Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * execAmi.c
4 : * miscellaneous executor access method routines
5 : *
6 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : * src/backend/executor/execAmi.c
10 : *
11 : *-------------------------------------------------------------------------
12 : */
13 : #include "postgres.h"
14 :
15 : #include "access/amapi.h"
16 : #include "access/htup_details.h"
17 : #include "executor/execdebug.h"
18 : #include "executor/nodeAgg.h"
19 : #include "executor/nodeAppend.h"
20 : #include "executor/nodeBitmapAnd.h"
21 : #include "executor/nodeBitmapHeapscan.h"
22 : #include "executor/nodeBitmapIndexscan.h"
23 : #include "executor/nodeBitmapOr.h"
24 : #include "executor/nodeCtescan.h"
25 : #include "executor/nodeCustom.h"
26 : #include "executor/nodeForeignscan.h"
27 : #include "executor/nodeFunctionscan.h"
28 : #include "executor/nodeGather.h"
29 : #include "executor/nodeGatherMerge.h"
30 : #include "executor/nodeGroup.h"
31 : #include "executor/nodeHash.h"
32 : #include "executor/nodeHashjoin.h"
33 : #include "executor/nodeIncrementalSort.h"
34 : #include "executor/nodeIndexonlyscan.h"
35 : #include "executor/nodeIndexscan.h"
36 : #include "executor/nodeLimit.h"
37 : #include "executor/nodeLockRows.h"
38 : #include "executor/nodeMaterial.h"
39 : #include "executor/nodeMemoize.h"
40 : #include "executor/nodeMergeAppend.h"
41 : #include "executor/nodeMergejoin.h"
42 : #include "executor/nodeModifyTable.h"
43 : #include "executor/nodeNamedtuplestorescan.h"
44 : #include "executor/nodeNestloop.h"
45 : #include "executor/nodeProjectSet.h"
46 : #include "executor/nodeRecursiveunion.h"
47 : #include "executor/nodeResult.h"
48 : #include "executor/nodeSamplescan.h"
49 : #include "executor/nodeSeqscan.h"
50 : #include "executor/nodeSetOp.h"
51 : #include "executor/nodeSort.h"
52 : #include "executor/nodeSubplan.h"
53 : #include "executor/nodeSubqueryscan.h"
54 : #include "executor/nodeTableFuncscan.h"
55 : #include "executor/nodeTidrangescan.h"
56 : #include "executor/nodeTidscan.h"
57 : #include "executor/nodeUnique.h"
58 : #include "executor/nodeValuesscan.h"
59 : #include "executor/nodeWindowAgg.h"
60 : #include "executor/nodeWorktablescan.h"
61 : #include "nodes/extensible.h"
62 : #include "nodes/nodeFuncs.h"
63 : #include "nodes/pathnodes.h"
64 : #include "utils/rel.h"
65 : #include "utils/syscache.h"
66 :
67 : static bool IndexSupportsBackwardScan(Oid indexid);
68 :
69 :
70 : /*
71 : * ExecReScan
72 : * Reset a plan node so that its output can be re-scanned.
73 : *
74 : * Note that if the plan node has parameters that have changed value,
75 : * the output might be different from last time.
76 : */
77 : void
78 2848936 : ExecReScan(PlanState *node)
79 : {
80 : /* If collecting timing stats, update them */
81 2848936 : if (node->instrument)
82 29614 : InstrEndLoop(node->instrument);
83 :
84 : /*
85 : * If we have changed parameters, propagate that info.
86 : *
87 : * Note: ExecReScanSetParamPlan() can add bits to node->chgParam,
88 : * corresponding to the output param(s) that the InitPlan will update.
89 : * Since we make only one pass over the list, that means that an InitPlan
90 : * can depend on the output param(s) of a sibling InitPlan only if that
91 : * sibling appears earlier in the list. This is workable for now given
92 : * the limited ways in which one InitPlan could depend on another, but
93 : * eventually we might need to work harder (or else make the planner
94 : * enlarge the extParam/allParam sets to include the params of depended-on
95 : * InitPlans).
