summaryrefslogtreecommitdiffstats
path: root/storage/innobase/include/mtr0mtr.h
blob: c916edc9bdd6f21c96707a4bc3552f2d011371ec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
/*****************************************************************************

Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2013, 2023, MariaDB Corporation.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA

*****************************************************************************/

/**************************************************//**
@file include/mtr0mtr.h
Mini-transaction buffer

Created 11/26/1995 Heikki Tuuri
*******************************************************/

#pragma once

#include "fil0fil.h"
#include "dyn0buf.h"
#include "buf0buf.h"
#include "small_vector.h"

/** Start a mini-transaction. */
#define mtr_start(m)		(m)->start()

/** Commit a mini-transaction. */
#define mtr_commit(m)		(m)->commit()

/** Change the logging mode of a mini-transaction.
@return	old mode */
#define mtr_set_log_mode(m, d)	(m)->set_log_mode((d))

#ifdef UNIV_PFS_RWLOCK
# define mtr_s_lock_index(i,m)	(m)->s_lock(__FILE__, __LINE__, &(i)->lock)
# define mtr_x_lock_index(i,m)	(m)->x_lock(__FILE__, __LINE__, &(i)->lock)
# define mtr_sx_lock_index(i,m)	(m)->u_lock(__FILE__, __LINE__, &(i)->lock)
#else
# define mtr_s_lock_index(i,m)	(m)->s_lock(&(i)->lock)
# define mtr_x_lock_index(i,m)	(m)->x_lock(&(i)->lock)
# define mtr_sx_lock_index(i,m)	(m)->u_lock(&(i)->lock)
#endif

/** Mini-transaction memo stack slot. */
struct mtr_memo_slot_t
{
  /** pointer to the object */
  void *object;
  /** type of the stored object */
  mtr_memo_type_t type;

  /** Release the object */
  void release() const;
};

/** Mini-transaction handle and buffer */
struct mtr_t {
  mtr_t();
  ~mtr_t();

  /** Start a mini-transaction. */
  void start();

  /** Commit the mini-transaction. */
  void commit();

  /** Release latches of unmodified buffer pages.
  @param begin   first slot to release
  @param end     last slot to release, or get_savepoint() */
  void rollback_to_savepoint(ulint begin, ulint end);

  /** Release latches of unmodified buffer pages.
  @param begin   first slot to release */
  void rollback_to_savepoint(ulint begin)
  { rollback_to_savepoint(begin, m_memo.size()); }

  /** Release the last acquired buffer page latch. */
  void release_last_page()
  { auto s= m_memo.size(); rollback_to_savepoint(s - 1, s); }

  /** Commit a mini-transaction that is shrinking a tablespace.
  @param space   tablespace that is being shrunk
  @param size    new size in pages */
  ATTRIBUTE_COLD void commit_shrink(fil_space_t &space, uint32_t size);

  /** Commit a mini-transaction that is deleting or renaming a file.
  @param space           tablespace that is being renamed or deleted
  @param name            new file name (nullptr=the file will be deleted)
  @return whether the operation succeeded */
  ATTRIBUTE_COLD bool commit_file(fil_space_t &space, const char *name);

  /** Commit a mini-transaction that did not modify any pages,
  but generated some redo log on a higher level, such as
  FILE_MODIFY records and an optional FILE_CHECKPOINT marker.
  The caller must hold exclusive log_sys.latch.
  This is to be used at log_checkpoint().
  @param checkpoint_lsn   the log sequence number of a checkpoint, or 0
  @return current LSN */
  ATTRIBUTE_COLD lsn_t commit_files(lsn_t checkpoint_lsn= 0);

  /** @return mini-transaction savepoint (current size of m_memo) */
  ulint get_savepoint() const
  {
    ut_ad(is_active());
    return m_memo.size();
  }

  /** Get the block at a savepoint */
  buf_block_t *at_savepoint(ulint savepoint) const
  {
    ut_ad(is_active());
    const mtr_memo_slot_t &slot= m_memo[savepoint];
    ut_ad(slot.type < MTR_MEMO_S_LOCK);
    ut_ad(slot.object);
    return static_cast<buf_block_t*>(slot.object);
  }

