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
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
|
/*-------------------------------------------------------------------------
*
* subselect.c
* Planning routines for subselects.
*
* This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
* not sub-SELECT-in-FROM cases).
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/optimizer/plan/subselect.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/optimizer.h"
#include "optimizer/paramassign.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "parser/parse_relation.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
typedef struct convert_testexpr_context
{
PlannerInfo *root;
List *subst_nodes; /* Nodes to substitute for Params */
} convert_testexpr_context;
typedef struct process_sublinks_context
{
PlannerInfo *root;
bool isTopQual;
} process_sublinks_context;
typedef struct finalize_primnode_context
{
PlannerInfo *root;
Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
} finalize_primnode_context;
typedef struct inline_cte_walker_context
{
const char *ctename; /* name and relative level of target CTE */
int levelsup;
Query *ctequery; /* query to substitute */
} inline_cte_walker_context;
static Node *build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
List *plan_params,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, List *testexpr_paramids,
bool unknownEqFalse);
static List *generate_subquery_params(PlannerInfo *root, List *tlist,
List **paramIds);
static List *generate_subquery_vars(PlannerInfo *root, List *tlist,
Index varno);
static Node *convert_testexpr(PlannerInfo *root,
Node *testexpr,
List *subst_nodes);
static Node *convert_testexpr_mutator(Node *node,
convert_testexpr_context *context);
static bool subplan_is_hashable(Plan *plan);
static bool subpath_is_hashable(Path *path);
static bool testexpr_is_hashable(Node *testexpr, List *param_ids);
static bool test_opexpr_is_hashable(OpExpr *testexpr, List *param_ids);
static bool hash_ok_operator(OpExpr *expr);
static bool contain_dml(Node *node);
static bool contain_dml_walker(Node *node, void *context);
static bool contain_outer_selfref(Node *node);
static bool contain_outer_selfref_walker(Node *node, Index *depth);
static void inline_cte(PlannerInfo *root, CommonTableExpr *cte);
static bool inline_cte_walker(Node *node, inline_cte_walker_context *context);
static bool simplify_EXISTS_query(PlannerInfo *root, Query *query);
static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
Node **testexpr, List **paramIds);
static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
static Node *process_sublinks_mutator(Node *node,
process_sublinks_context *context);
static Bitmapset *finalize_plan(PlannerInfo *root,
Plan *plan,
int gather_param,
Bitmapset *valid_params,
Bitmapset *scan_params);
static bool finalize_primnode(Node *node, finalize_primnode_context *context);
static bool finalize_agg_primnode(Node *node, finalize_primnode_context *context);
/*
* Get the datatype/typmod/collation of the first column of the plan's output.
*
* This information is stored for ARRAY_SUBLINK execution and for
* exprType()/exprTypmod()/exprCollation(), which have no way to get at the
* plan associated with a SubPlan node. We really only need the info for
* EXPR_SUBLINK and ARRAY_SUBLINK subplans, but for consistency we save it
* always.
*/
static void
get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod,
Oid *colcollation)
{
/* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
if (plan->targetlist)
{
TargetEntry *tent = linitial_node(TargetEntry, plan->targetlist);
if (!tent->resjunk)
{
*coltype = exprType((Node *) tent->expr);
*coltypmod = exprTypmod((Node *) tent->expr);
*colcollation = exprCollation((Node *) tent->expr);
return;
}
}
*coltype = VOIDOID;
*coltypmod = -1;
*colcollation = InvalidOid;
}
/*
* Convert a SubLink (as created by the parser) into a SubPlan.
*
* We are given the SubLink's contained query, type, ID, and testexpr. We are
* also told if this expression appears at top level of a WHERE/HAVING qual.
*
* Note: we assume that the testexpr has been AND/OR flattened (actually,
* it's been through eval_const_expressions), but not converted to
* implicit-AND form; and any SubLinks in it should already have been
* converted to SubPlans. The subquery is as yet untouched, however.
*
* The result is whatever we need to substitute in place of the SubLink node
* in the executable expression. If we're going to do the subplan as a
* regular subplan, this will be the constructed SubPlan node. If we're going
* to do the subplan as an InitPlan, the SubPlan node instead goes into
* root->init_plans, and what we return here is an expression tree
* representing the InitPlan's result: usually just a Param node representing
* a single scalar result, but possibly a row comparison tree containing
* multiple Param nodes, or for a MULTIEXPR subquery a simple NULL constant
* (since the real output Params are elsewhere in the tree, and the MULTIEXPR
* subquery itself is in a resjunk tlist entry whose value is uninteresting).
*/
static Node *
make_subplan(PlannerInfo *root, Query *orig_subquery,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, bool isTopQual)
{
Query *subquery;
bool simple_exists = false;
double tuple_fraction;
PlannerInfo *subroot;
RelOptInfo *final_rel;
Path *best_path;
Plan *plan;
List *plan_params;
Node *result;
/*
* Copy the source Query node. This is a quick and dirty kluge to resolve
* the fact that the parser can generate trees with multiple links to the
* same sub-Query node, but the planner wants to scribble on the Query.
* Try to clean this up when we do querytree redesign...
*/
subquery = copyObject(orig_subquery);
/*
* If it's an EXISTS subplan, we might be able to simplify it.
*/
if (subLinkType == EXISTS_SUBLINK)
simple_exists = simplify_EXISTS_query(root, subquery);
/*
* For an EXISTS subplan, tell lower-level planner to expect that only the
* first tuple will be retrieved. For ALL and ANY subplans, we will be
* able to stop evaluating if the test condition fails or matches, so very
* often not all the tuples will be retrieved; for lack of a better idea,
* specify 50% retrieval. For EXPR, MULTIEXPR, and ROWCOMPARE subplans,
* use default behavior (we're only expecting one row out, anyway).
*
* NOTE: if you change these numbers, also change cost_subplan() in
* path/costsize.c.
*
* XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
* its output. In that case it would've been better to specify full
* retrieval. At present, however, we can only check hashability after
* we've made the subplan :-(. (Determining whether it'll fit in hash_mem
* is the really hard part.) Therefore, we don't want to be too
* optimistic about the percentage of tuples retrieved, for fear of
* selecting a plan that's bad for the materialization case.
*/
if (subLinkType == EXISTS_SUBLINK)
tuple_fraction = 1.0; /* just like a LIMIT 1 */
else if (subLinkType == ALL_SUBLINK ||
subLinkType == ANY_SUBLINK)
tuple_fraction = 0.5; /* 50% */
else
tuple_fraction = 0.0; /* default behavior */
/* plan_params should not be in use in current query level */
Assert(root->plan_params == NIL);
/* Generate Paths for the subquery */
subroot = subquery_planner(root->glob, subquery,
root,
false, tuple_fraction);
/* Isolate the params needed by this specific subplan */
plan_params = root->plan_params;
root->plan_params = NIL;
/*
* Select best Path and turn it into a Plan. At least for now, there
* seems no reason to postpone doing that.
*/
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
plan = create_plan(subroot, best_path);
/* And convert to SubPlan or InitPlan format. */
result = build_subplan(root, plan, subroot, plan_params,
subLinkType, subLinkId,
testexpr, NIL, isTopQual);
/*
* If it's a correlated EXISTS with an unimportant targetlist, we might be
* able to transform it to the equivalent of an IN and then implement it
* by hashing. We don't have enough information yet to tell which way is
* likely to be better (it depends on the expected number of executions of
* the EXISTS qual, and we are much too early in planning the outer query
* to be able to guess that). So we generate both plans, if possible, and
* leave it to setrefs.c to decide which to use.
*/
if (simple_exists && IsA(result, SubPlan))
{
Node *newtestexpr;
List *paramIds;
/* Make a second copy of the original subquery */
subquery = copyObject(orig_subquery);
/* and re-simplify */
simple_exists = simplify_EXISTS_query(root, subquery);
Assert(simple_exists);
/* See if it can be converted to an ANY query */
subquery = convert_EXISTS_to_ANY(root, subquery,
&newtestexpr, ¶mIds);
if (subquery)
{
/* Generate Paths for the ANY subquery; we'll need all rows */
subroot = subquery_planner(root->glob, subquery,
root,
false, 0.0);
/* Isolate the params needed by this specific subplan */
plan_params = root->plan_params;
root->plan_params = NIL;
/* Select best Path */
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = final_rel->cheapest_total_path;
/* Now we can check if it'll fit in hash_mem */
if (subpath_is_hashable(best_path))
{
SubPlan *hashplan;
AlternativeSubPlan *asplan;
/* OK, finish planning the ANY subquery */
plan = create_plan(subroot, best_path);
/* ... and convert to SubPlan format */
hashplan = castNode(SubPlan,
build_subplan(root, plan, subroot,
plan_params,
ANY_SUBLINK, 0,
newtestexpr,
paramIds,
true));
/* Check we got what we expected */
Assert(hashplan->parParam == NIL);
Assert(hashplan->useHashTable);
/* Leave it to setrefs.c to decide which plan to use */
asplan = makeNode(AlternativeSubPlan);
asplan->subplans = list_make2(result, hashplan);
result = (Node *) asplan;
root->hasAlternativeSubPlans = true;
}
}
}
return result;
}
/*
* Build a SubPlan node given the raw inputs --- subroutine for make_subplan
*
* Returns either the SubPlan, or a replacement expression if we decide to
* make it an InitPlan, as explained in the comments for make_subplan.
*/
static Node *
build_subplan(PlannerInfo *root, Plan *plan, PlannerInfo *subroot,
List *plan_params,
SubLinkType subLinkType, int subLinkId,
Node *testexpr, List *testexpr_paramids,
bool unknownEqFalse)
{
Node *result;
SubPlan *splan;
bool isInitPlan;
ListCell *lc;
/*
* Initialize the SubPlan node. Note plan_id, plan_name, and cost fields
* are set further down.
*/
splan = makeNode(SubPlan);
splan->subLinkType = subLinkType;
splan->testexpr = NULL;
splan->paramIds = NIL;
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
&splan->firstColCollation);
splan->useHashTable = false;
splan->unknownEqFalse = unknownEqFalse;
splan->parallel_safe = plan->parallel_safe;
splan->setParam = NIL;
splan->parParam = NIL;
splan->args = NIL;
/*
* Make parParam and args lists of param IDs and expressions that current
* query level will pass to this child plan.
