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
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
|
#ifndef SQL_SELECT_INCLUDED
#define SQL_SELECT_INCLUDED
/* Copyright (c) 2000, 2013, Oracle and/or its affiliates.
Copyright (c) 2008, 2017, 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 St, Fifth Floor, Boston, MA 02110-1301 USA */
/**
@file
@brief
classes to use when handling where clause
*/
#ifdef USE_PRAGMA_INTERFACE
#pragma interface /* gcc class implementation */
#endif
#include "procedure.h"
#include "sql_array.h" /* Array */
#include "records.h" /* READ_RECORD */
#include "opt_range.h" /* SQL_SELECT, QUICK_SELECT_I */
#include "filesort.h"
typedef struct st_join_table JOIN_TAB;
/* Values in optimize */
#define KEY_OPTIMIZE_EXISTS 1U
#define KEY_OPTIMIZE_REF_OR_NULL 2U
#define KEY_OPTIMIZE_EQ 4U
inline uint get_hash_join_key_no() { return MAX_KEY; }
inline bool is_hash_join_key_no(uint key) { return key == MAX_KEY; }
typedef struct keyuse_t {
TABLE *table;
Item *val; /**< or value if no field */
table_map used_tables;
uint key, keypart, optimize;
key_part_map keypart_map;
ha_rows ref_table_rows;
/**
If true, the comparison this value was created from will not be
satisfied if val has NULL 'value'.
*/
bool null_rejecting;
/*
!NULL - This KEYUSE was created from an equality that was wrapped into
an Item_func_trig_cond. This means the equality (and validity of
this KEYUSE element) can be turned on and off. The on/off state
is indicted by the pointed value:
*cond_guard == TRUE <=> equality condition is on
*cond_guard == FALSE <=> equality condition is off
NULL - Otherwise (the source equality can't be turned off)
*/
bool *cond_guard;
/*
0..64 <=> This was created from semi-join IN-equality # sj_pred_no.
MAX_UINT Otherwise
*/
uint sj_pred_no;
/*
If this is NULL than KEYUSE is always enabled.
Otherwise it points to the enabling flag for this keyuse (true <=> enabled)
*/
bool *validity_ref;
bool is_for_hash_join() { return is_hash_join_key_no(key); }
} KEYUSE;
struct KEYUSE_EXT: public KEYUSE
{
/*
This keyuse can be used only when the partial join being extended
contains the tables from this table map
*/
table_map needed_in_prefix;
/* The enabling flag for keyuses usable for splitting */
bool validity_var;
};
/// Used when finding key fields
struct KEY_FIELD {
Field *field;
Item_bool_func *cond;
Item *val; ///< May be empty if diff constant
uint level;
uint optimize;
bool eq_func;
/**
If true, the condition this struct represents will not be satisfied
when val IS NULL.
*/
bool null_rejecting;
bool *cond_guard; /* See KEYUSE::cond_guard */
uint sj_pred_no; /* See KEYUSE::sj_pred_no */
};
#define NO_KEYPART ((uint)(-1))
class store_key;
const int NO_REF_PART= uint(-1);
typedef struct st_table_ref
{
bool key_err;
/** True if something was read into buffer in join_read_key. */
bool has_record;
uint key_parts; ///< num of ...
uint key_length; ///< length of key_buff
int key; ///< key no
uchar *key_buff; ///< value to look for with key
uchar *key_buff2; ///< key_buff+key_length
store_key **key_copy; //
/*
Bitmap of key parts which refer to constants. key_copy only has copiers for
non-const key parts.
*/
key_part_map const_ref_part_map;
Item **items; ///< val()'s for each keypart
/*
Array of pointers to trigger variables. Some/all of the pointers may be
NULL. The ref access can be used iff
for each used key part i, (!cond_guards[i] || *cond_guards[i])
This array is used by subquery code. The subquery code may inject
triggered conditions, i.e. conditions that can be 'switched off'. A ref
access created from such condition is not valid when at least one of the
underlying conditions is switched off (see subquery code for more details)
*/
bool **cond_guards;
/**
(null_rejecting & (1<<i)) means the condition is '=' and no matching
rows will be produced if items[i] IS NULL (see add_not_null_conds())
*/
key_part_map null_rejecting;
table_map depend_map; ///< Table depends on these tables.
/* null byte position in the key_buf. Used for REF_OR_NULL optimization */
uchar *null_ref_key;
/*
ref_or_null optimization: number of key part that alternates between
the lookup value or NULL (there's only one such part).
If we're not using ref_or_null, the value is NO_REF_PART
*/
uint null_ref_part;
/*
The number of times the record associated with this key was used
in the join.
*/
ha_rows use_count;
/*
TRUE <=> disable the "cache" as doing lookup with the same key value may
produce different results (because of Index Condition Pushdown)
*/
bool disable_cache;
bool tmp_table_index_lookup_init(THD *thd, KEY *tmp_key, Item_iterator &it,
bool value, uint skip= 0);
bool is_access_triggered();
} TABLE_REF;
/*
The structs which holds the join connections and join states
*/
enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF,
JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL,
JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE,
JT_HASH, JT_HASH_RANGE, JT_HASH_NEXT, JT_HASH_INDEX_MERGE};
class JOIN;
enum enum_nested_loop_state
{
NESTED_LOOP_KILLED= -2, NESTED_LOOP_ERROR= -1,
NESTED_LOOP_OK= 0, NESTED_LOOP_NO_MORE_ROWS= 1,
NESTED_LOOP_QUERY_LIMIT= 3, NESTED_LOOP_CURSOR_LIMIT= 4
};
/* Possible sj_strategy values */
enum sj_strategy_enum
{
SJ_OPT_NONE=0,
SJ_OPT_DUPS_WEEDOUT=1,
SJ_OPT_LOOSE_SCAN =2,
SJ_OPT_FIRST_MATCH =3,
SJ_OPT_MATERIALIZE =4,
SJ_OPT_MATERIALIZE_SCAN=5
};
/* Values for JOIN_TAB::packed_info */
#define TAB_INFO_HAVE_VALUE 1U
#define TAB_INFO_USING_INDEX 2U
#define TAB_INFO_USING_WHERE 4U
#define TAB_INFO_FULL_SCAN_ON_NULL 8U
typedef enum_nested_loop_state
(*Next_select_func)(JOIN *, struct st_join_table *, bool);
Next_select_func setup_end_select_func(JOIN *join, JOIN_TAB *tab);
int rr_sequential(READ_RECORD *info);
int rr_sequential_and_unpack(READ_RECORD *info);
Item *remove_pushed_top_conjuncts(THD *thd, Item *cond);
#include "sql_explain.h"
/**************************************************************************************
* New EXPLAIN structures END
*************************************************************************************/
class JOIN_CACHE;
class SJ_TMP_TABLE;
class JOIN_TAB_RANGE;
class AGGR_OP;
class Filesort;
struct SplM_plan_info;
class SplM_opt_info;
typedef struct st_join_table {
st_join_table() {}
TABLE *table;
TABLE_LIST *tab_list;
KEYUSE *keyuse; /**< pointer to first used key */
KEY *hj_key; /**< descriptor of the used best hash join key
not supported by any index */
SQL_SELECT *select;
COND *select_cond;
COND *on_precond; /**< part of on condition to check before
accessing the first inner table */
QUICK_SELECT_I *quick;
/*
The value of select_cond before we've attempted to do Index Condition
Pushdown. We may need to restore everything back if we first choose one
index but then reconsider (see test_if_skip_sort_order() for such
scenarios).
NULL means no index condition pushdown was performed.
*/
Item *pre_idx_push_select_cond;
/*
Pointer to the associated ON expression. on_expr_ref=!NULL except for
degenerate joins.
*on_expr_ref!=NULL for tables that are first inner tables within an outer
join.
*/
Item **on_expr_ref;
COND_EQUAL *cond_equal; /**< multiple equalities for the on expression */
st_join_table *first_inner; /**< first inner table for including outerjoin */
bool found; /**< true after all matches or null complement */
bool not_null_compl;/**< true before null complement is added */
st_join_table *last_inner; /**< last table table for embedding outer join */
st_join_table *first_upper; /**< first inner table for embedding outer join */
st_join_table *first_unmatched; /**< used for optimization purposes only */
/*
For join tabs that are inside an SJM bush: root of the bush
*/
st_join_table *bush_root_tab;
/* TRUE <=> This join_tab is inside an SJM bush and is the last leaf tab here */
bool last_leaf_in_bush;
/*
ptr - this is a bush, and ptr points to description of child join_tab
range
NULL - this join tab has no bush children
*/
JOIN_TAB_RANGE *bush_children;
/* Special content for EXPLAIN 'Extra' column or NULL if none */
enum explain_extra_tag info;
Table_access_tracker *tracker;
Table_access_tracker *jbuf_tracker;
/*
Bitmap of TAB_INFO_* bits that encodes special line for EXPLAIN 'Extra'
column, or 0 if there is no info.
*/
uint packed_info;
// READ_RECORD::Setup_func materialize_table;
READ_RECORD::Setup_func read_first_record;
Next_select_func next_select;
READ_RECORD read_record;
/*
Currently the following two fields are used only for a [NOT] IN subquery
if it is executed by an alternative full table scan when the left operand of
the subquery predicate is evaluated to NULL.