  /** Try to get a block at a savepoint.
  @param savepoint the savepoint right before the block was acquired
  @return the block at the savepoint
  @retval nullptr  if no buffer block was registered at that savepoint */
  buf_block_t *block_at_savepoint(ulint savepoint) const
  {
    ut_ad(is_active());
    const mtr_memo_slot_t &slot= m_memo[savepoint];
    return slot.type < MTR_MEMO_S_LOCK
      ? static_cast<buf_block_t*>(slot.object)
      : nullptr;
  }

  /** Retrieve a page that has already been latched.
  @param id    page identifier
  @param type  page latch type
  @return block
  @retval nullptr if the block had not been latched yet */
  buf_block_t *get_already_latched(const page_id_t id, mtr_memo_type_t type)
    const;

  /** @return the logging mode */
  mtr_log_t get_log_mode() const
  {
    static_assert(MTR_LOG_ALL == 0, "efficiency");
    return static_cast<mtr_log_t>(m_log_mode);
  }

  /** @return whether log is to be written for changes */
  bool is_logged() const
  {
    static_assert(MTR_LOG_ALL == 0, "efficiency");
    static_assert(MTR_LOG_NONE & MTR_LOG_NO_REDO, "efficiency");
    static_assert(!(MTR_LOG_NONE & MTR_LOG_SUB), "efficiency");
    return !(m_log_mode & MTR_LOG_NONE);
  }

  /** Change the logging mode.
  @param mode	 logging mode
  @return	old mode */
  mtr_log_t set_log_mode(mtr_log_t mode)
  {
    const mtr_log_t old_mode= get_log_mode();
    m_log_mode= mode & 3;
    return old_mode;
  }

  /** Set the log mode of a sub-minitransaction
  @param mtr  parent mini-transaction */
  void set_log_mode_sub(const mtr_t &mtr)
  {
    ut_ad(mtr.m_log_mode == MTR_LOG_ALL || mtr.m_log_mode == MTR_LOG_NO_REDO);
    m_log_mode= mtr.m_log_mode | MTR_LOG_SUB;
    static_assert((MTR_LOG_SUB | MTR_LOG_NO_REDO) == MTR_LOG_NO_REDO, "");
  }

  /** Check if we are holding a block latch in exclusive mode
  @param block  buffer pool block to search for */
  bool have_x_latch(const buf_block_t &block) const;

  /** Check if we are holding a block latch in S or U mode
  @param block  buffer pool block to search for */
  bool have_u_or_x_latch(const buf_block_t &block) const;

	/** Copy the tablespaces associated with the mini-transaction
	(needed for generating FILE_MODIFY records)
	@param[in]	mtr	mini-transaction that may modify
	the same set of tablespaces as this one */
	void set_spaces(const mtr_t& mtr)
	{
		ut_ad(!m_user_space_id);
		ut_ad(!m_user_space);

		ut_d(m_user_space_id = mtr.m_user_space_id);
		m_user_space = mtr.m_user_space;
	}

	/** Set the tablespace associated with the mini-transaction
	(needed for generating a FILE_MODIFY record)
	@param[in]	space_id	user or system tablespace ID
	@return	the tablespace */
	fil_space_t* set_named_space_id(uint32_t space_id)
	{
		ut_ad(!m_user_space_id);
		ut_d(m_user_space_id = space_id);
		if (!space_id) {
			return fil_system.sys_space;
		} else {
			ut_ad(m_user_space_id == space_id);
			ut_ad(!m_user_space);
			m_user_space = fil_space_get(space_id);
			ut_ad(m_user_space);
			return m_user_space;
		}
	}

	/** Set the tablespace associated with the mini-transaction
	(needed for generating a FILE_MODIFY record)
	@param[in]	space	user or system tablespace */
	void set_named_space(fil_space_t* space)
	{
		ut_ad(!m_user_space_id);
		ut_d(m_user_space_id = space->id);
		if (space->id) {
			m_user_space = space;
		}
	}

#ifdef UNIV_DEBUG
	/** Check the tablespace associated with the mini-transaction
	(needed for generating a FILE_MODIFY record)
	@param[in]	space	tablespace
	@return whether the mini-transaction is associated with the space */
	bool is_named_space(uint32_t space) const;
	/** Check the tablespace associated with the mini-transaction
	(needed for generating a FILE_MODIFY record)
	@param[in]	space	tablespace
	@return whether the mini-transaction is associated with the space */
	bool is_named_space(const fil_space_t* space) const;
#endif /* UNIV_DEBUG */

