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
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
|
/*****************************************************************************
Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved.
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., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/**************************************************//**
@file include/buf0buf.h
The database buffer pool high-level routines
Created 11/5/1995 Heikki Tuuri
*******************************************************/
#ifndef buf0buf_h
#define buf0buf_h
#include "univ.i"
#include "fil0fil.h"
#include "mtr0types.h"
#include "buf0types.h"
#include "hash0hash.h"
#include "ut0byte.h"
#include "page0types.h"
#ifndef UNIV_HOTBACKUP
#include "os0proc.h"
/** @name Modes for buf_page_get_gen */
/* @{ */
#define BUF_GET 10 /*!< get always */
#define BUF_GET_IF_IN_POOL 11 /*!< get if in pool */
#define BUF_GET_NO_LATCH 14 /*!< get and bufferfix, but
set no latch; we have
separated this case, because
it is error-prone programming
not to set a latch, and it
should be used with care */
/* @} */
/** @name Modes for buf_page_get_known_nowait */
/* @{ */
#define BUF_MAKE_YOUNG 51 /*!< Move the block to the
start of the LRU list if there
is a danger that the block
would drift out of the buffer
pool*/
#define BUF_KEEP_OLD 52 /*!< Preserve the current LRU
position of the block. */
/* @} */
extern buf_pool_t* buf_pool; /*!< The buffer pool of the database */
#ifdef UNIV_DEBUG
extern ibool buf_debug_prints;/*!< If this is set TRUE, the program
prints info whenever read or flush
occurs */
#endif /* UNIV_DEBUG */
extern ulint srv_buf_pool_write_requests; /*!< variable to count write request
issued */
#else /* !UNIV_HOTBACKUP */
extern buf_block_t* back_block1; /*!< first block, for --apply-log */
extern buf_block_t* back_block2; /*!< second block, for page reorganize */
#endif /* !UNIV_HOTBACKUP */
/** Magic value to use instead of checksums when they are disabled */
#define BUF_NO_CHECKSUM_MAGIC 0xDEADBEEFUL
/** @brief States of a control block
@see buf_page_struct
The enumeration values must be 0..7. */
enum buf_page_state {
BUF_BLOCK_ZIP_FREE = 0, /*!< contains a free
compressed page */
BUF_BLOCK_ZIP_PAGE, /*!< contains a clean
compressed page */
BUF_BLOCK_ZIP_DIRTY, /*!< contains a compressed
page that is in the
buf_pool->flush_list */
BUF_BLOCK_NOT_USED, /*!< is in the free list;
must be after the BUF_BLOCK_ZIP_
constants for compressed-only pages
@see buf_block_state_valid() */
BUF_BLOCK_READY_FOR_USE, /*!< when buf_LRU_get_free_block
returns a block, it is in this state */
BUF_BLOCK_FILE_PAGE, /*!< contains a buffered file page */
BUF_BLOCK_MEMORY, /*!< contains some main memory
object */
BUF_BLOCK_REMOVE_HASH /*!< hash index should be removed
before putting to the free list */
};
#ifndef UNIV_HOTBACKUP
/********************************************************************//**
Creates the buffer pool.
@return own: buf_pool object, NULL if not enough memory or error */
UNIV_INTERN
buf_pool_t*
buf_pool_init(void);
/*===============*/
/********************************************************************//**
Frees the buffer pool at shutdown. This must not be invoked before
freeing all mutexes. */
UNIV_INTERN
void
buf_pool_free(void);
/*===============*/
/********************************************************************//**
Drops the adaptive hash index. To prevent a livelock, this function
is only to be called while holding btr_search_latch and while
btr_search_enabled == FALSE. */
UNIV_INTERN
void
buf_pool_drop_hash_index(void);
/*==========================*/
/********************************************************************//**
Relocate a buffer control block. Relocates the block on the LRU list
and in buf_pool->page_hash. Does not relocate bpage->list.
The caller must take care of relocating bpage->list. */
UNIV_INTERN
void
buf_relocate(
/*=========*/
buf_page_t* bpage, /*!< in/out: control block being relocated;
buf_page_get_state(bpage) must be
BUF_BLOCK_ZIP_DIRTY or BUF_BLOCK_ZIP_PAGE */
buf_page_t* dpage) /*!< in/out: destination control block */
__attribute__((nonnull));
/********************************************************************//**
Resizes the buffer pool. */
UNIV_INTERN
void
buf_pool_resize(void);
/*=================*/
/*********************************************************************//**
Gets the current size of buffer buf_pool in bytes.
@return size in bytes */
UNIV_INLINE
ulint
buf_pool_get_curr_size(void);
/*========================*/
/********************************************************************//**
Gets the smallest oldest_modification lsn for any page in the pool. Returns
zero if all modified pages have been flushed to disk.
@return oldest modification in pool, zero if none */
UNIV_INLINE
ib_uint64_t
buf_pool_get_oldest_modification(void);
/*==================================*/
/********************************************************************//**
Allocates a buffer block.
@return own: the allocated block, in state BUF_BLOCK_MEMORY */
UNIV_INLINE
buf_block_t*
buf_block_alloc(
/*============*/
ulint zip_size); /*!< in: compressed page size in bytes,
or 0 if uncompressed tablespace */
/********************************************************************//**
Frees a buffer block which does not contain a file page. */
UNIV_INLINE
void
buf_block_free(
/*===========*/
buf_block_t* block); /*!< in, own: block to be freed */
#endif /* !UNIV_HOTBACKUP */
/*********************************************************************//**
Copies contents of a buffer frame to a given buffer.
@return buf */
UNIV_INLINE
byte*
buf_frame_copy(
/*===========*/
byte* buf, /*!< in: buffer to copy to */
const buf_frame_t* frame); /*!< in: buffer frame */
#ifndef UNIV_HOTBACKUP
/**************************************************************//**
NOTE! The following macros should be used instead of buf_page_get_gen,
to improve debugging. Only values RW_S_LATCH and RW_X_LATCH are allowed
in LA! */
#define buf_page_get(SP, ZS, OF, LA, MTR) buf_page_get_gen(\
SP, ZS, OF, LA, NULL,\
BUF_GET, __FILE__, __LINE__, MTR)
/**************************************************************//**
Use these macros to bufferfix a page with no latching. Remember not to
read the contents of the page unless you know it is safe. Do not modify
the contents of the page! We have separated this case, because it is
error-prone programming not to set a latch, and it should be used
with care. */
#define buf_page_get_with_no_latch(SP, ZS, OF, MTR) buf_page_get_gen(\
SP, ZS, OF, RW_NO_LATCH, NULL,\
BUF_GET_NO_LATCH, __FILE__, __LINE__, MTR)
/**************************************************************//**
NOTE! The following macros should be used instead of
buf_page_optimistic_get_func, to improve debugging. Only values RW_S_LATCH and
RW_X_LATCH are allowed as LA! */
#define buf_page_optimistic_get(LA, BL, MC, MTR) \
buf_page_optimistic_get_func(LA, BL, MC, __FILE__, __LINE__, MTR)
/********************************************************************//**
This is the general function used to get optimistic access to a database
page.
