InnoDB: Keep the "compact format" flag in SYS_TABLES.N_COLS

instead of SYS_TABLES.MIX_LEN, because the latter was not
initialized to zero in old MySQL 3.23 releases. This will break
existing MySQL/InnoDB 5.0.3-bk databases for which
SHOW TABLE STATUS displays Row_format=Compact.


innobase/dict/dict0crea.c:
  Write the "compact format" flag to N_COLS instead of MIX_LEN.
  Remove corruption analysis for MIX_LEN, as it has been tracked down
  to MySQL 3.23.4x not initializing MIX_LEN.
innobase/dict/dict0load.c:
  Read the "compact format" flag from N_COLS instead of MIX_LEN.

innobase/dict/dict0crea.c

@@ -63,8 +63,8 @@ dict_create_sys_tables_tuple(
 	dfield = dtuple_get_nth_field(entry, 2);
 
 	ptr = mem_heap_alloc(heap, 4);
-	mach_write_to_4(ptr, table->n_def);
-
+	mach_write_to_4(ptr, table->n_def
+			| ((ulint) table->comp << 31));
 	dfield_set_data(dfield, ptr, 4);
 	/* 5: TYPE -----------------------------*/
 	dfield = dtuple_get_nth_field(entry, 3);
@@ -82,21 +82,10 @@ dict_create_sys_tables_tuple(
 	dfield_set_data(dfield, ptr, 8);
 	/* 7: MIX_LEN --------------------------*/
 
-	/* Track corruption reported on mailing list Jan 14, 2005 */
-	if (table->mix_len != 0 && table->mix_len != 0x80000000) {
-		fprintf(stderr,
-"InnoDB: Error: mix_len is %lu in table %s\n", (ulong)table->mix_len,
-							table->name);
-		mem_analyze_corruption((byte*)&(table->mix_len));
-	
-		ut_error;
-	}
-
 	dfield = dtuple_get_nth_field(entry, 5);
 
 	ptr = mem_heap_alloc(heap, 4);
-	mach_write_to_4(ptr, (table->mix_len & 0x7fffffff) |
-			((ulint) table->comp << 31));
+	mach_write_to_4(ptr, table->mix_len);
 
 	dfield_set_data(dfield, ptr, 4);
 	/* 8: CLUSTER_NAME ---------------------*/

innobase/dict/dict0load.c

@@ -818,8 +818,10 @@ dict_load_table(
 	field = rec_get_nth_field_old(rec, 4, &len);
 	n_cols = mach_read_from_4(field);
 
-	/* table->comp will be initialized later, in this function */
-	table = dict_mem_table_create(name, space, n_cols, FALSE);
+	/* The high-order bit of N_COLS is the "compact format" flag. */
+	table = dict_mem_table_create(name, space,
+					n_cols & ~0x80000000UL,
+					!!(n_cols & 0x80000000UL));
 
 	table->ibd_file_missing = ibd_file_missing;
 
@@ -844,14 +846,12 @@ dict_load_table(
 #endif
 	}
 
-	/* The high-order bit of MIX_LEN is the "compact format" flag */
-	field = rec_get_nth_field_old(rec, 7, &len);
-	table->comp = !!(mach_read_from_1(field) & 0x80);
-
 	if ((table->type == DICT_TABLE_CLUSTER)
 	    || (table->type == DICT_TABLE_CLUSTER_MEMBER)) {
 
-		table->mix_len = mach_read_from_4(field) & 0x7fffffff;
+		field = rec_get_nth_field_old(rec, 7, &len);
+		ut_a(len == 4);
+		table->mix_len = mach_read_from_4(field);
 	}
 
 	btr_pcur_close(&pcur);