  /** Acquire a tablespace X-latch.
  @param space_id   tablespace ID
  @return the tablespace object (never NULL) */
  fil_space_t *x_lock_space(uint32_t space_id);

  /** Acquire a shared rw-latch. */
  void s_lock(
#ifdef UNIV_PFS_RWLOCK
    const char *file, unsigned line,
#endif
    index_lock *lock)
  {
    lock->s_lock(SRW_LOCK_ARGS(file, line));
    memo_push(lock, MTR_MEMO_S_LOCK);
  }

  /** Acquire an exclusive rw-latch. */
  void x_lock(
#ifdef UNIV_PFS_RWLOCK
    const char *file, unsigned line,
#endif
    index_lock *lock)
  {
    lock->x_lock(SRW_LOCK_ARGS(file, line));
    memo_push(lock, MTR_MEMO_X_LOCK);
  }

  /** Acquire an update latch. */
  void u_lock(
#ifdef UNIV_PFS_RWLOCK
    const char *file, unsigned line,
#endif
    index_lock *lock)
  {
    lock->u_lock(SRW_LOCK_ARGS(file, line));
    memo_push(lock, MTR_MEMO_SX_LOCK);
  }

  /** Acquire an exclusive tablespace latch.
  @param space  tablespace */
  void x_lock_space(fil_space_t *space);

  /** Release an index latch. */
  void release(const index_lock &lock) { release(&lock); }
  /** Release a latch to an unmodified page. */
  void release(const buf_block_t &block) { release(&block); }
private:
  /** Release an unmodified object. */
  void release(const void *object);
public:
  /** Mark the given latched page as modified.
  @param block   page that will be modified */
  void set_modified(const buf_block_t &block);

  /** Set the state to not-modified. This will not log the changes.
  This is only used during redo log apply, to avoid logging the changes. */
  void discard_modifications() { m_modifications= false; }

  /** Get the LSN of commit().
  @return the commit LSN
  @retval 0 if the transaction only modified temporary tablespaces */
  lsn_t commit_lsn() const { ut_ad(has_committed()); return m_commit_lsn; }

  /** Note that we are inside the change buffer code. */
  void enter_ibuf() { m_inside_ibuf= true; }

  /** Note that we have exited from the change buffer code. */
  void exit_ibuf() { m_inside_ibuf= false; }

  /** @return true if we are inside the change buffer code */
  bool is_inside_ibuf() const { return m_inside_ibuf; }

  /** Note that some pages have been freed */
  void set_trim_pages() { m_trim_pages= true; }

  /** Latch a buffer pool block.
  @param block    block to be latched
  @param rw_latch RW_S_LATCH, RW_SX_LATCH, RW_X_LATCH, RW_NO_LATCH */
  void page_lock(buf_block_t *block, ulint rw_latch);

  /** Acquire a latch on a buffer-fixed buffer pool block.
  @param savepoint   savepoint location of the buffer-fixed block
  @param rw_latch    latch to acquire */
  void upgrade_buffer_fix(ulint savepoint, rw_lock_type_t rw_latch);

  /** Register a change to the page latch state. */
  void lock_register(ulint savepoint, mtr_memo_type_t type)
  {
    mtr_memo_slot_t &slot= m_memo[savepoint];
    ut_ad(slot.type <= MTR_MEMO_BUF_FIX);
    ut_ad(type < MTR_MEMO_S_LOCK);
    slot.type= type;
  }

  /** Upgrade U locks on a block to X */
  void page_lock_upgrade(const buf_block_t &block);

  /** Upgrade index U lock to X */
  ATTRIBUTE_COLD void index_lock_upgrade();

  /** Check if we are holding tablespace latch
  @param space  tablespace to search for
  @return whether space.latch is being held */
  bool memo_contains(const fil_space_t& space) const
    MY_ATTRIBUTE((warn_unused_result));
#ifdef UNIV_DEBUG
  /** Check if we are holding an rw-latch in this mini-transaction
  @param lock   latch to search for
  @param type   held latch type
  @return whether (lock,type) is contained */
  bool memo_contains(const index_lock &lock, mtr_memo_type_t type) const
    MY_ATTRIBUTE((warn_unused_result));