@return TRUE if success */
UNIV_INTERN
ibool
buf_page_optimistic_get_func(
/*=========================*/
ulint rw_latch,/*!< in: RW_S_LATCH, RW_X_LATCH */
buf_block_t* block, /*!< in: guessed block */
ib_uint64_t modify_clock,/*!< in: modify clock value if mode is
..._GUESS_ON_CLOCK */
const char* file, /*!< in: file name */
ulint line, /*!< in: line where called */
mtr_t* mtr); /*!< in: mini-transaction */
/********************************************************************//**
This is used to get access to a known database page, when no waiting can be
done.
@return TRUE if success */
UNIV_INTERN
ibool
buf_page_get_known_nowait(
/*======================*/
ulint rw_latch,/*!< in: RW_S_LATCH, RW_X_LATCH */
buf_block_t* block, /*!< in: the known page */
ulint mode, /*!< in: BUF_MAKE_YOUNG or BUF_KEEP_OLD */
const char* file, /*!< in: file name */
ulint line, /*!< in: line where called */
mtr_t* mtr); /*!< in: mini-transaction */
/*******************************************************************//**
Given a tablespace id and page number tries to get that page. If the
page is not in the buffer pool it is not loaded and NULL is returned.
Suitable for using when holding the kernel mutex. */
UNIV_INTERN
const buf_block_t*
buf_page_try_get_func(
/*==================*/
ulint space_id,/*!< in: tablespace id */
ulint page_no,/*!< in: page number */
const char* file, /*!< in: file name */
ulint line, /*!< in: line where called */
mtr_t* mtr); /*!< in: mini-transaction */
/** Tries to get a page. If the page is not in the buffer pool it is
not loaded. Suitable for using when holding the kernel mutex.
@param space_id in: tablespace id
@param page_no in: page number
@param mtr in: mini-transaction
@return the page if in buffer pool, NULL if not */
#define buf_page_try_get(space_id, page_no, mtr) \
buf_page_try_get_func(space_id, page_no, __FILE__, __LINE__, mtr);
/********************************************************************//**
Get read access to a compressed page (usually of type
FIL_PAGE_TYPE_ZBLOB or FIL_PAGE_TYPE_ZBLOB2).
The page must be released with buf_page_release_zip().
NOTE: the page is not protected by any latch. Mutual exclusion has to
be implemented at a higher level. In other words, all possible
accesses to a given page through this function must be protected by
the same set of mutexes or latches.
@return pointer to the block, or NULL if not compressed */
UNIV_INTERN
buf_page_t*
buf_page_get_zip(
/*=============*/
ulint space, /*!< in: space id */
ulint zip_size,/*!< in: compressed page size */
ulint offset);/*!< in: page number */
/********************************************************************//**
This is the general function used to get access to a database page.
@return pointer to the block or NULL */
UNIV_INTERN
buf_block_t*
buf_page_get_gen(
/*=============*/
ulint space, /*!< in: space id */
ulint zip_size,/*!< in: compressed page size in bytes
or 0 for uncompressed pages */
ulint offset, /*!< in: page number */
ulint rw_latch,/*!< in: RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH */
buf_block_t* guess, /*!< in: guessed block or NULL */
ulint mode, /*!< in: BUF_GET, BUF_GET_IF_IN_POOL,
BUF_GET_NO_LATCH */
const char* file, /*!< in: file name */
ulint line, /*!< in: line where called */
mtr_t* mtr); /*!< in: mini-transaction */
/********************************************************************//**
Initializes a page to the buffer buf_pool. The page is usually not read
from a file even if it cannot be found in the buffer buf_pool. This is one
of the functions which perform to a block a state transition NOT_USED =>
FILE_PAGE (the other is buf_page_get_gen).
@return pointer to the block, page bufferfixed */
UNIV_INTERN
buf_block_t*
buf_page_create(
/*============*/
ulint space, /*!< in: space id */
ulint offset, /*!< in: offset of the page within space in units of
a page */
ulint zip_size,/*!< in: compressed page size, or 0 */
mtr_t* mtr); /*!< in: mini-transaction handle */
#else /* !UNIV_HOTBACKUP */
/********************************************************************//**
Inits a page to the buffer buf_pool, for use in ibbackup --restore. */
UNIV_INTERN
void
buf_page_init_for_backup_restore(
/*=============================*/
ulint space, /*!< in: space id */
ulint offset, /*!< in: offset of the page within space
in units of a page */
ulint zip_size,/*!< in: compressed page size in bytes
or 0 for uncompressed pages */
buf_block_t* block); /*!< in: block to init */
#endif /* !UNIV_HOTBACKUP */
#ifndef UNIV_HOTBACKUP
/********************************************************************//**
Releases a compressed-only page acquired with buf_page_get_zip(). */
UNIV_INLINE
void
buf_page_release_zip(
/*=================*/
buf_page_t* bpage); /*!< in: buffer block */
/********************************************************************//**
Decrements the bufferfix count of a buffer control block and releases
a latch, if specified. */
UNIV_INLINE
void
buf_page_release(
/*=============*/
buf_block_t* block, /*!< in: buffer block */
ulint rw_latch, /*!< in: RW_S_LATCH, RW_X_LATCH,
RW_NO_LATCH */
mtr_t* mtr); /*!< in: mtr */
/********************************************************************//**
Moves a page to the start of the buffer pool LRU list. This high-level
function can be used to prevent an important page from from slipping out of
the buffer pool. */
UNIV_INTERN
void
buf_page_make_young(
/*================*/
buf_page_t* bpage); /*!< in: buffer block of a file page */
/********************************************************************//**
Returns TRUE if the page can be found in the buffer pool hash table.
