1/*****************************************************************************
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3Copyright (c) 1996, 2018, Oracle and/or its affiliates. All Rights Reserved.
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25*****************************************************************************/
26
27/** @file include/trx0roll.ic
28 Transaction rollback
29
30 Created 3/26/1996 Heikki Tuuri
31 *******************************************************/
32
33#ifdef UNIV_DEBUG
34/** Check if undo numbering is maintained while processing undo records
35 for rollback.
36 @return true if undo numbering is maintained. */
37UNIV_INLINE
38bool trx_roll_check_undo_rec_ordering(
39    undo_no_t curr_undo_rec_no,    /*!< in: record number of
40                                   undo record to process. */
41    space_id_t curr_undo_space_id, /*!< in: space-id of rollback
42                                   segment that contains the
43                                   undo record to process. */
44    const trx_t *trx)              /*!< in: transaction */
45{
46  /* Each transaction now can have multiple rollback segments.
47  If a transaction involves temp and non-temp tables, both the rollback
48  segments will be active. In this case undo records will be distrubuted
49  across the two rollback segments.
50  CASE-1: UNDO action will apply all undo records from one rollback
51  segment before moving to next. This means undo record numbers can't be
52  sequential but ordering is still enforced as next undo record number
53  should be < processed undo record number.
54  CASE-2: For normal rollback (not initiated by crash) all rollback
55  segments will be active (including non-redo).
56  Based on transaction operation pattern undo record number of first
57  undo record from this new rollback segment can be > last undo number
58  from previous rollback segment and so we ignore this check if
59  rollback segments are switching. Once switched new rollback segment
60  should re-follow undo record number pattern (as mentioned in CASE-1). */
61
62  return (curr_undo_space_id != trx->undo_rseg_space ||
63          curr_undo_rec_no + 1 <= trx->undo_no);
64}
65#endif /* UNIV_DEBUG */
66