mariadb/storage/innobase/include/trx0roll.ic

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/**************************************************//**
@file include/trx0roll.ic
Transaction rollback

Created 3/26/1996 Heikki Tuuri
*******************************************************/

#ifdef UNIV_DEBUG
/*******************************************************************//**
Check if undo numbering is maintained while processing undo records
for rollback.
@return true if undo numbering is maintained. */
UNIV_INLINE
bool
trx_roll_check_undo_rec_ordering(
/*=============================*/
	undo_no_t	curr_undo_rec_no,	/*!< in: record number of
						undo record to process. */
	ulint		curr_undo_space_id,	/*!< in: space-id of rollback
						segment that contains the
						undo record to process. */
	const trx_t*	trx)			/*!< in: transaction */
{
	/* Each transaction now can have multiple rollback segments.
	If a transaction involves temp and non-temp tables, both the rollback
	segments will be active. In this case undo records will be distrubuted
	across the two rollback segments.
	CASE-1: UNDO action will apply all undo records from one rollback
	segment before moving to next. This means undo record numbers can't be
	sequential but ordering is still enforced as next undo record number
	should be < processed undo record number.
	CASE-2: For normal rollback (not initiated by crash) all rollback
	segments will be active (including non-redo).
	Based on transaction operation pattern undo record number of first
	undo record from this new rollback segment can be > last undo number
	from previous rollback segment and so we ignore this check if
	rollback segments are switching. Once switched new rollback segment
	should re-follow undo record number pattern (as mentioned in CASE-1). */

	return(curr_undo_space_id != trx->undo_rseg_space
	       || curr_undo_rec_no + 1 <= trx->undo_no);
}
#endif /* UNIV_DEBUG */