NOTE that it is possible that the page is not yet read from disk,
though.
@return TRUE if found in the page hash table */
UNIV_INLINE
ibool
buf_page_peek(
/*==========*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: page number */
/********************************************************************//**
Resets the check_index_page_at_flush field of a page if found in the buffer
pool. */
UNIV_INTERN
void
buf_reset_check_index_page_at_flush(
/*================================*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: page number */
#ifdef UNIV_DEBUG_FILE_ACCESSES
/********************************************************************//**
Sets file_page_was_freed TRUE if the page is found in the buffer pool.
This function should be called when we free a file page and want the
debug version to check that it is not accessed any more unless
reallocated.
@return control block if found in page hash table, otherwise NULL */
UNIV_INTERN
buf_page_t*
buf_page_set_file_page_was_freed(
/*=============================*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: page number */
/********************************************************************//**
Sets file_page_was_freed FALSE if the page is found in the buffer pool.
This function should be called when we free a file page and want the
debug version to check that it is not accessed any more unless
reallocated.
@return control block if found in page hash table, otherwise NULL */
UNIV_INTERN
buf_page_t*
buf_page_reset_file_page_was_freed(
/*===============================*/
ulint space, /*!< in: space id */
ulint offset); /*!< in: page number */
#endif /* UNIV_DEBUG_FILE_ACCESSES */
/********************************************************************//**
Reads the freed_page_clock of a buffer block.
@return freed_page_clock */
UNIV_INLINE
ulint
buf_page_get_freed_page_clock(
/*==========================*/
const buf_page_t* bpage) /*!< in: block */
__attribute__((pure));
/********************************************************************//**
Reads the freed_page_clock of a buffer block.
@return freed_page_clock */
UNIV_INLINE
ulint
buf_block_get_freed_page_clock(
/*===========================*/
const buf_block_t* block) /*!< in: block */
__attribute__((pure));
/********************************************************************//**
Recommends a move of a block to the start of the LRU list if there is danger
of dropping from the buffer pool. NOTE: does not reserve the buffer pool
mutex.
@return TRUE if should be made younger */
UNIV_INLINE
ibool
buf_page_peek_if_too_old(
/*=====================*/
const buf_page_t* bpage); /*!< in: block to make younger */
/********************************************************************//**
Returns the current state of is_hashed of a page. FALSE if the page is
not in the pool. NOTE that this operation does not fix the page in the
pool if it is found there.
@return TRUE if page hash index is built in search system */
UNIV_INTERN
ibool
buf_page_peek_if_search_hashed(
/*===========================*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: page number */
/********************************************************************//**
Gets the youngest modification log sequence number for a frame.
Returns zero if not file page or no modification occurred yet.
@return newest modification to page */
UNIV_INLINE
ib_uint64_t
buf_page_get_newest_modification(
/*=============================*/
const buf_page_t* bpage); /*!< in: block containing the
page frame */
/********************************************************************//**
Increments the modify clock of a frame by 1. The caller must (1) own the
buf_pool mutex and block bufferfix count has to be zero, (2) or own an x-lock
on the block. */
UNIV_INLINE
void
buf_block_modify_clock_inc(
/*=======================*/
buf_block_t* block); /*!< in: block */
/********************************************************************//**
Returns the value of the modify clock. The caller must have an s-lock
or x-lock on the block.
@return value */
UNIV_INLINE
ib_uint64_t
buf_block_get_modify_clock(
/*=======================*/
buf_block_t* block); /*!< in: block */
#else /* !UNIV_HOTBACKUP */
# define buf_block_modify_clock_inc(block) ((void) 0)
#endif /* !UNIV_HOTBACKUP */
/********************************************************************//**
Calculates a page checksum which is stored to the page when it is written
to a file. Note that we must be careful to calculate the same value
on 32-bit and 64-bit architectures.
@return checksum */
UNIV_INTERN
ulint
buf_calc_page_new_checksum(
/*=======================*/
const byte* page); /*!< in: buffer page */
/********************************************************************//**
In versions < 4.0.14 and < 4.1.1 there was a bug that the checksum only
looked at the first few bytes of the page. This calculates that old
checksum.
NOTE: we must first store the new formula checksum to
FIL_PAGE_SPACE_OR_CHKSUM before calculating and storing this old checksum
because this takes that field as an input!
@return checksum */
UNIV_INTERN
ulint
buf_calc_page_old_checksum(
/*=======================*/
const byte* page); /*!< in: buffer page */
/********************************************************************//**
Checks if a page is corrupt.
@return TRUE if corrupted */
UNIV_INTERN
ibool
buf_page_is_corrupted(
/*==================*/
const byte* read_buf, /*!< in: a database page */
ulint zip_size); /*!< in: size of compressed page;
0 for uncompressed pages */
#ifndef UNIV_HOTBACKUP
/**********************************************************************//**
Gets the space id, page offset, and byte offset within page of a
pointer pointing to a buffer frame containing a file page. */
UNIV_INLINE
void
buf_ptr_get_fsp_addr(
/*=================*/
const void* ptr, /*!< in: pointer to a buffer frame */
ulint* space, /*!< out: space id */
fil_addr_t* addr); /*!< out: page offset and byte offset */
/**********************************************************************//**
Gets the hash value of a block. This can be used in searches in the
lock hash table.
@return lock hash value */
UNIV_INLINE
ulint
buf_block_get_lock_hash_val(
/*========================*/
const buf_block_t* block) /*!< in: block */
__attribute__((pure));
#ifdef UNIV_DEBUG
/*********************************************************************//**
Finds a block in the buffer pool that points to a
given compressed page.
@return buffer block pointing to the compressed page, or NULL */
UNIV_INTERN
buf_block_t*
buf_pool_contains_zip(
/*==================*/
const void* data); /*!< in: pointer to compressed page */
#endif /* UNIV_DEBUG */
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/*********************************************************************//**
Validates the buffer pool data structure.
@return TRUE */
UNIV_INTERN
ibool
buf_validate(void);
/*==============*/
#endif /* UNIV_DEBUG || UNIV_BUF_DEBUG */
#if defined UNIV_DEBUG_PRINT || defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/*********************************************************************//**
Prints info of the buffer pool data structure. */
UNIV_INTERN
void
buf_print(void);
/*============*/
#endif /* UNIV_DEBUG_PRINT || UNIV_DEBUG || UNIV_BUF_DEBUG */
#endif /* !UNIV_HOTBACKUP */
/********************************************************************//**
Prints a page to stderr. */
UNIV_INTERN
void
buf_page_print(
/*===========*/
const byte* read_buf, /*!< in: a database page */
ulint zip_size); /*!< in: compressed page size, or
0 for uncompressed pages */
/********************************************************************//**
Decompress a block.