*/
READ_RECORD::Setup_func save_read_first_record;/* to save read_first_record */
READ_RECORD::Read_func save_read_record;/* to save read_record.read_record */
double worst_seeks;
key_map const_keys; /**< Keys with constant part */
key_map checked_keys; /**< Keys checked in find_best */
key_map needed_reg;
key_map keys; /**< all keys with can be used */
/* Either #rows in the table or 1 for const table. */
ha_rows records;
/*
Number of records that will be scanned (yes scanned, not returned) by the
best 'independent' access method, i.e. table scan or QUICK_*_SELECT)
*/
ha_rows found_records;
/*
Cost of accessing the table using "ALL" or range/index_merge access
method (but not 'index' for some reason), i.e. this matches method which
E(#records) is in found_records.
*/
double read_time;
/* Copy of POSITION::records_read, set by get_best_combination() */
double records_read;
/* The selectivity of the conditions that can be pushed to the table */
double cond_selectivity;
/* Startup cost for execution */
double startup_cost;
double partial_join_cardinality;
table_map dependent,key_dependent;
/*
1 - use quick select
2 - use "Range checked for each record"
*/
uint use_quick;
/*
Index to use. Note: this is valid only for 'index' access, but not range or
ref access.
*/
uint index;
uint status; ///< Save status for cache
uint used_fields;
ulong used_fieldlength;
ulong max_used_fieldlength;
uint used_blobs;
uint used_null_fields;
uint used_uneven_bit_fields;
enum join_type type;
bool cached_eq_ref_table,eq_ref_table;
bool shortcut_for_distinct;
bool sorted;
/*
If it's not 0 the number stored this field indicates that the index
scan has been chosen to access the table data and we expect to scan
this number of rows for the table.
*/
ha_rows limit;
TABLE_REF ref;
/* TRUE <=> condition pushdown supports other tables presence */
bool icp_other_tables_ok;
/*
TRUE <=> condition pushed to the index has to be factored out of
the condition pushed to the table
*/
bool idx_cond_fact_out;
bool use_join_cache;
uint used_join_cache_level;
ulong join_buffer_size_limit;
JOIN_CACHE *cache;
/*
Index condition for BKA access join
*/
Item *cache_idx_cond;
SQL_SELECT *cache_select;
AGGR_OP *aggr;
JOIN *join;
/*
Embedding SJ-nest (may be not the direct parent), or NULL if none.
This variable holds the result of table pullout.
*/
TABLE_LIST *emb_sj_nest;
/* FirstMatch variables (final QEP) */
struct st_join_table *first_sj_inner_tab;
struct st_join_table *last_sj_inner_tab;
/* Variables for semi-join duplicate elimination */
SJ_TMP_TABLE *flush_weedout_table;
SJ_TMP_TABLE *check_weed_out_table;
/* for EXPLAIN only: */
SJ_TMP_TABLE *first_weedout_table;
/**
reference to saved plan and execution statistics
*/
Explain_table_access *explain_plan;
/*
If set, means we should stop join enumeration after we've got the first
match and return to the specified join tab. May point to
join->join_tab[-1] which means stop join execution after the first
match.
*/
struct st_join_table *do_firstmatch;
/*
ptr - We're doing a LooseScan, this join tab is the first (i.e.
"driving") join tab), and ptr points to the last join tab
handled by the strategy. loosescan_match_tab->found_match
should be checked to see if the current value group had a match.
NULL - Not doing a loose scan on this join tab.
*/
struct st_join_table *loosescan_match_tab;
/* TRUE <=> we are inside LooseScan range */
bool inside_loosescan_range;
/* Buffer to save index tuple to be able to skip duplicates */
uchar *loosescan_buf;
/*
Index used by LooseScan (we store it here separately because ref access
stores it in tab->ref.key, while range scan stores it in tab->index, etc)
*/
uint loosescan_key;
/* Length of key tuple (depends on #keyparts used) to store in the above */
uint loosescan_key_len;
/* Used by LooseScan. TRUE<=> there has been a matching record combination */
bool found_match;
/*
Used by DuplicateElimination. tab->table->ref must have the rowid
whenever we have a current record.
*/
int keep_current_rowid;
/* NestedOuterJoins: Bitmap of nested joins this table is part of */
nested_join_map embedding_map;
/* Tmp table info */
TMP_TABLE_PARAM *tmp_table_param;
/* Sorting related info */
Filesort *filesort;
SORT_INFO *filesort_result;
/*
Non-NULL value means this join_tab must do window function computation
before reading.
*/
Window_funcs_computation* window_funcs_step;
/**
List of topmost expressions in the select list. The *next* JOIN TAB
in the plan should use it to obtain correct values. Same applicable to
all_fields. These lists are needed because after tmp tables functions
will be turned to fields. These variables are pointing to
tmp_fields_list[123]. Valid only for tmp tables and the last non-tmp
table in the query plan.
@see JOIN::make_aggr_tables_info()
*/
List<Item> *fields;
/** List of all expressions in the select list */
List<Item> *all_fields;
/*
Pointer to the ref array slice which to switch to before sending
records. Valid only for tmp tables.
*/
Ref_ptr_array *ref_array;
/** Number of records saved in tmp table */
ha_rows send_records;
/** HAVING condition for checking prior saving a record into tmp table*/
Item *having;
/** TRUE <=> remove duplicates on this table. */
bool distinct;
/*
Semi-join strategy to be used for this join table. This is a copy of
POSITION::sj_strategy field. This field is set up by the
fix_semijoin_strategies_for_picked_join_order.
*/
enum sj_strategy_enum sj_strategy;
uint n_sj_tables;
bool preread_init_done;
void cleanup();
inline bool is_using_loose_index_scan()
{
const SQL_SELECT *sel= filesort ? filesort->select : select;
return (sel && sel->quick &&
(sel->quick->get_type() == QUICK_SELECT_I::QS_TYPE_GROUP_MIN_MAX));
}
bool is_using_agg_loose_index_scan ()
{
return (is_using_loose_index_scan() &&
((QUICK_GROUP_MIN_MAX_SELECT *)select->quick)->is_agg_distinct());
}
bool is_inner_table_of_semi_join_with_first_match()
{
return first_sj_inner_tab != NULL;
}
bool is_inner_table_of_semijoin()
{
return emb_sj_nest != NULL;
}
bool is_inner_table_of_outer_join()
{
return first_inner != NULL;
}
bool is_single_inner_of_semi_join_with_first_match()
{
return first_sj_inner_tab == this && last_sj_inner_tab == this;
}
bool is_single_inner_of_outer_join()
{
return first_inner == this && first_inner->last_inner == this;
}
bool is_first_inner_for_outer_join()
{
return first_inner && first_inner == this;
}
bool use_match_flag()
{
return is_first_inner_for_outer_join() || first_sj_inner_tab == this ;
}
bool check_only_first_match()
{
return is_inner_table_of_semi_join_with_first_match() ||
(is_inner_table_of_outer_join() &&
table->reginfo.not_exists_optimize);
}
bool is_last_inner_table()
{
return (first_inner && first_inner->last_inner == this) ||
last_sj_inner_tab == this;
}
/*
Check whether the table belongs to a nest of inner tables of an
outer join or to a nest of inner tables of a semi-join
*/
bool is_nested_inner()
{
if (first_inner &&
(first_inner != first_inner->last_inner || first_inner->first_upper))
return TRUE;
if (first_sj_inner_tab && first_sj_inner_tab != last_sj_inner_tab)
return TRUE;
return FALSE;
}
struct st_join_table *get_first_inner_table()
{
if (first_inner)
return first_inner;
return first_sj_inner_tab;
}
void set_select_cond(COND *to, uint line)
{
DBUG_PRINT("info", ("select_cond changes %p -> %p at line %u tab %p",
select_cond, to, line, this));
select_cond= to;
}
COND *set_cond(COND *new_cond)
{
COND *tmp_select_cond= select_cond;
set_select_cond(new_cond, __LINE__);
if (select)
select->cond= new_cond;
return tmp_select_cond;
}
void calc_used_field_length(bool max_fl);
ulong get_used_fieldlength()
{
if (!used_fieldlength)
calc_used_field_length(FALSE);
return used_fieldlength;
}
ulong get_max_used_fieldlength()
{
if (!max_used_fieldlength)
calc_used_field_length(TRUE);
return max_used_fieldlength;
}
double get_partial_join_cardinality() { return partial_join_cardinality; }
bool hash_join_is_possible();
int make_scan_filter();
bool is_ref_for_hash_join() { return is_hash_join_key_no(ref.key); }
KEY *get_keyinfo_by_key_no(uint key)
{
return (is_hash_join_key_no(key) ? hj_key : table->key_info+key);
}
double scan_time();
ha_rows get_examined_rows();
bool preread_init();
bool is_sjm_nest() { return MY_TEST(bush_children); }
/*
If this join_tab reads a non-merged semi-join (also called jtbm), return
the select's number. Otherwise, return 0.
