summaryrefslogtreecommitdiff
path: root/storage/innobase/include/page0page.ic
blob: d9e67f3eeeb45c54b7d455a13c3b4ccbe2c345ee (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
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
/******************************************************
Index page routines

(c) 1994-1996 Innobase Oy

Created 2/2/1994 Heikki Tuuri
*******************************************************/

#include "mach0data.h"
#include "rem0cmp.h"
#include "mtr0log.h"

#ifdef UNIV_MATERIALIZE
#undef UNIV_INLINE
#define UNIV_INLINE
#endif

/****************************************************************
Gets the start of a page. */
UNIV_INLINE
page_t*
page_align(
/*=======*/
			/* out: start of the page */
	void*	ptr)	/* in: pointer to page frame */
{
	return((page_t*) ut_align_down(ptr, UNIV_PAGE_SIZE));
}
/****************************************************************
Gets the offset within a page. */
UNIV_INLINE
ulint
page_offset(
/*========*/
				/* out: offset from the start of the page */
	const void*	ptr)	/* in: pointer to page frame */
{
	return(ut_align_offset(ptr, UNIV_PAGE_SIZE));
}
/*****************************************************************
Returns the max trx id field value. */
UNIV_INLINE
dulint
page_get_max_trx_id(
/*================*/
	page_t*	page)	/* in: page */
{
	ut_ad(page);

	return(mach_read_from_8(page + PAGE_HEADER + PAGE_MAX_TRX_ID));
}

/*****************************************************************
Sets the max trx id field value if trx_id is bigger than the previous
value. */
UNIV_INLINE
void
page_update_max_trx_id(
/*===================*/
	page_t*	page,	/* in: page */
	dulint	trx_id)	/* in: transaction id */
{
	ut_ad(page);

	if (ut_dulint_cmp(page_get_max_trx_id(page), trx_id) < 0) {

		page_set_max_trx_id(page, trx_id);
	}
}

/*****************************************************************
Reads the given header field. */
UNIV_INLINE
ulint
page_header_get_field(
/*==================*/
	page_t*	page,	/* in: page */
	ulint	field)	/* in: PAGE_LEVEL, ... */
{
	ut_ad(page);
	ut_ad(field <= PAGE_INDEX_ID);

	return(mach_read_from_2(page + PAGE_HEADER + field));
}

/*****************************************************************
Sets the given header field. */
UNIV_INLINE
void
page_header_set_field(
/*==================*/
	page_t*	page,	/* in: page */
	ulint	field,	/* in: PAGE_LEVEL, ... */
	ulint	val)	/* in: value */
{
	ut_ad(page);
	ut_ad(field <= PAGE_N_RECS);
	ut_ad(field == PAGE_N_HEAP || val < UNIV_PAGE_SIZE);
	ut_ad(field != PAGE_N_HEAP || (val & 0x7fff) < UNIV_PAGE_SIZE);

	mach_write_to_2(page + PAGE_HEADER + field, val);
}

/*****************************************************************
Returns the pointer stored in the given header field. */
UNIV_INLINE
byte*
page_header_get_ptr(
/*================*/
			/* out: pointer or NULL */
	page_t*	page,	/* in: page */
	ulint	field)	/* in: PAGE_FREE, ... */
{
	ulint	offs;

	ut_ad(page);
	ut_ad((field == PAGE_FREE)
	      || (field == PAGE_LAST_INSERT)
	      || (field == PAGE_HEAP_TOP));

	offs = page_header_get_field(page, field);

	ut_ad((field != PAGE_HEAP_TOP) || offs);

	if (offs == 0) {

		return(NULL);
	}

	return(page + offs);
}

/*****************************************************************
Sets the pointer stored in the given header field. */
UNIV_INLINE
void
page_header_set_ptr(
/*================*/
	page_t*	page,	/* in: page */
	ulint	field,	/* in: PAGE_FREE, ... */
	byte*	ptr)	/* in: pointer or NULL*/
{
	ulint	offs;

	ut_ad(page);
	ut_ad((field == PAGE_FREE)
	      || (field == PAGE_LAST_INSERT)
	      || (field == PAGE_HEAP_TOP));

	if (ptr == NULL) {
		offs = 0;
	} else {
		offs = ptr - page;
	}

	ut_ad((field != PAGE_HEAP_TOP) || offs);

	page_header_set_field(page, field, offs);
}

/*****************************************************************
Resets the last insert info field in the page header. Writes to mlog
about this operation. */
UNIV_INLINE
void
page_header_reset_last_insert(
/*==========================*/
	page_t*	page,	/* in: page */
	mtr_t*	mtr)	/* in: mtr */
{
	ut_ad(page && mtr);

	mlog_write_ulint(page + PAGE_HEADER + PAGE_LAST_INSERT, 0,
			 MLOG_2BYTES, mtr);
}