@return TRUE if successful */
UNIV_INTERN
ibool
buf_zip_decompress(
/*===============*/
buf_block_t* block, /*!< in/out: block */
ibool check); /*!< in: TRUE=verify the page checksum */
#ifndef UNIV_HOTBACKUP
#ifdef UNIV_DEBUG
/*********************************************************************//**
Returns the number of latched pages in the buffer pool.
@return number of latched pages */
UNIV_INTERN
ulint
buf_get_latched_pages_number(void);
/*==============================*/
#endif /* UNIV_DEBUG */
/*********************************************************************//**
Returns the number of pending buf pool ios.
@return number of pending I/O operations */
UNIV_INTERN
ulint
buf_get_n_pending_ios(void);
/*=======================*/
/*********************************************************************//**
Prints info of the buffer i/o. */
UNIV_INTERN
void
buf_print_io(
/*=========*/
FILE* file); /*!< in: file where to print */
/*********************************************************************//**
Returns the ratio in percents of modified pages in the buffer pool /
database pages in the buffer pool.
@return modified page percentage ratio */
UNIV_INTERN
ulint
buf_get_modified_ratio_pct(void);
/*============================*/
/**********************************************************************//**
Refreshes the statistics used to print per-second averages. */
UNIV_INTERN
void
buf_refresh_io_stats(void);
/*======================*/
/*********************************************************************//**
Asserts that all file pages in the buffer are in a replaceable state.
@return TRUE */
UNIV_INTERN
ibool
buf_all_freed(void);
/*===============*/
/*********************************************************************//**
Checks that there currently are no pending i/o-operations for the buffer
pool.
@return TRUE if there is no pending i/o */
UNIV_INTERN
ibool
buf_pool_check_no_pending_io(void);
/*==============================*/
/*********************************************************************//**
Invalidates the file pages in the buffer pool when an archive recovery is
completed. All the file pages buffered must be in a replaceable state when
this function is called: not latched and not modified. */
UNIV_INTERN
void
buf_pool_invalidate(void);
/*=====================*/
#endif /* !UNIV_HOTBACKUP */
/*========================================================================
--------------------------- LOWER LEVEL ROUTINES -------------------------
=========================================================================*/
#ifdef UNIV_SYNC_DEBUG
/*********************************************************************//**
Adds latch level info for the rw-lock protecting the buffer frame. This
should be called in the debug version after a successful latching of a
page if we know the latching order level of the acquired latch. */
UNIV_INLINE
void
buf_block_dbg_add_level(
/*====================*/
buf_block_t* block, /*!< in: buffer page
where we have acquired latch */
ulint level); /*!< in: latching order level */
#else /* UNIV_SYNC_DEBUG */
# define buf_block_dbg_add_level(block, level) /* nothing */
#endif /* UNIV_SYNC_DEBUG */
/*********************************************************************//**
Gets the state of a block.
@return state */
UNIV_INLINE
enum buf_page_state
buf_page_get_state(
/*===============*/
const buf_page_t* bpage); /*!< in: pointer to the control block */
/*********************************************************************//**
Gets the state of a block.
@return state */
UNIV_INLINE
enum buf_page_state
buf_block_get_state(
/*================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Sets the state of a block. */
UNIV_INLINE
void
buf_page_set_state(
/*===============*/
buf_page_t* bpage, /*!< in/out: pointer to control block */
enum buf_page_state state); /*!< in: state */
/*********************************************************************//**
Sets the state of a block. */
UNIV_INLINE
void
buf_block_set_state(
/*================*/
buf_block_t* block, /*!< in/out: pointer to control block */
enum buf_page_state state); /*!< in: state */
/*********************************************************************//**
Determines if a block is mapped to a tablespace.
@return TRUE if mapped */
UNIV_INLINE
ibool
buf_page_in_file(
/*=============*/
const buf_page_t* bpage) /*!< in: pointer to control block */
__attribute__((pure));
#ifndef UNIV_HOTBACKUP
/*********************************************************************//**
Determines if a block should be on unzip_LRU list.
@return TRUE if block belongs to unzip_LRU */
UNIV_INLINE
ibool
buf_page_belongs_to_unzip_LRU(
/*==========================*/
const buf_page_t* bpage) /*!< in: pointer to control block */
__attribute__((pure));
/*********************************************************************//**
Determine the approximate LRU list position of a block.
@return LRU list position */
UNIV_INLINE
ulint
buf_page_get_LRU_position(
/*======================*/
const buf_page_t* bpage) /*!< in: control block */
__attribute__((pure));
/*********************************************************************//**
Gets the mutex of a block.
@return pointer to mutex protecting bpage */
UNIV_INLINE
mutex_t*
buf_page_get_mutex(
/*===============*/
const buf_page_t* bpage) /*!< in: pointer to control block */
__attribute__((pure));
/*********************************************************************//**
Get the flush type of a page.
@return flush type */
UNIV_INLINE
enum buf_flush
buf_page_get_flush_type(
/*====================*/
const buf_page_t* bpage) /*!< in: buffer page */
__attribute__((pure));
/*********************************************************************//**
Set the flush type of a page. */
UNIV_INLINE
void
buf_page_set_flush_type(
/*====================*/
buf_page_t* bpage, /*!< in: buffer page */
enum buf_flush flush_type); /*!< in: flush type */
/*********************************************************************//**
Map a block to a file page. */
UNIV_INLINE
void
buf_block_set_file_page(
/*====================*/
buf_block_t* block, /*!< in/out: pointer to control block */
ulint space, /*!< in: tablespace id */
ulint page_no);/*!< in: page number */
/*********************************************************************//**
Gets the io_fix state of a block.
@return io_fix state */
UNIV_INLINE
enum buf_io_fix
buf_page_get_io_fix(
/*================*/
const buf_page_t* bpage) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the io_fix state of a block.