96 : */
97 2848936 : if (node->chgParam != NULL)
98 : {
99 : ListCell *l;
100 :
101 2104086 : foreach(l, node->initPlan)
102 : {
103 1234 : SubPlanState *sstate = (SubPlanState *) lfirst(l);
104 1234 : PlanState *splan = sstate->planstate;
105 :
106 1234 : if (splan->plan->extParam != NULL) /* don't care about child
107 : * local Params */
108 1086 : UpdateChangedParamSet(splan, node->chgParam);
109 1234 : if (splan->chgParam != NULL)
110 846 : ExecReScanSetParamPlan(sstate, node);
111 : }
112 2104462 : foreach(l, node->subPlan)
113 : {
114 1610 : SubPlanState *sstate = (SubPlanState *) lfirst(l);
115 1610 : PlanState *splan = sstate->planstate;
116 :
117 1610 : if (splan->plan->extParam != NULL)
118 1604 : UpdateChangedParamSet(splan, node->chgParam);
119 : }
120 : /* Well. Now set chgParam for child trees. */
121 2102852 : if (outerPlanState(node) != NULL)
122 750866 : UpdateChangedParamSet(outerPlanState(node), node->chgParam);
123 2102852 : if (innerPlanState(node) != NULL)
124 11560 : UpdateChangedParamSet(innerPlanState(node), node->chgParam);
125 : }
126 :
127 : /* Call expression callbacks */
128 2848936 : if (node->ps_ExprContext)
129 2197332 : ReScanExprContext(node->ps_ExprContext);
130 :
131 : /* And do node-type-specific processing */
132 2848936 : switch (nodeTag(node))
133 : {
134 164834 : case T_ResultState:
135 164834 : ExecReScanResult((ResultState *) node);
136 164834 : break;
137 :
138 78358 : case T_ProjectSetState:
139 78358 : ExecReScanProjectSet((ProjectSetState *) node);
140 78358 : break;
141 :
142 0 : case T_ModifyTableState:
143 0 : ExecReScanModifyTable((ModifyTableState *) node);
144 0 : break;
145 :
146 82908 : case T_AppendState:
147 82908 : ExecReScanAppend((AppendState *) node);
148 82908 : break;
149 :
150 18 : case T_MergeAppendState:
151 18 : ExecReScanMergeAppend((MergeAppendState *) node);
152 18 : break;
153 :
154 12 : case T_RecursiveUnionState:
155 12 : ExecReScanRecursiveUnion((RecursiveUnionState *) node);
156 12 : break;
157 :
158 34 : case T_BitmapAndState:
159 34 : ExecReScanBitmapAnd((BitmapAndState *) node);
160 34 : break;
161 :
162 28 : case T_BitmapOrState:
163 28 : ExecReScanBitmapOr((BitmapOrState *) node);
164 28 : break;
165 :
166 755246 : case T_SeqScanState:
167 755246 : ExecReScanSeqScan((SeqScanState *) node);
168 755246 : break;
169 :
170 58 : case T_SampleScanState:
171 58 : ExecReScanSampleScan((SampleScanState *) node);
172 58 : break;
173 :
174 300 : case T_GatherState:
175 300 : ExecReScanGather((GatherState *) node);
176 300 : break;
177 :
178 48 : case T_GatherMergeState:
179 48 : ExecReScanGatherMerge((GatherMergeState *) node);
180 48 : break;
181 :
182 327720 : case T_IndexScanState:
183 327720 : ExecReScanIndexScan((IndexScanState *) node);
184 327714 : break;
185 :
186 83082 : case T_IndexOnlyScanState:
187 83082 : ExecReScanIndexOnlyScan((IndexOnlyScanState *) node);
188 83082 : break;
189 :
190 4036 : case T_BitmapIndexScanState:
191 4036 : ExecReScanBitmapIndexScan((BitmapIndexScanState *) node);
192 4036 : break;
193 :
194 3452 : case T_BitmapHeapScanState:
195 3452 : ExecReScanBitmapHeapScan((BitmapHeapScanState *) node);
196 3452 : break;
197 :
198 18 : case T_TidScanState:
199 18 : ExecReScanTidScan((TidScanState *) node);
200 18 : break;
201 :
202 66 : case T_TidRangeScanState:
203 66 : ExecReScanTidRangeScan((TidRangeScanState *) node);
204 66 : break;
205 :
206 2162 : case T_SubqueryScanState:
207 2162 : ExecReScanSubqueryScan((SubqueryScanState *) node);
208 2162 : break;
209 :
210 77232 : case T_FunctionScanState:
211 77232 : ExecReScanFunctionScan((FunctionScanState *) node);
212 77232 : break;
213 :
214 192 : case T_TableFuncScanState:
215 192 : ExecReScanTableFuncScan((TableFuncScanState *) node);
216 192 : break;
217 :
218 60386 : case T_ValuesScanState:
219 60386 : ExecReScanValuesScan((ValuesScanState *) node);
220 60386 : break;
221 :
222 3722 : case T_CteScanState:
223 3722 : ExecReScanCteScan((CteScanState *) node);
224 3722 : break;
225 :
226 0 : case T_NamedTuplestoreScanState:
227 0 : ExecReScanNamedTuplestoreScan((NamedTuplestoreScanState *) node);
228 0 : break;
229 :
230 6196 : case T_WorkTableScanState:
231 6196 : ExecReScanWorkTableScan((WorkTableScanState *) node);
232 6196 : break;
233 :
234 802 : case T_ForeignScanState:
235 802 : ExecReScanForeignScan((ForeignScanState *) node);
236 802 : break;
237 :
238 0 : case T_CustomScanState:
239 0 : ExecReScanCustomScan((CustomScanState *) node);
240 0 : break;
241 :
242 10158 : case T_NestLoopState:
243 10158 : ExecReScanNestLoop((NestLoopState *) node);
244 10158 : break;
245 :
246 394 : case T_MergeJoinState:
247 394 : ExecReScanMergeJoin((MergeJoinState *) node);
248 394 : break;
249 :
250 2236 : case T_HashJoinState:
251 2236 : ExecReScanHashJoin((HashJoinState *) node);
252 2236 : break;
253 :
254 531314 : case T_MaterialState:
255 531314 : ExecReScanMaterial((MaterialState *) node);
256 531314 : break;
257 :
258 450864 : case T_MemoizeState:
259 450864 : ExecReScanMemoize((MemoizeState *) node);
260 450864 : break;
261 :
262 36494 : case T_SortState:
263 36494 : ExecReScanSort((SortState *) node);
264 36494 : break;
265 :
266 12 : case T_IncrementalSortState:
267 12 : ExecReScanIncrementalSort((IncrementalSortState *) node);
268 12 : break;
269 :
270 24 : case T_GroupState:
271 24 : ExecReScanGroup((GroupState *) node);
272 24 : break;
273 :
274 163938 : case T_AggState:
275 163938 : ExecReScanAgg((AggState *) node);
276 163938 : break;
277 :
278 78 : case T_WindowAggState:
279 78 : ExecReScanWindowAgg((WindowAggState *) node);
280 78 : break;
281 :
282 0 : case T_UniqueState:
283 0 : ExecReScanUnique((UniqueState *) node);
284 0 : break;
285 :
286 998 : case T_HashState:
287 998 : ExecReScanHash((HashState *) node);
288 998 : break;
289 :
290 600 : case T_SetOpState:
291 600 : ExecReScanSetOp((SetOpState *) node);
292 600 : break;
293 :
294 16 : case T_LockRowsState:
295 16 : ExecReScanLockRows((LockRowsState *) node);
296 16 : break;
297 :
298 900 : case T_LimitState:
299 900 : ExecReScanLimit((LimitState *) node);
300 900 : break;
301 :
302 0 : default:
303 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
304 : break;
305 : }
306 :
307 2848930 : if (node->chgParam != NULL)
308 : {
309 2102852 : bms_free(node->chgParam);
310 2102852 : node->chgParam = NULL;
311 : }
312 2848930 : }
313 :
314 : /*
315 : * ExecMarkPos
316 : *
317 : * Marks the current scan position.