*/
foreach(lc, plan_params)
{
PlannerParamItem *pitem = (PlannerParamItem *) lfirst(lc);
Node *arg = pitem->item;
/*
* The Var, PlaceHolderVar, Aggref or GroupingFunc has already been
* adjusted to have the correct varlevelsup, phlevelsup, or
* agglevelsup.
*
* If it's a PlaceHolderVar, Aggref or GroupingFunc, its arguments
* might contain SubLinks, which have not yet been processed (see the
* comments for SS_replace_correlation_vars). Do that now.
*/
if (IsA(arg, PlaceHolderVar) ||
IsA(arg, Aggref) ||
IsA(arg, GroupingFunc))
arg = SS_process_sublinks(root, arg, false);
splan->parParam = lappend_int(splan->parParam, pitem->paramId);
splan->args = lappend(splan->args, arg);
}
/*
* Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY,
* ROWCOMPARE, or MULTIEXPR types can be used as initPlans. For EXISTS,
* EXPR, or ARRAY, we return a Param referring to the result of evaluating
* the initPlan. For ROWCOMPARE, we must modify the testexpr tree to
* contain PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted
* by the parser, and then return that tree. For MULTIEXPR, we return a
* null constant: the resjunk targetlist item containing the SubLink does
* not need to return anything useful, since the referencing Params are
* elsewhere.
*/
if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
{
Param *prm;
Assert(testexpr == NULL);
prm = generate_new_exec_param(root, BOOLOID, -1, InvalidOid);
splan->setParam = list_make1_int(prm->paramid);
isInitPlan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
{
TargetEntry *te = linitial(plan->targetlist);
Param *prm;
Assert(!te->resjunk);
Assert(testexpr == NULL);
prm = generate_new_exec_param(root,
exprType((Node *) te->expr),
exprTypmod((Node *) te->expr),
exprCollation((Node *) te->expr));
splan->setParam = list_make1_int(prm->paramid);
isInitPlan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
{
TargetEntry *te = linitial(plan->targetlist);
Oid arraytype;
Param *prm;
Assert(!te->resjunk);
Assert(testexpr == NULL);
arraytype = get_promoted_array_type(exprType((Node *) te->expr));
if (!OidIsValid(arraytype))
elog(ERROR, "could not find array type for datatype %s",
format_type_be(exprType((Node *) te->expr)));
prm = generate_new_exec_param(root,
arraytype,
exprTypmod((Node *) te->expr),
exprCollation((Node *) te->expr));
splan->setParam = list_make1_int(prm->paramid);
isInitPlan = true;
result = (Node *) prm;
}
else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
{
/* Adjust the Params */
List *params;
Assert(testexpr != NULL);
params = generate_subquery_params(root,
plan->targetlist,
&splan->paramIds);
result = convert_testexpr(root,
testexpr,
params);
splan->setParam = list_copy(splan->paramIds);
isInitPlan = true;
/*
* The executable expression is returned to become part of the outer
* plan's expression tree; it is not kept in the initplan node.
*/
}
else if (subLinkType == MULTIEXPR_SUBLINK)
{
/*
* Whether it's an initplan or not, it needs to set a PARAM_EXEC Param
* for each output column.
*/
List *params;
Assert(testexpr == NULL);
params = generate_subquery_params(root,
plan->targetlist,
&splan->setParam);
/*
* Save the list of replacement Params in the n'th cell of
* root->multiexpr_params; setrefs.c will use it to replace
* PARAM_MULTIEXPR Params.
*/
while (list_length(root->multiexpr_params) < subLinkId)
root->multiexpr_params = lappend(root->multiexpr_params, NIL);
lc = list_nth_cell(root->multiexpr_params, subLinkId - 1);
Assert(lfirst(lc) == NIL);
lfirst(lc) = params;
/* It can be an initplan if there are no parParams. */
if (splan->parParam == NIL)
{
isInitPlan = true;
result = (Node *) makeNullConst(RECORDOID, -1, InvalidOid);
}
else
{
isInitPlan = false;
result = (Node *) splan;
}
}
else
{
/*
* Adjust the Params in the testexpr, unless caller already took care
* of it (as indicated by passing a list of Param IDs).
*/
if (testexpr && testexpr_paramids == NIL)
{
List *params;
params = generate_subquery_params(root,
plan->targetlist,
&splan->paramIds);
splan->testexpr = convert_testexpr(root,
testexpr,
params);
}
else
{
splan->testexpr = testexpr;
splan->paramIds = testexpr_paramids;
}
/*
* We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
* initPlans, even when they are uncorrelated or undirect correlated,
* because we need to scan the output of the subplan for each outer
* tuple. But if it's a not-direct-correlated IN (= ANY) test, we
* might be able to use a hashtable to avoid comparing all the tuples.
*/
if (subLinkType == ANY_SUBLINK &&
splan->parParam == NIL &&
subplan_is_hashable(plan) &&
testexpr_is_hashable(splan->testexpr, splan->paramIds))
splan->useHashTable = true;
/*
* Otherwise, we have the option to tack a Material node onto the top
* of the subplan, to reduce the cost of reading it repeatedly. This
* is pointless for a direct-correlated subplan, since we'd have to
* recompute its results each time anyway. For uncorrelated/undirect
* correlated subplans, we add Material unless the subplan's top plan
* node would materialize its output anyway. Also, if enable_material
* is false, then the user does not want us to materialize anything
* unnecessarily, so we don't.
*/
else if (splan->parParam == NIL && enable_material &&
!ExecMaterializesOutput(nodeTag(plan)))
plan = materialize_finished_plan(plan);
result = (Node *) splan;
isInitPlan = false;
}
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
splan->plan_id = list_length(root->glob->subplans);
if (isInitPlan)
root->init_plans = lappend(root->init_plans, splan);
/*
* A parameterless subplan (not initplan) should be prepared to handle
* REWIND efficiently. If it has direct parameters then there's no point
* since it'll be reset on each scan anyway; and if it's an initplan then
* there's no point since it won't get re-run without parameter changes
* anyway. The input of a hashed subplan doesn't need REWIND either.
*/
if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
splan->plan_id);
/* Label the subplan for EXPLAIN purposes */
splan->plan_name = palloc(32 + 12 * list_length(splan->setParam));
sprintf(splan->plan_name, "%s %d",
isInitPlan ? "InitPlan" : "SubPlan",
splan->plan_id);
if (splan->setParam)
{
char *ptr = splan->plan_name + strlen(splan->plan_name);
ptr += sprintf(ptr, " (returns ");
foreach(lc, splan->setParam)
{
ptr += sprintf(ptr, "$%d%s",
lfirst_int(lc),
lnext(splan->setParam, lc) ? "," : ")");
}
}
/* Lastly, fill in the cost estimates for use later */
cost_subplan(root, splan, plan);
return result;
}
/*
* generate_subquery_params: build a list of Params representing the output
* columns of a sublink's sub-select, given the sub-select's targetlist.
*
* We also return an integer list of the paramids of the Params.
*/
static List *
generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
{
List *result;
List *ids;
ListCell *lc;
result = ids = NIL;
foreach(lc, tlist)
{
TargetEntry *tent = (TargetEntry *) lfirst(lc);
Param *param;
if (tent->resjunk)
continue;
param = generate_new_exec_param(root,
exprType((Node *) tent->expr),
exprTypmod((Node *) tent->expr),
exprCollation((Node *) tent->expr));
result = lappend(result, param);
ids = lappend_int(ids, param->paramid);
}
*paramIds = ids;
return result;
}
/*
* generate_subquery_vars: build a list of Vars representing the output
* columns of a sublink's sub-select, given the sub-select's targetlist.
* The Vars have the specified varno (RTE index).
*/
static List *
generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
{
List *result;
ListCell *lc;
result = NIL;
foreach(lc, tlist)
{
TargetEntry *tent = (TargetEntry *) lfirst(lc);
Var *var;
if (tent->resjunk)
continue;
var = makeVarFromTargetEntry(varno, tent);
result = lappend(result, var);
}
return result;
}
/*
* convert_testexpr: convert the testexpr given by the parser into
* actually executable form. This entails replacing PARAM_SUBLINK Params
* with Params or Vars representing the results of the sub-select. The
* nodes to be substituted are passed in as the List result from
* generate_subquery_params or generate_subquery_vars.
*/
static Node *
convert_testexpr(PlannerInfo *root,
Node *testexpr,
List *subst_nodes)
{
convert_testexpr_context context;
context.root = root;
context.subst_nodes = subst_nodes;
return convert_testexpr_mutator(testexpr, &context);
}
static Node *
convert_testexpr_mutator(Node *node,
convert_testexpr_context *context)
{
if (node == NULL)
return NULL;
if (IsA(node, Param))
{
Param *param = (Param *) node;
if (param->paramkind == PARAM_SUBLINK)
{
if (param->paramid <= 0 ||
param->paramid > list_length(context->subst_nodes))
elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
/*
* We copy the list item to avoid having doubly-linked
* substructure in the modified parse tree. This is probably
* unnecessary when it's a Param, but be safe.
*/
return (Node *) copyObject(list_nth(context->subst_nodes,
param->paramid - 1));
}
}
if (IsA(node, SubLink))
{
/*
* If we come across a nested SubLink, it is neither necessary nor
* correct to recurse into it: any PARAM_SUBLINKs we might find inside
* belong to the inner SubLink not the outer. So just return it as-is.
*
* This reasoning depends on the assumption that nothing will pull
* subexpressions into or out of the testexpr field of a SubLink, at
* least not without replacing PARAM_SUBLINKs first. If we did want
* to do that we'd need to rethink the parser-output representation
* altogether, since currently PARAM_SUBLINKs are only unique per
* SubLink not globally across the query. The whole point of
* replacing them with Vars or PARAM_EXEC nodes is to make them
* globally unique before they escape from the SubLink's testexpr.
*
* Note: this can't happen when called during SS_process_sublinks,
* because that recursively processes inner SubLinks first. It can
* happen when called from convert_ANY_sublink_to_join, though.
*/
return node;
}
return expression_tree_mutator(node,
convert_testexpr_mutator,
(void *) context);
}
/*
* subplan_is_hashable: can we implement an ANY subplan by hashing?