@return io_fix state */
UNIV_INLINE
enum buf_io_fix
buf_block_get_io_fix(
/*================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Sets the io_fix state of a block. */
UNIV_INLINE
void
buf_page_set_io_fix(
/*================*/
buf_page_t* bpage, /*!< in/out: control block */
enum buf_io_fix io_fix);/*!< in: io_fix state */
/*********************************************************************//**
Sets the io_fix state of a block. */
UNIV_INLINE
void
buf_block_set_io_fix(
/*=================*/
buf_block_t* block, /*!< in/out: control block */
enum buf_io_fix io_fix);/*!< in: io_fix state */
/********************************************************************//**
Determine if a buffer block can be relocated in memory. The block
can be dirty, but it must not be I/O-fixed or bufferfixed. */
UNIV_INLINE
ibool
buf_page_can_relocate(
/*==================*/
const buf_page_t* bpage) /*!< control block being relocated */
__attribute__((pure));
/*********************************************************************//**
Determine if a block has been flagged old.
@return TRUE if old */
UNIV_INLINE
ibool
buf_page_is_old(
/*============*/
const buf_page_t* bpage) /*!< in: control block */
__attribute__((pure));
/*********************************************************************//**
Flag a block old. */
UNIV_INLINE
void
buf_page_set_old(
/*=============*/
buf_page_t* bpage, /*!< in/out: control block */
ibool old); /*!< in: old */
/*********************************************************************//**
Determine if a block has been accessed in the buffer pool.
@return TRUE if accessed */
UNIV_INLINE
ibool
buf_page_is_accessed(
/*=================*/
const buf_page_t* bpage) /*!< in: control block */
__attribute__((pure));
/*********************************************************************//**
Flag a block accessed. */
UNIV_INLINE
void
buf_page_set_accessed(
/*==================*/
buf_page_t* bpage, /*!< in/out: control block */
ibool accessed); /*!< in: accessed */
/*********************************************************************//**
Gets the buf_block_t handle of a buffered file block if an uncompressed
page frame exists, or NULL.
@return control block, or NULL */
UNIV_INLINE
buf_block_t*
buf_page_get_block(
/*===============*/
buf_page_t* bpage) /*!< in: control block, or NULL */
__attribute__((pure));
#endif /* !UNIV_HOTBACKUP */
#ifdef UNIV_DEBUG
/*********************************************************************//**
Gets a pointer to the memory frame of a block.
@return pointer to the frame */
UNIV_INLINE
buf_frame_t*
buf_block_get_frame(
/*================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
#else /* UNIV_DEBUG */
# define buf_block_get_frame(block) (block)->frame
#endif /* UNIV_DEBUG */
/*********************************************************************//**
Gets the space id of a block.
@return space id */
UNIV_INLINE
ulint
buf_page_get_space(
/*===============*/
const buf_page_t* bpage) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the space id of a block.
@return space id */
UNIV_INLINE
ulint
buf_block_get_space(
/*================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the page number of a block.
@return page number */
UNIV_INLINE
ulint
buf_page_get_page_no(
/*=================*/
const buf_page_t* bpage) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the page number of a block.
@return page number */
UNIV_INLINE
ulint
buf_block_get_page_no(
/*==================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the compressed page size of a block.
@return compressed page size, or 0 */
UNIV_INLINE
ulint
buf_page_get_zip_size(
/*==================*/
const buf_page_t* bpage) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the compressed page size of a block.
@return compressed page size, or 0 */
UNIV_INLINE
ulint
buf_block_get_zip_size(
/*===================*/
const buf_block_t* block) /*!< in: pointer to the control block */
__attribute__((pure));
/*********************************************************************//**
Gets the compressed page descriptor corresponding to an uncompressed page
if applicable. */
#define buf_block_get_page_zip(block) \
(UNIV_LIKELY_NULL((block)->page.zip.data) ? &(block)->page.zip : NULL)
#ifndef UNIV_HOTBACKUP
/*******************************************************************//**
Gets the block to whose frame the pointer is pointing to.
@return pointer to block, never NULL */
UNIV_INTERN
buf_block_t*
buf_block_align(
/*============*/
const byte* ptr); /*!< in: pointer to a frame */
/********************************************************************//**
Find out if a pointer belongs to a buf_block_t. It can be a pointer to
the buf_block_t itself or a member of it
@return TRUE if ptr belongs to a buf_block_t struct */
UNIV_INTERN
ibool
buf_pointer_is_block_field(
/*=======================*/
const void* ptr); /*!< in: pointer not
dereferenced */
/** Find out if a pointer corresponds to a buf_block_t::mutex.
@param m in: mutex candidate
@return TRUE if m is a buf_block_t::mutex */
#define buf_pool_is_block_mutex(m) \
buf_pointer_is_block_field((const void*)(m))
/** Find out if a pointer corresponds to a buf_block_t::lock.
@param l in: rw-lock candidate
@return TRUE if l is a buf_block_t::lock */
#define buf_pool_is_block_lock(l) \
buf_pointer_is_block_field((const void*)(l))
#if defined UNIV_DEBUG || defined UNIV_ZIP_DEBUG
/*********************************************************************//**
Gets the compressed page descriptor corresponding to an uncompressed page
if applicable.
@return compressed page descriptor, or NULL */
UNIV_INLINE
const page_zip_des_t*
buf_frame_get_page_zip(
/*===================*/
const byte* ptr); /*!< in: pointer to the page */
#endif /* UNIV_DEBUG || UNIV_ZIP_DEBUG */
/********************************************************************//**
Function which inits a page for read to the buffer buf_pool. If the page is
(1) already in buf_pool, or
(2) if we specify to read only ibuf pages and the page is not an ibuf page, or
(3) if the space is deleted or being deleted,
then this function does nothing.
Sets the io_fix flag to BUF_IO_READ and sets a non-recursive exclusive lock
on the buffer frame. The io-handler must take care that the flag is cleared
and the lock released later.
@return pointer to the block or NULL */
UNIV_INTERN
buf_page_t*
buf_page_init_for_read(
/*===================*/
ulint* err, /*!< out: DB_SUCCESS or DB_TABLESPACE_DELETED */
ulint mode, /*!< in: BUF_READ_IBUF_PAGES_ONLY, ... */
ulint space, /*!< in: space id */
ulint zip_size,/*!< in: compressed page size, or 0 */
ibool unzip, /*!< in: TRUE=request uncompressed page */
ib_int64_t tablespace_version,/*!< in: prevents reading from a wrong
version of the tablespace in case we have done
DISCARD + IMPORT */
ulint offset);/*!< in: page number */
/********************************************************************//**
Completes an asynchronous read or write request of a file page to or from
the buffer pool. */
UNIV_INTERN
void
buf_page_io_complete(
/*=================*/
buf_page_t* bpage); /*!< in: pointer to the block in question */
/********************************************************************//**
Calculates a folded value of a file page address to use in the page hash
table.