  /** Check if memo contains an index or buffer block latch.
  @param object    object to search
  @param flags     specify types of object latches
  @return true if contains */
  bool memo_contains_flagged(const void *object, ulint flags) const
    MY_ATTRIBUTE((warn_unused_result, nonnull));

  /** Check if memo contains the given page.
  @param ptr   pointer to within page frame
  @param flags types latch to look for
  @return the block
  @retval nullptr    if not found */
  buf_block_t *memo_contains_page_flagged(const byte *ptr, ulint flags) const;

  /** @return whether this mini-transaction modifies persistent data */
  bool has_modifications() const { return m_modifications; }
#endif /* UNIV_DEBUG */

  /** Push a buffer page to an the memo.
  @param block  buffer block
  @param type	object type: MTR_MEMO_S_LOCK, ... */
  void memo_push(buf_block_t *block, mtr_memo_type_t type)
    __attribute__((nonnull))
  {
    ut_ad(is_active());
    ut_ad(type <= MTR_MEMO_PAGE_SX_MODIFY);
    ut_ad(block->page.buf_fix_count());
    ut_ad(block->page.in_file());
#ifdef UNIV_DEBUG
    switch (type) {
    case MTR_MEMO_PAGE_S_FIX:
      ut_ad(block->page.lock.have_s());
      break;
    case MTR_MEMO_PAGE_X_FIX: case MTR_MEMO_PAGE_X_MODIFY:
      ut_ad(block->page.lock.have_x());
      break;
    case MTR_MEMO_PAGE_SX_FIX: case MTR_MEMO_PAGE_SX_MODIFY:
      ut_ad(block->page.lock.have_u_or_x());
      break;
    case MTR_MEMO_BUF_FIX:
      break;
    case MTR_MEMO_MODIFY:
    case MTR_MEMO_S_LOCK: case MTR_MEMO_X_LOCK: case MTR_MEMO_SX_LOCK:
    case MTR_MEMO_SPACE_X_LOCK:
      ut_ad("invalid type" == 0);
    }
#endif
    if (!(type & MTR_MEMO_MODIFY));
    else if (block->page.id().space() >= SRV_TMP_SPACE_ID)
    {
      block->page.set_temp_modified();
      type= mtr_memo_type_t(type & ~MTR_MEMO_MODIFY);
    }
    else
    {
      m_modifications= true;
      if (!m_made_dirty)
        /* If we are going to modify a previously clean persistent page,
        we must set m_made_dirty, so that commit() will acquire
        log_sys.flush_order_mutex and insert the block into
        buf_pool.flush_list. */
        m_made_dirty= block->page.oldest_modification() <= 1;
    }
    m_memo.emplace_back(mtr_memo_slot_t{block, type});
  }

  /** Push an index lock or tablespace latch to the memo.
  @param object index lock or tablespace latch
  @param type	object type: MTR_MEMO_S_LOCK, ... */
  void memo_push(void *object, mtr_memo_type_t type) __attribute__((nonnull))
  {
    ut_ad(is_active());
    ut_ad(type >= MTR_MEMO_S_LOCK);
    m_memo.emplace_back(mtr_memo_slot_t{object, type});
  }

  /** @return the size of the log is empty */
  size_t get_log_size() const { return m_log.size(); }
  /** @return whether the log and memo are empty */
  bool is_empty() const { return !get_savepoint() && !get_log_size(); }

  /** Write an OPT_PAGE_CHECKSUM record. */
  inline void page_checksum(const buf_page_t &bpage);

  /** Write request types */
  enum write_type
  {
    /** the page is guaranteed to always change */
    NORMAL= 0,
    /** optional: the page contents might not change */
    MAYBE_NOP,
    /** force a write, even if the page contents is not changing */
    FORCED
  };

  /** Write 1, 2, 4, or 8 bytes to a file page.
  @param[in]      block   file page
  @param[in,out]  ptr     pointer in file page
  @param[in]      val     value to write
  @tparam l       number of bytes to write
  @tparam w       write request type
  @tparam V       type of val
  @return whether any log was written */
  template<unsigned l,write_type w= NORMAL,typename V>
  inline bool write(const buf_block_t &block, void *ptr, V val)
    MY_ATTRIBUTE((nonnull));