*/
int get_non_merged_semijoin_select() const
{
Item_in_subselect *subq;
if (table->pos_in_table_list &&
(subq= table->pos_in_table_list->jtbm_subselect))
{
return subq->unit->first_select()->select_number;
}
return 0; /* Not a merged semi-join */
}
bool access_from_tables_is_allowed(table_map used_tables,
table_map sjm_lookup_tables)
{
table_map used_sjm_lookup_tables= used_tables & sjm_lookup_tables;
return !used_sjm_lookup_tables ||
(emb_sj_nest &&
!(used_sjm_lookup_tables & ~emb_sj_nest->sj_inner_tables));
}
bool keyuse_is_valid_for_access_in_chosen_plan(JOIN *join, KEYUSE *keyuse);
void remove_redundant_bnl_scan_conds();
bool save_explain_data(Explain_table_access *eta, table_map prefix_tables,
bool distinct, struct st_join_table *first_top_tab);
bool use_order() const; ///< Use ordering provided by chosen index?
bool sort_table();
bool remove_duplicates();
void add_keyuses_for_splitting();
SplM_plan_info *choose_best_splitting(double record_count,
table_map remaining_tables);
bool fix_splitting(SplM_plan_info *spl_plan, table_map remaining_tables);
} JOIN_TAB;
#include "sql_join_cache.h"
enum_nested_loop_state
sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
enum_nested_loop_state
sub_select(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
enum_nested_loop_state
sub_select_postjoin_aggr(JOIN *join, JOIN_TAB *join_tab, bool end_of_records);
enum_nested_loop_state
end_send_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records);
enum_nested_loop_state
end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records);
struct st_position;
class Semi_join_strategy_picker
{
public:
/* Called when starting to build a new join prefix */
virtual void set_empty() = 0;
/*
Update internal state after another table has been added to the join
prefix
*/
virtual void set_from_prev(struct st_position *prev) = 0;
virtual bool check_qep(JOIN *join,
uint idx,
table_map remaining_tables,
const JOIN_TAB *new_join_tab,
double *record_count,
double *read_time,
table_map *handled_fanout,
sj_strategy_enum *strategy,
struct st_position *loose_scan_pos) = 0;
virtual void mark_used() = 0;
virtual ~Semi_join_strategy_picker() {}
};
/*
Duplicate Weedout strategy optimization state
*/
class Duplicate_weedout_picker : public Semi_join_strategy_picker
{
/* The first table that the strategy will need to handle */
uint first_dupsweedout_table;
/*
Tables that we will need to have in the prefix to do the weedout step
(all inner and all outer that the involved semi-joins are correlated with)
*/
table_map dupsweedout_tables;
bool is_used;
public:
void set_empty()
{
dupsweedout_tables= 0;
first_dupsweedout_table= MAX_TABLES;
is_used= FALSE;
}
void set_from_prev(struct st_position *prev);
bool check_qep(JOIN *join,
uint idx,
table_map remaining_tables,
const JOIN_TAB *new_join_tab,
double *record_count,
double *read_time,
table_map *handled_fanout,
sj_strategy_enum *stratey,
struct st_position *loose_scan_pos);
void mark_used() { is_used= TRUE; }
friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join);
};
class Firstmatch_picker : public Semi_join_strategy_picker
{
/*
Index of the first inner table that we intend to handle with this
strategy
*/
uint first_firstmatch_table;
/*
Tables that were not in the join prefix when we've started considering
FirstMatch strategy.
*/
table_map first_firstmatch_rtbl;
/*
Tables that need to be in the prefix before we can calculate the cost
of using FirstMatch strategy.
*/
table_map firstmatch_need_tables;
bool is_used;
bool in_firstmatch_prefix() { return (first_firstmatch_table != MAX_TABLES); }
void invalidate_firstmatch_prefix() { first_firstmatch_table= MAX_TABLES; }
public:
void set_empty()
{
invalidate_firstmatch_prefix();
is_used= FALSE;
}
void set_from_prev(struct st_position *prev);
bool check_qep(JOIN *join,
uint idx,
table_map remaining_tables,
const JOIN_TAB *new_join_tab,
double *record_count,
double *read_time,
table_map *handled_fanout,
sj_strategy_enum *strategy,
struct st_position *loose_scan_pos);
void mark_used() { is_used= TRUE; }
friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join);
};
class LooseScan_picker : public Semi_join_strategy_picker
{
/* The first (i.e. driving) table we're doing loose scan for */
uint first_loosescan_table;
/*
Tables that need to be in the prefix before we can calculate the cost
of using LooseScan strategy.
*/
table_map loosescan_need_tables;
/*
keyno - Planning to do LooseScan on this key. If keyuse is NULL then
this is a full index scan, otherwise this is a ref+loosescan
scan (and keyno matches the KEUSE's)
MAX_KEY - Not doing a LooseScan
*/
uint loosescan_key; // final (one for strategy instance )
uint loosescan_parts; /* Number of keyparts to be kept distinct */
bool is_used;
public:
void set_empty()
{
first_loosescan_table= MAX_TABLES;
is_used= FALSE;
}
void set_from_prev(struct st_position *prev);
bool check_qep(JOIN *join,
uint idx,
table_map remaining_tables,
const JOIN_TAB *new_join_tab,
double *record_count,
double *read_time,
table_map *handled_fanout,
sj_strategy_enum *strategy,
struct st_position *loose_scan_pos);
void mark_used() { is_used= TRUE; }
friend class Loose_scan_opt;
friend void best_access_path(JOIN *join,
JOIN_TAB *s,
table_map remaining_tables,
uint idx,
bool disable_jbuf,
double record_count,
struct st_position *pos,
struct st_position *loose_scan_pos);
friend bool get_best_combination(JOIN *join);
friend int setup_semijoin_loosescan(JOIN *join);
friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join);
};
class Sj_materialization_picker : public Semi_join_strategy_picker
{
bool is_used;
/* The last inner table (valid once we're after it) */
uint sjm_scan_last_inner;
/*
Tables that we need to have in the prefix to calculate the correct cost.
Basically, we need all inner tables and outer tables mentioned in the
semi-join's ON expression so we can correctly account for fanout.
*/
table_map sjm_scan_need_tables;
public:
void set_empty()
{
sjm_scan_need_tables= 0;
LINT_INIT_STRUCT(sjm_scan_last_inner);
is_used= FALSE;
}
void set_from_prev(struct st_position *prev);
bool check_qep(JOIN *join,
uint idx,
table_map remaining_tables,
const JOIN_TAB *new_join_tab,
double *record_count,
double *read_time,
table_map *handled_fanout,
sj_strategy_enum *strategy,
struct st_position *loose_scan_pos);
void mark_used() { is_used= TRUE; }
friend void fix_semijoin_strategies_for_picked_join_order(JOIN *join);
};
/**
Information about a position of table within a join order. Used in join
optimization.
*/
typedef struct st_position
{
/* The table that's put into join order */
JOIN_TAB *table;
/*
The "fanout": number of output rows that will be produced (after
pushed down selection condition is applied) per each row combination of
previous tables.
*/
double records_read;
/* The selectivity of the pushed down conditions */
double cond_selectivity;
/*
Cost accessing the table in course of the entire complete join execution,
i.e. cost of one access method use (e.g. 'range' or 'ref' scan ) times
number the access method will be invoked.
*/
double read_time;
/* Cumulative cost and record count for the join prefix */
Cost_estimate prefix_cost;
double prefix_record_count;
/*
NULL - 'index' or 'range' or 'index_merge' or 'ALL' access is used.
Other - [eq_]ref[_or_null] access is used. Pointer to {t.keypart1 = expr}
*/
KEYUSE *key;
/* If ref-based access is used: bitmap of tables this table depends on */
table_map ref_depend_map;
/*
TRUE <=> join buffering will be used. At the moment this is based on
*very* imprecise guesses made in best_access_path().
*/
bool use_join_buffer;
/*
Current optimization state: Semi-join strategy to be used for this
and preceding join tables.
Join optimizer sets this for the *last* join_tab in the
duplicate-generating range. That is, in order to interpret this field,
one needs to traverse join->[best_]positions array from right to left.
When you see a join table with sj_strategy!= SJ_OPT_NONE, some other
field (depending on the strategy) tells how many preceding positions
this applies to. The values of covered_preceding_positions->sj_strategy
must be ignored.
*/
enum sj_strategy_enum sj_strategy;
/*
Valid only after fix_semijoin_strategies_for_picked_join_order() call:
if sj_strategy!=SJ_OPT_NONE, this is the number of subsequent tables that
are covered by the specified semi-join strategy
*/
uint n_sj_tables;
/*
Bitmap of semi-join inner tables that are in the join prefix and for
which there's no provision for how to eliminate semi-join duplicates
they produce.
*/
table_map dups_producing_tables;
table_map inner_tables_handled_with_other_sjs;
Duplicate_weedout_picker dups_weedout_picker;
Firstmatch_picker firstmatch_picker;
LooseScan_picker loosescan_picker;
Sj_materialization_picker sjmat_picker;
/* Info on splitting plan used at this position */
SplM_plan_info *spl_plan;
} POSITION;
typedef Bounds_checked_array<Item_null_result*> Item_null_array;
typedef struct st_rollup
{
enum State { STATE_NONE, STATE_INITED, STATE_READY };
State state;
Item_null_array null_items;
Ref_ptr_array *ref_pointer_arrays;
List<Item> *fields;
} ROLLUP;
class JOIN_TAB_RANGE: public Sql_alloc
{
public:
JOIN_TAB *start;
JOIN_TAB *end;
};
class Pushdown_query;
/**
@brief
Class to perform postjoin aggregation operations
@details
The result records are obtained on the put_record() call.
The aggrgation process is determined by the write_func, it could be:
end_write Simply store all records in tmp table.
end_write_group Perform grouping using join->group_fields,
records are expected to be sorted.
end_update Perform grouping using the key generated on tmp
table. Input records aren't expected to be sorted.
Tmp table uses the heap engine
end_update_unique Same as above, but the engine is myisam.