*
* This is not responsible for checking whether the combining testexpr
* is suitable for hashing. We only look at the subquery itself.
*/
static bool
subplan_is_hashable(Plan *plan)
{
double subquery_size;
/*
* The estimated size of the subquery result must fit in hash_mem. (Note:
* we use heap tuple overhead here even though the tuples will actually be
* stored as MinimalTuples; this provides some fudge factor for hashtable
* overhead.)
*/
subquery_size = plan->plan_rows *
(MAXALIGN(plan->plan_width) + MAXALIGN(SizeofHeapTupleHeader));
if (subquery_size > get_hash_memory_limit())
return false;
return true;
}
/*
* subpath_is_hashable: can we implement an ANY subplan by hashing?
*
* Identical to subplan_is_hashable, but work from a Path for the subplan.
*/
static bool
subpath_is_hashable(Path *path)
{
double subquery_size;
/*
* The estimated size of the subquery result must fit in hash_mem. (Note:
* we use heap tuple overhead here even though the tuples will actually be
* stored as MinimalTuples; this provides some fudge factor for hashtable
* overhead.)
*/
subquery_size = path->rows *
(MAXALIGN(path->pathtarget->width) + MAXALIGN(SizeofHeapTupleHeader));
if (subquery_size > get_hash_memory_limit())
return false;
return true;
}
/*
* testexpr_is_hashable: is an ANY SubLink's test expression hashable?
*
* To identify LHS vs RHS of the hash expression, we must be given the
* list of output Param IDs of the SubLink's subquery.
*/
static bool
testexpr_is_hashable(Node *testexpr, List *param_ids)
{
/*
* The testexpr must be a single OpExpr, or an AND-clause containing only
* OpExprs, each of which satisfy test_opexpr_is_hashable().
*/
if (testexpr && IsA(testexpr, OpExpr))
{
if (test_opexpr_is_hashable((OpExpr *) testexpr, param_ids))
return true;
}
else if (is_andclause(testexpr))
{
ListCell *l;
foreach(l, ((BoolExpr *) testexpr)->args)
{
Node *andarg = (Node *) lfirst(l);
if (!IsA(andarg, OpExpr))
return false;
if (!test_opexpr_is_hashable((OpExpr *) andarg, param_ids))
return false;
}
return true;
}
return false;
}
static bool
test_opexpr_is_hashable(OpExpr *testexpr, List *param_ids)
{
/*
* The combining operator must be hashable and strict. The need for
* hashability is obvious, since we want to use hashing. Without
* strictness, behavior in the presence of nulls is too unpredictable. We
* actually must assume even more than plain strictness: it can't yield
* NULL for non-null inputs, either (see nodeSubplan.c). However, hash
* indexes and hash joins assume that too.
*/
if (!hash_ok_operator(testexpr))
return false;
/*
* The left and right inputs must belong to the outer and inner queries
* respectively; hence Params that will be supplied by the subquery must
* not appear in the LHS, and Vars of the outer query must not appear in
* the RHS. (Ordinarily, this must be true because of the way that the
* parser builds an ANY SubLink's testexpr ... but inlining of functions
* could have changed the expression's structure, so we have to check.
* Such cases do not occur often enough to be worth trying to optimize, so
* we don't worry about trying to commute the clause or anything like
* that; we just need to be sure not to build an invalid plan.)
*/
if (list_length(testexpr->args) != 2)
return false;
if (contain_exec_param((Node *) linitial(testexpr->args), param_ids))
return false;
if (contain_var_clause((Node *) lsecond(testexpr->args)))
return false;
return true;
}
/*
* Check expression is hashable + strict
*
* We could use op_hashjoinable() and op_strict(), but do it like this to
* avoid a redundant cache lookup.
*/
static bool
hash_ok_operator(OpExpr *expr)
{
Oid opid = expr->opno;
/* quick out if not a binary operator */
if (list_length(expr->args) != 2)
return false;
if (opid == ARRAY_EQ_OP ||
opid == RECORD_EQ_OP)
{
/* these are strict, but must check input type to ensure hashable */
Node *leftarg = linitial(expr->args);
return op_hashjoinable(opid, exprType(leftarg));
}
else
{
/* else must look up the operator properties */
HeapTuple tup;
Form_pg_operator optup;
tup = SearchSysCache1(OPEROID, ObjectIdGetDatum(opid));
if (!HeapTupleIsValid(tup))
elog(ERROR, "cache lookup failed for operator %u", opid);
optup = (Form_pg_operator) GETSTRUCT(tup);
if (!optup->oprcanhash || !func_strict(optup->oprcode))
{
ReleaseSysCache(tup);
return false;
}
ReleaseSysCache(tup);
return true;
}
}
/*
* SS_process_ctes: process a query's WITH list
*
* Consider each CTE in the WITH list and either ignore it (if it's an
* unreferenced SELECT), "inline" it to create a regular sub-SELECT-in-FROM,
* or convert it to an initplan.
*
* A side effect is to fill in root->cte_plan_ids with a list that
* parallels root->parse->cteList and provides the subplan ID for
* each CTE's initplan, or a dummy ID (-1) if we didn't make an initplan.
*/
void
SS_process_ctes(PlannerInfo *root)
{
ListCell *lc;
Assert(root->cte_plan_ids == NIL);
foreach(lc, root->parse->cteList)
{
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
CmdType cmdType = ((Query *) cte->ctequery)->commandType;
Query *subquery;
PlannerInfo *subroot;
RelOptInfo *final_rel;
Path *best_path;
Plan *plan;
SubPlan *splan;
int paramid;
/*
* Ignore SELECT CTEs that are not actually referenced anywhere.
*/
if (cte->cterefcount == 0 && cmdType == CMD_SELECT)
{
/* Make a dummy entry in cte_plan_ids */
root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
continue;
}
/*
* Consider inlining the CTE (creating RTE_SUBQUERY RTE(s)) instead of
* implementing it as a separately-planned CTE.
*
* We cannot inline if any of these conditions hold:
*
* 1. The user said not to (the CTEMaterializeAlways option).
*
* 2. The CTE is recursive.
*
* 3. The CTE has side-effects; this includes either not being a plain
* SELECT, or containing volatile functions. Inlining might change
* the side-effects, which would be bad.
*
* 4. The CTE is multiply-referenced and contains a self-reference to
* a recursive CTE outside itself. Inlining would result in multiple
* recursive self-references, which we don't support.
*
* Otherwise, we have an option whether to inline or not. That should
* always be a win if there's just a single reference, but if the CTE
* is multiply-referenced then it's unclear: inlining adds duplicate
* computations, but the ability to absorb restrictions from the outer
* query level could outweigh that. We do not have nearly enough
* information at this point to tell whether that's true, so we let
* the user express a preference. Our default behavior is to inline
* only singly-referenced CTEs, but a CTE marked CTEMaterializeNever
* will be inlined even if multiply referenced.
*
* Note: we check for volatile functions last, because that's more
* expensive than the other tests needed.
*/
if ((cte->ctematerialized == CTEMaterializeNever ||
(cte->ctematerialized == CTEMaterializeDefault &&
cte->cterefcount == 1)) &&
!cte->cterecursive &&
cmdType == CMD_SELECT &&
!contain_dml(cte->ctequery) &&
(cte->cterefcount <= 1 ||
!contain_outer_selfref(cte->ctequery)) &&
!contain_volatile_functions(cte->ctequery))
{
inline_cte(root, cte);
/* Make a dummy entry in cte_plan_ids */
root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
continue;
}
/*
* Copy the source Query node. Probably not necessary, but let's keep
* this similar to make_subplan.
*/
subquery = (Query *) copyObject(cte->ctequery);
/* plan_params should not be in use in current query level */
Assert(root->plan_params == NIL);
/*
* Generate Paths for the CTE query. Always plan for full retrieval
* --- we don't have enough info to predict otherwise.
*/
subroot = subquery_planner(root->glob, subquery,
root,
cte->cterecursive, 0.0);
/*
* Since the current query level doesn't yet contain any RTEs, it
* should not be possible for the CTE to have requested parameters of
* this level.
*/
if (root->plan_params)
elog(ERROR, "unexpected outer reference in CTE query");
/*
* Select best Path and turn it into a Plan. At least for now, there
* seems no reason to postpone doing that.
*/
final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
best_path = final_rel->cheapest_total_path;
plan = create_plan(subroot, best_path);
/*
* Make a SubPlan node for it. This is just enough unlike
* build_subplan that we can't share code.
*
* Note plan_id, plan_name, and cost fields are set further down.
*/
splan = makeNode(SubPlan);
splan->subLinkType = CTE_SUBLINK;
splan->testexpr = NULL;
splan->paramIds = NIL;
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod,
&splan->firstColCollation);
splan->useHashTable = false;
splan->unknownEqFalse = false;
/*
* CTE scans are not considered for parallelism (cf
* set_rel_consider_parallel), and even if they were, initPlans aren't
* parallel-safe.
*/
splan->parallel_safe = false;
splan->setParam = NIL;
splan->parParam = NIL;
splan->args = NIL;
/*
* The node can't have any inputs (since it's an initplan), so the
* parParam and args lists remain empty. (It could contain references
* to earlier CTEs' output param IDs, but CTE outputs are not
* propagated via the args list.)
*/
/*
* Assign a param ID to represent the CTE's output. No ordinary
* "evaluation" of this param slot ever happens, but we use the param
* ID for setParam/chgParam signaling just as if the CTE plan were
* returning a simple scalar output. (Also, the executor abuses the
* ParamExecData slot for this param ID for communication among
* multiple CteScan nodes that might be scanning this CTE.)
*/
paramid = assign_special_exec_param(root);
splan->setParam = list_make1_int(paramid);
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
splan->plan_id = list_length(root->glob->subplans);
root->init_plans = lappend(root->init_plans, splan);
root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
/* Label the subplan for EXPLAIN purposes */
splan->plan_name = psprintf("CTE %s", cte->ctename);
/* Lastly, fill in the cost estimates for use later */
cost_subplan(root, splan, plan);
}
}
/*
* contain_dml: is any subquery not a plain SELECT?
*
* We reject SELECT FOR UPDATE/SHARE as well as INSERT etc.
