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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * pquery.c
4 : : * POSTGRES process query command code
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/tcop/pquery.c
12 : : *
13 : : *-------------------------------------------------------------------------
14 : : */
15 : :
16 : : #include "postgres.h"
17 : :
18 : : #include <limits.h>
19 : :
20 : : #include "access/xact.h"
21 : : #include "commands/prepare.h"
22 : : #include "executor/executor.h"
23 : : #include "executor/tstoreReceiver.h"
24 : : #include "miscadmin.h"
25 : : #include "pg_trace.h"
26 : : #include "tcop/pquery.h"
27 : : #include "tcop/utility.h"
28 : : #include "utils/memutils.h"
29 : : #include "utils/snapmgr.h"
30 : :
31 : :
32 : : /*
33 : : * ActivePortal is the currently executing Portal (the most closely nested,
34 : : * if there are several).
35 : : */
36 : : Portal ActivePortal = NULL;
37 : :
38 : :
39 : : static void ProcessQuery(PlannedStmt *plan,
40 : : const char *sourceText,
41 : : ParamListInfo params,
42 : : QueryEnvironment *queryEnv,
43 : : DestReceiver *dest,
44 : : QueryCompletion *qc);
45 : : static void FillPortalStore(Portal portal, bool isTopLevel);
46 : : static uint64 RunFromStore(Portal portal, ScanDirection direction, uint64 count,
47 : : DestReceiver *dest);
48 : : static uint64 PortalRunSelect(Portal portal, bool forward, long count,
49 : : DestReceiver *dest);
50 : : static void PortalRunUtility(Portal portal, PlannedStmt *pstmt,
51 : : bool isTopLevel, bool setHoldSnapshot,
52 : : DestReceiver *dest, QueryCompletion *qc);
53 : : static void PortalRunMulti(Portal portal,
54 : : bool isTopLevel, bool setHoldSnapshot,
55 : : DestReceiver *dest, DestReceiver *altdest,
56 : : QueryCompletion *qc);
57 : : static uint64 DoPortalRunFetch(Portal portal,
58 : : FetchDirection fdirection,
59 : : long count,
60 : : DestReceiver *dest);
61 : : static void DoPortalRewind(Portal portal);
62 : :
63 : :
64 : : /*
65 : : * CreateQueryDesc
66 : : */
67 : : QueryDesc *
68 : 366634 : CreateQueryDesc(PlannedStmt *plannedstmt,
69 : : const char *sourceText,
70 : : Snapshot snapshot,
71 : : Snapshot crosscheck_snapshot,
72 : : DestReceiver *dest,
73 : : ParamListInfo params,
74 : : QueryEnvironment *queryEnv,
75 : : int instrument_options)
76 : : {
77 : 366634 : QueryDesc *qd = palloc_object(QueryDesc);
78 : :
79 : 366634 : qd->operation = plannedstmt->commandType; /* operation */
80 : 366634 : qd->plannedstmt = plannedstmt; /* plan */
81 : 366634 : qd->sourceText = sourceText; /* query text */
82 : 366634 : qd->snapshot = RegisterSnapshot(snapshot); /* snapshot */
83 : : /* RI check snapshot */
84 : 366634 : qd->crosscheck_snapshot = RegisterSnapshot(crosscheck_snapshot);
85 : 366634 : qd->dest = dest; /* output dest */
86 : 366634 : qd->params = params; /* parameter values passed into query */
87 : 366634 : qd->queryEnv = queryEnv;
88 : 366634 : qd->instrument_options = instrument_options; /* instrumentation wanted? */
89 : 366634 : qd->query_instr_options = 0;
90 : :
91 : : /* null these fields until set by ExecutorStart */
92 : 366634 : qd->tupDesc = NULL;
93 : 366634 : qd->estate = NULL;
94 : 366634 : qd->planstate = NULL;
95 : 366634 : qd->query_instr = NULL;
96 : :
97 : : /* not yet executed */
98 : 366634 : qd->already_executed = false;
99 : :
100 : 366634 : return qd;
101 : : }
102 : :
103 : : /*
104 : : * FreeQueryDesc
105 : : */
106 : : void
107 : 347561 : FreeQueryDesc(QueryDesc *qdesc)
108 : : {
109 : : /* Can't be a live query */
110 : : Assert(qdesc->estate == NULL);
111 : :
112 : : /* forget our snapshots */
113 : 347561 : UnregisterSnapshot(qdesc->snapshot);
114 : 347561 : UnregisterSnapshot(qdesc->crosscheck_snapshot);
115 : :
116 : : /* Only the QueryDesc itself need be freed */
117 : 347561 : pfree(qdesc);
118 : 347561 : }
119 : :
120 : :
121 : : /*
122 : : * ProcessQuery
123 : : * Execute a single plannable query within a PORTAL_MULTI_QUERY,
124 : : * PORTAL_ONE_RETURNING, or PORTAL_ONE_MOD_WITH portal
125 : : *
126 : : * plan: the plan tree for the query
127 : : * sourceText: the source text of the query
128 : : * params: any parameters needed
129 : : * dest: where to send results
130 : : * qc: where to store the command completion status data.
131 : : *
132 : : * qc may be NULL if caller doesn't want a status string.
133 : : *
134 : : * Must be called in a memory context that will be reset or deleted on
135 : : * error; otherwise the executor's memory usage will be leaked.
136 : : */
137 : : static void
138 : 56688 : ProcessQuery(PlannedStmt *plan,
139 : : const char *sourceText,
140 : : ParamListInfo params,
141 : : QueryEnvironment *queryEnv,
142 : : DestReceiver *dest,
143 : : QueryCompletion *qc)
144 : : {
145 : : QueryDesc *queryDesc;
146 : :
147 : : /*
148 : : * Create the QueryDesc object
149 : : */
150 : 56688 : queryDesc = CreateQueryDesc(plan, sourceText,
151 : : GetActiveSnapshot(), InvalidSnapshot,
152 : : dest, params, queryEnv, 0);
153 : :
154 : : /*
155 : : * Call ExecutorStart to prepare the plan for execution
156 : : */
157 : 56688 : ExecutorStart(queryDesc, 0);
158 : :
159 : : /*
160 : : * Run the plan to completion.
161 : : */
162 : 55954 : ExecutorRun(queryDesc, ForwardScanDirection, 0);
163 : :
164 : : /*
165 : : * Build command completion status data, if caller wants one.
166 : : */
167 [ + + ]: 53696 : if (qc)
168 : : {
169 : : CommandTag tag;
170 : :
171 [ + + ]: 53232 : if (queryDesc->operation == CMD_SELECT)
172 : 84 : tag = CMDTAG_SELECT;
173 [ + + ]: 53148 : else if (queryDesc->operation == CMD_INSERT)
174 : 42534 : tag = CMDTAG_INSERT;
175 [ + + ]: 10614 : else if (queryDesc->operation == CMD_UPDATE)
176 : 7303 : tag = CMDTAG_UPDATE;
177 [ + + ]: 3311 : else if (queryDesc->operation == CMD_DELETE)
178 : 2569 : tag = CMDTAG_DELETE;
179 [ + - ]: 742 : else if (queryDesc->operation == CMD_MERGE)
180 : 742 : tag = CMDTAG_MERGE;
181 : : else
182 : 0 : tag = CMDTAG_UNKNOWN;
183 : :
184 : 53232 : SetQueryCompletion(qc, tag, queryDesc->estate->es_processed);
185 : : }
186 : :
187 : : /*
188 : : * Now, we close down all the scans and free allocated resources.
189 : : */
190 : 53696 : ExecutorFinish(queryDesc);
191 : 52909 : ExecutorEnd(queryDesc);
192 : :
193 : 52909 : FreeQueryDesc(queryDesc);
194 : 52909 : }
195 : :
196 : : /*
197 : : * ChoosePortalStrategy
198 : : * Select portal execution strategy given the intended statement list.