Lazy table initialization is used - the table will be instantiated and
rnd/index scan started on the first put_record() call.
*/
class AGGR_OP :public Sql_alloc
{
public:
JOIN_TAB *join_tab;
AGGR_OP(JOIN_TAB *tab) : join_tab(tab), write_func(NULL)
{};
enum_nested_loop_state put_record() { return put_record(false); };
/*
Send the result of operation further (to a next operation/client)
This function is called after all records were put into tmp table.
@return return one of enum_nested_loop_state values.
*/
enum_nested_loop_state end_send();
/** write_func setter */
void set_write_func(Next_select_func new_write_func)
{
write_func= new_write_func;
}
private:
/** Write function that would be used for saving records in tmp table. */
Next_select_func write_func;
enum_nested_loop_state put_record(bool end_of_records);
bool prepare_tmp_table();
};
class JOIN :public Sql_alloc
{
private:
JOIN(const JOIN &rhs); /**< not implemented */
JOIN& operator=(const JOIN &rhs); /**< not implemented */
protected:
/**
The subset of the state of a JOIN that represents an optimized query
execution plan. Allows saving/restoring different JOIN plans for the same
query.
*/
class Join_plan_state {
public:
DYNAMIC_ARRAY keyuse; /* Copy of the JOIN::keyuse array. */
POSITION *best_positions; /* Copy of JOIN::best_positions */
/* Copies of the JOIN_TAB::keyuse pointers for each JOIN_TAB. */
KEYUSE **join_tab_keyuse;
/* Copies of JOIN_TAB::checked_keys for each JOIN_TAB. */
key_map *join_tab_checked_keys;
SJ_MATERIALIZATION_INFO **sj_mat_info;
my_bool error;
public:
Join_plan_state(uint tables) : error(0)
{
keyuse.elements= 0;
keyuse.buffer= NULL;
keyuse.malloc_flags= 0;
best_positions= 0; /* To detect errors */
error= my_multi_malloc(MYF(MY_WME),
&best_positions,
sizeof(*best_positions) * (tables + 1),
&join_tab_keyuse,
sizeof(*join_tab_keyuse) * tables,
&join_tab_checked_keys,
sizeof(*join_tab_checked_keys) * tables,
&sj_mat_info,
sizeof(sj_mat_info) * tables,
NullS) == 0;
}
Join_plan_state(JOIN *join);
~Join_plan_state()
{
delete_dynamic(&keyuse);
my_free(best_positions);
}
};
/* Results of reoptimizing a JOIN via JOIN::reoptimize(). */
enum enum_reopt_result {
REOPT_NEW_PLAN, /* there is a new reoptimized plan */
REOPT_OLD_PLAN, /* no new improved plan can be found, use the old one */
REOPT_ERROR, /* an irrecovarable error occurred during reoptimization */
REOPT_NONE /* not yet reoptimized */
};
/* Support for plan reoptimization with rewritten conditions. */
enum_reopt_result reoptimize(Item *added_where, table_map join_tables,
Join_plan_state *save_to);
/* Choose a subquery plan for a table-less subquery. */
bool choose_tableless_subquery_plan();
public:
void save_query_plan(Join_plan_state *save_to);
void reset_query_plan();
void restore_query_plan(Join_plan_state *restore_from);
public:
JOIN_TAB *join_tab, **best_ref;
/* List of fields that aren't under an aggregate function */
List<Item_field> non_agg_fields;
JOIN_TAB **map2table; ///< mapping between table indexes and JOIN_TABs
List<JOIN_TAB_RANGE> join_tab_ranges;
/*
Base tables participating in the join. After join optimization is done, the
tables are stored in the join order (but the only really important part is
that const tables are first).
*/
TABLE **table;
/**
The table which has an index that allows to produce the requried ordering.
A special value of 0x1 means that the ordering will be produced by
passing 1st non-const table to filesort(). NULL means no such table exists.
*/
TABLE *sort_by_table;
/*
Number of tables in the join.
(In MySQL, it is named 'tables' and is also the number of elements in
join->join_tab array. In MariaDB, the latter is not true, so we've renamed
the variable)
*/
uint table_count;
uint outer_tables; /**< Number of tables that are not inside semijoin */
uint const_tables;
/*
Number of tables in the top join_tab array. Normally this matches
(join_tab_ranges.head()->end - join_tab_ranges.head()->start).
We keep it here so that it is saved/restored with JOIN::restore_tmp.
*/
uint top_join_tab_count;
uint aggr_tables; ///< Number of post-join tmp tables
uint send_group_parts;
/*
True if the query has GROUP BY.
(that is, if group_by != NULL. when DISTINCT is converted into GROUP BY, it
will set this, too. It is not clear why we need a separate var from
group_list)
*/
bool group;
bool need_distinct;
/**
Indicates that grouping will be performed on the result set during
query execution. This field belongs to query execution.
@see make_group_fields, alloc_group_fields, JOIN::exec
*/
bool sort_and_group;
bool first_record,full_join, no_field_update;
bool hash_join;
bool do_send_rows;
table_map const_table_map;
/**
Bitmap of semijoin tables that the current partial plan decided
to materialize and access by lookups
*/
table_map sjm_lookup_tables;
/**
Bitmap of semijoin tables that the chosen plan decided
to materialize to scan the results of materialization
*/
table_map sjm_scan_tables;
/*
Constant tables for which we have found a row (as opposed to those for
which we didn't).
*/
table_map found_const_table_map;
/* Tables removed by table elimination. Set to 0 before the elimination. */
table_map eliminated_tables;
/*
Bitmap of all inner tables from outer joins (set at start of
make_join_statistics)
*/
table_map outer_join;
/* Bitmap of tables used in the select list items */
table_map select_list_used_tables;
ha_rows send_records,found_records,join_examined_rows;
/*
LIMIT for the JOIN operation. When not using aggregation or DISITNCT, this
is the same as select's LIMIT clause specifies.
Note that this doesn't take sql_calc_found_rows into account.
*/
ha_rows row_limit;
/*
How many output rows should be produced after GROUP BY.
(if sql_calc_found_rows is used, LIMIT is ignored)
*/
ha_rows select_limit;
/*
Number of duplicate rows found in UNION.
*/
ha_rows duplicate_rows;
/**
Used to fetch no more than given amount of rows per one
fetch operation of server side cursor.
The value is checked in end_send and end_send_group in fashion, similar
to offset_limit_cnt:
- fetch_limit= HA_POS_ERROR if there is no cursor.
- when we open a cursor, we set fetch_limit to 0,
- on each fetch iteration we add num_rows to fetch to fetch_limit
NOTE: currently always HA_POS_ERROR.
*/
ha_rows fetch_limit;
/* Finally picked QEP. This is result of join optimization */
POSITION *best_positions;
Pushdown_query *pushdown_query;
JOIN_TAB *original_join_tab;
uint original_table_count;
/******* Join optimization state members start *******/
/*
pointer - we're doing optimization for a semi-join materialization nest.
NULL - otherwise
*/
TABLE_LIST *emb_sjm_nest;
/* Current join optimization state */
POSITION *positions;
/*
Bitmap of nested joins embedding the position at the end of the current
partial join (valid only during join optimizer run).
*/
nested_join_map cur_embedding_map;
/*
Bitmap of inner tables of semi-join nests that have a proper subset of
their tables in the current join prefix. That is, of those semi-join
nests that have their tables both in and outside of the join prefix.
*/
table_map cur_sj_inner_tables;
/* We also maintain a stack of join optimization states in * join->positions[] */
/******* Join optimization state members end *******/
/*
Tables within complex firstmatch ranges (i.e. those where inner tables are
interleaved with outer tables). Join buffering cannot be used for these.
*/
table_map complex_firstmatch_tables;
Next_select_func first_select;
/*
The cost of best complete join plan found so far during optimization,
after optimization phase - cost of picked join order (not taking into
account the changes made by test_if_skip_sort_order()).
*/
double best_read;
/*
Estimated result rows (fanout) of the join operation. If this is a subquery
that is reexecuted multiple times, this value includes the estiamted # of
reexecutions. This value is equal to the multiplication of all
join->positions[i].records_read of a JOIN.
*/
double join_record_count;
List<Item> *fields;
List<Cached_item> group_fields, group_fields_cache;
THD *thd;
Item_sum **sum_funcs, ***sum_funcs_end;
/** second copy of sumfuncs (for queries with 2 temporary tables */
Item_sum **sum_funcs2, ***sum_funcs_end2;
Procedure *procedure;
Item *having;
Item *tmp_having; ///< To store having when processed temporary table
Item *having_history; ///< Store having for explain
ORDER *group_list_for_estimates;
bool having_is_correlated;
ulonglong select_options;
/*
Bitmap of allowed types of the join caches that
can be used for join operations
*/
uint allowed_join_cache_types;
bool allowed_semijoin_with_cache;
bool allowed_outer_join_with_cache;
/* Maximum level of the join caches that can be used for join operations */
uint max_allowed_join_cache_level;
select_result *result;
TMP_TABLE_PARAM tmp_table_param;
MYSQL_LOCK *lock;
/// unit structure (with global parameters) for this select
SELECT_LEX_UNIT *unit;
/// select that processed
SELECT_LEX *select_lex;
/**
TRUE <=> optimizer must not mark any table as a constant table.
This is needed for subqueries in form "a IN (SELECT .. UNION SELECT ..):
when we optimize the select that reads the results of the union from a
temporary table, we must not mark the temp. table as constant because
the number of rows in it may vary from one subquery execution to another.