*/
static bool
contain_dml(Node *node)
{
return contain_dml_walker(node, NULL);
}
static bool
contain_dml_walker(Node *node, void *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
if (query->commandType != CMD_SELECT ||
query->rowMarks != NIL)
return true;
return query_tree_walker(query, contain_dml_walker, context, 0);
}
return expression_tree_walker(node, contain_dml_walker, context);
}
/*
* contain_outer_selfref: is there an external recursive self-reference?
*/
static bool
contain_outer_selfref(Node *node)
{
Index depth = 0;
/*
* We should be starting with a Query, so that depth will be 1 while
* examining its immediate contents.
*/
Assert(IsA(node, Query));
return contain_outer_selfref_walker(node, &depth);
}
static bool
contain_outer_selfref_walker(Node *node, Index *depth)
{
if (node == NULL)
return false;
if (IsA(node, RangeTblEntry))
{
RangeTblEntry *rte = (RangeTblEntry *) node;
/*
* Check for a self-reference to a CTE that's above the Query that our
* search started at.
*/
if (rte->rtekind == RTE_CTE &&
rte->self_reference &&
rte->ctelevelsup >= *depth)
return true;
return false; /* allow range_table_walker to continue */
}
if (IsA(node, Query))
{
/* Recurse into subquery, tracking nesting depth properly */
Query *query = (Query *) node;
bool result;
(*depth)++;
result = query_tree_walker(query, contain_outer_selfref_walker,
(void *) depth, QTW_EXAMINE_RTES_BEFORE);
(*depth)--;
return result;
}
return expression_tree_walker(node, contain_outer_selfref_walker,
(void *) depth);
}
/*
* inline_cte: convert RTE_CTE references to given CTE into RTE_SUBQUERYs
*/
static void
inline_cte(PlannerInfo *root, CommonTableExpr *cte)
{
struct inline_cte_walker_context context;
context.ctename = cte->ctename;
/* Start at levelsup = -1 because we'll immediately increment it */
context.levelsup = -1;
context.ctequery = castNode(Query, cte->ctequery);
(void) inline_cte_walker((Node *) root->parse, &context);
}
static bool
inline_cte_walker(Node *node, inline_cte_walker_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Query))
{
Query *query = (Query *) node;
context->levelsup++;
/*
* Visit the query's RTE nodes after their contents; otherwise
* query_tree_walker would descend into the newly inlined CTE query,
* which we don't want.
*/
(void) query_tree_walker(query, inline_cte_walker, context,
QTW_EXAMINE_RTES_AFTER);
context->levelsup--;
return false;
}
else if (IsA(node, RangeTblEntry))
{
RangeTblEntry *rte = (RangeTblEntry *) node;
if (rte->rtekind == RTE_CTE &&
strcmp(rte->ctename, context->ctename) == 0 &&
rte->ctelevelsup == context->levelsup)
{
/*
* Found a reference to replace. Generate a copy of the CTE query
* with appropriate level adjustment for outer references (e.g.,
* to other CTEs).
*/
Query *newquery = copyObject(context->ctequery);
if (context->levelsup > 0)
IncrementVarSublevelsUp((Node *) newquery, context->levelsup, 1);
/*
* Convert the RTE_CTE RTE into a RTE_SUBQUERY.
*
* Historically, a FOR UPDATE clause has been treated as extending
* into views and subqueries, but not into CTEs. We preserve this
* distinction by not trying to push rowmarks into the new
* subquery.
*/
rte->rtekind = RTE_SUBQUERY;
rte->subquery = newquery;
rte->security_barrier = false;
/* Zero out CTE-specific fields */
rte->ctename = NULL;
rte->ctelevelsup = 0;
rte->self_reference = false;
rte->coltypes = NIL;
rte->coltypmods = NIL;
rte->colcollations = NIL;
}
return false;
}
return expression_tree_walker(node, inline_cte_walker, context);
}
/*
* convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
*
* The caller has found an ANY SubLink at the top level of one of the query's
* qual clauses, but has not checked the properties of the SubLink further.
* Decide whether it is appropriate to process this SubLink in join style.
* If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
* be converted to a join.
*
* The only non-obvious input parameter is available_rels: this is the set
* of query rels that can safely be referenced in the sublink expression.
* (We must restrict this to avoid changing the semantics when a sublink
* is present in an outer join's ON qual.) The conversion must fail if
* the converted qual would reference any but these parent-query relids.
*
* On success, the returned JoinExpr has larg = NULL and rarg = the jointree
* item representing the pulled-up subquery. The caller must set larg to
* represent the relation(s) on the lefthand side of the new join, and insert
* the JoinExpr into the upper query's jointree at an appropriate place
* (typically, where the lefthand relation(s) had been). Note that the
* passed-in SubLink must also be removed from its original position in the
* query quals, since the quals of the returned JoinExpr replace it.
* (Notionally, we replace the SubLink with a constant TRUE, then elide the
* redundant constant from the qual.)
*
* On success, the caller is also responsible for recursively applying
* pull_up_sublinks processing to the rarg and quals of the returned JoinExpr.
* (On failure, there is no need to do anything, since pull_up_sublinks will
* be applied when we recursively plan the sub-select.)
*
* Side effects of a successful conversion include adding the SubLink's
* subselect to the query's rangetable, so that it can be referenced in
* the JoinExpr's rarg.
*/
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Relids upper_varnos;
int rtindex;
ParseNamespaceItem *nsitem;
RangeTblEntry *rte;
RangeTblRef *rtr;
List *subquery_vars;
Node *quals;
ParseState *pstate;
Assert(sublink->subLinkType == ANY_SUBLINK);
/*
* The sub-select must not refer to any Vars of the parent query. (Vars of
* higher levels should be okay, though.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
return NULL;
/*
* The test expression must contain some Vars of the parent query, else
* it's not gonna be a join. (Note that it won't have Vars referring to
* the subquery, rather Params.)
*/
upper_varnos = pull_varnos(root, sublink->testexpr);
if (bms_is_empty(upper_varnos))
return NULL;
/*
* However, it can't refer to anything outside available_rels.
*/
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/*
* The combining operators and left-hand expressions mustn't be volatile.
*/
if (contain_volatile_functions(sublink->testexpr))
return NULL;
/* Create a dummy ParseState for addRangeTableEntryForSubquery */
pstate = make_parsestate(NULL);
/*
* Okay, pull up the sub-select into upper range table.
*
* We rely here on the assumption that the outer query has no references
* to the inner (necessarily true, other than the Vars that we build
* below). Therefore this is a lot easier than what pull_up_subqueries has
* to go through.
*/
nsitem = addRangeTableEntryForSubquery(pstate,
subselect,
makeAlias("ANY_subquery", NIL),
false,
false);
rte = nsitem->p_rte;
parse->rtable = lappend(parse->rtable, rte);
rtindex = list_length(parse->rtable);
/*
* Form a RangeTblRef for the pulled-up sub-select.
*/
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
/*
* Build a list of Vars representing the subselect outputs.
*/
subquery_vars = generate_subquery_vars(root,
subselect->targetList,
rtindex);
/*
* Build the new join's qual expression, replacing Params with these Vars.
*/
quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
/*
* And finally, build the JoinExpr node.
*/
result = makeNode(JoinExpr);
result->jointype = JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
result->rarg = (Node *) rtr;
result->usingClause = NIL;
result->join_using_alias = NULL;
result->quals = quals;
result->alias = NULL;
result->rtindex = 0; /* we don't need an RTE for it */
return result;
}
/*
* convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
*
* The API of this function is identical to convert_ANY_sublink_to_join's,
* except that we also support the case where the caller has found NOT EXISTS,
* so we need an additional input parameter "under_not".
*/
JoinExpr *
convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
bool under_not, Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Node *whereClause;
int rtoffset;
int varno;
Relids clause_varnos;
Relids upper_varnos;
Assert(sublink->subLinkType == EXISTS_SUBLINK);
/*
* Can't flatten if it contains WITH. (We could arrange to pull up the
* WITH into the parent query's cteList, but that risks changing the
* semantics, since a WITH ought to be executed once per associated query
* call.) Note that convert_ANY_sublink_to_join doesn't have to reject
* this case, since it just produces a subquery RTE that doesn't have to
* get flattened into the parent query.
*/
if (subselect->cteList)
return NULL;
/*
* Copy the subquery so we can modify it safely (see comments in
* make_subplan).
*/
subselect = copyObject(subselect);
/*
* See if the subquery can be simplified based on the knowledge that it's
* being used in EXISTS(). If we aren't able to get rid of its
* targetlist, we have to fail, because the pullup operation leaves us
* with noplace to evaluate the targetlist.
*/
if (!simplify_EXISTS_query(root, subselect))
return NULL;
/*
* Separate out the WHERE clause. (We could theoretically also remove
* top-level plain JOIN/ON clauses, but it's probably not worth the
* trouble.)
*/
whereClause = subselect->jointree->quals;
subselect->jointree->quals = NULL;
/*
* The rest of the sub-select must not refer to any Vars of the parent
* query. (Vars of higher levels should be okay, though.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
return NULL;
/*
* On the other hand, the WHERE clause must contain some Vars of the
* parent query, else it's not gonna be a join.
*/
if (!contain_vars_of_level(whereClause, 1))
return NULL;
/*
* We don't risk optimizing if the WHERE clause is volatile, either.
*/
if (contain_volatile_functions(whereClause))
return NULL;
/*
* The subquery must have a nonempty jointree, but we can make it so.
*/
replace_empty_jointree(subselect);
/*
* Prepare to pull up the sub-select into top range table.
*
* We rely here on the assumption that the outer query has no references
* to the inner (necessarily true). Therefore this is a lot easier than
* what pull_up_subqueries has to go through.
*
* In fact, it's even easier than what convert_ANY_sublink_to_join has to
* do. The machinations of simplify_EXISTS_query ensured that there is
* nothing interesting in the subquery except an rtable and jointree, and
* even the jointree FromExpr no longer has quals. So we can just append
* the rtable to our own and use the FromExpr in our jointree. But first,
* adjust all level-zero varnos in the subquery to account for the rtable
* merger.
*/
rtoffset = list_length(parse->rtable);
OffsetVarNodes((Node *) subselect, rtoffset, 0);
OffsetVarNodes(whereClause, rtoffset, 0);
/*
* Upper-level vars in subquery will now be one level closer to their
* parent than before; in particular, anything that had been level 1
* becomes level zero.