/****************************************************************
Determine whether the page is in new-style compact format. */
UNIV_INLINE
ulint
page_is_comp(
/*=========*/
			/* out: nonzero if the page is in compact
			format, zero if it is in old-style format */
	page_t*	page)	/* in: index page */
{
	return(UNIV_EXPECT(page_header_get_field(page, PAGE_N_HEAP) & 0x8000,
			   0x8000));
}

/****************************************************************
TRUE if the record is on a page in compact format. */
UNIV_INLINE
ulint
page_rec_is_comp(
/*=============*/
				/* out: nonzero if in compact format */
	const rec_t*	rec)	/* in: record */
{
	return(page_is_comp(page_align((rec_t*) rec)));
}

/****************************************************************
Gets the first record on the page. */
UNIV_INLINE
rec_t*
page_get_infimum_rec(
/*=================*/
			/* out: the first record in record list */
	page_t*	page)	/* in: page which must have record(s) */
{
	ut_ad(page);

	if (page_is_comp(page)) {
		return(page + PAGE_NEW_INFIMUM);
	} else {
		return(page + PAGE_OLD_INFIMUM);
	}
}

/****************************************************************
Gets the last record on the page. */
UNIV_INLINE
rec_t*
page_get_supremum_rec(
/*==================*/
			/* out: the last record in record list */
	page_t*	page)	/* in: page which must have record(s) */
{
	ut_ad(page);

	if (page_is_comp(page)) {
		return(page + PAGE_NEW_SUPREMUM);
	} else {
		return(page + PAGE_OLD_SUPREMUM);
	}
}

/****************************************************************
TRUE if the record is a user record on the page. */
UNIV_INLINE
ibool
page_rec_is_user_rec_low(
/*=====================*/
			/* out: TRUE if a user record */
	ulint	offset)	/* in: record offset on page */
{
	ut_ad(offset >= PAGE_NEW_INFIMUM);
#if PAGE_OLD_INFIMUM < PAGE_NEW_INFIMUM
# error "PAGE_OLD_INFIMUM < PAGE_NEW_INFIMUM"
#endif
#if PAGE_OLD_SUPREMUM < PAGE_NEW_SUPREMUM
# error "PAGE_OLD_SUPREMUM < PAGE_NEW_SUPREMUM"
#endif
#if PAGE_NEW_INFIMUM > PAGE_OLD_SUPREMUM
# error "PAGE_NEW_INFIMUM > PAGE_OLD_SUPREMUM"
#endif
#if PAGE_OLD_INFIMUM > PAGE_NEW_SUPREMUM
# error "PAGE_OLD_INFIMUM > PAGE_NEW_SUPREMUM"
#endif
#if PAGE_NEW_SUPREMUM > PAGE_OLD_SUPREMUM_END
# error "PAGE_NEW_SUPREMUM > PAGE_OLD_SUPREMUM_END"
#endif
#if PAGE_OLD_SUPREMUM > PAGE_NEW_SUPREMUM_END
# error "PAGE_OLD_SUPREMUM > PAGE_NEW_SUPREMUM_END"
#endif
	ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

	return(UNIV_LIKELY(offset != PAGE_NEW_SUPREMUM)
	       && UNIV_LIKELY(offset != PAGE_NEW_INFIMUM)
	       && UNIV_LIKELY(offset != PAGE_OLD_INFIMUM)
	       && UNIV_LIKELY(offset != PAGE_OLD_SUPREMUM));
}

/****************************************************************
TRUE if the record is the supremum record on a page. */
UNIV_INLINE
ibool
page_rec_is_supremum_low(
/*=====================*/
			/* out: TRUE if the supremum record */
	ulint	offset)	/* in: record offset on page */
{
	ut_ad(offset >= PAGE_NEW_INFIMUM);
	ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

	return(UNIV_UNLIKELY(offset == PAGE_NEW_SUPREMUM)
	       || UNIV_UNLIKELY(offset == PAGE_OLD_SUPREMUM));
}

