uint len, CHARSET_INFO *cs)
 
 int Field_decimal::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   if (unsigned_flag && nr < 0)
   {
     overflow(1);
@@ -2303,7 +2299,7 @@ int Field_decimal::store(double nr)
 
 int Field_decimal::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   char buff[22];
   uint length, int_part;
   char fyllchar;
@@ -2486,12 +2482,97 @@ Field_new_decimal::Field_new_decimal(uint32 len_arg,
 {
   precision= my_decimal_length_to_precision(len_arg, dec_arg, unsigned_arg);
   set_if_smaller(precision, DECIMAL_MAX_PRECISION);
+  DBUG_ASSERT(precision >= dec);
   DBUG_ASSERT((precision <= DECIMAL_MAX_PRECISION) &&
               (dec <= DECIMAL_MAX_SCALE));
   bin_size= my_decimal_get_binary_size(precision, dec);
 }
 
 
+/**
+  Create a field to hold a decimal value from an item.
+
+  @remark The MySQL DECIMAL data type has a characteristic that needs to be
+          taken into account when deducing the type from a Item_decimal.
+
+  But first, let's briefly recap what is the new MySQL DECIMAL type:
+
+  The declaration syntax for a decimal is DECIMAL(M,D), where:
+
+  * M is the maximum number of digits (the precision).
+    It has a range of 1 to 65.
+  * D is the number of digits to the right of the decimal separator (the scale).
+    It has a range of 0 to 30 and must be no larger than M.
+
+  D and M are used to determine the storage requirements for the integer
+  and fractional parts of each value. The integer part is to the left of
+  the decimal separator and to the right is the fractional part. Hence:
+
+  M is the number of digits for the integer and fractional part.
+  D is the number of digits for the fractional part.
+
+  Consequently, M - D is the number of digits for the integer part. For
+  example, a DECIMAL(20,10) column has ten digits on either side of
+  the decimal separator.
+
+  The characteristic that needs to be taken into account is that the
+  backing type for Item_decimal is a my_decimal that has a higher
+  precision (DECIMAL_MAX_POSSIBLE_PRECISION, see my_decimal.h) than
+  DECIMAL.
+
+  Drawing a comparison between my_decimal and DECIMAL:
+
+  * M has a range of 1 to 81.
+  * D has a range of 0 to 81.
+
+  There can be a difference in range if the decimal contains a integer
+  part. This is because the fractional part must always be on a group
+  boundary, leaving at least one group for the integer part. Since each
+  group is 9 (DIG_PER_DEC1) digits and there are 9 (DECIMAL_BUFF_LENGTH)
+  groups, the fractional part is limited to 72 digits if there is at
+  least one digit in the integral part.
+
+  Although the backing type for a DECIMAL is also my_decimal, every
+  time a my_decimal is stored in a DECIMAL field, the precision and
+  scale are explicitly capped at 65 (DECIMAL_MAX_PRECISION) and 30
+  (DECIMAL_MAX_SCALE) digits, following my_decimal truncation procedure
+  (FIX_INTG_FRAC_ERROR).
+*/
+
+Field_new_decimal *
+Field_new_decimal::new_decimal_field(const Item *item)
+{
+  uint32 len;
+  uint intg= item->decimal_int_part(), scale= item->decimals;
+
+  DBUG_ASSERT(item->decimal_precision() >= item->decimals);
+
+  /*
+    Employ a procedure along the lines of the my_decimal truncation process:
+    - If the integer part is equal to or bigger than the maximum precision:
+      Truncate integer part to fit and the fractional becomes zero.
+    - Otherwise:
+      Truncate fractional part to fit.
+  */
+  if (intg >= DECIMAL_MAX_PRECISION)
+  {
+    intg= DECIMAL_MAX_PRECISION;
+    scale= 0;
+  }
+  else
+  {
+    uint room= min(DECIMAL_MAX_PRECISION - intg, DECIMAL_MAX_SCALE);
+    if (scale > room)
+      scale= room;
+  }
+
+  len= my_decimal_precision_to_length(intg + scale, scale, item->unsigned_flag);
+
+  return new Field_new_decimal(len, item->maybe_null, item->name, scale,
+                               item->unsigned_flag);
+}
+
+
 int Field_new_decimal::reset(void)
 {
   store_value(&decimal_zero);
@@ -2539,7 +2620,7 @@ void Field_new_decimal::set_value_on_overflow(my_decimal *decimal_value,
 
 bool Field_new_decimal::store_value(const my_decimal *decimal_value)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   DBUG_ENTER("Field_new_decimal::store_value");
 #ifndef DBUG_OFF
@@ -2584,7 +2665,7 @@ bool Field_new_decimal::store_value(const my_decimal *decimal_value)
 int Field_new_decimal::store(const char *from, uint length,
                              CHARSET_INFO *charset_arg)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int err;
   my_decimal decimal_value;
   DBUG_ENTER("Field_new_decimal::store(char*)");
@@ -2651,7 +2732,7 @@ int Field_new_decimal::store(const char *from, uint length,
 
 int Field_new_decimal::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   my_decimal decimal_value;
   int err;
   DBUG_ENTER("Field_new_decimal::store(double)");
@@ -2686,7 +2767,7 @@ int Field_new_decimal::store(double nr)
 
 int Field_new_decimal::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   my_decimal decimal_value;
   int err;
 