*/
IncrementVarSublevelsUp((Node *) subselect, -1, 1);
IncrementVarSublevelsUp(whereClause, -1, 1);
/*
* Now that the WHERE clause is adjusted to match the parent query
* environment, we can easily identify all the level-zero rels it uses.
* The ones <= rtoffset belong to the upper query; the ones > rtoffset do
* not.
*/
clause_varnos = pull_varnos(root, whereClause);
upper_varnos = NULL;
varno = -1;
while ((varno = bms_next_member(clause_varnos, varno)) >= 0)
{
if (varno <= rtoffset)
upper_varnos = bms_add_member(upper_varnos, varno);
}
bms_free(clause_varnos);
Assert(!bms_is_empty(upper_varnos));
/*
* Now that we've got the set of upper-level varnos, we can make the last
* check: only available_rels can be referenced.
*/
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/*
* Now we can attach the modified subquery rtable to the parent. This also
* adds subquery's RTEPermissionInfos into the upper query.
*/
CombineRangeTables(&parse->rtable, &parse->rteperminfos,
subselect->rtable, subselect->rteperminfos);
/*
* And finally, build the JoinExpr node.
*/
result = makeNode(JoinExpr);
result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
/* flatten out the FromExpr node if it's useless */
if (list_length(subselect->jointree->fromlist) == 1)
result->rarg = (Node *) linitial(subselect->jointree->fromlist);
else
result->rarg = (Node *) subselect->jointree;
result->usingClause = NIL;
result->join_using_alias = NULL;
result->quals = whereClause;
result->alias = NULL;
result->rtindex = 0; /* we don't need an RTE for it */
return result;
}
/*
* simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
*
* The only thing that matters about an EXISTS query is whether it returns
* zero or more than zero rows. Therefore, we can remove certain SQL features
* that won't affect that. The only part that is really likely to matter in
* typical usage is simplifying the targetlist: it's a common habit to write
* "SELECT * FROM" even though there is no need to evaluate any columns.
*
* Note: by suppressing the targetlist we could cause an observable behavioral
* change, namely that any errors that might occur in evaluating the tlist
* won't occur, nor will other side-effects of volatile functions. This seems
* unlikely to bother anyone in practice.
*
* Returns true if was able to discard the targetlist, else false.
*/
static bool
simplify_EXISTS_query(PlannerInfo *root, Query *query)
{
/*
* We don't try to simplify at all if the query uses set operations,
* aggregates, grouping sets, SRFs, modifying CTEs, HAVING, OFFSET, or FOR
* UPDATE/SHARE; none of these seem likely in normal usage and their
* possible effects are complex. (Note: we could ignore an "OFFSET 0"
* clause, but that traditionally is used as an optimization fence, so we
* don't.)
*/
if (query->commandType != CMD_SELECT ||
query->setOperations ||
query->hasAggs ||
query->groupingSets ||
query->hasWindowFuncs ||
query->hasTargetSRFs ||
query->hasModifyingCTE ||
query->havingQual ||
query->limitOffset ||
query->rowMarks)
return false;
/*
* LIMIT with a constant positive (or NULL) value doesn't affect the
* semantics of EXISTS, so let's ignore such clauses. This is worth doing
* because people accustomed to certain other DBMSes may be in the habit
* of writing EXISTS(SELECT ... LIMIT 1) as an optimization. If there's a
* LIMIT with anything else as argument, though, we can't simplify.
*/
if (query->limitCount)
{
/*
* The LIMIT clause has not yet been through eval_const_expressions,
* so we have to apply that here. It might seem like this is a waste
* of cycles, since the only case plausibly worth worrying about is
* "LIMIT 1" ... but what we'll actually see is "LIMIT int8(1::int4)",
* so we have to fold constants or we're not going to recognize it.
*/
Node *node = eval_const_expressions(root, query->limitCount);
Const *limit;
/* Might as well update the query if we simplified the clause. */
query->limitCount = node;
if (!IsA(node, Const))
return false;
limit = (Const *) node;
Assert(limit->consttype == INT8OID);
if (!limit->constisnull && DatumGetInt64(limit->constvalue) <= 0)
return false;
/* Whether or not the targetlist is safe, we can drop the LIMIT. */
query->limitCount = NULL;
}
/*
* Otherwise, we can throw away the targetlist, as well as any GROUP,
* WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
* change a nonzero-rows result to zero rows or vice versa. (Furthermore,
* since our parsetree representation of these clauses depends on the
* targetlist, we'd better throw them away if we drop the targetlist.)
*/
query->targetList = NIL;
query->groupClause = NIL;
query->windowClause = NIL;
query->distinctClause = NIL;
query->sortClause = NIL;
query->hasDistinctOn = false;
return true;
}
/*
* convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
*
* The subselect is expected to be a fresh copy that we can munge up,
* and to have been successfully passed through simplify_EXISTS_query.
*
* On success, the modified subselect is returned, and we store a suitable
* upper-level test expression at *testexpr, plus a list of the subselect's
* output Params at *paramIds. (The test expression is already Param-ified
* and hence need not go through convert_testexpr, which is why we have to
* deal with the Param IDs specially.)
*
* On failure, returns NULL.
*/
static Query *
convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
Node **testexpr, List **paramIds)
{
Node *whereClause;
List *leftargs,
*rightargs,
*opids,
*opcollations,
*newWhere,
*tlist,
*testlist,
*paramids;
ListCell *lc,
*rc,
*oc,
*cc;
AttrNumber resno;
/*
* Query must not require a targetlist, since we have to insert a new one.
* Caller should have dealt with the case already.
*/
Assert(subselect->targetList == NIL);
/*
* Separate out the WHERE clause. (We could theoretically also remove
* top-level plain JOIN/ON clauses, but it's probably not worth the
* trouble.)
*/
whereClause = subselect->jointree->quals;
subselect->jointree->quals = NULL;
/*
* The rest of the sub-select must not refer to any Vars of the parent
* query. (Vars of higher levels should be okay, though.)
*
* Note: we need not check for Aggrefs separately because we know the
* sub-select is as yet unoptimized; any uplevel Aggref must therefore
* contain an uplevel Var reference. This is not the case below ...
*/
if (contain_vars_of_level((Node *) subselect, 1))
return NULL;
/*
* We don't risk optimizing if the WHERE clause is volatile, either.
*/
if (contain_volatile_functions(whereClause))
return NULL;
/*
* Clean up the WHERE clause by doing const-simplification etc on it.
* Aside from simplifying the processing we're about to do, this is
* important for being able to pull chunks of the WHERE clause up into the
* parent query. Since we are invoked partway through the parent's
* preprocess_expression() work, earlier steps of preprocess_expression()
* wouldn't get applied to the pulled-up stuff unless we do them here. For
* the parts of the WHERE clause that get put back into the child query,
* this work is partially duplicative, but it shouldn't hurt.
*
* Note: we do not run flatten_join_alias_vars. This is OK because any
* parent aliases were flattened already, and we're not going to pull any
* child Vars (of any description) into the parent.
*
* Note: passing the parent's root to eval_const_expressions is
* technically wrong, but we can get away with it since only the
* boundParams (if any) are used, and those would be the same in a
* subroot.
*/
whereClause = eval_const_expressions(root, whereClause);
whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
/*
* We now have a flattened implicit-AND list of clauses, which we try to
* break apart into "outervar = innervar" hash clauses. Anything that
* can't be broken apart just goes back into the newWhere list. Note that
* we aren't trying hard yet to ensure that we have only outer or only
* inner on each side; we'll check that if we get to the end.
*/
leftargs = rightargs = opids = opcollations = newWhere = NIL;
foreach(lc, (List *) whereClause)
{
OpExpr *expr = (OpExpr *) lfirst(lc);
if (IsA(expr, OpExpr) &&
hash_ok_operator(expr))
{
Node *leftarg = (Node *) linitial(expr->args);
Node *rightarg = (Node *) lsecond(expr->args);
if (contain_vars_of_level(leftarg, 1))
{
leftargs = lappend(leftargs, leftarg);
rightargs = lappend(rightargs, rightarg);
opids = lappend_oid(opids, expr->opno);
opcollations = lappend_oid(opcollations, expr->inputcollid);
continue;
}
if (contain_vars_of_level(rightarg, 1))
{
/*
* We must commute the clause to put the outer var on the
* left, because the hashing code in nodeSubplan.c expects
* that. This probably shouldn't ever fail, since hashable
* operators ought to have commutators, but be paranoid.
*/
expr->opno = get_commutator(expr->opno);
if (OidIsValid(expr->opno) && hash_ok_operator(expr))
{
leftargs = lappend(leftargs, rightarg);
rightargs = lappend(rightargs, leftarg);
opids = lappend_oid(opids, expr->opno);
opcollations = lappend_oid(opcollations, expr->inputcollid);
continue;
}
/* If no commutator, no chance to optimize the WHERE clause */
return NULL;
}
}
/* Couldn't handle it as a hash clause */
newWhere = lappend(newWhere, expr);
}
/*
* If we didn't find anything we could convert, fail.
*/
if (leftargs == NIL)
return NULL;
/*
* There mustn't be any parent Vars or Aggs in the stuff that we intend to
* put back into the child query. Note: you might think we don't need to
* check for Aggs separately, because an uplevel Agg must contain an
* uplevel Var in its argument. But it is possible that the uplevel Var
* got optimized away by eval_const_expressions. Consider
*
* SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
*/
if (contain_vars_of_level((Node *) newWhere, 1) ||
contain_vars_of_level((Node *) rightargs, 1))
return NULL;
if (root->parse->hasAggs &&
(contain_aggs_of_level((Node *) newWhere, 1) ||
contain_aggs_of_level((Node *) rightargs, 1)))
return NULL;
/*
* And there can't be any child Vars in the stuff we intend to pull up.
* (Note: we'd need to check for child Aggs too, except we know the child
* has no aggs at all because of simplify_EXISTS_query's check. The same
* goes for window functions.)
*/
if (contain_vars_of_level((Node *) leftargs, 0))
return NULL;
/*
* Also reject sublinks in the stuff we intend to pull up. (It might be
* possible to support this, but doesn't seem worth the complication.)