  /** Log a write of a byte string to a page.
  @param[in]      b       buffer page
  @param[in]      ofs     byte offset from b->frame
  @param[in]      len     length of the data to write */
  inline void memcpy(const buf_block_t &b, ulint ofs, ulint len);

  /** Write a byte string to a page.
  @param[in,out]  b       buffer page
  @param[in]      dest    destination within b.frame
  @param[in]      str     the data to write
  @param[in]      len     length of the data to write
  @tparam w       write request type */
  template<write_type w= NORMAL>
  inline void memcpy(const buf_block_t &b, void *dest, const void *str,
                     ulint len);

  /** Log a write of a byte string to a ROW_FORMAT=COMPRESSED page.
  @param[in]      b       ROW_FORMAT=COMPRESSED index page
  @param[in]      offset  byte offset from b.zip.data
  @param[in]      len     length of the data to write */
  inline void zmemcpy(const buf_block_t &b, ulint offset, ulint len);

  /** Write a byte string to a ROW_FORMAT=COMPRESSED page.
  @param[in]      b       ROW_FORMAT=COMPRESSED index page
  @param[in]      dest    destination within b.zip.data
  @param[in]      str     the data to write
  @param[in]      len     length of the data to write
  @tparam w       write request type */
  template<write_type w= NORMAL>
  inline void zmemcpy(const buf_block_t &b, void *dest, const void *str,
                      ulint len);

  /** Log an initialization of a string of bytes.
  @param[in]      b       buffer page
  @param[in]      ofs     byte offset from b->frame
  @param[in]      len     length of the data to write
  @param[in]      val     the data byte to write */
  inline void memset(const buf_block_t &b, ulint ofs, ulint len, byte val);

  /** Initialize a string of bytes.
  @param[in,out]        b       buffer page
  @param[in]            ofs     byte offset from b->frame
  @param[in]            len     length of the data to write
  @param[in]            val     the data byte to write */
  inline void memset(const buf_block_t *b, ulint ofs, ulint len, byte val);

  /** Log an initialization of a repeating string of bytes.
  @param[in]      b       buffer page
  @param[in]      ofs     byte offset from b->frame
  @param[in]      len     length of the data to write, in bytes
  @param[in]      str     the string to write
  @param[in]      size    size of str, in bytes */
  inline void memset(const buf_block_t &b, ulint ofs, size_t len,
                     const void *str, size_t size);

  /** Initialize a repeating string of bytes.
  @param[in,out]  b       buffer page
  @param[in]      ofs     byte offset from b->frame
  @param[in]      len     length of the data to write, in bytes
  @param[in]      str     the string to write
  @param[in]      size    size of str, in bytes */
  inline void memset(const buf_block_t *b, ulint ofs, size_t len,
                     const void *str, size_t size);

  /** Log that a string of bytes was copied from the same page.
  @param[in]      b       buffer page
  @param[in]      d       destination offset within the page
  @param[in]      s       source offset within the page
  @param[in]      len     length of the data to copy */
  inline void memmove(const buf_block_t &b, ulint d, ulint s, ulint len);

  /** Initialize an entire page.
  @param[in,out]        b       buffer page */
  void init(buf_block_t *b);
  /** Free a page.
  @param space   tablespace
  @param offset  offset of the page to be freed */
  void free(const fil_space_t &space, uint32_t offset);
  /** Write log for partly initializing a B-tree or R-tree page.
  @param block    B-tree or R-tree page
  @param comp     false=ROW_FORMAT=REDUNDANT, true=COMPACT or DYNAMIC */
  inline void page_create(const buf_block_t &block, bool comp);