318 : *
319 : * NOTE: mark/restore capability is currently needed only for plan nodes
320 : * that are the immediate inner child of a MergeJoin node. Since MergeJoin
321 : * requires sorted input, there is never any need to support mark/restore in
322 : * node types that cannot produce sorted output. There are some cases in
323 : * which a node can pass through sorted data from its child; if we don't
324 : * implement mark/restore for such a node type, the planner compensates by
325 : * inserting a Material node above that node.
326 : */
327 : void
328 706676 : ExecMarkPos(PlanState *node)
329 : {
330 706676 : switch (nodeTag(node))
331 : {
332 6050 : case T_IndexScanState:
333 6050 : ExecIndexMarkPos((IndexScanState *) node);
334 6050 : break;
335 :
336 124010 : case T_IndexOnlyScanState:
337 124010 : ExecIndexOnlyMarkPos((IndexOnlyScanState *) node);
338 124010 : break;
339 :
340 0 : case T_CustomScanState:
341 0 : ExecCustomMarkPos((CustomScanState *) node);
342 0 : break;
343 :
344 6440 : case T_MaterialState:
345 6440 : ExecMaterialMarkPos((MaterialState *) node);
346 6440 : break;
347 :
348 570176 : case T_SortState:
349 570176 : ExecSortMarkPos((SortState *) node);
350 570176 : break;
351 :
352 0 : case T_ResultState:
353 0 : ExecResultMarkPos((ResultState *) node);
354 0 : break;
355 :
356 0 : default:
357 : /* don't make hard error unless caller asks to restore... */
358 0 : elog(DEBUG2, "unrecognized node type: %d", (int) nodeTag(node));
359 0 : break;
360 : }
361 706676 : }
362 :
363 : /*
364 : * ExecRestrPos
365 : *
366 : * restores the scan position previously saved with ExecMarkPos()
367 : *
368 : * NOTE: the semantics of this are that the first ExecProcNode following
369 : * the restore operation will yield the same tuple as the first one following
370 : * the mark operation. It is unspecified what happens to the plan node's
371 : * result TupleTableSlot. (In most cases the result slot is unchanged by
372 : * a restore, but the node may choose to clear it or to load it with the
373 : * restored-to tuple.) Hence the caller should discard any previously
374 : * returned TupleTableSlot after doing a restore.
375 : */
376 : void
377 137270 : ExecRestrPos(PlanState *node)
378 : {
379 137270 : switch (nodeTag(node))
380 : {
381 54024 : case T_IndexScanState:
382 54024 : ExecIndexRestrPos((IndexScanState *) node);
383 54024 : break;
384 :
385 6 : case T_IndexOnlyScanState:
386 6 : ExecIndexOnlyRestrPos((IndexOnlyScanState *) node);
387 6 : break;
388 :
389 0 : case T_CustomScanState:
390 0 : ExecCustomRestrPos((CustomScanState *) node);
391 0 : break;
392 :
393 54032 : case T_MaterialState:
394 54032 : ExecMaterialRestrPos((MaterialState *) node);
395 54032 : break;
396 :
397 29208 : case T_SortState:
398 29208 : ExecSortRestrPos((SortState *) node);
399 29208 : break;
400 :
401 0 : case T_ResultState:
402 0 : ExecResultRestrPos((ResultState *) node);
403 0 : break;
404 :
405 0 : default:
406 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
407 : break;
408 : }
409 137270 : }
410 :
411 : /*
412 : * ExecSupportsMarkRestore - does a Path support mark/restore?
413 : *
414 : * This is used during planning and so must accept a Path, not a Plan.
415 : * We keep it here to be adjacent to the routines above, which also must
416 : * know which plan types support mark/restore.
417 : */
418 : bool
419 4224 : ExecSupportsMarkRestore(Path *pathnode)
420 : {
421 : /*
422 : * For consistency with the routines above, we do not examine the nodeTag
423 : * but rather the pathtype, which is the Plan node type the Path would
424 : * produce.