*/
bool no_const_tables;
/*
This flag is set if we call no_rows_in_result() as par of end_group().
This is used as a simple speed optimization to avoiding calling
restore_no_rows_in_result() in ::reinit()
*/
bool no_rows_in_result_called;
/**
This is set if SQL_CALC_ROWS was calculated by filesort()
and should be taken from the appropriate JOIN_TAB
*/
bool filesort_found_rows;
bool subq_exit_fl;
ROLLUP rollup; ///< Used with rollup
bool mixed_implicit_grouping;
bool select_distinct; ///< Set if SELECT DISTINCT
/**
If we have the GROUP BY statement in the query,
but the group_list was emptied by optimizer, this
flag is TRUE.
It happens when fields in the GROUP BY are from
constant table
*/
bool group_optimized_away;
/*
simple_xxxxx is set if ORDER/GROUP BY doesn't include any references
to other tables than the first non-constant table in the JOIN.
It's also set if ORDER/GROUP BY is empty.
Used for deciding for or against using a temporary table to compute
GROUP/ORDER BY.
*/
bool simple_order, simple_group;
/*
ordered_index_usage is set if an ordered index access
should be used instead of a filesort when computing
ORDER/GROUP BY.
*/
enum
{
ordered_index_void, // No ordered index avail.
ordered_index_group_by, // Use index for GROUP BY
ordered_index_order_by // Use index for ORDER BY
} ordered_index_usage;
/**
Is set only in case if we have a GROUP BY clause
and no ORDER BY after constant elimination of 'order'.
*/
bool no_order;
/** Is set if we have a GROUP BY and we have ORDER BY on a constant. */
bool skip_sort_order;
bool need_tmp;
bool hidden_group_fields;
/* TRUE if there was full cleunap of the JOIN */
bool cleaned;
DYNAMIC_ARRAY keyuse;
Item::cond_result cond_value, having_value;
/**
Impossible where after reading const tables
(set in make_join_statistics())
*/
bool impossible_where;
List<Item> all_fields; ///< to store all fields that used in query
///Above list changed to use temporary table
List<Item> tmp_all_fields1, tmp_all_fields2, tmp_all_fields3;
///Part, shared with list above, emulate following list
List<Item> tmp_fields_list1, tmp_fields_list2, tmp_fields_list3;
List<Item> &fields_list; ///< hold field list passed to mysql_select
List<Item> procedure_fields_list;
int error;
ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select
COND *conds; // ---"---
Item *conds_history; // store WHERE for explain
COND *outer_ref_cond; ///<part of conds containing only outer references
COND *pseudo_bits_cond; // part of conds containing special bita
TABLE_LIST *tables_list; ///<hold 'tables' parameter of mysql_select
List<TABLE_LIST> *join_list; ///< list of joined tables in reverse order
COND_EQUAL *cond_equal;
COND_EQUAL *having_equal;
/*
Constant codition computed during optimization, but evaluated during
join execution. Typically expensive conditions that should not be
evaluated at optimization time.
*/
Item *exec_const_cond;
/*
Constant ORDER and/or GROUP expressions that contain subqueries. Such
expressions need to evaluated to verify that the subquery indeed
returns a single row. The evaluation of such expressions is delayed
until query execution.
*/
List<Item> exec_const_order_group_cond;
SQL_SELECT *select; ///<created in optimisation phase
JOIN_TAB *return_tab; ///<used only for outer joins
/*
Used pointer reference for this select.
select_lex->ref_pointer_array contains five "slices" of the same length:
|========|========|========|========|========|
ref_ptrs items0 items1 items2 items3
*/
Ref_ptr_array ref_ptrs;
// Copy of the initial slice above, to be used with different lists
Ref_ptr_array items0, items1, items2, items3;
// Used by rollup, to restore ref_ptrs after overwriting it.
Ref_ptr_array current_ref_ptrs;
const char *zero_result_cause; ///< not 0 if exec must return zero result
bool union_part; ///< this subselect is part of union
enum join_optimization_state { NOT_OPTIMIZED=0,
OPTIMIZATION_IN_PROGRESS=1,
OPTIMIZATION_PHASE_1_DONE=2,
OPTIMIZATION_DONE=3};
// state of JOIN optimization
enum join_optimization_state optimization_state;
bool initialized; ///< flag to avoid double init_execution calls
Explain_select *explain;
enum { QEP_NOT_PRESENT_YET, QEP_AVAILABLE, QEP_DELETED} have_query_plan;
/*
Additional WHERE and HAVING predicates to be considered for IN=>EXISTS
subquery transformation of a JOIN object.
*/
Item *in_to_exists_where;
Item *in_to_exists_having;
/* Temporary tables used to weed-out semi-join duplicates */
List<TABLE> sj_tmp_tables;
/* SJM nests that are executed with SJ-Materialization strategy */
List<SJ_MATERIALIZATION_INFO> sjm_info_list;
/** TRUE <=> ref_pointer_array is set to items3. */
bool set_group_rpa;
/** Exec time only: TRUE <=> current group has been sent */
bool group_sent;
/**
TRUE if the query contains an aggregate function but has no GROUP
BY clause.
*/
bool implicit_grouping;
bool with_two_phase_optimization;
/* Saved execution plan for this join */
Join_plan_state *save_qep;
/* Info on splittability of the table materialized by this plan*/
SplM_opt_info *spl_opt_info;
/* Contains info on keyuses usable for splitting */
Dynamic_array<KEYUSE_EXT> *ext_keyuses_for_splitting;
JOIN_TAB *sort_and_group_aggr_tab;
JOIN(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg,
select_result *result_arg)
:fields_list(fields_arg)
{
init(thd_arg, fields_arg, select_options_arg, result_arg);
}
void init(THD *thd_arg, List<Item> &fields_arg, ulonglong select_options_arg,
select_result *result_arg)
{
join_tab= 0;
table= 0;
table_count= 0;
top_join_tab_count= 0;
const_tables= 0;
const_table_map= found_const_table_map= 0;
aggr_tables= 0;
eliminated_tables= 0;
join_list= 0;
implicit_grouping= FALSE;
sort_and_group= 0;
first_record= 0;
do_send_rows= 1;
duplicate_rows= send_records= 0;
found_records= 0;
fetch_limit= HA_POS_ERROR;
thd= thd_arg;
sum_funcs= sum_funcs2= 0;
procedure= 0;
having= tmp_having= having_history= 0;
having_is_correlated= false;
group_list_for_estimates= 0;
select_options= select_options_arg;
result= result_arg;
lock= thd_arg->lock;
select_lex= 0; //for safety
select_distinct= MY_TEST(select_options & SELECT_DISTINCT);
no_order= 0;
simple_order= 0;
simple_group= 0;
ordered_index_usage= ordered_index_void;
need_distinct= 0;
skip_sort_order= 0;
with_two_phase_optimization= 0;
save_qep= 0;
spl_opt_info= 0;
ext_keyuses_for_splitting= 0;
spl_opt_info= 0;
need_tmp= 0;
hidden_group_fields= 0; /*safety*/
error= 0;
select= 0;
return_tab= 0;
ref_ptrs.reset();
items0.reset();
items1.reset();
items2.reset();
items3.reset();
zero_result_cause= 0;
optimization_state= JOIN::NOT_OPTIMIZED;
have_query_plan= QEP_NOT_PRESENT_YET;
initialized= 0;
cleaned= 0;
cond_equal= 0;
having_equal= 0;
exec_const_cond= 0;
group_optimized_away= 0;
no_rows_in_result_called= 0;
positions= best_positions= 0;
pushdown_query= 0;
original_join_tab= 0;
explain= NULL;
all_fields= fields_arg;
if (&fields_list != &fields_arg) /* Avoid valgrind-warning */
fields_list= fields_arg;
non_agg_fields.empty();
bzero((char*) &keyuse,sizeof(keyuse));
tmp_table_param.init();
tmp_table_param.end_write_records= HA_POS_ERROR;
rollup.state= ROLLUP::STATE_NONE;
no_const_tables= FALSE;
first_select= sub_select;
set_group_rpa= false;
group_sent= 0;
outer_ref_cond= pseudo_bits_cond= NULL;
in_to_exists_where= NULL;
in_to_exists_having= NULL;
emb_sjm_nest= NULL;
sjm_lookup_tables= 0;
sjm_scan_tables= 0;
}
/* True if the plan guarantees that it will be returned zero or one row */
bool only_const_tables() { return const_tables == table_count; }
/* Number of tables actually joined at the top level */
uint exec_join_tab_cnt() { return tables_list ? top_join_tab_count : 0; }
int prepare(TABLE_LIST *tables, uint wind_num,
COND *conds, uint og_num, ORDER *order, bool skip_order_by,
ORDER *group, Item *having, ORDER *proc_param, SELECT_LEX *select,
SELECT_LEX_UNIT *unit);
bool prepare_stage2();
int optimize();
int optimize_inner();
int optimize_stage2();
bool build_explain();
int reinit();
int init_execution();
void exec();
void exec_inner();
bool prepare_result(List<Item> **columns_list);
int destroy();
void restore_tmp();
bool alloc_func_list();
bool flatten_subqueries();
bool optimize_unflattened_subqueries();
bool optimize_constant_subqueries();
int init_join_caches();
bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields,
bool before_group_by, bool recompute= FALSE);
/// Initialzes a slice, see comments for ref_ptrs above.