  /** Write log for inserting a B-tree or R-tree record in
  ROW_FORMAT=REDUNDANT.
  @param block      B-tree or R-tree page
  @param reuse      false=allocate from PAGE_HEAP_TOP; true=reuse PAGE_FREE
  @param prev_rec   byte offset of the predecessor of the record to insert,
                    starting from PAGE_OLD_INFIMUM
  @param info_bits  info_bits of the record
  @param n_fields_s number of fields << 1 | rec_get_1byte_offs_flag()
  @param hdr_c      number of common record header bytes with prev_rec
  @param data_c     number of common data bytes with prev_rec
  @param hdr        record header bytes to copy to the log
  @param hdr_l      number of copied record header bytes
  @param data       record payload bytes to copy to the log
  @param data_l     number of copied record data bytes */
  inline void page_insert(const buf_block_t &block, bool reuse,
                          ulint prev_rec, byte info_bits,
                          ulint n_fields_s, size_t hdr_c, size_t data_c,
                          const byte *hdr, size_t hdr_l,
                          const byte *data, size_t data_l);
  /** Write log for inserting a B-tree or R-tree record in
  ROW_FORMAT=COMPACT or ROW_FORMAT=DYNAMIC.
  @param block       B-tree or R-tree page
  @param reuse       false=allocate from PAGE_HEAP_TOP; true=reuse PAGE_FREE
  @param prev_rec    byte offset of the predecessor of the record to insert,
                     starting from PAGE_NEW_INFIMUM
  @param info_status rec_get_info_and_status_bits()
  @param shift       unless !reuse: number of bytes the PAGE_FREE is moving
  @param hdr_c       number of common record header bytes with prev_rec
  @param data_c      number of common data bytes with prev_rec
  @param hdr         record header bytes to copy to the log
  @param hdr_l       number of copied record header bytes
  @param data        record payload bytes to copy to the log
  @param data_l      number of copied record data bytes */
  inline void page_insert(const buf_block_t &block, bool reuse,
                          ulint prev_rec, byte info_status,
                          ssize_t shift, size_t hdr_c, size_t data_c,
                          const byte *hdr, size_t hdr_l,
                          const byte *data, size_t data_l);
  /** Write log for deleting a B-tree or R-tree record in ROW_FORMAT=REDUNDANT.
  @param block      B-tree or R-tree page
  @param prev_rec   byte offset of the predecessor of the record to delete,
                    starting from PAGE_OLD_INFIMUM */
  inline void page_delete(const buf_block_t &block, ulint prev_rec);
  /** Write log for deleting a COMPACT or DYNAMIC B-tree or R-tree record.
  @param block      B-tree or R-tree page
  @param prev_rec   byte offset of the predecessor of the record to delete,
                    starting from PAGE_NEW_INFIMUM
  @param hdr_size   record header size, excluding REC_N_NEW_EXTRA_BYTES
  @param data_size  data payload size, in bytes */
  inline void page_delete(const buf_block_t &block, ulint prev_rec,
                          size_t hdr_size, size_t data_size);

  /** Write log for initializing an undo log page.
  @param block    undo page */
  inline void undo_create(const buf_block_t &block);
  /** Write log for appending an undo log record.
  @param block    undo page
  @param data     record within the undo page
  @param len      length of the undo record, in bytes */
  inline void undo_append(const buf_block_t &block,
                          const void *data, size_t len);
  /** Trim the end of a tablespace.
  @param id       first page identifier that will not be in the file */
  inline void trim_pages(const page_id_t id);

  /** Write a log record about a file operation.
  @param type           file operation
  @param space_id       tablespace identifier
  @param path           file path
  @param new_path       new file path for type=FILE_RENAME */
  inline void log_file_op(mfile_type_t type, uint32_t space_id,
                          const char *path,
                          const char *new_path= nullptr);

  /** Add freed page numbers to freed_pages */
  void add_freed_offset(fil_space_t *space, uint32_t page)
  {
    ut_ad(is_named_space(space));
    if (!m_freed_pages)
    {
      m_freed_pages= new range_set();
      ut_ad(!m_freed_space);
      m_freed_space= space;
    }
    else
      ut_ad(m_freed_space == space);
    m_freed_pages->add_value(page);
  }

  /** Determine the added buffer fix count of a block.
  @param block block to be checked
  @return number of buffer count added by this mtr */
  uint32_t get_fix_count(const buf_block_t *block) const;

  /** Note that log_sys.latch is no longer being held exclusively. */
  void flag_wr_unlock() noexcept { ut_ad(m_latch_ex); m_latch_ex= false; }

  /** type of page flushing is needed during commit() */
  enum page_flush_ahead
  {
    /** no need to trigger page cleaner */
    PAGE_FLUSH_NO= 0,
    /** asynchronous flushing is needed */
    PAGE_FLUSH_ASYNC,
    /** furious flushing is needed */
    PAGE_FLUSH_SYNC
  };

private:
  /** Handle any pages that were freed during the mini-transaction. */
  void process_freed_pages();
  /** Release modified pages when no log was written. */
  void release_unlogged();