/****************************************************************
TRUE if the record is the infimum record on a page. */
UNIV_INLINE
ibool
page_rec_is_infimum_low(
/*====================*/
			/* out: TRUE if the infimum record */
	ulint	offset)	/* in: record offset on page */
{
	ut_ad(offset >= PAGE_NEW_INFIMUM);
	ut_ad(offset <= UNIV_PAGE_SIZE - PAGE_EMPTY_DIR_START);

	return(UNIV_UNLIKELY(offset == PAGE_NEW_INFIMUM)
	       || UNIV_UNLIKELY(offset == PAGE_OLD_INFIMUM));
}

/****************************************************************
TRUE if the record is a user record on the page. */
UNIV_INLINE
ibool
page_rec_is_user_rec(
/*=================*/
				/* out: TRUE if a user record */
	const rec_t*	rec)	/* in: record */
{
	return(page_rec_is_user_rec_low(page_offset(rec)));
}

/****************************************************************
TRUE if the record is the supremum record on a page. */
UNIV_INLINE
ibool
page_rec_is_supremum(
/*=================*/
				/* out: TRUE if the supremum record */
	const rec_t*	rec)	/* in: record */
{
	return(page_rec_is_supremum_low(page_offset(rec)));
}

/****************************************************************
TRUE if the record is the infimum record on a page. */
UNIV_INLINE
ibool
page_rec_is_infimum(
/*================*/
				/* out: TRUE if the infimum record */
	const rec_t*	rec)	/* in: record */
{
	return(page_rec_is_infimum_low(page_offset(rec)));
}

/*****************************************************************
Compares a data tuple to a physical record. Differs from the function
cmp_dtuple_rec_with_match in the way that the record must reside on an
index page, and also page infimum and supremum records can be given in
the parameter rec. These are considered as the negative infinity and
the positive infinity in the alphabetical order. */
UNIV_INLINE
int
page_cmp_dtuple_rec_with_match(
/*===========================*/
				/* out: 1, 0, -1, if dtuple is greater, equal,
				less than rec, respectively, when only the
				common first fields are compared */
	dtuple_t*	dtuple,	/* in: data tuple */
	rec_t*		rec,	/* in: physical record on a page; may also
				be page infimum or supremum, in which case
				matched-parameter values below are not
				affected */
	const ulint*	offsets,/* in: array returned by rec_get_offsets() */
	ulint*		matched_fields, /* in/out: number of already completely
				matched fields; when function returns
				contains the value for current comparison */
	ulint*		matched_bytes) /* in/out: number of already matched
				bytes within the first field not completely
				matched; when function returns contains the
				value for current comparison */
{
	ulint	rec_offset;

	ut_ad(dtuple_check_typed(dtuple));
	ut_ad(rec_offs_validate(rec, NULL, offsets));
	ut_ad(!rec_offs_comp(offsets) == !page_rec_is_comp(rec));

	rec_offset = page_offset(rec);

	if (UNIV_UNLIKELY(rec_offset == PAGE_NEW_INFIMUM)
	    || UNIV_UNLIKELY(rec_offset == PAGE_OLD_INFIMUM)) {
		return(1);
	}
	if (UNIV_UNLIKELY(rec_offset == PAGE_NEW_SUPREMUM)
	    || UNIV_UNLIKELY(rec_offset == PAGE_OLD_SUPREMUM)) {
		return(-1);
	}

	return(cmp_dtuple_rec_with_match(dtuple, rec, offsets,
					 matched_fields,
					 matched_bytes));
}

/*****************************************************************
Gets the number of user records on page (infimum and supremum records
are not user records). */
UNIV_INLINE
ulint
page_get_n_recs(
/*============*/
			/* out: number of user records */
	page_t*	page)	/* in: index page */
{
	return(page_header_get_field(page, PAGE_N_RECS));
}