Ref_ptr_array ref_ptr_array_slice(size_t slice_num)
{
size_t slice_sz= select_lex->ref_pointer_array.size() / 5U;
DBUG_ASSERT(select_lex->ref_pointer_array.size() % 5 == 0);
DBUG_ASSERT(slice_num < 5U);
return Ref_ptr_array(&select_lex->ref_pointer_array[slice_num * slice_sz],
slice_sz);
}
/**
Overwrites one slice with the contents of another slice.
In the normal case, dst and src have the same size().
However: the rollup slices may have smaller size than slice_sz.
*/
void copy_ref_ptr_array(Ref_ptr_array dst_arr, Ref_ptr_array src_arr)
{
DBUG_ASSERT(dst_arr.size() >= src_arr.size());
void *dest= dst_arr.array();
const void *src= src_arr.array();
memcpy(dest, src, src_arr.size() * src_arr.element_size());
}
/// Overwrites 'ref_ptrs' and remembers the the source as 'current'.
void set_items_ref_array(Ref_ptr_array src_arr)
{
copy_ref_ptr_array(ref_ptrs, src_arr);
current_ref_ptrs= src_arr;
}
/// Initializes 'items0' and remembers that it is 'current'.
void init_items_ref_array()
{
items0= ref_ptr_array_slice(1);
copy_ref_ptr_array(items0, ref_ptrs);
current_ref_ptrs= items0;
}
bool rollup_init();
bool rollup_process_const_fields();
bool rollup_make_fields(List<Item> &all_fields, List<Item> &fields,
Item_sum ***func);
int rollup_send_data(uint idx);
int rollup_write_data(uint idx, TMP_TABLE_PARAM *tmp_table_param, TABLE *table);
void join_free();
/** Cleanup this JOIN, possibly for reuse */
void cleanup(bool full);
void clear();
bool send_row_on_empty_set()
{
return (do_send_rows && implicit_grouping && !group_optimized_away &&
having_value != Item::COND_FALSE);
}
bool empty_result() { return (zero_result_cause && !implicit_grouping); }
bool change_result(select_result *new_result, select_result *old_result);
bool is_top_level_join() const
{
return (unit == &thd->lex->unit && (unit->fake_select_lex == 0 ||
select_lex == unit->fake_select_lex));
}
void cache_const_exprs();
inline table_map all_tables_map()
{
return (table_map(1) << table_count) - 1;
}
void drop_unused_derived_keys();
bool get_best_combination();
bool add_sorting_to_table(JOIN_TAB *tab, ORDER *order);
inline void eval_select_list_used_tables();
/*
Return the table for which an index scan can be used to satisfy
the sort order needed by the ORDER BY/(implicit) GROUP BY clause
*/
JOIN_TAB *get_sort_by_join_tab()
{
return (need_tmp || !sort_by_table || skip_sort_order ||
((group || tmp_table_param.sum_func_count) && !group_list)) ?
NULL : join_tab+const_tables;
}
bool setup_subquery_caches();
bool shrink_join_buffers(JOIN_TAB *jt,
ulonglong curr_space,
ulonglong needed_space);
void set_allowed_join_cache_types();
bool is_allowed_hash_join_access()
{
return MY_TEST(allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT;
}
/*
Check if we need to create a temporary table.
This has to be done if all tables are not already read (const tables)
and one of the following conditions holds:
- We are using DISTINCT (simple distinct's are already optimized away)
- We are using an ORDER BY or GROUP BY on fields not in the first table
- We are using different ORDER BY and GROUP BY orders
- The user wants us to buffer the result.
When the WITH ROLLUP modifier is present, we cannot skip temporary table
creation for the DISTINCT clause just because there are only const tables.
*/
bool test_if_need_tmp_table()
{
return ((const_tables != table_count &&
((select_distinct || !simple_order || !simple_group) ||
(group_list && order) ||
MY_TEST(select_options & OPTION_BUFFER_RESULT))) ||
(rollup.state != ROLLUP::STATE_NONE && select_distinct));
}
bool choose_subquery_plan(table_map join_tables);
void get_partial_cost_and_fanout(int end_tab_idx,
table_map filter_map,
double *read_time_arg,
double *record_count_arg);
void get_prefix_cost_and_fanout(uint n_tables,
double *read_time_arg,
double *record_count_arg);
double get_examined_rows();
/* defined in opt_subselect.cc */
bool transform_max_min_subquery();
/* True if this JOIN is a subquery under an IN predicate. */
bool is_in_subquery()
{
return (unit->item && unit->item->is_in_predicate());
}
bool save_explain_data(Explain_query *output, bool can_overwrite,
bool need_tmp_table, bool need_order, bool distinct);
int save_explain_data_intern(Explain_query *output, bool need_tmp_table,
bool need_order, bool distinct,
const char *message);
JOIN_TAB *first_breadth_first_tab() { return join_tab; }
bool check_two_phase_optimization(THD *thd);
bool inject_cond_into_where(Item *injected_cond);
bool check_for_splittable_materialized();
void add_keyuses_for_splitting();
bool inject_best_splitting_cond(table_map remaining_tables);
bool fix_all_splittings_in_plan();
bool transform_in_predicates_into_in_subq(THD *thd);
private:
/**
Create a temporary table to be used for processing DISTINCT/ORDER
BY/GROUP BY.
@note Will modify JOIN object wrt sort/group attributes
@param tab the JOIN_TAB object to attach created table to
@param tmp_table_fields List of items that will be used to define
column types of the table.
@param tmp_table_group Group key to use for temporary table, NULL if none.
@param save_sum_fields If true, do not replace Item_sum items in
@c tmp_fields list with Item_field items referring
to fields in temporary table.
@returns false on success, true on failure
*/
bool create_postjoin_aggr_table(JOIN_TAB *tab, List<Item> *tmp_table_fields,
ORDER *tmp_table_group,
bool save_sum_fields,
bool distinct,
bool keep_row_ordermake);
/**
Optimize distinct when used on a subset of the tables.
E.g.,: SELECT DISTINCT t1.a FROM t1,t2 WHERE t1.b=t2.b
In this case we can stop scanning t2 when we have found one t1.a
*/
void optimize_distinct();
void cleanup_item_list(List<Item> &items) const;
bool add_having_as_table_cond(JOIN_TAB *tab);
bool make_aggr_tables_info();
void vers_check_items();
};
enum enum_with_bush_roots { WITH_BUSH_ROOTS, WITHOUT_BUSH_ROOTS};
enum enum_with_const_tables { WITH_CONST_TABLES, WITHOUT_CONST_TABLES};
JOIN_TAB *first_linear_tab(JOIN *join,
enum enum_with_bush_roots include_bush_roots,
enum enum_with_const_tables const_tbls);
JOIN_TAB *next_linear_tab(JOIN* join, JOIN_TAB* tab,
enum enum_with_bush_roots include_bush_roots);
JOIN_TAB *first_top_level_tab(JOIN *join, enum enum_with_const_tables with_const);
JOIN_TAB *next_top_level_tab(JOIN *join, JOIN_TAB *tab);
typedef struct st_select_check {
uint const_ref,reg_ref;
} SELECT_CHECK;
extern const char *join_type_str[];
/* Extern functions in sql_select.cc */
void count_field_types(SELECT_LEX *select_lex, TMP_TABLE_PARAM *param,
List<Item> &fields, bool reset_with_sum_func);
bool setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
Ref_ptr_array ref_pointer_array,
List<Item> &new_list1, List<Item> &new_list2,
uint elements, List<Item> &fields);
void copy_fields(TMP_TABLE_PARAM *param);
bool copy_funcs(Item **func_ptr, const THD *thd);
uint find_shortest_key(TABLE *table, const key_map *usable_keys);
Field* create_tmp_field_from_field(THD *thd, Field* org_field,
LEX_CSTRING *name, TABLE *table,
Item_field *item);
bool is_indexed_agg_distinct(JOIN *join, List<Item_field> *out_args);
/* functions from opt_sum.cc */
bool simple_pred(Item_func *func_item, Item **args, bool *inv_order);
int opt_sum_query(THD* thd,
List<TABLE_LIST> &tables, List<Item> &all_fields, COND *conds);
/* from sql_delete.cc, used by opt_range.cc */
extern "C" int refpos_order_cmp(void* arg, const void *a,const void *b);
/** class to copying an field/item to a key struct */
class store_key :public Sql_alloc
{
public:
bool null_key; /* TRUE <=> the value of the key has a null part */
enum store_key_result { STORE_KEY_OK, STORE_KEY_FATAL, STORE_KEY_CONV };
enum Type { FIELD_STORE_KEY, ITEM_STORE_KEY, CONST_ITEM_STORE_KEY };
store_key(THD *thd, Field *field_arg, uchar *ptr, uchar *null, uint length)
:null_key(0), null_ptr(null), err(0)
{
to_field=field_arg->new_key_field(thd->mem_root, field_arg->table,
ptr, length, null, 1);
}
store_key(store_key &arg)
:Sql_alloc(), null_key(arg.null_key), to_field(arg.to_field),
null_ptr(arg.null_ptr), err(arg.err)
{}
virtual ~store_key() {} /** Not actually needed */
virtual enum Type type() const=0;
virtual const char *name() const=0;
virtual bool store_key_is_const() { return false; }
/**
@brief sets ignore truncation warnings mode and calls the real copy method
@details this function makes sure truncation warnings when preparing the
key buffers don't end up as errors (because of an enclosing INSERT/UPDATE).