199 : : *
200 : : * The list elements can be Querys or PlannedStmts.
201 : : * That's more general than portals need, but plancache.c uses this too.
202 : : *
203 : : * See the comments in portal.h.
204 : : */
205 : : PortalStrategy
206 : 528162 : ChoosePortalStrategy(List *stmts)
207 : : {
208 : : int nSetTag;
209 : : ListCell *lc;
210 : :
211 : : /*
212 : : * PORTAL_ONE_SELECT and PORTAL_UTIL_SELECT need only consider the
213 : : * single-statement case, since there are no rewrite rules that can add
214 : : * auxiliary queries to a SELECT or a utility command. PORTAL_ONE_MOD_WITH
215 : : * likewise allows only one top-level statement.
216 : : */
217 [ + + ]: 528162 : if (list_length(stmts) == 1)
218 : : {
219 : 527906 : Node *stmt = (Node *) linitial(stmts);
220 : :
221 [ + + ]: 527906 : if (IsA(stmt, Query))
222 : : {
223 : 52552 : Query *query = (Query *) stmt;
224 : :
225 [ + - ]: 52552 : if (query->canSetTag)
226 : : {
227 [ + + ]: 52552 : if (query->commandType == CMD_SELECT)
228 : : {
229 [ - + ]: 35265 : if (query->hasModifyingCTE)
230 : 0 : return PORTAL_ONE_MOD_WITH;
231 : : else
232 : 35265 : return PORTAL_ONE_SELECT;
233 : : }
234 [ + + ]: 17287 : if (query->commandType == CMD_UTILITY)
235 : : {
236 [ + + ]: 12862 : if (UtilityReturnsTuples(query->utilityStmt))
237 : 6736 : return PORTAL_UTIL_SELECT;
238 : : /* it can't be ONE_RETURNING, so give up */
239 : 6126 : return PORTAL_MULTI_QUERY;
240 : : }
241 : : }
242 : : }
243 [ + - ]: 475354 : else if (IsA(stmt, PlannedStmt))
244 : : {
245 : 475354 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
246 : :
247 [ + + ]: 475354 : if (pstmt->canSetTag)
248 : : {
249 [ + + ]: 475318 : if (pstmt->commandType == CMD_SELECT)
250 : : {
251 [ + + ]: 186281 : if (pstmt->hasModifyingCTE)
252 : 92 : return PORTAL_ONE_MOD_WITH;
253 : : else
254 : 186189 : return PORTAL_ONE_SELECT;
255 : : }
256 [ + + ]: 289037 : if (pstmt->commandType == CMD_UTILITY)
257 : : {
258 [ + + ]: 233149 : if (UtilityReturnsTuples(pstmt->utilityStmt))
259 : 29378 : return PORTAL_UTIL_SELECT;
260 : : /* it can't be ONE_RETURNING, so give up */
261 : 203771 : return PORTAL_MULTI_QUERY;
262 : : }
263 : : }
264 : : }
265 : : else
266 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(stmt));
267 : : }
268 : :
269 : : /*
270 : : * PORTAL_ONE_RETURNING has to allow auxiliary queries added by rewrite.
271 : : * Choose PORTAL_ONE_RETURNING if there is exactly one canSetTag query and
272 : : * it has a RETURNING list.
273 : : */
274 : 60605 : nSetTag = 0;
275 [ + + + + : 63043 : foreach(lc, stmts)
+ + ]
276 : : {
277 : 60741 : Node *stmt = (Node *) lfirst(lc);
278 : :
279 [ + + ]: 60741 : if (IsA(stmt, Query))
280 : : {
281 : 4433 : Query *query = (Query *) stmt;
282 : :
283 [ + + ]: 4433 : if (query->canSetTag)
284 : : {
285 [ - + ]: 4429 : if (++nSetTag > 1)
286 : 58303 : return PORTAL_MULTI_QUERY; /* no need to look further */
287 [ + - ]: 4429 : if (query->commandType == CMD_UTILITY ||
288 [ + + ]: 4429 : query->returningList == NIL)
289 : 4239 : return PORTAL_MULTI_QUERY; /* no need to look further */
290 : : }
291 : : }
292 [ + - ]: 56308 : else if (IsA(stmt, PlannedStmt))
293 : : {
294 : 56308 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
295 : :
296 [ + + ]: 56308 : if (pstmt->canSetTag)
297 : : {
298 [ - + ]: 56128 : if (++nSetTag > 1)
299 : 0 : return PORTAL_MULTI_QUERY; /* no need to look further */
300 [ + - ]: 56128 : if (pstmt->commandType == CMD_UTILITY ||
301 [ + + ]: 56128 : !pstmt->hasReturning)
302 : 54064 : return PORTAL_MULTI_QUERY; /* no need to look further */
303 : : }
304 : : }
305 : : else
306 [ # # ]: 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(stmt));
307 : : }
308 [ + + ]: 2302 : if (nSetTag == 1)
309 : 2254 : return PORTAL_ONE_RETURNING;
310 : :
311 : : /* Else, it's the general case... */
312 : 48 : return PORTAL_MULTI_QUERY;
313 : : }
314 : :
315 : : /*
316 : : * FetchPortalTargetList
317 : : * Given a portal that returns tuples, extract the query targetlist.
318 : : * Returns NIL if the portal doesn't have a determinable targetlist.
319 : : *
320 : : * Note: do not modify the result.
321 : : */
322 : : List *
323 : 200431 : FetchPortalTargetList(Portal portal)
324 : : {
325 : : /* no point in looking if we determined it doesn't return tuples */
326 [ + + ]: 200431 : if (portal->strategy == PORTAL_MULTI_QUERY)
327 : 20 : return NIL;
328 : : /* get the primary statement and find out what it returns */
329 : 200411 : return FetchStatementTargetList((Node *) PortalGetPrimaryStmt(portal));
330 : : }
331 : :
332 : : /*
333 : : * FetchStatementTargetList
334 : : * Given a statement that returns tuples, extract the query targetlist.
335 : : * Returns NIL if the statement doesn't have a determinable targetlist.
336 : : *
337 : : * This can be applied to a Query or a PlannedStmt.
338 : : * That's more general than portals need, but plancache.c uses this too.
339 : : *
340 : : * Note: do not modify the result.
341 : : *
342 : : * XXX be careful to keep this in sync with UtilityReturnsTuples.
343 : : */
344 : : List *
345 : 209038 : FetchStatementTargetList(Node *stmt)
346 : : {
347 [ - + ]: 209038 : if (stmt == NULL)
348 : 0 : return NIL;
349 [ + + ]: 209038 : if (IsA(stmt, Query))
350 : : {
351 : 8627 : Query *query = (Query *) stmt;
352 : :
353 [ + + ]: 8627 : if (query->commandType == CMD_UTILITY)
354 : : {
355 : : /* transfer attention to utility statement */
356 : 8 : stmt = query->utilityStmt;
357 : : }
358 : : else
359 : : {
360 [ + + ]: 8619 : if (query->commandType == CMD_SELECT)
361 : 8609 : return query->targetList;
362 [ + - ]: 10 : if (query->returningList)
363 : 10 : return query->returningList;
364 : 0 : return NIL;
365 : : }
366 : : }
367 [ + + ]: 200419 : if (IsA(stmt, PlannedStmt))
368 : : {
369 : 200411 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
370 : :
371 [ + + ]: 200411 : if (pstmt->commandType == CMD_UTILITY)
372 : : {
373 : : /* transfer attention to utility statement */
374 : 23701 : stmt = pstmt->utilityStmt;
375 : : }
376 : : else
377 : : {
378 [ + + ]: 176710 : if (pstmt->commandType == CMD_SELECT)
379 : 174777 : return pstmt->planTree->targetlist;
380 [ + - ]: 1933 : if (pstmt->hasReturning)
381 : 1933 : return pstmt->planTree->targetlist;
382 : 0 : return NIL;
383 : : }
384 : : }
385 [ + + ]: 23709 : if (IsA(stmt, FetchStmt))
386 : : {
387 : 3187 : FetchStmt *fstmt = (FetchStmt *) stmt;
388 : : Portal subportal;
389 : :
390 : : Assert(!fstmt->ismove);
391 : 3187 : subportal = GetPortalByName(fstmt->portalname);
392 : : Assert(PortalIsValid(subportal));
393 : 3187 : return FetchPortalTargetList(subportal);
394 : : }
395 [ + + ]: 20522 : if (IsA(stmt, ExecuteStmt))
396 : : {
397 : 8556 : ExecuteStmt *estmt = (ExecuteStmt *) stmt;
398 : : PreparedStatement *entry;
399 : :
400 : 8556 : entry = FetchPreparedStatement(estmt->name, true);
401 : 8556 : return FetchPreparedStatementTargetList(entry);
402 : : }
403 : 11966 : return NIL;
404 : : }
405 : :
406 : : /*
407 : : * PortalStart
408 : : * Prepare a portal for execution.