/*****************************************************************
Gets the number of dir slots in directory. */
UNIV_INLINE
ulint
page_dir_get_n_slots(
/*=================*/
			/* out: number of slots */
	page_t*	page)	/* in: index page */
{
	return(page_header_get_field(page, PAGE_N_DIR_SLOTS));
}
/*****************************************************************
Sets the number of dir slots in directory. */
UNIV_INLINE
void
page_dir_set_n_slots(
/*=================*/
			/* out: number of slots */
	page_t*	page,	/* in: index page */
	ulint	n_slots)/* in: number of slots */
{
	page_header_set_field(page, PAGE_N_DIR_SLOTS, n_slots);
}

/*****************************************************************
Gets the number of records in the heap. */
UNIV_INLINE
ulint
page_dir_get_n_heap(
/*================*/
			/* out: number of user records */
	page_t*	page)	/* in: index page */
{
	return(page_header_get_field(page, PAGE_N_HEAP) & 0x7fff);
}

/*****************************************************************
Sets the number of records in the heap. */
UNIV_INLINE
void
page_dir_set_n_heap(
/*================*/
	page_t*	page,	/* in: index page */
	ulint	n_heap)	/* in: number of records */
{
	ut_ad(n_heap < 0x8000);

	page_header_set_field(page, PAGE_N_HEAP, n_heap
			      | (0x8000
				 & page_header_get_field(page, PAGE_N_HEAP)));
}

/*****************************************************************
Gets pointer to nth directory slot. */
UNIV_INLINE
page_dir_slot_t*
page_dir_get_nth_slot(
/*==================*/
			/* out: pointer to dir slot */
	page_t*	page,	/* in: index page */
	ulint	n)	/* in: position */
{
	ut_ad(page_dir_get_n_slots(page) > n);

	return(page + UNIV_PAGE_SIZE - PAGE_DIR
	       - (n + 1) * PAGE_DIR_SLOT_SIZE);
}

/******************************************************************
Used to check the consistency of a record on a page. */
UNIV_INLINE
ibool
page_rec_check(
/*===========*/
			/* out: TRUE if succeed */
	rec_t*	rec)	/* in: record */
{
	page_t*	page;

	ut_a(rec);

	page = buf_frame_align(rec);

	ut_a(rec <= page_header_get_ptr(page, PAGE_HEAP_TOP));
	ut_a(rec >= page + PAGE_DATA);

	return(TRUE);
}

/*******************************************************************
Gets the record pointed to by a directory slot. */
UNIV_INLINE
rec_t*
page_dir_slot_get_rec(
/*==================*/
					/* out: pointer to record */
	page_dir_slot_t*	slot)	/* in: directory slot */
{
	return(buf_frame_align(slot) + mach_read_from_2(slot));
}

/*******************************************************************
This is used to set the record offset in a directory slot. */
UNIV_INLINE
void
page_dir_slot_set_rec(
/*==================*/
	page_dir_slot_t* slot,	/* in: directory slot */
	rec_t*		 rec)	/* in: record on the page */
{
	ut_ad(page_rec_check(rec));

	mach_write_to_2(slot, page_offset(rec));
}

/*******************************************************************
Gets the number of records owned by a directory slot. */
UNIV_INLINE
ulint
page_dir_slot_get_n_owned(
/*======================*/
					/* out: number of records */
	page_dir_slot_t*	slot)	/* in: page directory slot */
{
	rec_t*	rec	= page_dir_slot_get_rec(slot);
	return(rec_get_n_owned(rec, page_rec_is_comp(rec)));
}

/*******************************************************************
This is used to set the owned records field of a directory slot. */
UNIV_INLINE
void
page_dir_slot_set_n_owned(
/*======================*/
	page_dir_slot_t*	slot,	/* in: directory slot */
	ulint			n)	/* in: number of records owned
					by the slot */
{
	rec_t*	rec	= page_dir_slot_get_rec(slot);
	rec_set_n_owned(rec, page_rec_is_comp(rec), n);
}

/****************************************************************
Calculates the space reserved for directory slots of a given number of
records. The exact value is a fraction number n * PAGE_DIR_SLOT_SIZE /
PAGE_DIR_SLOT_MIN_N_OWNED, and it is rounded upwards to an integer. */
UNIV_INLINE
ulint
page_dir_calc_reserved_space(
/*=========================*/
	ulint	n_recs)		/* in: number of records */
{
	return((PAGE_DIR_SLOT_SIZE * n_recs + PAGE_DIR_SLOT_MIN_N_OWNED - 1)
	       / PAGE_DIR_SLOT_MIN_N_OWNED);
}