@return the folded value */
UNIV_INLINE
ulint
buf_page_address_fold(
/*==================*/
ulint space, /*!< in: space id */
ulint offset) /*!< in: offset of the page within space */
__attribute__((const));
/******************************************************************//**
Returns the control block of a file page, NULL if not found.
@return block, NULL if not found */
UNIV_INLINE
buf_page_t*
buf_page_hash_get(
/*==============*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: offset of the page within space */
/******************************************************************//**
Returns the control block of a file page, NULL if not found
or an uncompressed page frame does not exist.
@return block, NULL if not found */
UNIV_INLINE
buf_block_t*
buf_block_hash_get(
/*===============*/
ulint space, /*!< in: space id */
ulint offset);/*!< in: offset of the page within space */
/*******************************************************************//**
Increments the pool clock by one and returns its new value. Remember that
in the 32 bit version the clock wraps around at 4 billion!
@return new clock value */
UNIV_INLINE
ulint
buf_pool_clock_tic(void);
/*====================*/
/*********************************************************************//**
Gets the current length of the free list of buffer blocks.
@return length of the free list */
UNIV_INTERN
ulint
buf_get_free_list_len(void);
/*=======================*/
#endif /* !UNIV_HOTBACKUP */
/** The common buffer control block structure
for compressed and uncompressed frames */
struct buf_page_struct{
/** @name General fields
None of these bit-fields must be modified without holding
buf_page_get_mutex() [buf_block_struct::mutex or
buf_pool_zip_mutex], since they can be stored in the same
machine word. Some of these fields are additionally protected
by buf_pool_mutex. */
/* @{ */
unsigned space:32; /*!< tablespace id; also protected
by buf_pool_mutex. */
unsigned offset:32; /*!< page number; also protected
by buf_pool_mutex. */
unsigned state:3; /*!< state of the control block; also
protected by buf_pool_mutex.
State transitions from
BUF_BLOCK_READY_FOR_USE to
BUF_BLOCK_MEMORY need not be
protected by buf_page_get_mutex().
@see enum buf_page_state */
#ifndef UNIV_HOTBACKUP
unsigned flush_type:2; /*!< if this block is currently being
flushed to disk, this tells the
flush_type.
@see enum buf_flush */
unsigned accessed:1; /*!< TRUE if the page has been accessed
while in the buffer pool: read-ahead
may read in pages which have not been
accessed yet; a thread is allowed to
read this for heuristic purposes
without holding any mutex or latch */
unsigned io_fix:2; /*!< type of pending I/O operation;
also protected by buf_pool_mutex
@see enum buf_io_fix */
unsigned buf_fix_count:24;/*!< count of how manyfold this block
is currently bufferfixed */
/* @} */
#endif /* !UNIV_HOTBACKUP */
page_zip_des_t zip; /*!< compressed page; zip.data
(but not the data it points to) is
also protected by buf_pool_mutex */
#ifndef UNIV_HOTBACKUP
buf_page_t* hash; /*!< node used in chaining to
buf_pool->page_hash or
buf_pool->zip_hash */
#ifdef UNIV_DEBUG
ibool in_page_hash; /*!< TRUE if in buf_pool->page_hash */
ibool in_zip_hash; /*!< TRUE if in buf_pool->zip_hash */
#endif /* UNIV_DEBUG */
/** @name Page flushing fields
All these are protected by buf_pool_mutex. */
/* @{ */
UT_LIST_NODE_T(buf_page_t) list;
/*!< based on state, this is a
list node, protected only by
buf_pool_mutex, in one of the
following lists in buf_pool:
- BUF_BLOCK_NOT_USED: free
- BUF_BLOCK_FILE_PAGE: flush_list
- BUF_BLOCK_ZIP_DIRTY: flush_list
- BUF_BLOCK_ZIP_PAGE: zip_clean
- BUF_BLOCK_ZIP_FREE: zip_free[] */
#ifdef UNIV_DEBUG
ibool in_flush_list; /*!< TRUE if in buf_pool->flush_list;
when buf_pool_mutex is free, the
following should hold: in_flush_list
== (state == BUF_BLOCK_FILE_PAGE
|| state == BUF_BLOCK_ZIP_DIRTY) */
ibool in_free_list; /*!< TRUE if in buf_pool->free; when
buf_pool_mutex is free, the following
should hold: in_free_list
== (state == BUF_BLOCK_NOT_USED) */
#endif /* UNIV_DEBUG */
ib_uint64_t newest_modification;
/*!< log sequence number of
the youngest modification to
this block, zero if not
modified */
ib_uint64_t oldest_modification;
/*!< log sequence number of
the START of the log entry
written of the oldest
modification to this block
which has not yet been flushed
on disk; zero if all
modifications are on disk */
/* @} */
/** @name LRU replacement algorithm fields
These fields are protected by buf_pool_mutex only (not
buf_pool_zip_mutex or buf_block_struct::mutex). */
/* @{ */
UT_LIST_NODE_T(buf_page_t) LRU;
/*!< node of the LRU list */
#ifdef UNIV_DEBUG
ibool in_LRU_list; /*!< TRUE if the page is in
the LRU list; used in
debugging */
#endif /* UNIV_DEBUG */
unsigned old:1; /*!< TRUE if the block is in the old
blocks in the LRU list */
unsigned LRU_position:31;/*!< value which monotonically
decreases (or may stay
constant if old==TRUE) toward
the end of the LRU list, if
buf_pool->ulint_clock has not