409 : : *
410 : : * Caller must already have created the portal, done PortalDefineQuery(),
411 : : * and adjusted portal options if needed.
412 : : *
413 : : * If parameters are needed by the query, they must be passed in "params"
414 : : * (caller is responsible for giving them appropriate lifetime).
415 : : *
416 : : * The caller can also provide an initial set of "eflags" to be passed to
417 : : * ExecutorStart (but note these can be modified internally, and they are
418 : : * currently only honored for PORTAL_ONE_SELECT portals). Most callers
419 : : * should simply pass zero.
420 : : *
421 : : * The caller can optionally pass a snapshot to be used; pass InvalidSnapshot
422 : : * for the normal behavior of setting a new snapshot. This parameter is
423 : : * presently ignored for non-PORTAL_ONE_SELECT portals (it's only intended
424 : : * to be used for cursors).
425 : : *
426 : : * On return, portal is ready to accept PortalRun() calls, and the result
427 : : * tupdesc (if any) is known.
428 : : */
429 : : void
430 : 475602 : PortalStart(Portal portal, ParamListInfo params,
431 : : int eflags, Snapshot snapshot)
432 : : {
433 : : Portal saveActivePortal;
434 : : ResourceOwner saveResourceOwner;
435 : : MemoryContext savePortalContext;
436 : : MemoryContext oldContext;
437 : : QueryDesc *queryDesc;
438 : : int myeflags;
439 : :
440 : : Assert(PortalIsValid(portal));
441 : : Assert(portal->status == PORTAL_DEFINED);
442 : :
443 : : /*
444 : : * Set up global portal context pointers.
445 : : */
446 : 475602 : saveActivePortal = ActivePortal;
447 : 475602 : saveResourceOwner = CurrentResourceOwner;
448 : 475602 : savePortalContext = PortalContext;
449 [ + + ]: 475602 : PG_TRY();
450 : : {
451 : 475602 : ActivePortal = portal;
452 [ + - ]: 475602 : if (portal->resowner)
453 : 475602 : CurrentResourceOwner = portal->resowner;
454 : 475602 : PortalContext = portal->portalContext;
455 : :
456 : 475602 : oldContext = MemoryContextSwitchTo(PortalContext);
457 : :
458 : : /* Must remember portal param list, if any */
459 : 475602 : portal->portalParams = params;
460 : :
461 : : /*
462 : : * Determine the portal execution strategy
463 : : */
464 : 475602 : portal->strategy = ChoosePortalStrategy(portal->stmts);
465 : :
466 : : /*
467 : : * Fire her up according to the strategy
468 : : */
469 [ + + + + : 475602 : switch (portal->strategy)
- ]
470 : : {
471 : 186189 : case PORTAL_ONE_SELECT:
472 : :
473 : : /* Must set snapshot before starting executor. */
474 [ + + ]: 186189 : if (snapshot)
475 : 14129 : PushActiveSnapshot(snapshot);
476 : : else
477 : 172060 : PushActiveSnapshot(GetTransactionSnapshot());
478 : :
479 : : /*
480 : : * We could remember the snapshot in portal->portalSnapshot,
481 : : * but presently there seems no need to, as this code path
482 : : * cannot be used for non-atomic execution. Hence there can't
483 : : * be any commit/abort that might destroy the snapshot. Since
484 : : * we don't do that, there's also no need to force a
485 : : * non-default nesting level for the snapshot.
486 : : */
487 : :
488 : : /*
489 : : * Create QueryDesc in portal's context; for the moment, set
490 : : * the destination to DestNone.
491 : : */
492 : 186189 : queryDesc = CreateQueryDesc(linitial_node(PlannedStmt, portal->stmts),
493 : : portal->sourceText,
494 : : GetActiveSnapshot(),
495 : : InvalidSnapshot,
496 : : None_Receiver,
497 : : params,
498 : : portal->queryEnv,
499 : : 0);
500 : :
501 : : /*
502 : : * If it's a scrollable cursor, executor needs to support
503 : : * REWIND and backwards scan, as well as whatever the caller
504 : : * might've asked for.
505 : : */
506 [ + + ]: 186189 : if (portal->cursorOptions & CURSOR_OPT_SCROLL)
507 : 2454 : myeflags = eflags | EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD;
508 : : else
509 : 183735 : myeflags = eflags;
510 : :
511 : : /*
512 : : * Call ExecutorStart to prepare the plan for execution
513 : : */
514 : 186189 : ExecutorStart(queryDesc, myeflags);
515 : :
516 : : /*
517 : : * This tells PortalCleanup to shut down the executor
518 : : */
519 : 185754 : portal->queryDesc = queryDesc;
520 : :
521 : : /*
522 : : * Remember tuple descriptor (computed by ExecutorStart)
523 : : */
524 : 185754 : portal->tupDesc = queryDesc->tupDesc;
525 : :
526 : : /*
527 : : * Reset cursor position data to "start of query"
528 : : */
529 : 185754 : portal->atStart = true;
530 : 185754 : portal->atEnd = false; /* allow fetches */
531 : 185754 : portal->portalPos = 0;
532 : :
533 : 185754 : PopActiveSnapshot();
534 : 185754 : break;
535 : :
536 : 2156 : case PORTAL_ONE_RETURNING:
537 : : case PORTAL_ONE_MOD_WITH:
538 : :
539 : : /*
540 : : * We don't start the executor until we are told to run the
541 : : * portal. We do need to set up the result tupdesc.
542 : : */
543 : : {
544 : : PlannedStmt *pstmt;
545 : :
546 : 2156 : pstmt = PortalGetPrimaryStmt(portal);
547 : 2156 : portal->tupDesc =
548 : 2156 : ExecCleanTypeFromTL(pstmt->planTree->targetlist);
549 : : }
550 : :
551 : : /*
552 : : * Reset cursor position data to "start of query"
553 : : */
554 : 2156 : portal->atStart = true;
555 : 2156 : portal->atEnd = false; /* allow fetches */
556 : 2156 : portal->portalPos = 0;
557 : 2156 : break;
558 : :
559 : 29378 : case PORTAL_UTIL_SELECT:
560 : :
561 : : /*
562 : : * We don't set snapshot here, because PortalRunUtility will
563 : : * take care of it if needed.