/****************************************************************
Gets the pointer to the next record on the page. */
UNIV_INLINE
rec_t*
page_rec_get_next(
/*==============*/
			/* out: pointer to next record */
	rec_t*	rec)	/* in: pointer to record */
{
	ulint	offs;
	page_t*	page;

	ut_ad(page_rec_check(rec));

	page = page_align(rec);

	offs = rec_get_next_offs(rec, page_is_comp(page));

	if (UNIV_UNLIKELY(offs >= UNIV_PAGE_SIZE)) {
		fprintf(stderr,
			"InnoDB: Next record offset is nonsensical %lu"
			" in record at offset %lu\n"
			"InnoDB: rec address %p, first buffer frame %p\n"
			"InnoDB: buffer pool high end %p, buf fix count %lu\n",
			(ulong)offs, (ulong)(rec - page),
			(void*) rec, (void*) buf_pool->frame_zero,
			(void*) buf_pool->high_end,
			(ulong) buf_block_align(rec)->buf_fix_count);
		buf_page_print(page);

		ut_error;
	}

	if (UNIV_UNLIKELY(offs == 0)) {

		return(NULL);
	}

	return(page + offs);
}

/****************************************************************
Sets the pointer to the next record on the page. */
UNIV_INLINE
void
page_rec_set_next(
/*==============*/
	rec_t*	rec,	/* in: pointer to record, must not be page supremum */
	rec_t*	next)	/* in: pointer to next record, must not be page
			infimum */
{
	page_t*	page;
	ulint	offs;

	ut_ad(page_rec_check(rec));
	ut_ad(!page_rec_is_supremum(rec));
	page = page_align(rec);

	if (next) {
		ut_ad(!page_rec_is_infimum(next));
		ut_ad(page == page_align(next));
		offs = (ulint) (next - page);
	} else {
		offs = 0;
	}

	rec_set_next_offs(rec, page_is_comp(page), offs);
}

/****************************************************************
Gets the pointer to the previous record. */
UNIV_INLINE
rec_t*
page_rec_get_prev(
/*==============*/
			/* out: pointer to previous record */
	rec_t*	rec)	/* in: pointer to record, must not be page
			infimum */
{
	page_dir_slot_t*	slot;
	ulint			slot_no;
	rec_t*			rec2;
	rec_t*			prev_rec = NULL;
	page_t*			page;

	ut_ad(page_rec_check(rec));

	page = page_align(rec);

	ut_ad(!page_rec_is_infimum(rec));

	slot_no = page_dir_find_owner_slot(rec);

	ut_a(slot_no != 0);

	slot = page_dir_get_nth_slot(page, slot_no - 1);

	rec2 = page_dir_slot_get_rec(slot);

	while (rec != rec2) {
		prev_rec = rec2;
		rec2 = page_rec_get_next(rec2);
	}

	ut_a(prev_rec);

	return(prev_rec);
}

/*******************************************************************
Looks for the record which owns the given record. */
UNIV_INLINE
rec_t*
page_rec_find_owner_rec(
/*====================*/
			/* out: the owner record */
	rec_t*	rec)	/* in: the physical record */
{
	ut_ad(page_rec_check(rec));

	if (page_rec_is_comp(rec)) {
		while (rec_get_n_owned(rec, TRUE) == 0) {
			rec = page_rec_get_next(rec);
		}
	} else {
		while (rec_get_n_owned(rec, FALSE) == 0) {
			rec = page_rec_get_next(rec);
		}
	}

	return(rec);
}

/****************************************************************
Returns the sum of the sizes of the records in the record list, excluding
the infimum and supremum records. */
UNIV_INLINE
ulint
page_get_data_size(
/*===============*/
			/* out: data in bytes */
	page_t*	page)	/* in: index page */
{
	ulint	ret;

	ret = (ulint)(page_header_get_field(page, PAGE_HEAP_TOP)
		      - (page_is_comp(page)
			 ? PAGE_NEW_SUPREMUM_END
			 : PAGE_OLD_SUPREMUM_END)
		      - page_header_get_field(page, PAGE_GARBAGE));

	ut_ad(ret < UNIV_PAGE_SIZE);

	return(ret);
}

/*****************************************************************
Calculates free space if a page is emptied. */
UNIV_INLINE
ulint
page_get_free_space_of_empty(
/*=========================*/
				/* out: free space */
	ulint	comp)		/* in: nonzero=compact page layout */
{
	if (UNIV_LIKELY(comp)) {
		return((ulint)(UNIV_PAGE_SIZE
			       - PAGE_NEW_SUPREMUM_END
			       - PAGE_DIR
			       - 2 * PAGE_DIR_SLOT_SIZE));
	}

	return((ulint)(UNIV_PAGE_SIZE
		       - PAGE_OLD_SUPREMUM_END
		       - PAGE_DIR
		       - 2 * PAGE_DIR_SLOT_SIZE));
}