*/
enum store_key_result copy()
{
enum store_key_result result;
THD *thd= to_field->table->in_use;
enum_check_fields saved_count_cuted_fields= thd->count_cuted_fields;
sql_mode_t orig_sql_mode= thd->variables.sql_mode;
thd->variables.sql_mode&= ~(MODE_NO_ZERO_IN_DATE | MODE_NO_ZERO_DATE);
thd->variables.sql_mode|= MODE_INVALID_DATES;
thd->count_cuted_fields= CHECK_FIELD_IGNORE;
result= copy_inner();
thd->count_cuted_fields= saved_count_cuted_fields;
thd->variables.sql_mode= orig_sql_mode;
return result;
}
protected:
Field *to_field; // Store data here
uchar *null_ptr;
uchar err;
virtual enum store_key_result copy_inner()=0;
};
class store_key_field: public store_key
{
Copy_field copy_field;
const char *field_name;
public:
store_key_field(THD *thd, Field *to_field_arg, uchar *ptr,
uchar *null_ptr_arg,
uint length, Field *from_field, const char *name_arg)
:store_key(thd, to_field_arg,ptr,
null_ptr_arg ? null_ptr_arg : from_field->maybe_null() ? &err
: (uchar*) 0, length), field_name(name_arg)
{
if (to_field)
{
copy_field.set(to_field,from_field,0);
}
}
enum Type type() const { return FIELD_STORE_KEY; }
const char *name() const { return field_name; }
void change_source_field(Item_field *fld_item)
{
copy_field.set(to_field, fld_item->field, 0);
field_name= fld_item->full_name();
}
protected:
enum store_key_result copy_inner()
{
TABLE *table= copy_field.to_field->table;
my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
table->write_set);
/*
It looks like the next statement is needed only for a simplified
hash function over key values used now in BNLH join.
When the implementation of this function will be replaced for a proper
full version this statement probably should be removed.
*/
bzero(copy_field.to_ptr,copy_field.to_length);
copy_field.do_copy(©_field);
dbug_tmp_restore_column_map(table->write_set, old_map);
null_key= to_field->is_null();
return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK;
}
};
class store_key_item :public store_key
{
protected:
Item *item;
/*
Flag that forces usage of save_val() method which save value of the
item instead of save_in_field() method which saves result.
*/
bool use_value;
public:
store_key_item(THD *thd, Field *to_field_arg, uchar *ptr,
uchar *null_ptr_arg, uint length, Item *item_arg, bool val)
:store_key(thd, to_field_arg, ptr,
null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
&err : (uchar*) 0, length), item(item_arg), use_value(val)
{}
store_key_item(store_key &arg, Item *new_item, bool val)
:store_key(arg), item(new_item), use_value(val)
{}
enum Type type() const { return ITEM_STORE_KEY; }
const char *name() const { return "func"; }
protected:
enum store_key_result copy_inner()
{
TABLE *table= to_field->table;
my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
table->write_set);
int res= FALSE;
/*
It looks like the next statement is needed only for a simplified
hash function over key values used now in BNLH join.
When the implementation of this function will be replaced for a proper
full version this statement probably should be removed.
*/
to_field->reset();
if (use_value)
item->save_val(to_field);
else
res= item->save_in_field(to_field, 1);
/*
Item::save_in_field() may call Item::val_xxx(). And if this is a subquery
we need to check for errors executing it and react accordingly
*/
if (!res && table->in_use->is_error())
res= 1; /* STORE_KEY_FATAL */
dbug_tmp_restore_column_map(table->write_set, old_map);
null_key= to_field->is_null() || item->null_value;
return ((err != 0 || res < 0 || res > 2) ? STORE_KEY_FATAL :
(store_key_result) res);
}
};
class store_key_const_item :public store_key_item
{
bool inited;
public:
store_key_const_item(THD *thd, Field *to_field_arg, uchar *ptr,
uchar *null_ptr_arg, uint length,
Item *item_arg)
:store_key_item(thd, to_field_arg, ptr,
null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
&err : (uchar*) 0, length, item_arg, FALSE), inited(0)
{
}
store_key_const_item(store_key &arg, Item *new_item)
:store_key_item(arg, new_item, FALSE), inited(0)
{}
enum Type type() const { return CONST_ITEM_STORE_KEY; }
const char *name() const { return "const"; }
bool store_key_is_const() { return true; }
protected:
enum store_key_result copy_inner()
{
int res;
if (!inited)
{
inited=1;
TABLE *table= to_field->table;
my_bitmap_map *old_map= dbug_tmp_use_all_columns(table,
table->write_set);
if ((res= item->save_in_field(to_field, 1)))
{
if (!err)
err= res < 0 ? 1 : res; /* 1=STORE_KEY_FATAL */
}
/*
Item::save_in_field() may call Item::val_xxx(). And if this is a subquery
we need to check for errors executing it and react accordingly
*/
if (!err && to_field->table->in_use->is_error())
err= 1; /* STORE_KEY_FATAL */
dbug_tmp_restore_column_map(table->write_set, old_map);
}
null_key= to_field->is_null() || item->null_value;
return (err > 2 ? STORE_KEY_FATAL : (store_key_result) err);
}
};
bool cp_buffer_from_ref(THD *thd, TABLE *table, TABLE_REF *ref);
bool error_if_full_join(JOIN *join);
int report_error(TABLE *table, int error);
int safe_index_read(JOIN_TAB *tab);
int get_quick_record(SQL_SELECT *select);
int setup_order(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List <Item> &all_fields, ORDER *order,
bool from_window_spec= false);
int setup_group(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields, ORDER *order,
bool *hidden_group_fields, bool from_window_spec= false);
bool fix_inner_refs(THD *thd, List<Item> &all_fields, SELECT_LEX *select,
Ref_ptr_array ref_pointer_array);
int join_read_key2(THD *thd, struct st_join_table *tab, TABLE *table,
struct st_table_ref *table_ref);
bool handle_select(THD *thd, LEX *lex, select_result *result,
ulong setup_tables_done_option);
bool mysql_select(THD *thd,
TABLE_LIST *tables, uint wild_num, List<Item> &list,
COND *conds, uint og_num, ORDER *order, ORDER *group,
Item *having, ORDER *proc_param, ulonglong select_type,
select_result *result, SELECT_LEX_UNIT *unit,
SELECT_LEX *select_lex);
void free_underlaid_joins(THD *thd, SELECT_LEX *select);
bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit,
select_result *result);
Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type,
Item ***copy_func, Field **from_field,
Field **def_field,
bool group, bool modify_item,
bool table_cant_handle_bit_fields,
bool make_copy_field);
/*
General routine to change field->ptr of a NULL-terminated array of Field
objects. Useful when needed to call val_int, val_str or similar and the
field data is not in table->record[0] but in some other structure.
set_key_field_ptr changes all fields of an index using a key_info object.
All methods presume that there is at least one field to change.
*/
class Virtual_tmp_table: public TABLE
{
/**
Destruct collected fields. This method can be called on errors,
when we could not make the virtual temporary table completely,
e.g. when some of the fields could not be created or added.
This is needed to avoid memory leaks, as some fields can be BLOB
variants and thus can have String onboard. Strings must be destructed
as they store data on the heap (not on MEM_ROOT).
*/
void destruct_fields()
{
for (uint i= 0; i < s->fields; i++)
{
field[i]->free();
delete field[i]; // to invoke the field destructor
}
s->fields= 0; // safety
}
protected:
/**
The number of the fields that are going to be in the table.
We remember the number of the fields at init() time, and
at open() we check that all of the fields were really added.
*/
uint m_alloced_field_count;
/**
Setup field pointers and null-bit pointers.
*/
void setup_field_pointers();
public:
/**
Create a new empty virtual temporary table on the thread mem_root.
After creation, the caller must:
- call init()
- populate the table with new fields using add().
- call open().
@param thd - Current thread.
*/
static void *operator new(size_t size, THD *thd) throw();
static void operator delete(void *ptr, size_t size) { TRASH(ptr, size); }
Virtual_tmp_table(THD *thd)
{
bzero(this, sizeof(*this));
temp_pool_slot= MY_BIT_NONE;
in_use= thd;
copy_blobs= true;
alias.set("", 0, &my_charset_bin);
}
~Virtual_tmp_table()
{
if (s)
destruct_fields();
}
/**
Allocate components for the given number of fields.
- fields[]
- s->blob_fields[],
- bitmaps: def_read_set, def_write_set, tmp_set, eq_join_set, cond_set.
@param field_count - The number of fields we plan to add to the table.
@returns false - on success.
@returns true - on error.
*/
bool init(uint field_count);
/**
Add one Field to the end of the field array, update members:
s->reclength, s->fields, s->blob_fields, s->null_fuelds.
*/
bool add(Field *new_field)
{
DBUG_ASSERT(s->fields < m_alloced_field_count);
new_field->init(this);
field[s->fields]= new_field;
s->reclength+= new_field->pack_length();
if (!(new_field->flags & NOT_NULL_FLAG))
s->null_fields++;
if (new_field->flags & BLOB_FLAG)
{
// Note, s->blob_fields was incremented in Field_blob::Field_blob
DBUG_ASSERT(s->blob_fields);
DBUG_ASSERT(s->blob_fields <= m_alloced_field_count);
s->blob_field[s->blob_fields - 1]= s->fields;
}
new_field->field_index= s->fields++;
return false;
}
/**
Add fields from a Spvar_definition list
@returns false - on success.