564 : : */
565 : : {
566 : 29378 : PlannedStmt *pstmt = PortalGetPrimaryStmt(portal);
567 : :
568 : : Assert(pstmt->commandType == CMD_UTILITY);
569 : 29378 : portal->tupDesc = UtilityTupleDescriptor(pstmt->utilityStmt);
570 : : }
571 : :
572 : : /*
573 : : * Reset cursor position data to "start of query"
574 : : */
575 : 29360 : portal->atStart = true;
576 : 29360 : portal->atEnd = false; /* allow fetches */
577 : 29360 : portal->portalPos = 0;
578 : 29360 : break;
579 : :
580 : 257879 : case PORTAL_MULTI_QUERY:
581 : : /* Need do nothing now */
582 : 257879 : portal->tupDesc = NULL;
583 : 257879 : break;
584 : : }
585 : : }
586 : 453 : PG_CATCH();
587 : : {
588 : : /* Uncaught error while executing portal: mark it dead */
589 : 453 : MarkPortalFailed(portal);
590 : :
591 : : /* Restore global vars and propagate error */
592 : 453 : ActivePortal = saveActivePortal;
593 : 453 : CurrentResourceOwner = saveResourceOwner;
594 : 453 : PortalContext = savePortalContext;
595 : :
596 : 453 : PG_RE_THROW();
597 : : }
598 [ - + ]: 475149 : PG_END_TRY();
599 : :
600 : 475149 : MemoryContextSwitchTo(oldContext);
601 : :
602 : 475149 : ActivePortal = saveActivePortal;
603 : 475149 : CurrentResourceOwner = saveResourceOwner;
604 : 475149 : PortalContext = savePortalContext;
605 : :
606 : 475149 : portal->status = PORTAL_READY;
607 : 475149 : }
608 : :
609 : : /*
610 : : * PortalSetResultFormat
611 : : * Select the format codes for a portal's output.
612 : : *
613 : : * This must be run after PortalStart for a portal that will be read by
614 : : * a DestRemote or DestRemoteExecute destination. It is not presently needed
615 : : * for other destination types.
616 : : *
617 : : * formats[] is the client format request, as per Bind message conventions.
618 : : */
619 : : void
620 : 455495 : PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
621 : : {
622 : : int natts;
623 : : int i;
624 : :
625 : : /* Do nothing if portal won't return tuples */
626 [ + + ]: 455495 : if (portal->tupDesc == NULL)
627 : 257808 : return;
628 : 197687 : natts = portal->tupDesc->natts;
629 : 197687 : portal->formats = (int16 *)
630 : 197687 : MemoryContextAlloc(portal->portalContext,
631 : : natts * sizeof(int16));
632 [ - + ]: 197687 : if (nFormats > 1)
633 : : {
634 : : /* format specified for each column */
635 [ # # ]: 0 : if (nFormats != natts)
636 [ # # ]: 0 : ereport(ERROR,
637 : : (errcode(ERRCODE_PROTOCOL_VIOLATION),
638 : : errmsg("bind message has %d result formats but query has %d columns",
639 : : nFormats, natts)));
640 : 0 : memcpy(portal->formats, formats, natts * sizeof(int16));
641 : : }
642 [ + - ]: 197687 : else if (nFormats > 0)
643 : : {
644 : : /* single format specified, use for all columns */
645 : 197687 : int16 format1 = formats[0];
646 : :
647 [ + + ]: 803955 : for (i = 0; i < natts; i++)
648 : 606268 : portal->formats[i] = format1;
649 : : }
650 : : else
651 : : {
652 : : /* use default format for all columns */
653 [ # # ]: 0 : for (i = 0; i < natts; i++)
654 : 0 : portal->formats[i] = 0;
655 : : }
656 : : }
657 : :
658 : : /*
659 : : * PortalRun
660 : : * Run a portal's query or queries.
661 : : *
662 : : * count <= 0 is interpreted as a no-op: the destination gets started up
663 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
664 : : * interpreted as "all rows". Note that count is ignored in multi-query
665 : : * situations, where we always run the portal to completion.
666 : : *
667 : : * isTopLevel: true if query is being executed at backend "top level"
668 : : * (that is, directly from a client command message)
669 : : *
670 : : * dest: where to send output of primary (canSetTag) query
671 : : *
672 : : * altdest: where to send output of non-primary queries
673 : : *
674 : : * qc: where to store command completion status data.
675 : : * May be NULL if caller doesn't want status data.
676 : : *
677 : : * Returns true if the portal's execution is complete, false if it was
678 : : * suspended due to exhaustion of the count parameter.
679 : : */
680 : : bool
681 : 464153 : PortalRun(Portal portal, long count, bool isTopLevel,
682 : : DestReceiver *dest, DestReceiver *altdest,
683 : : QueryCompletion *qc)
684 : : {
685 : : bool result;
686 : : uint64 nprocessed;
687 : : ResourceOwner saveTopTransactionResourceOwner;
688 : : MemoryContext saveTopTransactionContext;
689 : : Portal saveActivePortal;
690 : : ResourceOwner saveResourceOwner;
691 : : MemoryContext savePortalContext;
692 : : MemoryContext saveMemoryContext;
693 : :
694 : : Assert(PortalIsValid(portal));
695 : :
696 : : TRACE_POSTGRESQL_QUERY_EXECUTE_START();
697 : :
698 : : /* Initialize empty completion data */
699 [ + - ]: 464153 : if (qc)
700 : 464153 : InitializeQueryCompletion(qc);
701 : :
702 [ - + - - ]: 464153 : if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
703 : : {
704 [ # # ]: 0 : elog(DEBUG3, "PortalRun");
705 : : /* PORTAL_MULTI_QUERY logs its own stats per query */
706 : 0 : ResetUsage();
707 : : }
708 : :
709 : : /*
710 : : * Check for improper portal use, and mark portal active.
711 : : */
712 : 464153 : MarkPortalActive(portal);
713 : :
714 : : /*
715 : : * Set up global portal context pointers.
716 : : *
717 : : * We have to play a special game here to support utility commands like
718 : : * VACUUM and CLUSTER, which internally start and commit transactions.
719 : : * When we are called to execute such a command, CurrentResourceOwner will
720 : : * be pointing to the TopTransactionResourceOwner --- which will be
721 : : * destroyed and replaced in the course of the internal commit and
722 : : * restart. So we need to be prepared to restore it as pointing to the
723 : : * exit-time TopTransactionResourceOwner. (Ain't that ugly? This idea of
724 : : * internally starting whole new transactions is not good.)
725 : : * CurrentMemoryContext has a similar problem, but the other pointers we
726 : : * save here will be NULL or pointing to longer-lived objects.
727 : : */
728 : 464153 : saveTopTransactionResourceOwner = TopTransactionResourceOwner;
729 : 464153 : saveTopTransactionContext = TopTransactionContext;
730 : 464153 : saveActivePortal = ActivePortal;
731 : 464153 : saveResourceOwner = CurrentResourceOwner;
732 : 464153 : savePortalContext = PortalContext;
733 : 464153 : saveMemoryContext = CurrentMemoryContext;
734 [ + + ]: 464153 : PG_TRY();
735 : : {
736 : 464153 : ActivePortal = portal;
737 [ + - ]: 464153 : if (portal->resowner)
738 : 464153 : CurrentResourceOwner = portal->resowner;
739 : 464153 : PortalContext = portal->portalContext;
740 : :
741 : 464153 : MemoryContextSwitchTo(PortalContext);
742 : :
743 [ + + - ]: 464153 : switch (portal->strategy)
744 : : {
745 : 206274 : case PORTAL_ONE_SELECT:
746 : : case PORTAL_ONE_RETURNING:
747 : : case PORTAL_ONE_MOD_WITH:
748 : : case PORTAL_UTIL_SELECT:
749 : :
750 : : /*
751 : : * If we have not yet run the command, do so, storing its
752 : : * results in the portal's tuplestore. But we don't do that
753 : : * for the PORTAL_ONE_SELECT case.
754 : : */
755 [ + + + - ]: 206274 : if (portal->strategy != PORTAL_ONE_SELECT && !portal->holdStore)
756 : 26076 : FillPortalStore(portal, isTopLevel);
757 : :
758 : : /*
759 : : * Now fetch desired portion of results.