@@ -2708,7 +2789,7 @@ int Field_new_decimal::store(longlong nr, bool unsigned_val)
 
 int Field_new_decimal::store_decimal(const my_decimal *decimal_value)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   return store_value(decimal_value);
 }
 
@@ -2929,7 +3010,7 @@ Field_new_decimal::unpack(uchar* to,
 
 int Field_tiny::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error;
   longlong rnd;
   
@@ -2941,7 +3022,7 @@ int Field_tiny::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_tiny::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   nr=rint(nr);
   if (unsigned_flag)
@@ -2984,7 +3065,7 @@ int Field_tiny::store(double nr)
 
 int Field_tiny::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
 
   if (unsigned_flag)
@@ -3104,7 +3185,7 @@ void Field_tiny::sql_type(String &res) const
 
 int Field_short::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int store_tmp;
   int error;
   longlong rnd;
@@ -3125,7 +3206,7 @@ int Field_short::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_short::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   int16 res;
   nr=rint(nr);
@@ -3177,7 +3258,7 @@ int Field_short::store(double nr)
 
 int Field_short::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   int16 res;
 
@@ -3351,7 +3432,7 @@ void Field_short::sql_type(String &res) const
 
 int Field_medium::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int store_tmp;
   int error;
   longlong rnd;
@@ -3365,7 +3446,7 @@ int Field_medium::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_medium::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   nr=rint(nr);
   if (unsigned_flag)
@@ -3411,7 +3492,7 @@ int Field_medium::store(double nr)
 
 int Field_medium::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
 
   if (unsigned_flag)
@@ -3541,7 +3622,7 @@ void Field_medium::sql_type(String &res) const
 
 int Field_long::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   long store_tmp;
   int error;
   longlong rnd;
@@ -3562,7 +3643,7 @@ int Field_long::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_long::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   int32 res;
   nr=rint(nr);
@@ -3614,7 +3695,7 @@ int Field_long::store(double nr)
 
 int Field_long::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   int32 res;
 
@@ -3788,7 +3869,7 @@ void Field_long::sql_type(String &res) const
 
 int Field_longlong::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   char *end;
   ulonglong tmp;
@@ -3818,7 +3899,7 @@ int Field_longlong::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_longlong::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   longlong res;
 
@@ -3870,7 +3951,7 @@ int Field_longlong::store(double nr)
 
 int Field_longlong::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
 
   if (nr < 0)                                   // Only possible error
@@ -4096,7 +4177,7 @@ int Field_float::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_float::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= truncate(&nr, FLT_MAX);
   float j= (float)nr;
 
@@ -4358,7 +4439,7 @@ int Field_double::store(const char *from,uint len,CHARSET_INFO *cs)
 
 int Field_double::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= truncate(&nr, DBL_MAX);
 
 #ifdef WORDS_BIGENDIAN
@@ -4785,7 +4866,7 @@ timestamp_auto_set_type Field_timestamp::get_auto_set_type() const
 
 int Field_timestamp::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME l_time;
   my_time_t tmp= 0;
   int error;
@@ -4848,7 +4929,7 @@ int Field_timestamp::store(double nr)
 
 int Field_timestamp::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME l_time;
   my_time_t timestamp= 0;
   int error;
@@ -5147,7 +5228,7 @@ int Field_time::store_time(MYSQL_TIME *ltime, timestamp_type time_type)
 
 int Field_time::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   long tmp;
   int error= 0;
   if (nr > (double)TIME_MAX_VALUE)
@@ -5185,7 +5266,7 @@ int Field_time::store(double nr)
 
 int Field_time::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   long tmp;
   int error= 0;
   if (nr < (longlong) -TIME_MAX_VALUE && !unsigned_val)
@@ -5356,7 +5437,7 @@ void Field_time::sql_type(String &res) const
 
 int Field_year::store(const char *from, uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   char *end;
   int error;
   longlong nr= cs->cset->strntoull10rnd(cs, from, len, 0, &end, &error);
@@ -5404,7 +5485,7 @@ int Field_year::store(double nr)
 
