Remove TRX_SYS_OLD_N_RSEGS

storage/innobase/include/trx0sys.h

@@ -403,10 +403,6 @@ byte, therefore 128; each slot is currently 8 bytes in size. If you want
 to raise the level to 256 then you will need to fix some assertions that
 impose the 7 bit restriction. e.g., mach_write_to_3() */
 #define	TRX_SYS_N_RSEGS			128
-/* Originally, InnoDB defined TRX_SYS_N_RSEGS as 256 but created only one
-rollback segment.  It initialized some arrays with this number of entries.
-We must remember this limit in order to keep file compatibility. */
-#define TRX_SYS_OLD_N_RSEGS		256
 
 /** Maximum length of MySQL binlog file name, in bytes. */
 #define TRX_SYS_MYSQL_LOG_NAME_LEN	512

storage/innobase/trx/trx0sys.cc

@@ -446,7 +446,6 @@ trx_sysf_create(
 	page_t*		page;
 	ulint		page_no;
 	byte*		ptr;
-	ulint		len;
 
 	ut_ad(mtr);
 
@@ -481,13 +480,12 @@ trx_sysf_create(
 	mach_write_to_8(sys_header + TRX_SYS_TRX_ID_STORE, 1);
 
 	/* Reset the rollback segment slots.  Old versions of InnoDB
-	define TRX_SYS_N_RSEGS as 256 (TRX_SYS_OLD_N_RSEGS) and expect
+	(before MySQL 5.5) define TRX_SYS_N_RSEGS as 256 and expect
 	that the whole array is initialized. */
 	ptr = TRX_SYS_RSEGS + sys_header;
-	len = ut_max(TRX_SYS_OLD_N_RSEGS, TRX_SYS_N_RSEGS)
-		* TRX_SYS_RSEG_SLOT_SIZE;
-	memset(ptr, 0xff, len);
-	ptr += len;
+	compile_time_assert(256 >= TRX_SYS_N_RSEGS);
+	memset(ptr, 0xff, 256 * TRX_SYS_RSEG_SLOT_SIZE);
+	ptr += 256 * TRX_SYS_RSEG_SLOT_SIZE;
 	ut_a(ptr <= page + (UNIV_PAGE_SIZE - FIL_PAGE_DATA_END));
 
 	/* Initialize all of the page.  This part used to be uninitialized. */