wrapped around: NOTE that this
value can only be used in
heuristic algorithms, because
of the possibility of a
wrap-around! */
unsigned freed_page_clock:32;/*!< the value of
buf_pool->freed_page_clock
when this block was the last
time put to the head of the
LRU list; a thread is allowed
to read this for heuristic
purposes without holding any
mutex or latch */
/* @} */
# ifdef UNIV_DEBUG_FILE_ACCESSES
ibool file_page_was_freed;
/*!< this is set to TRUE when fsp
frees a page in buffer pool */
# endif /* UNIV_DEBUG_FILE_ACCESSES */
#endif /* !UNIV_HOTBACKUP */
};
/** The buffer control block structure */
struct buf_block_struct{
/** @name General fields */
/* @{ */
buf_page_t page; /*!< page information; this must
be the first field, so that
buf_pool->page_hash can point
to buf_page_t or buf_block_t */
byte* frame; /*!< pointer to buffer frame which
is of size UNIV_PAGE_SIZE, and
aligned to an address divisible by
UNIV_PAGE_SIZE */
#ifndef UNIV_HOTBACKUP
UT_LIST_NODE_T(buf_block_t) unzip_LRU;
/*!< node of the decompressed LRU list;
a block is in the unzip_LRU list
if page.state == BUF_BLOCK_FILE_PAGE
and page.zip.data != NULL */
#ifdef UNIV_DEBUG
ibool in_unzip_LRU_list;/*!< TRUE if the page is in the
decompressed LRU list;
used in debugging */
#endif /* UNIV_DEBUG */
mutex_t mutex; /*!< mutex protecting this block:
state (also protected by the buffer
pool mutex), io_fix, buf_fix_count,
and accessed; we introduce this new
mutex in InnoDB-5.1 to relieve
contention on the buffer pool mutex */
rw_lock_t lock; /*!< read-write lock of the buffer
frame */
unsigned lock_hash_val:32;/*!< hashed value of the page address
in the record lock hash table */
unsigned check_index_page_at_flush:1;
/*!< TRUE if we know that this is
an index page, and want the database
to check its consistency before flush;
note that there may be pages in the
buffer pool which are index pages,
but this flag is not set because
we do not keep track of all pages */
/* @} */
/** @name Optimistic search field */
/* @{ */
ib_uint64_t modify_clock; /*!< this clock is incremented every
time a pointer to a record on the
page may become obsolete; this is
used in the optimistic cursor
positioning: if the modify clock has
not changed, we know that the pointer
is still valid; this field may be
changed if the thread (1) owns the
pool mutex and the page is not
bufferfixed, or (2) the thread has an
x-latch on the block */
/* @} */
/** @name Hash search fields (unprotected)
NOTE that these fields are NOT protected by any semaphore! */
/* @{ */
ulint n_hash_helps; /*!< counter which controls building
of a new hash index for the page */
ulint n_fields; /*!< recommended prefix length for hash
search: number of full fields */
ulint n_bytes; /*!< recommended prefix: number of bytes
in an incomplete field */
ibool left_side; /*!< TRUE or FALSE, depending on
whether the leftmost record of several
records with the same prefix should be
indexed in the hash index */
/* @} */
/** @name Hash search fields
These 6 fields may only be modified when we have
an x-latch on btr_search_latch AND
- we are holding an s-latch or x-latch on buf_block_struct::lock or
- we know that buf_block_struct::buf_fix_count == 0.
An exception to this is when we init or create a page
in the buffer pool in buf0buf.c. */
/* @{ */
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
ulint n_pointers; /*!< used in debugging: the number of
pointers in the adaptive hash index
pointing to this frame */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
unsigned is_hashed:1; /*!< TRUE if hash index has
already been built on this
page; note that it does not
guarantee that the index is
complete, though: there may
have been hash collisions,
record deletions, etc. */
unsigned curr_n_fields:10;/*!< prefix length for hash indexing:
number of full fields */
unsigned curr_n_bytes:15;/*!< number of bytes in hash
indexing */
unsigned curr_left_side:1;/*!< TRUE or FALSE in hash indexing */
dict_index_t* index; /*!< Index for which the adaptive
hash index has been created. */
/* @} */
# ifdef UNIV_SYNC_DEBUG
/** @name Debug fields */
/* @{ */
rw_lock_t debug_latch; /*!< in the debug version, each thread
which bufferfixes the block acquires
an s-latch here; so we can use the
debug utilities in sync0rw */
/* @} */
# endif
#endif /* !UNIV_HOTBACKUP */
};
/** Check if a buf_block_t object is in a valid state
@param block buffer block
@return TRUE if valid */
#define buf_block_state_valid(block) \
(buf_block_get_state(block) >= BUF_BLOCK_NOT_USED \
&& (buf_block_get_state(block) <= BUF_BLOCK_REMOVE_HASH))
#ifndef UNIV_HOTBACKUP
/**********************************************************************//**
Compute the hash fold value for blocks in buf_pool->zip_hash. */
/* @{ */
#define BUF_POOL_ZIP_FOLD_PTR(ptr) ((ulint) (ptr) / UNIV_PAGE_SIZE)
#define BUF_POOL_ZIP_FOLD(b) BUF_POOL_ZIP_FOLD_PTR((b)->frame)
#define BUF_POOL_ZIP_FOLD_BPAGE(b) BUF_POOL_ZIP_FOLD((buf_block_t*) (b))
/* @} */
/** @brief The buffer pool structure.