 int Field_year::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   if (nr < 0 || (nr >= 100 && nr <= 1900) || nr > 2155)
   {
     *ptr= 0;
@@ -5477,7 +5558,7 @@ void Field_year::sql_type(String &res) const
 
 int Field_date::store(const char *from, uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME l_time;
   uint32 tmp;
   int error;
@@ -5532,7 +5613,7 @@ int Field_date::store(double nr)
 
 int Field_date::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME not_used;
   int error;
   longlong initial_nr= nr;
@@ -5711,7 +5792,7 @@ void Field_date::sql_type(String &res) const
 
 int Field_newdate::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   long tmp;
   MYSQL_TIME l_time;
   int error;
@@ -5761,7 +5842,7 @@ int Field_newdate::store(double nr)
 
 int Field_newdate::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME l_time;
   longlong tmp;
   int error;
@@ -5797,7 +5878,7 @@ int Field_newdate::store(longlong nr, bool unsigned_val)
 
 int Field_newdate::store_time(MYSQL_TIME *ltime,timestamp_type time_type)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   long tmp;
   int error= 0;
   if (time_type == MYSQL_TIMESTAMP_DATE ||
@@ -5944,7 +6025,7 @@ void Field_newdate::sql_type(String &res) const
 
 int Field_datetime::store(const char *from,uint len,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME time_tmp;
   int error;
   ulonglong tmp= 0;
@@ -5997,7 +6078,7 @@ int Field_datetime::store(double nr)
 
 int Field_datetime::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   MYSQL_TIME not_used;
   int error;
   longlong initial_nr= nr;
@@ -6035,7 +6116,7 @@ int Field_datetime::store(longlong nr, bool unsigned_val)
 
 int Field_datetime::store_time(MYSQL_TIME *ltime,timestamp_type time_type)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   longlong tmp;
   int error= 0;
   /*
@@ -6338,7 +6419,7 @@ Field_longstr::report_if_important_data(const char *ptr, const char *end,
 
 int Field_string::store(const char *from,uint length,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   uint copy_length;
   const char *well_formed_error_pos;
   const char *cannot_convert_error_pos;
@@ -6379,7 +6460,7 @@ int Field_string::store(const char *from,uint length,CHARSET_INFO *cs)
 
 int Field_str::store(double nr)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   char buff[DOUBLE_TO_STRING_CONVERSION_BUFFER_SIZE];
   uint length;
   uint local_char_length= field_length / charset()->mbmaxlen;
@@ -6994,7 +7075,7 @@ int Field_varstring::do_save_field_metadata(uchar *metadata_ptr)
 
 int Field_varstring::store(const char *from,uint length,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   uint copy_length;
   const char *well_formed_error_pos;
   const char *cannot_convert_error_pos;
@@ -7658,7 +7739,7 @@ void Field_blob::put_length(uchar *pos, uint32 length)
 
 int Field_blob::store(const char *from,uint length,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   uint copy_length, new_length;
   const char *well_formed_error_pos;
   const char *cannot_convert_error_pos;
@@ -8420,7 +8501,7 @@ void Field_enum::store_type(ulonglong value)
 
 int Field_enum::store(const char *from,uint length,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int err= 0;
   uint32 not_used;
   char buff[STRING_BUFFER_USUAL_SIZE];
@@ -8469,7 +8550,7 @@ int Field_enum::store(double nr)
 
 int Field_enum::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   if ((ulonglong) nr > typelib->count || nr == 0)
   {
@@ -8638,7 +8719,7 @@ Field *Field_enum::new_field(MEM_ROOT *root, struct st_table *new_table,
 
 int Field_set::store(const char *from,uint length,CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   bool got_warning= 0;
   int err= 0;
   char *not_used;
@@ -8678,7 +8759,7 @@ int Field_set::store(const char *from,uint length,CHARSET_INFO *cs)
 
 int Field_set::store(longlong nr, bool unsigned_val)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int error= 0;
   ulonglong max_nr= set_bits(ulonglong, typelib->count);
   if ((ulonglong) nr > max_nr)
@@ -8942,7 +9023,7 @@ uint Field_bit::is_equal(Create_field *new_field)
                        
 int Field_bit::store(const char *from, uint length, CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int delta;
 
   for (; length && !*from; from++, length--)          // skip left 0's
@@ -9353,7 +9434,7 @@ Field_bit_as_char::Field_bit_as_char(uchar *ptr_arg, uint32 len_arg,
 
 int Field_bit_as_char::store(const char *from, uint length, CHARSET_INFO *cs)
 {
-  ASSERT_COLUMN_MARKED_FOR_WRITE;
+  ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED;
   int delta;
   uchar bits= (uchar) (field_length & 7);
 