425 : */
426 4224 : switch (pathnode->pathtype)
427 : {
428 3484 : case T_IndexScan:
429 : case T_IndexOnlyScan:
430 :
431 : /*
432 : * Not all index types support mark/restore.
433 : */
434 3484 : return castNode(IndexPath, pathnode)->indexinfo->amcanmarkpos;
435 :
436 0 : case T_Material:
437 : case T_Sort:
438 0 : return true;
439 :
440 0 : case T_CustomScan:
441 0 : if (castNode(CustomPath, pathnode)->flags & CUSTOMPATH_SUPPORT_MARK_RESTORE)
442 0 : return true;
443 0 : return false;
444 :
445 0 : case T_Result:
446 :
447 : /*
448 : * Result supports mark/restore iff it has a child plan that does.
449 : *
450 : * We have to be careful here because there is more than one Path
451 : * type that can produce a Result plan node.
452 : */
453 0 : if (IsA(pathnode, ProjectionPath))
454 0 : return ExecSupportsMarkRestore(((ProjectionPath *) pathnode)->subpath);
455 0 : else if (IsA(pathnode, MinMaxAggPath))
456 0 : return false; /* childless Result */
457 0 : else if (IsA(pathnode, GroupResultPath))
458 0 : return false; /* childless Result */
459 : else
460 : {
461 : /* Simple RTE_RESULT base relation */
462 : Assert(IsA(pathnode, Path));
463 0 : return false; /* childless Result */
464 : }
465 :
466 84 : case T_Append:
467 : {
468 84 : AppendPath *appendPath = castNode(AppendPath, pathnode);
469 :
470 : /*
471 : * If there's exactly one child, then there will be no Append
472 : * in the final plan, so we can handle mark/restore if the
473 : * child plan node can.
474 : */
475 84 : if (list_length(appendPath->subpaths) == 1)
476 0 : return ExecSupportsMarkRestore((Path *) linitial(appendPath->subpaths));
477 : /* Otherwise, Append can't handle it */
478 84 : return false;
479 : }
480 :
481 36 : case T_MergeAppend:
482 : {
483 36 : MergeAppendPath *mapath = castNode(MergeAppendPath, pathnode);
484 :
485 : /*
486 : * Like the Append case above, single-subpath MergeAppends
487 : * won't be in the final plan, so just return the child's
488 : * mark/restore ability.
489 : */
490 36 : if (list_length(mapath->subpaths) == 1)
491 0 : return ExecSupportsMarkRestore((Path *) linitial(mapath->subpaths));
492 : /* Otherwise, MergeAppend can't handle it */
493 36 : return false;
494 : }
495 :
496 620 : default:
497 620 : break;
498 : }
499 :
500 620 : return false;
501 : }
502 :
503 : /*
504 : * ExecSupportsBackwardScan - does a plan type support backwards scanning?
505 : *
506 : * Ideally, all plan types would support backwards scan, but that seems
507 : * unlikely to happen soon. In some cases, a plan node passes the backwards
508 : * scan down to its children, and so supports backwards scan only if its
509 : * children do. Therefore, this routine must be passed a complete plan tree.
510 : */
511 : bool
512 3190 : ExecSupportsBackwardScan(Plan *node)
513 : {
514 3190 : if (node == NULL)
515 0 : return false;
516 :
517 : /*
518 : * Parallel-aware nodes return a subset of the tuples in each worker, and
519 : * in general we can't expect to have enough bookkeeping state to know
520 : * which ones we returned in this worker as opposed to some other worker.