760 : : */
761 : 205924 : nprocessed = PortalRunSelect(portal, true, count, dest);
762 : :
763 : : /*
764 : : * If the portal result contains a command tag and the caller
765 : : * gave us a pointer to store it, copy it and update the
766 : : * rowcount.
767 : : */
768 [ + - + - ]: 200883 : if (qc && portal->qc.commandTag != CMDTAG_UNKNOWN)
769 : : {
770 : 200883 : CopyQueryCompletion(qc, &portal->qc);
771 : 200883 : qc->nprocessed = nprocessed;
772 : : }
773 : :
774 : : /* Mark portal not active */
775 : 200883 : portal->status = PORTAL_READY;
776 : :
777 : : /*
778 : : * Since it's a forward fetch, say DONE iff atEnd is now true.
779 : : */
780 : 200883 : result = portal->atEnd;
781 : 200883 : break;
782 : :
783 : 257879 : case PORTAL_MULTI_QUERY:
784 : 257879 : PortalRunMulti(portal, isTopLevel, false,
785 : : dest, altdest, qc);
786 : :
787 : : /* Prevent portal's commands from being re-executed */
788 : 242831 : MarkPortalDone(portal);
789 : :
790 : : /* Always complete at end of RunMulti */
791 : 242831 : result = true;
792 : 242831 : break;
793 : :
794 : 0 : default:
795 [ # # ]: 0 : elog(ERROR, "unrecognized portal strategy: %d",
796 : : (int) portal->strategy);
797 : : result = false; /* keep compiler quiet */
798 : : break;
799 : : }
800 : : }
801 : 20434 : PG_CATCH();
802 : : {
803 : : /* Uncaught error while executing portal: mark it dead */
804 : 20434 : MarkPortalFailed(portal);
805 : :
806 : : /* Restore global vars and propagate error */
807 [ + + ]: 20434 : if (saveMemoryContext == saveTopTransactionContext)
808 : 20189 : MemoryContextSwitchTo(TopTransactionContext);
809 : : else
810 : 245 : MemoryContextSwitchTo(saveMemoryContext);
811 : 20434 : ActivePortal = saveActivePortal;
812 [ + + ]: 20434 : if (saveResourceOwner == saveTopTransactionResourceOwner)
813 : 20242 : CurrentResourceOwner = TopTransactionResourceOwner;
814 : : else
815 : 192 : CurrentResourceOwner = saveResourceOwner;
816 : 20434 : PortalContext = savePortalContext;
817 : :
818 : 20434 : PG_RE_THROW();
819 : : }
820 [ - + ]: 443714 : PG_END_TRY();
821 : :
822 [ + + ]: 443714 : if (saveMemoryContext == saveTopTransactionContext)
823 : 420059 : MemoryContextSwitchTo(TopTransactionContext);
824 : : else
825 : 23655 : MemoryContextSwitchTo(saveMemoryContext);
826 : 443714 : ActivePortal = saveActivePortal;
827 [ + + ]: 443714 : if (saveResourceOwner == saveTopTransactionResourceOwner)
828 : 431161 : CurrentResourceOwner = TopTransactionResourceOwner;
829 : : else
830 : 12553 : CurrentResourceOwner = saveResourceOwner;
831 : 443714 : PortalContext = savePortalContext;
832 : :
833 [ - + - - ]: 443714 : if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
834 : 0 : ShowUsage("EXECUTOR STATISTICS");
835 : :
836 : : TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
837 : :
838 : 443714 : return result;
839 : : }
840 : :
841 : : /*
842 : : * PortalRunSelect
843 : : * Execute a portal's query in PORTAL_ONE_SELECT mode, and also
844 : : * when fetching from a completed holdStore in PORTAL_ONE_RETURNING,
845 : : * PORTAL_ONE_MOD_WITH, and PORTAL_UTIL_SELECT cases.
846 : : *
847 : : * This handles simple N-rows-forward-or-backward cases. For more complex
848 : : * nonsequential access to a portal, see PortalRunFetch.
849 : : *
850 : : * count <= 0 is interpreted as a no-op: the destination gets started up
851 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
852 : : * interpreted as "all rows". (cf FetchStmt.howMany)
853 : : *
854 : : * Caller must already have validated the Portal and done appropriate
855 : : * setup (cf. PortalRun).
856 : : *
857 : : * Returns number of rows processed (suitable for use in result tag)
858 : : */
859 : : static uint64
860 : 240289 : PortalRunSelect(Portal portal,
861 : : bool forward,
862 : : long count,
863 : : DestReceiver *dest)
864 : : {
865 : : QueryDesc *queryDesc;
866 : : ScanDirection direction;
867 : : uint64 nprocessed;
868 : :
869 : : /*
870 : : * NB: queryDesc will be NULL if we are fetching from a held cursor or a
871 : : * completed utility query; can't use it in that path.
872 : : */
873 : 240289 : queryDesc = portal->queryDesc;
874 : :
875 : : /* Caller messed up if we have neither a ready query nor held data. */
876 : : Assert(queryDesc || portal->holdStore);
877 : :
878 : : /*
879 : : * Force the queryDesc destination to the right thing. This supports
880 : : * MOVE, for example, which will pass in dest = DestNone. This is okay to
881 : : * change as long as we do it on every fetch. (The Executor must not
882 : : * assume that dest never changes.)
883 : : */
884 [ + + ]: 240289 : if (queryDesc)
885 : 193099 : queryDesc->dest = dest;
886 : :
887 : : /*
888 : : * Determine which direction to go in, and check to see if we're already
889 : : * at the end of the available tuples in that direction. If so, set the
890 : : * direction to NoMovement to avoid trying to fetch any tuples. (This
891 : : * check exists because not all plan node types are robust about being
892 : : * called again if they've already returned NULL once.) Then call the
893 : : * executor (we must not skip this, because the destination needs to see a
894 : : * setup and shutdown even if no tuples are available). Finally, update
895 : : * the portal position state depending on the number of tuples that were
896 : : * retrieved.
897 : : */
898 [ + + ]: 240289 : if (forward)
899 : : {
900 [ + + + + ]: 239877 : if (portal->atEnd || count <= 0)
901 : : {
902 : 2505 : direction = NoMovementScanDirection;
903 : 2505 : count = 0; /* don't pass negative count to executor */
904 : : }
905 : : else
906 : 237372 : direction = ForwardScanDirection;
907 : :
908 : : /* In the executor, zero count processes all rows */
909 [ + + ]: 239877 : if (count == FETCH_ALL)
910 : 206139 : count = 0;
911 : :
912 [ + + ]: 239877 : if (portal->holdStore)
913 : 47178 : nprocessed = RunFromStore(portal, direction, (uint64) count, dest);
914 : : else
915 : : {
916 : 192699 : PushActiveSnapshot(queryDesc->snapshot);
917 : 192699 : ExecutorRun(queryDesc, direction, (uint64) count);
918 : 187630 : nprocessed = queryDesc->estate->es_processed;
919 : 187630 : PopActiveSnapshot();
920 : : }
921 : :
922 [ + + ]: 234808 : if (!ScanDirectionIsNoMovement(direction))
923 : : {
924 [ + + ]: 232303 : if (nprocessed > 0)
925 : 193840 : portal->atStart = false; /* OK to go backward now */
926 [ + + + + ]: 232303 : if (count == 0 || nprocessed < (uint64) count)
927 : 210362 : portal->atEnd = true; /* we retrieved 'em all */
928 : 232303 : portal->portalPos += nprocessed;
929 : : }
930 : : }
931 : : else
932 : : {
933 [ + + ]: 412 : if (portal->cursorOptions & CURSOR_OPT_NO_SCROLL)
934 [ + - ]: 16 : ereport(ERROR,
935 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
936 : : errmsg("cursor can only scan forward"),
937 : : errhint("Declare it with SCROLL option to enable backward scan.")));
938 : :
939 [ + + - + ]: 396 : if (portal->atStart || count <= 0)
940 : : {
941 : 48 : direction = NoMovementScanDirection;
942 : 48 : count = 0; /* don't pass negative count to executor */
943 : : }
944 : : else
945 : 348 : direction = BackwardScanDirection;
946 : :
947 : : /* In the executor, zero count processes all rows */
948 [ + + ]: 396 : if (count == FETCH_ALL)
949 : 41 : count = 0;
950 : :
951 [ + + ]: 396 : if (portal->holdStore)
952 : 8 : nprocessed = RunFromStore(portal, direction, (uint64) count, dest);
953 : : else
954 : : {
955 : 388 : PushActiveSnapshot(queryDesc->snapshot);
956 : 388 : ExecutorRun(queryDesc, direction, (uint64) count);
957 : 388 : nprocessed = queryDesc->estate->es_processed;
958 : 388 : PopActiveSnapshot();
959 : : }
960 : :
961 [ + + ]: 396 : if (!ScanDirectionIsNoMovement(direction))
962 : : {
963 [ + + + + ]: 348 : if (nprocessed > 0 && portal->atEnd)
964 : : {
965 : 106 : portal->atEnd = false; /* OK to go forward now */
966 : 106 : portal->portalPos++; /* adjust for endpoint case */
967 : : }
968 [ + + + + ]: 348 : if (count == 0 || nprocessed < (uint64) count)
969 : : {
970 : 125 : portal->atStart = true; /* we retrieved 'em all */
971 : 125 : portal->portalPos = 0;
972 : : }
973 : : else
974 : : {
975 : 223 : portal->portalPos -= nprocessed;
976 : : }
977 : : }
978 : : }
979 : :
980 : 235204 : return nprocessed;
981 : : }
982 : :
983 : : /*
984 : : * FillPortalStore
985 : : * Run the query and load result tuples into the portal's tuple store.