@returns true - on error.
*/
bool add(List<Spvar_definition> &field_list);
/**
Open a virtual table for read/write:
- Setup end markers in TABLE::field and TABLE_SHARE::blob_fields,
- Allocate a buffer in TABLE::record[0].
- Set field pointers (Field::ptr, Field::null_pos, Field::null_bit) to
the allocated record.
This method is called when all of the fields have been added to the table.
After calling this method the table is ready for read and write operations.
@return false - on success
@return true - on error (e.g. could not allocate the record buffer).
*/
bool open();
void set_all_fields_to_null()
{
for (uint i= 0; i < s->fields; i++)
field[i]->set_null();
}
/**
Set all fields from a compatible item list.
The number of fields in "this" must be equal to the number
of elements in "value".
*/
bool sp_set_all_fields_from_item_list(THD *thd, List<Item> &items);
/**
Set all fields from a compatible item.
The number of fields in "this" must be the same with the number
of elements in "value".
*/
bool sp_set_all_fields_from_item(THD *thd, Item *value);
/**
Find a ROW element index by its name
Assumes that "this" is used as a storage for a ROW-type SP variable.
@param [OUT] idx - the index of the found field is returned here
@param [IN] field_name - find a field with this name
@return true - on error (the field was not found)
@return false - on success (idx[0] was set to the field index)
*/
bool sp_find_field_by_name(uint *idx, const LEX_CSTRING &name) const;
/**
Find a ROW element index by its name.
If the element is not found, and error is issued.
@param [OUT] idx - the index of the found field is returned here
@param [IN] var_name - the name of the ROW variable (for error reporting)
@param [IN] field_name - find a field with this name
@return true - on error (the field was not found)
@return false - on success (idx[0] was set to the field index)
*/
bool sp_find_field_by_name_or_error(uint *idx,
const LEX_CSTRING &var_name,
const LEX_CSTRING &field_name) const;
};
/**
Create a reduced TABLE object with properly set up Field list from a
list of field definitions.
The created table doesn't have a table handler associated with
it, has no keys, no group/distinct, no copy_funcs array.
The sole purpose of this TABLE object is to use the power of Field
class to read/write data to/from table->record[0]. Then one can store
the record in any container (RB tree, hash, etc).
The table is created in THD mem_root, so are the table's fields.
Consequently, if you don't BLOB fields, you don't need to free it.
@param thd connection handle
@param field_list list of column definitions
@return
0 if out of memory, or a
TABLE object ready for read and write in case of success
*/
inline Virtual_tmp_table *
create_virtual_tmp_table(THD *thd, List<Spvar_definition> &field_list)
{
Virtual_tmp_table *table;
if (!(table= new(thd) Virtual_tmp_table(thd)))
return NULL;
/*
If "simulate_create_virtual_tmp_table_out_of_memory" debug option
is enabled, we now enable "simulate_out_of_memory". This effectively
makes table->init() fail on OOM inside multi_alloc_root().
This is done to test that ~Virtual_tmp_table() called from the "delete"
below correcly handles OOM.
*/
DBUG_EXECUTE_IF("simulate_create_virtual_tmp_table_out_of_memory",
DBUG_SET("+d,simulate_out_of_memory"););
if (table->init(field_list.elements) ||
table->add(field_list) ||
table->open())
{
delete table;
return NULL;
}
return table;
}
/**
Create a new virtual temporary table consisting of a single field.
SUM(DISTINCT expr) and similar numeric aggregate functions use this.
@param thd - Current thread
@param field - The field that will be added into the table.
@return NULL - On error.
@return !NULL - A pointer to the created table that is ready
for read and write.
*/
inline TABLE *
create_virtual_tmp_table(THD *thd, Field *field)
{
Virtual_tmp_table *table;
DBUG_ASSERT(field);
if (!(table= new(thd) Virtual_tmp_table(thd)))
return NULL;
if (table->init(1) ||
table->add(field) ||
table->open())
{
delete table;
return NULL;
}
return table;
}
int test_if_item_cache_changed(List<Cached_item> &list);
int join_init_read_record(JOIN_TAB *tab);
int join_read_record_no_init(JOIN_TAB *tab);
void set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key);
inline Item * and_items(THD *thd, Item* cond, Item *item)
{
return (cond ? (new (thd->mem_root) Item_cond_and(thd, cond, item)) : item);
}
inline Item * or_items(THD *thd, Item* cond, Item *item)
{
return (cond ? (new (thd->mem_root) Item_cond_or(thd, cond, item)) : item);
}
bool choose_plan(JOIN *join, table_map join_tables);
void optimize_wo_join_buffering(JOIN *join, uint first_tab, uint last_tab,
table_map last_remaining_tables,
bool first_alt, uint no_jbuf_before,
double *outer_rec_count, double *reopt_cost);
Item_equal *find_item_equal(COND_EQUAL *cond_equal, Field *field,
bool *inherited_fl);
extern bool test_if_ref(Item *,
Item_field *left_item,Item *right_item);
inline bool optimizer_flag(THD *thd, uint flag)
{
return (thd->variables.optimizer_switch & flag);
}
/*
int print_fake_select_lex_join(select_result_sink *result, bool on_the_fly,
SELECT_LEX *select_lex, uint8 select_options);
*/
uint get_index_for_order(ORDER *order, TABLE *table, SQL_SELECT *select,
ha_rows limit, ha_rows *scanned_limit,
bool *need_sort, bool *reverse);
ORDER *simple_remove_const(ORDER *order, COND *where);
bool const_expression_in_where(COND *cond, Item *comp_item,
Field *comp_field= NULL,
Item **const_item= NULL);
bool cond_is_datetime_is_null(Item *cond);
bool cond_has_datetime_is_null(Item *cond);
/* Table elimination entry point function */
void eliminate_tables(JOIN *join);
/* Index Condition Pushdown entry point function */
void push_index_cond(JOIN_TAB *tab, uint keyno);
#define OPT_LINK_EQUAL_FIELDS 1
/* EXPLAIN-related utility functions */
int print_explain_message_line(select_result_sink *result,
uint8 options, bool is_analyze,
uint select_number,
const char *select_type,
ha_rows *rows,
const char *message);
void explain_append_mrr_info(QUICK_RANGE_SELECT *quick, String *res);
int append_possible_keys(MEM_ROOT *alloc, String_list &list, TABLE *table,
key_map possible_keys);
/****************************************************************************
Temporary table support for SQL Runtime
***************************************************************************/
#define STRING_TOTAL_LENGTH_TO_PACK_ROWS 128
#define AVG_STRING_LENGTH_TO_PACK_ROWS 64
#define RATIO_TO_PACK_ROWS 2
#define MIN_STRING_LENGTH_TO_PACK_ROWS 10
TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
ORDER *group, bool distinct, bool save_sum_fields,
ulonglong select_options, ha_rows rows_limit,
const LEX_CSTRING *alias, bool do_not_open=FALSE,
bool keep_row_order= FALSE);
void free_tmp_table(THD *thd, TABLE *entry);
bool create_internal_tmp_table_from_heap(THD *thd, TABLE *table,
TMP_ENGINE_COLUMNDEF *start_recinfo,
TMP_ENGINE_COLUMNDEF **recinfo,
int error, bool ignore_last_dupp_key_error,
bool *is_duplicate);
bool create_internal_tmp_table(TABLE *table, KEY *keyinfo,
TMP_ENGINE_COLUMNDEF *start_recinfo,
TMP_ENGINE_COLUMNDEF **recinfo,
ulonglong options);
bool instantiate_tmp_table(TABLE *table, KEY *keyinfo,
TMP_ENGINE_COLUMNDEF *start_recinfo,
TMP_ENGINE_COLUMNDEF **recinfo,
ulonglong options);
bool open_tmp_table(TABLE *table);
void setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps);
double prev_record_reads(POSITION *positions, uint idx, table_map found_ref);
void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist);
double get_tmp_table_lookup_cost(THD *thd, double row_count, uint row_size);
double get_tmp_table_write_cost(THD *thd, double row_count, uint row_size);
void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
bool sort_and_filter_keyuse(THD *thd, DYNAMIC_ARRAY *keyuse,
bool skip_unprefixed_keyparts);
struct st_cond_statistic
{
Item *cond;
Field *field_arg;
ulong positive;
};
typedef struct st_cond_statistic COND_STATISTIC;
ulong check_selectivity(THD *thd,
ulong rows_to_read,
TABLE *table,
List<COND_STATISTIC> *conds);
class Pushdown_query: public Sql_alloc
{
public:
SELECT_LEX *select_lex;
bool store_data_in_temp_table;
group_by_handler *handler;
Item *having;
Pushdown_query(SELECT_LEX *select_lex_arg, group_by_handler *handler_arg)
: select_lex(select_lex_arg), store_data_in_temp_table(0),
handler(handler_arg), having(0) {}
~Pushdown_query() { delete handler; }
/* Function that calls the above scan functions */
int execute(JOIN *join);
};
bool test_if_order_compatible(SQL_I_List<ORDER> &a, SQL_I_List<ORDER> &b);
int test_if_group_changed(List<Cached_item> &list);
int create_sort_index(THD *thd, JOIN *join, JOIN_TAB *tab, Filesort *fsort);
JOIN_TAB *first_explain_order_tab(JOIN* join);
JOIN_TAB *next_explain_order_tab(JOIN* join, JOIN_TAB* tab);
#endif /* SQL_SELECT_INCLUDED */
|