@@ -9461,6 +9542,8 @@ void Create_field::init_for_tmp_table(enum_field_types sql_type_arg,
               ((decimals_arg & FIELDFLAG_MAX_DEC) << FIELDFLAG_DEC_SHIFT) |
               (maybe_null ? FIELDFLAG_MAYBE_NULL : 0) |
               (is_unsigned ? 0 : FIELDFLAG_DECIMAL));
+  vcol_info= 0;
+  stored_in_db= TRUE;
 }
 
 
@@ -9480,6 +9563,7 @@ void Create_field::init_for_tmp_table(enum_field_types sql_type_arg,
   @param fld_interval_list     Interval list (if any)
   @param fld_charset           Field charset
   @param fld_geom_type         Field geometry type (if any)
+  @param fld_vcol_info         Virtual column data
 
   @retval
     FALSE on success
@@ -9492,13 +9576,14 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type,
                         uint fld_type_modifier, Item *fld_default_value,
                         Item *fld_on_update_value, LEX_STRING *fld_comment,
                         char *fld_change, List<String> *fld_interval_list,
-                        CHARSET_INFO *fld_charset, uint fld_geom_type)
+                        CHARSET_INFO *fld_charset, uint fld_geom_type,
+			Virtual_column_info *fld_vcol_info)
 {
   uint sign_len, allowed_type_modifier= 0;
   ulong max_field_charlength= MAX_FIELD_CHARLENGTH;
 
   DBUG_ENTER("Create_field::init()");
-  
+
   field= 0;
   field_name= fld_name;
   def= fld_default_value;
@@ -9523,6 +9608,33 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type,
   interval_list.empty();
 
   comment= *fld_comment;
+  vcol_info= fld_vcol_info;
+  stored_in_db= TRUE;
+
+  /* Initialize data for a computed field */
+  if ((uchar)fld_type == (uchar)MYSQL_TYPE_VIRTUAL)
+  {
+    DBUG_ASSERT(vcol_info && vcol_info->expr_item);
+    stored_in_db= vcol_info->is_stored();
+    /*
+      Walk through the Item tree checking if all items are valid
+      to be part of the virtual column
+    */
+    if (vcol_info->expr_item->walk(&Item::check_vcol_func_processor, 0, NULL))
+    {
+      my_error(ER_VIRTUAL_COLUMN_FUNCTION_IS_NOT_ALLOWED, MYF(0), field_name);
+      DBUG_RETURN(TRUE);
+    }
+
+    /*
+      Make a field created for the real type.
+      Note that regular and computed fields differ from each other only by
+      Field::vcol_info. It is is always NULL for a column that is not
+      computed.
+    */
+    sql_type= fld_type= vcol_info->get_real_type();
+  }
+
   /*
     Set NO_DEFAULT_VALUE_FLAG if this field doesn't have a default value and
     it is NOT NULL, not an AUTO_INCREMENT field and not a TIMESTAMP.
@@ -9813,7 +9925,7 @@ bool Create_field::init(THD *thd, char *fld_name, enum_field_types fld_type,
     }
   case MYSQL_TYPE_DECIMAL:
     DBUG_ASSERT(0); /* Was obsolete */
-  }
+ }
   /* Remember the value of length */
   char_length= length;
 
@@ -9912,7 +10024,6 @@ uint pack_length_to_packflag(uint type)
   return 0;					// This shouldn't happen
 }
 
-
 Field *make_field(TABLE_SHARE *share, uchar *ptr, uint32 field_length,
 		  uchar *null_pos, uchar null_bit,
 		  uint pack_flag,
@@ -9923,10 +10034,8 @@ Field *make_field(TABLE_SHARE *share, uchar *ptr, uint32 field_length,
 		  TYPELIB *interval,
 		  const char *field_name)
 {
-  uchar *bit_ptr;
-  uchar bit_offset;
-  LINT_INIT(bit_ptr);
-  LINT_INIT(bit_offset);
+  uchar *UNINIT_VAR(bit_ptr);
+  uchar UNINIT_VAR(bit_offset);
   if (field_type == MYSQL_TYPE_BIT && !f_bit_as_char(pack_flag))
   {
     bit_ptr= null_pos;
@@ -10106,6 +10215,8 @@ Create_field::Create_field(Field *old_field,Field *orig_field)
   charset=    old_field->charset();		// May be NULL ptr
   comment=    old_field->comment;
   decimals=   old_field->decimals();
+  vcol_info=  old_field->vcol_info;
+  stored_in_db= old_field->stored_in_db;
 
   /* Fix if the original table had 4 byte pointer blobs */
   if (flags & BLOB_FLAG)