986 : : *
987 : : * This is used for PORTAL_ONE_RETURNING, PORTAL_ONE_MOD_WITH, and
988 : : * PORTAL_UTIL_SELECT cases only.
989 : : */
990 : : static void
991 : 31516 : FillPortalStore(Portal portal, bool isTopLevel)
992 : : {
993 : : DestReceiver *treceiver;
994 : : QueryCompletion qc;
995 : :
996 : 31516 : InitializeQueryCompletion(&qc);
997 : 31516 : PortalCreateHoldStore(portal);
998 : 31516 : treceiver = CreateDestReceiver(DestTuplestore);
999 : 31516 : SetTuplestoreDestReceiverParams(treceiver,
1000 : : portal->holdStore,
1001 : : portal->holdContext,
1002 : : false,
1003 : : NULL,
1004 : : NULL);
1005 : :
1006 [ + + - ]: 31516 : switch (portal->strategy)
1007 : : {
1008 : 2156 : case PORTAL_ONE_RETURNING:
1009 : : case PORTAL_ONE_MOD_WITH:
1010 : :
1011 : : /*
1012 : : * Run the portal to completion just as for the default
1013 : : * PORTAL_MULTI_QUERY case, but send the primary query's output to
1014 : : * the tuplestore. Auxiliary query outputs are discarded. Set the
1015 : : * portal's holdSnapshot to the snapshot used (or a copy of it).
1016 : : */
1017 : 2156 : PortalRunMulti(portal, isTopLevel, true,
1018 : : treceiver, None_Receiver, &qc);
1019 : 2026 : break;
1020 : :
1021 : 29360 : case PORTAL_UTIL_SELECT:
1022 : 29360 : PortalRunUtility(portal, linitial_node(PlannedStmt, portal->stmts),
1023 : : isTopLevel, true, treceiver, &qc);
1024 : 29136 : break;
1025 : :
1026 : 0 : default:
1027 [ # # ]: 0 : elog(ERROR, "unsupported portal strategy: %d",
1028 : : (int) portal->strategy);
1029 : : break;
1030 : : }
1031 : :
1032 : : /* Override portal completion data with actual command results */
1033 [ + + ]: 31162 : if (qc.commandTag != CMDTAG_UNKNOWN)
1034 : 13765 : CopyQueryCompletion(&portal->qc, &qc);
1035 : :
1036 : 31162 : treceiver->rDestroy(treceiver);
1037 : 31162 : }
1038 : :
1039 : : /*
1040 : : * RunFromStore
1041 : : * Fetch tuples from the portal's tuple store.
1042 : : *
1043 : : * Calling conventions are similar to ExecutorRun, except that we
1044 : : * do not depend on having a queryDesc or estate. Therefore we return the
1045 : : * number of tuples processed as the result, not in estate->es_processed.
1046 : : *
1047 : : * One difference from ExecutorRun is that the destination receiver functions
1048 : : * are run in the caller's memory context (since we have no estate). Watch
1049 : : * out for memory leaks.
1050 : : */
1051 : : static uint64
1052 : 47186 : RunFromStore(Portal portal, ScanDirection direction, uint64 count,
1053 : : DestReceiver *dest)
1054 : : {
1055 : 47186 : uint64 current_tuple_count = 0;
1056 : : TupleTableSlot *slot;
1057 : :
1058 : 47186 : slot = MakeSingleTupleTableSlot(portal->tupDesc, &TTSOpsMinimalTuple);
1059 : :
1060 : 47186 : dest->rStartup(dest, CMD_SELECT, portal->tupDesc);
1061 : :
1062 [ + + ]: 47186 : if (ScanDirectionIsNoMovement(direction))
1063 : : {
1064 : : /* do nothing except start/stop the destination */
1065 : : }
1066 : : else
1067 : : {
1068 : 45428 : bool forward = ScanDirectionIsForward(direction);
1069 : :
1070 : : for (;;)
1071 : 262355 : {
1072 : : MemoryContext oldcontext;
1073 : : bool ok;
1074 : :
1075 : 307783 : oldcontext = MemoryContextSwitchTo(portal->holdContext);
1076 : :
1077 : 307783 : ok = tuplestore_gettupleslot(portal->holdStore, forward, false,
1078 : : slot);
1079 : :
1080 : 307783 : MemoryContextSwitchTo(oldcontext);
1081 : :
1082 [ + + ]: 307783 : if (!ok)
1083 : 31194 : break;
1084 : :
1085 : : /*
1086 : : * If we are not able to send the tuple, we assume the destination
1087 : : * has closed and no more tuples can be sent. If that's the case,
1088 : : * end the loop.
1089 : : */
1090 [ - + ]: 276589 : if (!dest->receiveSlot(slot, dest))
1091 : 0 : break;
1092 : :
1093 : 276589 : ExecClearTuple(slot);
1094 : :
1095 : : /*
1096 : : * check our tuple count.. if we've processed the proper number
1097 : : * then quit, else loop again and process more tuples. Zero count
1098 : : * means no limit.
1099 : : */
1100 : 276589 : current_tuple_count++;
1101 [ + + + + ]: 276589 : if (count && count == current_tuple_count)
1102 : 14234 : break;
1103 : : }
1104 : : }
1105 : :
1106 : 47186 : dest->rShutdown(dest);
1107 : :
1108 : 47186 : ExecDropSingleTupleTableSlot(slot);
1109 : :
1110 : 47186 : return current_tuple_count;
1111 : : }
1112 : :
1113 : : /*
1114 : : * PortalRunUtility
1115 : : * Execute a utility statement inside a portal.
1116 : : */
1117 : : static void
1118 : 233131 : PortalRunUtility(Portal portal, PlannedStmt *pstmt,
1119 : : bool isTopLevel, bool setHoldSnapshot,
1120 : : DestReceiver *dest, QueryCompletion *qc)
1121 : : {
1122 : : /*
1123 : : * Set snapshot if utility stmt needs one.