  /** Log a write of a byte string to a page.
  @param block   buffer page
  @param offset  byte offset within page
  @param data    data to be written
  @param len     length of the data, in bytes */
  inline void memcpy_low(const buf_block_t &block, uint16_t offset,
                         const void *data, size_t len);
  /**
  Write a log record.
  @tparam type  redo log record type
  @param id     persistent page identifier
  @param bpage  buffer pool page, or nullptr
  @param len    number of additional bytes to write
  @param alloc  whether to allocate the additional bytes
  @param offset byte offset, or 0 if the record type does not allow one
  @return end of mini-transaction log, minus len */
  template<byte type>
  inline byte *log_write(const page_id_t id, const buf_page_t *bpage,
                         size_t len= 0, bool alloc= false, size_t offset= 0);

  /** Write an EXTENDED log record.
  @param block  buffer pool page
  @param type   extended record subtype; @see mrec_ext_t */
  inline void log_write_extended(const buf_block_t &block, byte type);

  /** Write a FILE_MODIFY record when a non-predefined persistent
  tablespace was modified for the first time since fil_names_clear(). */
  ATTRIBUTE_NOINLINE ATTRIBUTE_COLD void name_write();

  /** Encrypt the log */
  ATTRIBUTE_NOINLINE void encrypt();

  /** Append the redo log records to the redo log buffer.
  @return {start_lsn,flush_ahead} */
  std::pair<lsn_t,page_flush_ahead> do_write();

  /** Append the redo log records to the redo log buffer.
  @param len   number of bytes to write
  @return {start_lsn,flush_ahead} */
  std::pair<lsn_t,page_flush_ahead> finish_write(size_t len);

  /** Release all latches. */
  void release();
  /** Release the resources */
  inline void release_resources();

#ifdef UNIV_DEBUG
public:
  /** @return whether the mini-transaction is active */
  bool is_active() const
  { ut_ad(!m_commit || m_start); return m_start && !m_commit; }
  /** @return whether the mini-transaction has been committed */
  bool has_committed() const { ut_ad(!m_commit || m_start); return m_commit; }
  /** @return whether the mini-transaction is freeing an index tree */
  bool is_freeing_tree() const { return m_freeing_tree; }
  /** Notify that the mini-transaction is freeing an index tree */
  void freeing_tree() { m_freeing_tree= true; }
private:
  /** whether start() has been called */
  bool m_start= false;
  /** whether commit() has been called */
  bool m_commit= false;
  /** whether freeing_tree() has been called */
  bool m_freeing_tree= false;
#endif
private:
  /** The page of the most recent m_log record written, or NULL */
  const buf_page_t* m_last;
  /** The current byte offset in m_last, or 0 */
  uint16_t m_last_offset;

  /** specifies which operations should be logged; default MTR_LOG_ALL */
  uint16_t m_log_mode:2;

  /** whether at least one persistent page was written to */
  uint16_t m_modifications:1;

  /** whether at least one previously clean buffer pool page was written to */
  uint16_t m_made_dirty:1;

  /** whether log_sys.latch is locked exclusively */
  uint16_t m_latch_ex:1;

  /** whether change buffer is latched; only needed in non-debug builds
  to suppress some read-ahead operations, @see ibuf_inside() */
  uint16_t m_inside_ibuf:1;

  /** whether the pages has been trimmed */
  uint16_t m_trim_pages:1;

  /** CRC-32C of m_log */
  uint32_t m_crc;

#ifdef UNIV_DEBUG
  /** Persistent user tablespace associated with the
  mini-transaction, or 0 (TRX_SYS_SPACE) if none yet */
  uint32_t m_user_space_id;
#endif /* UNIV_DEBUG */

  /** acquired dict_index_t::lock, fil_space_t::latch, buf_block_t */
  small_vector<mtr_memo_slot_t, 16> m_memo;

  /** mini-transaction log */
  mtr_buf_t m_log;

  /** user tablespace that is being modified by the mini-transaction */
  fil_space_t* m_user_space;

  /** LSN at commit time */
  lsn_t m_commit_lsn;

  /** tablespace where pages have been freed */
  fil_space_t *m_freed_space= nullptr;
  /** set of freed page ids */
  range_set *m_freed_pages= nullptr;
};