*/
if (contain_subplans((Node *) leftargs))
return NULL;
/*
* Okay, adjust the sublevelsup in the stuff we're pulling up.
*/
IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
/*
* Put back any child-level-only WHERE clauses.
*/
if (newWhere)
subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
/*
* Build a new targetlist for the child that emits the expressions we
* need. Concurrently, build a testexpr for the parent using Params to
* reference the child outputs. (Since we generate Params directly here,
* there will be no need to convert the testexpr in build_subplan.)
*/
tlist = testlist = paramids = NIL;
resno = 1;
forfour(lc, leftargs, rc, rightargs, oc, opids, cc, opcollations)
{
Node *leftarg = (Node *) lfirst(lc);
Node *rightarg = (Node *) lfirst(rc);
Oid opid = lfirst_oid(oc);
Oid opcollation = lfirst_oid(cc);
Param *param;
param = generate_new_exec_param(root,
exprType(rightarg),
exprTypmod(rightarg),
exprCollation(rightarg));
tlist = lappend(tlist,
makeTargetEntry((Expr *) rightarg,
resno++,
NULL,
false));
testlist = lappend(testlist,
make_opclause(opid, BOOLOID, false,
(Expr *) leftarg, (Expr *) param,
InvalidOid, opcollation));
paramids = lappend_int(paramids, param->paramid);
}
/* Put everything where it should go, and we're done */
subselect->targetList = tlist;
*testexpr = (Node *) make_ands_explicit(testlist);
*paramIds = paramids;
return subselect;
}
/*
* Replace correlation vars (uplevel vars) with Params.
*
* Uplevel PlaceHolderVars and aggregates are replaced, too.
*
* Note: it is critical that this runs immediately after SS_process_sublinks.
* Since we do not recurse into the arguments of uplevel PHVs and aggregates,
* they will get copied to the appropriate subplan args list in the parent
* query with uplevel vars not replaced by Params, but only adjusted in level
* (see replace_outer_placeholdervar and replace_outer_agg). That's exactly
* what we want for the vars of the parent level --- but if a PHV's or
* aggregate's argument contains any further-up variables, they have to be
* replaced with Params in their turn. That will happen when the parent level
* runs SS_replace_correlation_vars. Therefore it must do so after expanding
* its sublinks to subplans. And we don't want any steps in between, else
* those steps would never get applied to the argument expressions, either in
* the parent or the child level.
*
* Another fairly tricky thing going on here is the handling of SubLinks in
* the arguments of uplevel PHVs/aggregates. Those are not touched inside the
* intermediate query level, either. Instead, SS_process_sublinks recurses on
* them after copying the PHV or Aggref expression into the parent plan level
* (this is actually taken care of in build_subplan).
*/
Node *
SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
{
/* No setup needed for tree walk, so away we go */
return replace_correlation_vars_mutator(expr, root);
}
static Node *
replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
{
if (node == NULL)
return NULL;
if (IsA(node, Var))
{
if (((Var *) node)->varlevelsup > 0)
return (Node *) replace_outer_var(root, (Var *) node);
}
if (IsA(node, PlaceHolderVar))
{
if (((PlaceHolderVar *) node)->phlevelsup > 0)
return (Node *) replace_outer_placeholdervar(root,
(PlaceHolderVar *) node);
}
if (IsA(node, Aggref))
{
if (((Aggref *) node)->agglevelsup > 0)
return (Node *) replace_outer_agg(root, (Aggref *) node);
}
if (IsA(node, GroupingFunc))
{
if (((GroupingFunc *) node)->agglevelsup > 0)
return (Node *) replace_outer_grouping(root, (GroupingFunc *) node);
}
return expression_tree_mutator(node,
replace_correlation_vars_mutator,
(void *) root);
}
/*
* Expand SubLinks to SubPlans in the given expression.
*
* The isQual argument tells whether or not this expression is a WHERE/HAVING
* qualifier expression. If it is, any sublinks appearing at top level need
* not distinguish FALSE from UNKNOWN return values.
*/
Node *
SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
{
process_sublinks_context context;
context.root = root;
context.isTopQual = isQual;
return process_sublinks_mutator(expr, &context);
}
static Node *
process_sublinks_mutator(Node *node, process_sublinks_context *context)
{
process_sublinks_context locContext;
locContext.root = context->root;
if (node == NULL)
return NULL;
if (IsA(node, SubLink))
{
SubLink *sublink = (SubLink *) node;
Node *testexpr;
/*
* First, recursively process the lefthand-side expressions, if any.
* They're not top-level anymore.
*/
locContext.isTopQual = false;
testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
/*
* Now build the SubPlan node and make the expr to return.
*/
return make_subplan(context->root,
(Query *) sublink->subselect,
sublink->subLinkType,
sublink->subLinkId,
testexpr,
context->isTopQual);
}
/*
* Don't recurse into the arguments of an outer PHV, Aggref or
* GroupingFunc here. Any SubLinks in the arguments have to be dealt with
* at the outer query level; they'll be handled when build_subplan
* collects the PHV, Aggref or GroupingFunc into the arguments to be
* passed down to the current subplan.
*/
if (IsA(node, PlaceHolderVar))
{
if (((PlaceHolderVar *) node)->phlevelsup > 0)
return node;
}
else if (IsA(node, Aggref))
{
if (((Aggref *) node)->agglevelsup > 0)
return node;
}
else if (IsA(node, GroupingFunc))
{
if (((GroupingFunc *) node)->agglevelsup > 0)
return node;
}
/*
* We should never see a SubPlan expression in the input (since this is
* the very routine that creates 'em to begin with). We shouldn't find
* ourselves invoked directly on a Query, either.
*/
Assert(!IsA(node, SubPlan));
Assert(!IsA(node, AlternativeSubPlan));
Assert(!IsA(node, Query));
/*
* Because make_subplan() could return an AND or OR clause, we have to
* take steps to preserve AND/OR flatness of a qual. We assume the input
* has been AND/OR flattened and so we need no recursion here.
*
* (Due to the coding here, we will not get called on the List subnodes of
* an AND; and the input is *not* yet in implicit-AND format. So no check
* is needed for a bare List.)
*
* Anywhere within the top-level AND/OR clause structure, we can tell
* make_subplan() that NULL and FALSE are interchangeable. So isTopQual
* propagates down in both cases. (Note that this is unlike the meaning
* of "top level qual" used in most other places in Postgres.)
*/
if (is_andclause(node))
{
List *newargs = NIL;
ListCell *l;
/* Still at qual top-level */
locContext.isTopQual = context->isTopQual;
foreach(l, ((BoolExpr *) node)->args)
{
Node *newarg;
newarg = process_sublinks_mutator(lfirst(l), &locContext);
if (is_andclause(newarg))
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
else
newargs = lappend(newargs, newarg);
}
return (Node *) make_andclause(newargs);
}
if (is_orclause(node))
{
List *newargs = NIL;
ListCell *l;
/* Still at qual top-level */
locContext.isTopQual = context->isTopQual;
foreach(l, ((BoolExpr *) node)->args)
{
Node *newarg;
newarg = process_sublinks_mutator(lfirst(l), &locContext);
if (is_orclause(newarg))
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
else
newargs = lappend(newargs, newarg);
}
return (Node *) make_orclause(newargs);
}
/*
* If we recurse down through anything other than an AND or OR node, we
* are definitely not at top qual level anymore.
*/
locContext.isTopQual = false;
return expression_tree_mutator(node,
process_sublinks_mutator,
(void *) &locContext);
}
/*
* SS_identify_outer_params - identify the Params available from outer levels
*
* This must be run after SS_replace_correlation_vars and SS_process_sublinks
* processing is complete in a given query level as well as all of its
* descendant levels (which means it's most practical to do it at the end of
* processing the query level). We compute the set of paramIds that outer
* levels will make available to this level+descendants, and record it in
* root->outer_params for use while computing extParam/allParam sets in final
* plan cleanup. (We can't just compute it then, because the upper levels'
* plan_params lists are transient and will be gone by then.)
*/
void
SS_identify_outer_params(PlannerInfo *root)
{
Bitmapset *outer_params;
PlannerInfo *proot;
ListCell *l;
/*
* If no parameters have been assigned anywhere in the tree, we certainly
* don't need to do anything here.
*/
if (root->glob->paramExecTypes == NIL)
return;
/*
* Scan all query levels above this one to see which parameters are due to
* be available from them, either because lower query levels have
* requested them (via plan_params) or because they will be available from
* initPlans of those levels.
*/
outer_params = NULL;
for (proot = root->parent_root; proot != NULL; proot = proot->parent_root)
{
/* Include ordinary Var/PHV/Aggref/GroupingFunc params */
foreach(l, proot->plan_params)
{
PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
outer_params = bms_add_member(outer_params, pitem->paramId);
}
/* Include any outputs of outer-level initPlans */
foreach(l, proot->init_plans)
{
SubPlan *initsubplan = (SubPlan *) lfirst(l);
ListCell *l2;
foreach(l2, initsubplan->setParam)
{
outer_params = bms_add_member(outer_params, lfirst_int(l2));
}
}
/* Include worktable ID, if a recursive query is being planned */
if (proot->wt_param_id >= 0)
outer_params = bms_add_member(outer_params, proot->wt_param_id);
}
root->outer_params = outer_params;
}
/*
* SS_charge_for_initplans - account for initplans in Path costs & parallelism
*
* If any initPlans have been created in the current query level, they will
* get attached to the Plan tree created from whichever Path we select from
* the given rel. Increment all that rel's Paths' costs to account for them,
* and make sure the paths get marked as parallel-unsafe, since we can't
* currently transmit initPlans to parallel workers.
*
* This is separate from SS_attach_initplans because we might conditionally
* create more initPlans during create_plan(), depending on which Path we
* select. However, Paths that would generate such initPlans are expected
* to have included their cost and parallel-safety effects already.
*/
void
SS_charge_for_initplans(PlannerInfo *root, RelOptInfo *final_rel)
{
Cost initplan_cost;
ListCell *lc;
/* Nothing to do if no initPlans */
if (root->init_plans == NIL)
return;
/*
* Compute the cost increment just once, since it will be the same for all
* Paths. We assume each initPlan gets run once during top plan startup.
* This is a conservative overestimate, since in fact an initPlan might be
* executed later than plan startup, or even not at all.