1124 : : */
1125 [ + + ]: 233131 : if (PlannedStmtRequiresSnapshot(pstmt))
1126 : : {
1127 : 182473 : Snapshot snapshot = GetTransactionSnapshot();
1128 : :
1129 : : /* If told to, register the snapshot we're using and save in portal */
1130 [ + + ]: 182473 : if (setHoldSnapshot)
1131 : : {
1132 : 25316 : snapshot = RegisterSnapshot(snapshot);
1133 : 25316 : portal->holdSnapshot = snapshot;
1134 : : }
1135 : :
1136 : : /*
1137 : : * In any case, make the snapshot active and remember it in portal.
1138 : : * Because the portal now references the snapshot, we must tell
1139 : : * snapmgr.c that the snapshot belongs to the portal's transaction
1140 : : * level, else we risk portalSnapshot becoming a dangling pointer.
1141 : : */
1142 : 182473 : PushActiveSnapshotWithLevel(snapshot, portal->createLevel);
1143 : : /* PushActiveSnapshotWithLevel might have copied the snapshot */
1144 : 182473 : portal->portalSnapshot = GetActiveSnapshot();
1145 : : }
1146 : : else
1147 : 50658 : portal->portalSnapshot = NULL;
1148 : :
1149 : 233131 : ProcessUtility(pstmt,
1150 : : portal->sourceText,
1151 : 233131 : (portal->cplan != NULL), /* protect tree if in plancache */
1152 : 233131 : isTopLevel ? PROCESS_UTILITY_TOPLEVEL : PROCESS_UTILITY_QUERY,
1153 : : portal->portalParams,
1154 : : portal->queryEnv,
1155 : : dest,
1156 : : qc);
1157 : :
1158 : : /* Some utility statements may change context on us */
1159 : 221508 : MemoryContextSwitchTo(portal->portalContext);
1160 : :
1161 : : /*
1162 : : * Some utility commands (e.g., VACUUM, WAIT FOR) pop the ActiveSnapshot
1163 : : * stack from under us, so don't complain if it's now empty. Otherwise,
1164 : : * our snapshot should be the top one; pop it. Note that this could be a
1165 : : * different snapshot from the one we made above; see
1166 : : * EnsurePortalSnapshotExists.
1167 : : */
1168 [ + + + - ]: 221508 : if (portal->portalSnapshot != NULL && ActiveSnapshotSet())
1169 : : {
1170 : : Assert(portal->portalSnapshot == GetActiveSnapshot());
1171 : 164414 : PopActiveSnapshot();
1172 : : }
1173 : 221508 : portal->portalSnapshot = NULL;
1174 : 221508 : }
1175 : :
1176 : : /*
1177 : : * PortalRunMulti
1178 : : * Execute a portal's queries in the general case (multi queries
1179 : : * or non-SELECT-like queries)
1180 : : */
1181 : : static void
1182 : 260035 : PortalRunMulti(Portal portal,
1183 : : bool isTopLevel, bool setHoldSnapshot,
1184 : : DestReceiver *dest, DestReceiver *altdest,
1185 : : QueryCompletion *qc)
1186 : : {
1187 : 260035 : bool active_snapshot_set = false;
1188 : : ListCell *stmtlist_item;
1189 : :
1190 : : /*
1191 : : * If the destination is DestRemoteExecute, change to DestNone. The
1192 : : * reason is that the client won't be expecting any tuples, and indeed has
1193 : : * no way to know what they are, since there is no provision for Describe
1194 : : * to send a RowDescription message when this portal execution strategy is
1195 : : * in effect. This presently will only affect SELECT commands added to
1196 : : * non-SELECT queries by rewrite rules: such commands will be executed,
1197 : : * but the results will be discarded unless you use "simple Query"
1198 : : * protocol.
1199 : : */
1200 [ + + ]: 260035 : if (dest->mydest == DestRemoteExecute)
1201 : 6405 : dest = None_Receiver;
1202 [ + + ]: 260035 : if (altdest->mydest == DestRemoteExecute)
1203 : 6405 : altdest = None_Receiver;
1204 : :
1205 : : /*
1206 : : * Loop to handle the individual queries generated from a single parsetree
1207 : : * by analysis and rewrite.
1208 : : */
1209 [ + - + + : 505316 : foreach(stmtlist_item, portal->stmts)
+ + ]
1210 : : {
1211 : 260459 : PlannedStmt *pstmt = lfirst_node(PlannedStmt, stmtlist_item);
1212 : :
1213 : : /*
1214 : : * If we got a cancel signal in prior command, quit
1215 : : */
1216 [ - + ]: 260459 : CHECK_FOR_INTERRUPTS();
1217 : :
1218 [ + + ]: 260459 : if (pstmt->utilityStmt == NULL)
1219 : : {
1220 : : /*
1221 : : * process a plannable query.
1222 : : */
1223 : : TRACE_POSTGRESQL_QUERY_EXECUTE_START();
1224 : :
1225 [ - + ]: 56688 : if (log_executor_stats)
1226 : 0 : ResetUsage();
1227 : :
1228 : : /*
1229 : : * Must always have a snapshot for plannable queries. First time
1230 : : * through, take a new snapshot; for subsequent queries in the
1231 : : * same portal, just update the snapshot's copy of the command
1232 : : * counter.
1233 : : */
1234 [ + + ]: 56688 : if (!active_snapshot_set)
1235 : : {
1236 : 56264 : Snapshot snapshot = GetTransactionSnapshot();
1237 : :
1238 : : /* If told to, register the snapshot and save in portal */
1239 [ + + ]: 56264 : if (setHoldSnapshot)
1240 : : {
1241 : 2156 : snapshot = RegisterSnapshot(snapshot);
1242 : 2156 : portal->holdSnapshot = snapshot;
1243 : : }
1244 : :
1245 : : /*
1246 : : * We can't have the holdSnapshot also be the active one,
1247 : : * because UpdateActiveSnapshotCommandId would complain. So
1248 : : * force an extra snapshot copy. Plain PushActiveSnapshot
1249 : : * would have copied the transaction snapshot anyway, so this
1250 : : * only adds a copy step when setHoldSnapshot is true. (It's
1251 : : * okay for the command ID of the active snapshot to diverge
1252 : : * from what holdSnapshot has.)
1253 : : */
1254 : 56264 : PushCopiedSnapshot(snapshot);
1255 : :
1256 : : /*
1257 : : * As for PORTAL_ONE_SELECT portals, it does not seem
1258 : : * necessary to maintain portal->portalSnapshot here.
1259 : : */
1260 : :
1261 : 56264 : active_snapshot_set = true;
1262 : : }
1263 : : else
1264 : 424 : UpdateActiveSnapshotCommandId();
1265 : :
1266 [ + + ]: 56688 : if (pstmt->canSetTag)
1267 : : {
1268 : : /* statement can set tag string */
1269 : 56220 : ProcessQuery(pstmt,
1270 : : portal->sourceText,
1271 : : portal->portalParams,
1272 : : portal->queryEnv,
1273 : : dest, qc);
1274 : : }
1275 : : else
1276 : : {
1277 : : /* stmt added by rewrite cannot set tag */
1278 : 468 : ProcessQuery(pstmt,
1279 : : portal->sourceText,
1280 : : portal->portalParams,
1281 : : portal->queryEnv,
1282 : : altdest, NULL);
1283 : : }
1284 : :
1285 [ - + ]: 52909 : if (log_executor_stats)
1286 : 0 : ShowUsage("EXECUTOR STATISTICS");
1287 : :
1288 : : TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
1289 : : }
1290 : : else
1291 : : {
1292 : : /*
1293 : : * process utility functions (create, destroy, etc..)
1294 : : *
1295 : : * We must not set a snapshot here for utility commands (if one is
1296 : : * needed, PortalRunUtility will do it). If a utility command is
1297 : : * alone in a portal then everything's fine. The only case where
1298 : : * a utility command can be part of a longer list is that rules
1299 : : * are allowed to include NotifyStmt. NotifyStmt doesn't care
1300 : : * whether it has a snapshot or not, so we just leave the current
1301 : : * snapshot alone if we have one.
