Revert changes to REC_OFFS_MASK

There is no need to omit dropped columns in rec_get_offsets() and
related functions. Dropped columns will have to be dealt with
at a higher level when converting between table rows and
clustered index records.

storage/innobase/btr/btr0cur.cc

@@ -399,7 +399,6 @@ btr_cur_instant_init_metadata(
 	const rec_t*	rec,
 	dict_index_t*	index)
 {
-	ulint		n_drop_nullable = 0;
 	ulint*		offsets;
 	ulint		len;
 	mem_heap_t*	heap = mem_heap_create(UNIV_PAGE_SIZE_MAX);
@@ -451,10 +450,8 @@ btr_cur_instant_init_metadata(
 			col->len = len;
 			index->fields[i].fixed_len = len;
 
-			if (!rec_offs_nth_drop_sql_null(offsets, i + 1)) {
+			if (!rec_offs_nth_sql_null(offsets, i + 1)) {
 				col->prtype = DATA_NOT_NULL;
-			} else {
-				n_drop_nullable++;
 			}
 		} else if (!rec_offs_nth_extern(offsets, i)) {
 			col->def_val.len = len;

storage/innobase/include/rem0rec.h

@@ -95,16 +95,10 @@ const ulint REC_OFFS_COMPACT = ~(ulint(~0) >> 1);
 const ulint REC_OFFS_SQL_NULL = REC_OFFS_COMPACT;
 /** External flag in offsets returned by rec_get_offsets() */
 const ulint REC_OFFS_EXTERNAL = REC_OFFS_COMPACT >> 1;
-
 /** Default value flag in offsets returned by rec_get_offsets() */
 const ulint REC_OFFS_DEFAULT = REC_OFFS_COMPACT >> 2;
-
-const ulint REC_OFFS_DROP_COL = REC_OFFS_COMPACT >> 3;
-
-const ulint REC_OFFS_DROP_SQL_NULL = REC_OFFS_COMPACT >> 4;
-
 /** Mask for offsets returned by rec_get_offsets() */
-const ulint REC_OFFS_MASK = REC_OFFS_DROP_SQL_NULL - 1;
+const ulint REC_OFFS_MASK = REC_OFFS_DEFAULT - 1;
 
 #ifndef UNIV_INNOCHECKSUM
 /******************************************************//**
@@ -713,20 +707,6 @@ rec_offs_nth_sql_null(const ulint* offsets, ulint n)
 	return rec_offs_nth_flag(offsets, n, REC_OFFS_SQL_NULL);
 }
 
-inline
-ulint
-rec_offs_nth_drop_sql_null(const ulint* offsets, ulint n)
-{
-	return rec_offs_nth_flag(offsets, n, REC_OFFS_DROP_SQL_NULL);
-}
-
-inline
-ulint
-rec_offs_nth_drop_col(const ulint* offsets, ulint n)
-{
-	return rec_offs_nth_flag(offsets, n, REC_OFFS_DROP_COL);
-}
-
 /** Determine if a record field is stored off-page.
 @param[in]	offsets	rec_get_offsets()
 @param[in]	n	nth field
@@ -884,11 +864,6 @@ rec_get_nth_cfield(
 {
 	ut_ad(rec_offs_validate(rec, index, offsets));
 
-	if (rec_offs_nth_drop_col(offsets, n)) {
-		*len = index->fields[n].col->len;
-		return field_ref_zero;
-	}
-
 	if (!rec_offs_nth_default(offsets, n)) {
 		return rec_get_nth_field(rec, offsets, n, len);
 	}

storage/innobase/rem/rem0rec.cc

@@ -381,10 +381,7 @@ rec_init_offsets_comp_ordinary(
 			goto resolved;
 		} else {
 			ulint dlen;
-			if (col->is_dropped()) {
-				len = offs | REC_OFFS_DROP_COL;
-				any |= REC_OFFS_DROP_COL;
-			} else if (!index->instant_field_value(i, &dlen)) {
+			if (!index->instant_field_value(i, &dlen)) {
 				len = offs | REC_OFFS_SQL_NULL;
 				ut_ad(dlen == UNIV_SQL_NULL);
 			} else {
@@ -583,11 +580,7 @@ number of fields in the record.	 The rest of the array will be
 initialized by this function.  rec_offs_base(offsets)[0] will be set
 to the extra size (if REC_OFFS_COMPACT is set, the record is in the
 new format; if REC_OFFS_EXTERNAL is set, the record contains externally
-stored columns; if REC_OFFS_DROP_SQL_NULL is set, the field for the dropped
-column is NULLABLE or length for the column is also maintained), and
-rec_offs_base(offsets)[1..n_fields] will be set to
-offsets past the end of fields 0..n_fields, or to the beginning of
-fields 1..n_fields+1.  When the high-order bit of the offset at [i+1]
+stored columns); When the high-order bit of the offset at [i+1]
 is set (REC_OFFS_SQL_NULL), the field i is NULL.  When the second
 high-order bit of the offset at [i+1] is set (REC_OFFS_EXTERNAL), the
 field i is being stored externally.
@@ -629,8 +622,6 @@ rec_init_offsets_for_metadata_low(
 	while(pos < rec_offs_n_fields(offsets) && pos < limit)
 	{
 		bool is_dropped = false;
-		bool is_nullable = false;
-		bool is_drop_null = false;
 
 		if (pos == n_pk_fields) {
 			/* Default row blob. */
@@ -667,16 +658,7 @@ rec_init_offsets_for_metadata_low(
 			}
 		}
 
-		is_nullable = !(col->prtype & DATA_NOT_NULL);
-
-		/* Maintain null bit for dropped column. */
-		if (is_dropped) {
-			if (*nulls & null_mask) {
-				is_drop_null = true;
-			}
-
-			null_mask <<= 1;
-		} else if (is_nullable) {
+		if (!(col->prtype & DATA_NOT_NULL)) {
 			if (*nulls & null_mask) {
 				null_mask <<= 1;
 				len = offs | REC_OFFS_SQL_NULL;
@@ -718,17 +700,7 @@ rec_init_offsets_for_metadata_low(
 
 		prev_offs = offs;
 		len = offs += len;
-
-		if (is_drop_null) {
-			/* Set the REC_OFFS_DROP_SQL_NULL flag if
-			the column is dropped and it is nullable. */
-			len = offs | REC_OFFS_DROP_SQL_NULL;
-		}
 resolved:
-		if (is_dropped && !is_drop_null) {
-			len = offs | REC_OFFS_DROP_COL;
-		}
-
 		if (!is_dropped) {
 			/* Initialize previous offset if the column
 			is not dropped. */
@@ -749,8 +721,7 @@ number of fields in the record.	 The rest of the array will be
 initialized by this function.  rec_offs_base(offsets)[0] will be set
 to the extra size (if REC_OFFS_COMPACT is set, the record is in the
 new format; if REC_OFFS_EXTERNAL is set, the record contains externally
-stored columns; if REC_OFFS_DROP_SQL_NULL is set, the field for the dropped
-column is NULLABLE or length for the column is also maintained), and
+stored columns), and
 rec_offs_base(offsets)[1..n_fields] will be set to
 offsets past the end of fields 0..n_fields, or to the beginning of
 fields 1..n_fields+1.  When the high-order bit of the offset at [i+1]