NOTE! The definition appears here only for other modules of this
directory (buf) to see it. Do not use from outside! */
struct buf_pool_struct{
/** @name General fields */
/* @{ */
ulint n_chunks; /*!< number of buffer pool chunks */
buf_chunk_t* chunks; /*!< buffer pool chunks */
ulint curr_size; /*!< current pool size in pages */
hash_table_t* page_hash; /*!< hash table of buf_page_t or
buf_block_t file pages,
buf_page_in_file() == TRUE,
indexed by (space_id, offset) */
hash_table_t* zip_hash; /*!< hash table of buf_block_t blocks
whose frames are allocated to the
zip buddy system,
indexed by block->frame */
ulint n_pend_reads; /*!< number of pending read operations */
ulint n_pend_unzip; /*!< number of pending decompressions */
time_t last_printout_time; /*!< when buf_print was last time
called */
ulint n_pages_read; /*!< number read operations */
ulint n_pages_written;/*!< number write operations */
ulint n_pages_created;/*!< number of pages created
in the pool with no read */
ulint n_page_gets; /*!< number of page gets performed;
also successful searches through
the adaptive hash index are
counted as page gets; this field
is NOT protected by the buffer
pool mutex */
ulint n_page_gets_old;/*!< n_page_gets when buf_print was
last time called: used to calculate
hit rate */
ulint n_pages_read_old;/*!< n_pages_read when buf_print was
last time called */
ulint n_pages_written_old;/*!< number write operations */
ulint n_pages_created_old;/*!< number of pages created in
the pool with no read */
/* @} */
/** @name Page flushing algorithm fields */
/* @{ */
UT_LIST_BASE_NODE_T(buf_page_t) flush_list;
/*!< base node of the modified block
list */
ibool init_flush[BUF_FLUSH_N_TYPES];
/*!< this is TRUE when a flush of the
given type is being initialized */
ulint n_flush[BUF_FLUSH_N_TYPES];
/*!< this is the number of pending
writes in the given flush type */
os_event_t no_flush[BUF_FLUSH_N_TYPES];
/*!< this is in the set state
when there is no flush batch
of the given type running */
ulint ulint_clock; /*!< a sequence number used to count
time. NOTE! This counter wraps
around at 4 billion (if ulint ==
32 bits)! */
ulint freed_page_clock;/*!< a sequence number used
to count the number of buffer
blocks removed from the end of
the LRU list; NOTE that this
counter may wrap around at 4
billion! A thread is allowed
to read this for heuristic
purposes without holding any
mutex or latch */
ulint LRU_flush_ended;/*!< when an LRU flush ends for a page,
this is incremented by one; this is
set to zero when a buffer block is
allocated */
/* @} */
/** @name LRU replacement algorithm fields */
/* @{ */
UT_LIST_BASE_NODE_T(buf_page_t) free;
/*!< base node of the free
block list */
UT_LIST_BASE_NODE_T(buf_page_t) LRU;
/*!< base node of the LRU list */
buf_page_t* LRU_old; /*!< pointer to the about 3/8 oldest
blocks in the LRU list; NULL if LRU
length less than BUF_LRU_OLD_MIN_LEN;
NOTE: when LRU_old != NULL, its length
should always equal LRU_old_len */
ulint LRU_old_len; /*!< length of the LRU list from
the block to which LRU_old points
onward, including that block;
see buf0lru.c for the restrictions
on this value; not defined if
LRU_old == NULL;
NOTE: LRU_old_len must be adjusted
whenever LRU_old shrinks or grows! */
UT_LIST_BASE_NODE_T(buf_block_t) unzip_LRU;
/*!< base node of the
unzip_LRU list */
/* @} */
/** @name Buddy allocator fields
The buddy allocator is used for allocating compressed page
frames and buf_page_t descriptors of blocks that exist
in the buffer pool only in compressed form. */
/* @{ */
UT_LIST_BASE_NODE_T(buf_page_t) zip_clean;
/*!< unmodified compressed pages */
UT_LIST_BASE_NODE_T(buf_page_t) zip_free[BUF_BUDDY_SIZES];
/*!< buddy free lists */
#if BUF_BUDDY_HIGH != UNIV_PAGE_SIZE
# error "BUF_BUDDY_HIGH != UNIV_PAGE_SIZE"
#endif
#if BUF_BUDDY_LOW > PAGE_ZIP_MIN_SIZE
# error "BUF_BUDDY_LOW > PAGE_ZIP_MIN_SIZE"
#endif
/* @} */
};
/** mutex protecting the buffer pool struct and control blocks, except the
read-write lock in them */
extern mutex_t buf_pool_mutex;
/** mutex protecting the control blocks of compressed-only pages
(of type buf_page_t, not buf_block_t) */
extern mutex_t buf_pool_zip_mutex;
/** @name Accessors for buf_pool_mutex.
Use these instead of accessing buf_pool_mutex directly. */
/* @{ */
/** Test if buf_pool_mutex is owned. */
#define buf_pool_mutex_own() mutex_own(&buf_pool_mutex)
/** Acquire the buffer pool mutex. */
#define buf_pool_mutex_enter() do { \
ut_ad(!mutex_own(&buf_pool_zip_mutex)); \
mutex_enter(&buf_pool_mutex); \
} while (0)
#if defined UNIV_DEBUG || defined UNIV_BUF_DEBUG
/** Flag to forbid the release of the buffer pool mutex.
Protected by buf_pool_mutex. */
extern ulint buf_pool_mutex_exit_forbidden;
/** Forbid the release of the buffer pool mutex. */
# define buf_pool_mutex_exit_forbid() do { \
ut_ad(buf_pool_mutex_own()); \
buf_pool_mutex_exit_forbidden++; \
} while (0)
/** Allow the release of the buffer pool mutex. */
# define buf_pool_mutex_exit_allow() do { \
ut_ad(buf_pool_mutex_own()); \
ut_a(buf_pool_mutex_exit_forbidden); \
buf_pool_mutex_exit_forbidden--; \
} while (0)
/** Release the buffer pool mutex. */
# define buf_pool_mutex_exit() do { \
ut_a(!buf_pool_mutex_exit_forbidden); \
mutex_exit(&buf_pool_mutex); \
} while (0)
#else
/** Forbid the release of the buffer pool mutex. */
# define buf_pool_mutex_exit_forbid() ((void) 0)
/** Allow the release of the buffer pool mutex. */
# define buf_pool_mutex_exit_allow() ((void) 0)
/** Release the buffer pool mutex. */
# define buf_pool_mutex_exit() mutex_exit(&buf_pool_mutex)
#endif
#endif /* !UNIV_HOTBACKUP */
/* @} */
/**********************************************************************
Let us list the consistency conditions for different control block states.
NOT_USED: is in free list, not in LRU list, not in flush list, nor
page hash table
READY_FOR_USE: is not in free list, LRU list, or flush list, nor page
hash table
MEMORY: is not in free list, LRU list, or flush list, nor page
hash table
FILE_PAGE: space and offset are defined, is in page hash table
if io_fix == BUF_IO_WRITE,
pool: no_flush[flush_type] is in reset state,
pool: n_flush[flush_type] > 0
(1) if buf_fix_count == 0, then
is in LRU list, not in free list
is in flush list,
if and only if oldest_modification > 0
is x-locked,
if and only if io_fix == BUF_IO_READ
is s-locked,
if and only if io_fix == BUF_IO_WRITE
(2) if buf_fix_count > 0, then
is not in LRU list, not in free list
is in flush list,
if and only if oldest_modification > 0
if io_fix == BUF_IO_READ,
is x-locked
if io_fix == BUF_IO_WRITE,
is s-locked
State transitions:
NOT_USED => READY_FOR_USE
READY_FOR_USE => MEMORY
READY_FOR_USE => FILE_PAGE
MEMORY => NOT_USED
FILE_PAGE => NOT_USED NOTE: This transition is allowed if and only if
(1) buf_fix_count == 0,
(2) oldest_modification == 0, and
(3) io_fix == 0.
*/
#ifndef UNIV_NONINL
#include "buf0buf.ic"
#endif
#endif
|