/****************************************************************
Each user record on a page, and also the deleted user records in the heap
takes its size plus the fraction of the dir cell size /
PAGE_DIR_SLOT_MIN_N_OWNED bytes for it. If the sum of these exceeds the
value of page_get_free_space_of_empty, the insert is impossible, otherwise
it is allowed. This function returns the maximum combined size of records
which can be inserted on top of the record heap. */
UNIV_INLINE
ulint
page_get_max_insert_size(
/*=====================*/
			/* out: maximum combined size for inserted records */
	page_t*	page,	/* in: index page */
	ulint	n_recs)	/* in: number of records */
{
	ulint	occupied;
	ulint	free_space;

	if (page_is_comp(page)) {
		occupied = page_header_get_field(page, PAGE_HEAP_TOP)
			- PAGE_NEW_SUPREMUM_END
			+ page_dir_calc_reserved_space(
				n_recs + page_dir_get_n_heap(page) - 2);

		free_space = page_get_free_space_of_empty(TRUE);
	} else {
		occupied = page_header_get_field(page, PAGE_HEAP_TOP)
			- PAGE_OLD_SUPREMUM_END
			+ page_dir_calc_reserved_space(
				n_recs + page_dir_get_n_heap(page) - 2);

		free_space = page_get_free_space_of_empty(FALSE);
	}

	/* Above the 'n_recs +' part reserves directory space for the new
	inserted records; the '- 2' excludes page infimum and supremum
	records */

	if (occupied > free_space) {

		return(0);
	}

	return(free_space - occupied);
}

/****************************************************************
Returns the maximum combined size of records which can be inserted on top
of the record heap if a page is first reorganized. */
UNIV_INLINE
ulint
page_get_max_insert_size_after_reorganize(
/*======================================*/
			/* out: maximum combined size for inserted records */
	page_t*	page,	/* in: index page */
	ulint	n_recs)	/* in: number of records */
{
	ulint	occupied;
	ulint	free_space;

	occupied = page_get_data_size(page)
		+ page_dir_calc_reserved_space(n_recs + page_get_n_recs(page));

	free_space = page_get_free_space_of_empty(page_is_comp(page));

	if (occupied > free_space) {

		return(0);
	}

	return(free_space - occupied);
}

/****************************************************************
Puts a record to free list. */
UNIV_INLINE
void
page_mem_free(
/*==========*/
	page_t*		page,	/* in: index page */
	rec_t*		rec,	/* in: pointer to the (origin of) record */
	const ulint*	offsets)/* in: array returned by rec_get_offsets() */
{
	rec_t*		free;
	ulint		garbage;

	ut_ad(rec_offs_validate(rec, NULL, offsets));
	ut_ad(!rec_offs_comp(offsets) == !page_rec_is_comp(rec));
	free = page_header_get_ptr(page, PAGE_FREE);

	page_rec_set_next(rec, free);
	page_header_set_ptr(page, PAGE_FREE, rec);

#if 0	/* It's better not to destroy the user's data. */

	/* Clear the data bytes of the deleted record in order to improve
	the compression ratio of the page and to make it easier to read
	page dumps in corruption reports.  The extra bytes of the record
	cannot be cleared, because page_mem_alloc() needs them in order
	to determine the size of the deleted record. */
	memset(rec, 0, rec_offs_data_size(offsets));
#endif

	garbage = page_header_get_field(page, PAGE_GARBAGE);

	page_header_set_field(page, PAGE_GARBAGE,
			      garbage + rec_offs_size(offsets));
}

#ifdef UNIV_MATERIALIZE
#undef UNIV_INLINE
#define UNIV_INLINE	UNIV_INLINE_ORIGINAL
#endif