*/
initplan_cost = 0;
foreach(lc, root->init_plans)
{
SubPlan *initsubplan = (SubPlan *) lfirst(lc);
initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
}
/*
* Now adjust the costs and parallel_safe flags.
*/
foreach(lc, final_rel->pathlist)
{
Path *path = (Path *) lfirst(lc);
path->startup_cost += initplan_cost;
path->total_cost += initplan_cost;
path->parallel_safe = false;
}
/*
* Forget about any partial paths and clear consider_parallel, too;
* they're not usable if we attached an initPlan.
*/
final_rel->partial_pathlist = NIL;
final_rel->consider_parallel = false;
/* We needn't do set_cheapest() here, caller will do it */
}
/*
* SS_attach_initplans - attach initplans to topmost plan node
*
* Attach any initplans created in the current query level to the specified
* plan node, which should normally be the topmost node for the query level.
* (In principle the initPlans could go in any node at or above where they're
* referenced; but there seems no reason to put them any lower than the
* topmost node, so we don't bother to track exactly where they came from.)
*
* We do not touch the plan node's cost or parallel_safe flag. The initplans
* must have been accounted for in SS_charge_for_initplans, or by any later
* code that adds initplans via SS_make_initplan_from_plan.
*/
void
SS_attach_initplans(PlannerInfo *root, Plan *plan)
{
plan->initPlan = root->init_plans;
}
/*
* SS_finalize_plan - do final parameter processing for a completed Plan.
*
* This recursively computes the extParam and allParam sets for every Plan
* node in the given plan tree. (Oh, and RangeTblFunction.funcparams too.)
*
* We assume that SS_finalize_plan has already been run on any initplans or
* subplans the plan tree could reference.
*/
void
SS_finalize_plan(PlannerInfo *root, Plan *plan)
{
/* No setup needed, just recurse through plan tree. */
(void) finalize_plan(root, plan, -1, root->outer_params, NULL);
}
/*
* Recursive processing of all nodes in the plan tree
*
* gather_param is the rescan_param of an ancestral Gather/GatherMerge,
* or -1 if there is none.
*
* valid_params is the set of param IDs supplied by outer plan levels
* that are valid to reference in this plan node or its children.
*
* scan_params is a set of param IDs to force scan plan nodes to reference.
* This is for EvalPlanQual support, and is always NULL at the top of the
* recursion.
*
* The return value is the computed allParam set for the given Plan node.
* This is just an internal notational convenience: we can add a child
* plan's allParams to the set of param IDs of interest to this level
* in the same statement that recurses to that child.
*
* Do not scribble on caller's values of valid_params or scan_params!
*
* Note: although we attempt to deal with initPlans anywhere in the tree, the
* logic is not really right. The problem is that a plan node might return an
* output Param of its initPlan as a targetlist item, in which case it's valid
* for the parent plan level to reference that same Param; the parent's usage
* will be converted into a Var referencing the child plan node by setrefs.c.
* But this function would see the parent's reference as out of scope and
* complain about it. For now, this does not matter because the planner only
* attaches initPlans to the topmost plan node in a query level, so the case
* doesn't arise. If we ever merge this processing into setrefs.c, maybe it
* can be handled more cleanly.
*/
static Bitmapset *
finalize_plan(PlannerInfo *root, Plan *plan,
int gather_param,
Bitmapset *valid_params,
Bitmapset *scan_params)
{
finalize_primnode_context context;
int locally_added_param;
Bitmapset *nestloop_params;
Bitmapset *initExtParam;
Bitmapset *initSetParam;
Bitmapset *child_params;
ListCell *l;
if (plan == NULL)
return NULL;
context.root = root;
context.paramids = NULL; /* initialize set to empty */
locally_added_param = -1; /* there isn't one */
nestloop_params = NULL; /* there aren't any */
/*
* Examine any initPlans to determine the set of external params they
* reference and the set of output params they supply. (We assume
* SS_finalize_plan was run on them already.)
*/
initExtParam = initSetParam = NULL;
foreach(l, plan->initPlan)
{
SubPlan *initsubplan = (SubPlan *) lfirst(l);
Plan *initplan = planner_subplan_get_plan(root, initsubplan);
ListCell *l2;
initExtParam = bms_add_members(initExtParam, initplan->extParam);
foreach(l2, initsubplan->setParam)
{
initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
}
}
/* Any setParams are validly referenceable in this node and children */
if (initSetParam)
valid_params = bms_union(valid_params, initSetParam);
/*
* When we call finalize_primnode, context.paramids sets are automatically
* merged together. But when recursing to self, we have to do it the hard
* way. We want the paramids set to include params in subplans as well as
* at this level.
*/
/* Find params in targetlist and qual */
finalize_primnode((Node *) plan->targetlist, &context);
finalize_primnode((Node *) plan->qual, &context);
/*
* If it's a parallel-aware scan node, mark it as dependent on the parent
* Gather/GatherMerge's rescan Param.
*/
if (plan->parallel_aware)
{
if (gather_param < 0)
elog(ERROR, "parallel-aware plan node is not below a Gather");
context.paramids =
bms_add_member(context.paramids, gather_param);
}
/* Check additional node-type-specific fields */
switch (nodeTag(plan))
{
case T_Result:
finalize_primnode(((Result *) plan)->resconstantqual,
&context);
break;
case T_SeqScan:
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_SampleScan:
finalize_primnode((Node *) ((SampleScan *) plan)->tablesample,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_IndexScan:
finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
&context);
finalize_primnode((Node *) ((IndexScan *) plan)->indexorderby,
&context);
/*
* we need not look at indexqualorig, since it will have the same
* param references as indexqual. Likewise, we can ignore
* indexorderbyorig.
*/
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_IndexOnlyScan:
finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexqual,
&context);
finalize_primnode((Node *) ((IndexOnlyScan *) plan)->recheckqual,
&context);
finalize_primnode((Node *) ((IndexOnlyScan *) plan)->indexorderby,
&context);
/*
* we need not look at indextlist, since it cannot contain Params.
*/
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_BitmapIndexScan:
finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
&context);
/*
* we need not look at indexqualorig, since it will have the same
* param references as indexqual.
*/
break;
case T_BitmapHeapScan:
finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_TidScan:
finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_TidRangeScan:
finalize_primnode((Node *) ((TidRangeScan *) plan)->tidrangequals,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_SubqueryScan:
{
SubqueryScan *sscan = (SubqueryScan *) plan;
RelOptInfo *rel;
Bitmapset *subquery_params;
/* We must run finalize_plan on the subquery */
rel = find_base_rel(root, sscan->scan.scanrelid);
subquery_params = rel->subroot->outer_params;
if (gather_param >= 0)
subquery_params = bms_add_member(bms_copy(subquery_params),
gather_param);
finalize_plan(rel->subroot, sscan->subplan, gather_param,
subquery_params, NULL);
/* Now we can add its extParams to the parent's params */
context.paramids = bms_add_members(context.paramids,
sscan->subplan->extParam);
/* We need scan_params too, though */
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_FunctionScan:
{
FunctionScan *fscan = (FunctionScan *) plan;
ListCell *lc;
/*
* Call finalize_primnode independently on each function
* expression, so that we can record which params are
* referenced in each, in order to decide which need
* re-evaluating during rescan.
*/
foreach(lc, fscan->functions)
{
RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc);
finalize_primnode_context funccontext;
funccontext = context;
funccontext.paramids = NULL;
finalize_primnode(rtfunc->funcexpr, &funccontext);
/* remember results for execution */
rtfunc->funcparams = funccontext.paramids;
/* add the function's params to the overall set */
context.paramids = bms_add_members(context.paramids,
funccontext.paramids);
}
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_TableFuncScan:
finalize_primnode((Node *) ((TableFuncScan *) plan)->tablefunc,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_ValuesScan:
finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
&context);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_CteScan:
{
/*
* You might think we should add the node's cteParam to
* paramids, but we shouldn't because that param is just a
* linkage mechanism for multiple CteScan nodes for the same
* CTE; it is never used for changed-param signaling. What we
* have to do instead is to find the referenced CTE plan and
* incorporate its external paramids, so that the correct
* things will happen if the CTE references outer-level
* variables. See test cases for bug #4902. (We assume
* SS_finalize_plan was run on the CTE plan already.)
*/
int plan_id = ((CteScan *) plan)->ctePlanId;
Plan *cteplan;
/* so, do this ... */
if (plan_id < 1 || plan_id > list_length(root->glob->subplans))
elog(ERROR, "could not find plan for CteScan referencing plan ID %d",
plan_id);
cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
context.paramids =
bms_add_members(context.paramids, cteplan->extParam);
#ifdef NOT_USED
/* ... but not this */
context.paramids =
bms_add_member(context.paramids,
((CteScan *) plan)->cteParam);
#endif
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_WorkTableScan:
context.paramids =
bms_add_member(context.paramids,
((WorkTableScan *) plan)->wtParam);
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_NamedTuplestoreScan:
context.paramids = bms_add_members(context.paramids, scan_params);
break;
case T_ForeignScan:
{
ForeignScan *fscan = (ForeignScan *) plan;
finalize_primnode((Node *) fscan->fdw_exprs,
&context);
finalize_primnode((Node *) fscan->fdw_recheck_quals,
&context);
/* We assume fdw_scan_tlist cannot contain Params */
context.paramids = bms_add_members(context.paramids,
scan_params);
}
break;
case T_CustomScan:
{
CustomScan *cscan = (CustomScan *) plan;
ListCell *lc;
finalize_primnode((Node *) cscan->custom_exprs,
&context);
/* We assume custom_scan_tlist cannot contain Params */
context.paramids =
bms_add_members(context.paramids, scan_params);
/* child nodes if any */
foreach(lc, cscan->custom_plans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(lc),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_ModifyTable:
{
ModifyTable *mtplan = (ModifyTable *) plan;
/* Force descendant scan nodes to reference epqParam */
locally_added_param = mtplan->epqParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
scan_params = bms_add_member(bms_copy(scan_params),
locally_added_param);
finalize_primnode((Node *) mtplan->returningLists,
&context);
finalize_primnode((Node *) mtplan->onConflictSet,
&context);
finalize_primnode((Node *) mtplan->onConflictWhere,
&context);
/* exclRelTlist contains only Vars, doesn't need examination */
}
break;
case T_Append:
{
foreach(l, ((Append *) plan)->appendplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_MergeAppend:
{
foreach(l, ((MergeAppend *) plan)->mergeplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_BitmapAnd:
{
foreach(l, ((BitmapAnd *) plan)->bitmapplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_BitmapOr:
{
foreach(l, ((BitmapOr *) plan)->bitmapplans)
{
context.paramids =
bms_add_members(context.paramids,
finalize_plan(root,
(Plan *) lfirst(l),
gather_param,
valid_params,
scan_params));
}
}
break;
case T_NestLoop:
{
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
/* collect set of params that will be passed to right child */
foreach(l, ((NestLoop *) plan)->nestParams)
{
NestLoopParam *nlp = (NestLoopParam *) lfirst(l);
nestloop_params = bms_add_member(nestloop_params,
nlp->paramno);
}
}
break;
case T_MergeJoin:
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
&context);
break;
case T_HashJoin:
finalize_primnode((Node *) ((Join *) plan)->joinqual,
&context);
finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
&context);
break;
case T_Hash:
finalize_primnode((Node *) ((Hash *) plan)->hashkeys,
&context);
break;
case T_Limit:
finalize_primnode(((Limit *) plan)->limitOffset,
&context);
finalize_primnode(((Limit *) plan)->limitCount,
&context);
break;
case T_RecursiveUnion:
/* child nodes are allowed to reference wtParam */
locally_added_param = ((RecursiveUnion *) plan)->wtParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/* wtParam does *not* get added to scan_params */
break;
case T_LockRows:
/* Force descendant scan nodes to reference epqParam */
locally_added_param = ((LockRows *) plan)->epqParam;
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
scan_params = bms_add_member(bms_copy(scan_params),
locally_added_param);
break;
case T_Agg:
{
Agg *agg = (Agg *) plan;
/*
* AGG_HASHED plans need to know which Params are referenced
* in aggregate calls. Do a separate scan to identify them.