521 : */
522 3190 : if (node->parallel_aware)
523 0 : return false;
524 :
525 3190 : switch (nodeTag(node))
526 : {
527 68 : case T_Result:
528 68 : if (outerPlan(node) != NULL)
529 0 : return ExecSupportsBackwardScan(outerPlan(node));
530 : else
531 68 : return false;
532 :
533 40 : case T_Append:
534 : {
535 : ListCell *l;
536 :
537 : /* With async, tuples may be interleaved, so can't back up. */
538 40 : if (((Append *) node)->nasyncplans > 0)
539 0 : return false;
540 :
541 136 : foreach(l, ((Append *) node)->appendplans)
542 : {
543 98 : if (!ExecSupportsBackwardScan((Plan *) lfirst(l)))
544 2 : return false;
545 : }
546 : /* need not check tlist because Append doesn't evaluate it */
547 38 : return true;
548 : }
549 :
550 6 : case T_SampleScan:
551 : /* Simplify life for tablesample methods by disallowing this */
552 6 : return false;
553 :
554 0 : case T_Gather:
555 0 : return false;
556 :
557 404 : case T_IndexScan:
558 404 : return IndexSupportsBackwardScan(((IndexScan *) node)->indexid);
559 :
560 118 : case T_IndexOnlyScan:
561 118 : return IndexSupportsBackwardScan(((IndexOnlyScan *) node)->indexid);
562 :
563 0 : case T_SubqueryScan:
564 0 : return ExecSupportsBackwardScan(((SubqueryScan *) node)->subplan);
565 :
566 0 : case T_CustomScan:
567 0 : if (((CustomScan *) node)->flags & CUSTOMPATH_SUPPORT_BACKWARD_SCAN)
568 0 : return true;
569 0 : return false;
570 :
571 1700 : case T_SeqScan:
572 : case T_TidScan:
573 : case T_TidRangeScan:
574 : case T_FunctionScan:
575 : case T_ValuesScan:
576 : case T_CteScan:
577 : case T_Material:
578 : case T_Sort:
579 : /* these don't evaluate tlist */
580 1700 : return true;
581 :
582 4 : case T_IncrementalSort:
583 :
584 : /*
585 : * Unlike full sort, incremental sort keeps only a single group of
586 : * tuples in memory, so it can't scan backwards.
587 : */
588 4 : return false;
589 :
590 132 : case T_LockRows:
591 : case T_Limit:
592 132 : return ExecSupportsBackwardScan(outerPlan(node));
593 :
594 718 : default:
595 718 : return false;
596 : }
597 : }
598 :
599 : /*
600 : * An IndexScan or IndexOnlyScan node supports backward scan only if the
601 : * index's AM does.
602 : */
603 : static bool
604 522 : IndexSupportsBackwardScan(Oid indexid)
605 : {
606 : bool result;
607 : HeapTuple ht_idxrel;
608 : Form_pg_class idxrelrec;
609 : IndexAmRoutine *amroutine;
610 :
611 : /* Fetch the pg_class tuple of the index relation */
612 522 : ht_idxrel = SearchSysCache1(RELOID, ObjectIdGetDatum(indexid));
613 522 : if (!HeapTupleIsValid(ht_idxrel))
614 0 : elog(ERROR, "cache lookup failed for relation %u", indexid);
615 522 : idxrelrec = (Form_pg_class) GETSTRUCT(ht_idxrel);
616 :
617 : /* Fetch the index AM's API struct */
618 522 : amroutine = GetIndexAmRoutineByAmId(idxrelrec->relam, false);
619 :
620 522 : result = amroutine->amcanbackward;
621 :
622 522 : pfree(amroutine);
623 522 : ReleaseSysCache(ht_idxrel);
624 :
625 522 : return result;
626 : }
627 :
628 : /*
629 : * ExecMaterializesOutput - does a plan type materialize its output?
630 : *
631 : * Returns true if the plan node type is one that automatically materializes
632 : * its output (typically by keeping it in a tuplestore). For such plans,
633 : * a rescan without any parameter change will have zero startup cost and
634 : * very low per-tuple cost.
635 : */
636 : bool
637 376816 : ExecMaterializesOutput(NodeTag plantype)
638 : {
639 376816 : switch (plantype)
640 : {
641 16330 : case T_Material:
642 : case T_FunctionScan:
643 : case T_TableFuncScan:
644 : case T_CteScan:
645 : case T_NamedTuplestoreScan:
646 : case T_WorkTableScan:
647 : case T_Sort:
648 16330 : return true;
649 :
650 360486 : default:
651 360486 : break;
652 : }
653 :
654 360486 : return false;
655 : }
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