*/
if (agg->aggstrategy == AGG_HASHED)
{
finalize_primnode_context aggcontext;
aggcontext.root = root;
aggcontext.paramids = NULL;
finalize_agg_primnode((Node *) agg->plan.targetlist,
&aggcontext);
finalize_agg_primnode((Node *) agg->plan.qual,
&aggcontext);
agg->aggParams = aggcontext.paramids;
}
}
break;
case T_WindowAgg:
finalize_primnode(((WindowAgg *) plan)->startOffset,
&context);
finalize_primnode(((WindowAgg *) plan)->endOffset,
&context);
break;
case T_Gather:
/* child nodes are allowed to reference rescan_param, if any */
locally_added_param = ((Gather *) plan)->rescan_param;
if (locally_added_param >= 0)
{
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/*
* We currently don't support nested Gathers. The issue so
* far as this function is concerned would be how to identify
* which child nodes depend on which Gather.
*/
Assert(gather_param < 0);
/* Pass down rescan_param to child parallel-aware nodes */
gather_param = locally_added_param;
}
/* rescan_param does *not* get added to scan_params */
break;
case T_GatherMerge:
/* child nodes are allowed to reference rescan_param, if any */
locally_added_param = ((GatherMerge *) plan)->rescan_param;
if (locally_added_param >= 0)
{
valid_params = bms_add_member(bms_copy(valid_params),
locally_added_param);
/*
* We currently don't support nested Gathers. The issue so
* far as this function is concerned would be how to identify
* which child nodes depend on which Gather.
*/
Assert(gather_param < 0);
/* Pass down rescan_param to child parallel-aware nodes */
gather_param = locally_added_param;
}
/* rescan_param does *not* get added to scan_params */
break;
case T_Memoize:
finalize_primnode((Node *) ((Memoize *) plan)->param_exprs,
&context);
break;
case T_ProjectSet:
case T_Material:
case T_Sort:
case T_IncrementalSort:
case T_Unique:
case T_SetOp:
case T_Group:
/* no node-type-specific fields need fixing */
break;
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(plan));
}
/* Process left and right child plans, if any */
child_params = finalize_plan(root,
plan->lefttree,
gather_param,
valid_params,
scan_params);
context.paramids = bms_add_members(context.paramids, child_params);
if (nestloop_params)
{
/* right child can reference nestloop_params as well as valid_params */
child_params = finalize_plan(root,
plan->righttree,
gather_param,
bms_union(nestloop_params, valid_params),
scan_params);
/* ... and they don't count as parameters used at my level */
child_params = bms_difference(child_params, nestloop_params);
bms_free(nestloop_params);
}
else
{
/* easy case */
child_params = finalize_plan(root,
plan->righttree,
gather_param,
valid_params,
scan_params);
}
context.paramids = bms_add_members(context.paramids, child_params);
/*
* Any locally generated parameter doesn't count towards its generating
* plan node's external dependencies. (Note: if we changed valid_params
* and/or scan_params, we leak those bitmapsets; not worth the notational
* trouble to clean them up.)
*/
if (locally_added_param >= 0)
{
context.paramids = bms_del_member(context.paramids,
locally_added_param);
}
/* Now we have all the paramids referenced in this node and children */
if (!bms_is_subset(context.paramids, valid_params))
elog(ERROR, "plan should not reference subplan's variable");
/*
* The plan node's allParam and extParam fields should include all its
* referenced paramids, plus contributions from any child initPlans.
* However, any setParams of the initPlans should not be present in the
* parent node's extParams, only in its allParams. (It's possible that
* some initPlans have extParams that are setParams of other initPlans.)
*/
/* allParam must include initplans' extParams and setParams */
plan->allParam = bms_union(context.paramids, initExtParam);
plan->allParam = bms_add_members(plan->allParam, initSetParam);
/* extParam must include any initplan extParams */
plan->extParam = bms_union(context.paramids, initExtParam);
/* but not any initplan setParams */
plan->extParam = bms_del_members(plan->extParam, initSetParam);
return plan->allParam;
}
/*
* finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
* expression tree to the result set.
*/
static bool
finalize_primnode(Node *node, finalize_primnode_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Param))
{
if (((Param *) node)->paramkind == PARAM_EXEC)
{
int paramid = ((Param *) node)->paramid;
context->paramids = bms_add_member(context->paramids, paramid);
}
return false; /* no more to do here */
}
if (IsA(node, SubPlan))
{
SubPlan *subplan = (SubPlan *) node;
Plan *plan = planner_subplan_get_plan(context->root, subplan);
ListCell *lc;
Bitmapset *subparamids;
/* Recurse into the testexpr, but not into the Plan */
finalize_primnode(subplan->testexpr, context);
/*
* Remove any param IDs of output parameters of the subplan that were
* referenced in the testexpr. These are not interesting for
* parameter change signaling since we always re-evaluate the subplan.
* Note that this wouldn't work too well if there might be uses of the
* same param IDs elsewhere in the plan, but that can't happen because
* generate_new_exec_param never tries to merge params.
*/
foreach(lc, subplan->paramIds)
{
context->paramids = bms_del_member(context->paramids,
lfirst_int(lc));
}
/* Also examine args list */
finalize_primnode((Node *) subplan->args, context);
/*
* Add params needed by the subplan to paramids, but excluding those
* we will pass down to it. (We assume SS_finalize_plan was run on
* the subplan already.)
*/
subparamids = bms_copy(plan->extParam);
foreach(lc, subplan->parParam)
{
subparamids = bms_del_member(subparamids, lfirst_int(lc));
}
context->paramids = bms_join(context->paramids, subparamids);
return false; /* no more to do here */
}
return expression_tree_walker(node, finalize_primnode,
(void *) context);
}
/*
* finalize_agg_primnode: find all Aggref nodes in the given expression tree,
* and add IDs of all PARAM_EXEC params appearing within their aggregated
* arguments to the result set.
*/
static bool
finalize_agg_primnode(Node *node, finalize_primnode_context *context)
{
if (node == NULL)
return false;
if (IsA(node, Aggref))
{
Aggref *agg = (Aggref *) node;
/* we should not consider the direct arguments, if any */
finalize_primnode((Node *) agg->args, context);
finalize_primnode((Node *) agg->aggfilter, context);
return false; /* there can't be any Aggrefs below here */
}
return expression_tree_walker(node, finalize_agg_primnode,
(void *) context);
}
/*
* SS_make_initplan_output_param - make a Param for an initPlan's output
*
* The plan is expected to return a scalar value of the given type/collation.
*
* Note that in some cases the initplan may not ever appear in the finished
* plan tree. If that happens, we'll have wasted a PARAM_EXEC slot, which
* is no big deal.
*/
Param *
SS_make_initplan_output_param(PlannerInfo *root,
Oid resulttype, int32 resulttypmod,
Oid resultcollation)
{
return generate_new_exec_param(root, resulttype,
resulttypmod, resultcollation);
}
/*
* SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
*
* We build an EXPR_SUBLINK SubPlan node and put it into the initplan
* list for the outer query level. A Param that represents the initplan's
* output has already been assigned using SS_make_initplan_output_param.
*/
void
SS_make_initplan_from_plan(PlannerInfo *root,
PlannerInfo *subroot, Plan *plan,
Param *prm)
{
SubPlan *node;
/*
* Add the subplan and its PlannerInfo to the global lists.
*/
root->glob->subplans = lappend(root->glob->subplans, plan);
root->glob->subroots = lappend(root->glob->subroots, subroot);
/*
* Create a SubPlan node and add it to the outer list of InitPlans. Note
* it has to appear after any other InitPlans it might depend on (see
* comments in ExecReScan).
*/
node = makeNode(SubPlan);
node->subLinkType = EXPR_SUBLINK;
node->plan_id = list_length(root->glob->subplans);
node->plan_name = psprintf("InitPlan %d (returns $%d)",
node->plan_id, prm->paramid);
get_first_col_type(plan, &node->firstColType, &node->firstColTypmod,
&node->firstColCollation);
node->setParam = list_make1_int(prm->paramid);
root->init_plans = lappend(root->init_plans, node);
/*
* The node can't have any inputs (since it's an initplan), so the
* parParam and args lists remain empty.
*/
/* Set costs of SubPlan using info from the plan tree */
cost_subplan(subroot, node, plan);
}
|