1302 : : */
1303 [ + - ]: 203771 : if (pstmt->canSetTag)
1304 : : {
1305 : : Assert(!active_snapshot_set);
1306 : : /* statement can set tag string */
1307 : 203771 : PortalRunUtility(portal, pstmt, isTopLevel, false,
1308 : : dest, qc);
1309 : : }
1310 : : else
1311 : : {
1312 : : Assert(IsA(pstmt->utilityStmt, NotifyStmt));
1313 : : /* stmt added by rewrite cannot set tag */
1314 : 0 : PortalRunUtility(portal, pstmt, isTopLevel, false,
1315 : : altdest, NULL);
1316 : : }
1317 : : }
1318 : :
1319 : : /*
1320 : : * Clear subsidiary contexts to recover temporary memory.
1321 : : */
1322 : : Assert(portal->portalContext == CurrentMemoryContext);
1323 : :
1324 : 245281 : MemoryContextDeleteChildren(portal->portalContext);
1325 : :
1326 : : /*
1327 : : * Avoid crashing if portal->stmts has been reset. This can only
1328 : : * occur if a CALL or DO utility statement executed an internal
1329 : : * COMMIT/ROLLBACK (cf PortalReleaseCachedPlan). The CALL or DO must
1330 : : * have been the only statement in the portal, so there's nothing left
1331 : : * for us to do; but we don't want to dereference a now-dangling list
1332 : : * pointer.
1333 : : */
1334 [ - + ]: 245281 : if (portal->stmts == NIL)
1335 : 0 : break;
1336 : :
1337 : : /*
1338 : : * Increment command counter between queries, but not after the last
1339 : : * one.
1340 : : */
1341 [ + + ]: 245281 : if (lnext(portal->stmts, stmtlist_item) != NULL)
1342 : 424 : CommandCounterIncrement();
1343 : : }
1344 : :
1345 : : /* Pop the snapshot if we pushed one. */
1346 [ + + ]: 244857 : if (active_snapshot_set)
1347 : 52485 : PopActiveSnapshot();
1348 : :
1349 : : /*
1350 : : * If a command tag was requested and we did not fill in a run-time-
1351 : : * determined tag above, copy the parse-time tag from the Portal. (There
1352 : : * might not be any tag there either, in edge cases such as empty prepared
1353 : : * statements. That's OK.)
1354 : : */
1355 [ + - ]: 244857 : if (qc &&
1356 [ + + ]: 244857 : qc->commandTag == CMDTAG_UNKNOWN &&
1357 [ + - ]: 184769 : portal->qc.commandTag != CMDTAG_UNKNOWN)
1358 : 184769 : CopyQueryCompletion(qc, &portal->qc);
1359 : 244857 : }
1360 : :
1361 : : /*
1362 : : * PortalRunFetch
1363 : : * Variant form of PortalRun that supports SQL FETCH directions.
1364 : : *
1365 : : * Note: we presently assume that no callers of this want isTopLevel = true.
1366 : : *
1367 : : * count <= 0 is interpreted as a no-op: the destination gets started up
1368 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
1369 : : * interpreted as "all rows". (cf FetchStmt.howMany)
1370 : : *
1371 : : * Returns number of rows processed (suitable for use in result tag)
1372 : : */
1373 : : uint64
1374 : 34314 : PortalRunFetch(Portal portal,
1375 : : FetchDirection fdirection,
1376 : : long count,
1377 : : DestReceiver *dest)
1378 : : {
1379 : : uint64 result;
1380 : : Portal saveActivePortal;
1381 : : ResourceOwner saveResourceOwner;
1382 : : MemoryContext savePortalContext;
1383 : : MemoryContext oldContext;
1384 : :
1385 : : Assert(PortalIsValid(portal));
1386 : :
1387 : : /*
1388 : : * Check for improper portal use, and mark portal active.
1389 : : */
1390 : 34314 : MarkPortalActive(portal);
1391 : :
1392 : : /*
1393 : : * Set up global portal context pointers.
1394 : : */
1395 : 34302 : saveActivePortal = ActivePortal;
1396 : 34302 : saveResourceOwner = CurrentResourceOwner;
1397 : 34302 : savePortalContext = PortalContext;
1398 [ + + ]: 34302 : PG_TRY();
1399 : : {
1400 : 34302 : ActivePortal = portal;
1401 [ + + ]: 34302 : if (portal->resowner)
1402 : 34195 : CurrentResourceOwner = portal->resowner;
1403 : 34302 : PortalContext = portal->portalContext;
1404 : :
1405 : 34302 : oldContext = MemoryContextSwitchTo(PortalContext);
1406 : :
1407 [ + + - ]: 34302 : switch (portal->strategy)
1408 : : {
1409 : 12941 : case PORTAL_ONE_SELECT:
1410 : 12941 : result = DoPortalRunFetch(portal, fdirection, count, dest);
1411 : 12893 : break;
1412 : :
1413 : 21361 : case PORTAL_ONE_RETURNING:
1414 : : case PORTAL_ONE_MOD_WITH:
1415 : : case PORTAL_UTIL_SELECT:
1416 : :
1417 : : /*
1418 : : * If we have not yet run the command, do so, storing its
1419 : : * results in the portal's tuplestore.
1420 : : */
1421 [ + + ]: 21361 : if (!portal->holdStore)
1422 : 5440 : FillPortalStore(portal, false /* isTopLevel */ );
1423 : :
1424 : : /*
1425 : : * Now fetch desired portion of results.
1426 : : */
1427 : 21357 : result = DoPortalRunFetch(portal, fdirection, count, dest);
1428 : 21357 : break;
1429 : :
1430 : 0 : default:
1431 [ # # ]: 0 : elog(ERROR, "unsupported portal strategy");
1432 : : result = 0; /* keep compiler quiet */
1433 : : break;
1434 : : }
1435 : : }
1436 : 52 : PG_CATCH();
1437 : : {
1438 : : /* Uncaught error while executing portal: mark it dead */
1439 : 52 : MarkPortalFailed(portal);
1440 : :
1441 : : /* Restore global vars and propagate error */
1442 : 52 : ActivePortal = saveActivePortal;
1443 : 52 : CurrentResourceOwner = saveResourceOwner;
1444 : 52 : PortalContext = savePortalContext;
1445 : :
1446 : 52 : PG_RE_THROW();
1447 : : }
1448 [ - + ]: 34250 : PG_END_TRY();
1449 : :
1450 : 34250 : MemoryContextSwitchTo(oldContext);
1451 : :
1452 : : /* Mark portal not active */
1453 : 34250 : portal->status = PORTAL_READY;
1454 : :
1455 : 34250 : ActivePortal = saveActivePortal;
1456 : 34250 : CurrentResourceOwner = saveResourceOwner;
1457 : 34250 : PortalContext = savePortalContext;
1458 : :
1459 : 34250 : return result;
1460 : : }
1461 : :
1462 : : /*
1463 : : * DoPortalRunFetch
1464 : : * Guts of PortalRunFetch --- the portal context is already set up
1465 : : *
1466 : : * Here, count < 0 typically reverses the direction. Also, count == FETCH_ALL
1467 : : * is interpreted as "all rows". (cf FetchStmt.howMany)
1468 : : *
1469 : : * Returns number of rows processed (suitable for use in result tag)
1470 : : */
1471 : : static uint64
1472 : 34298 : DoPortalRunFetch(Portal portal,
1473 : : FetchDirection fdirection,
1474 : : long count,
1475 : : DestReceiver *dest)
1476 : : {
1477 : : bool forward;
1478 : :
1479 : : Assert(portal->strategy == PORTAL_ONE_SELECT ||
1480 : : portal->strategy == PORTAL_ONE_RETURNING ||
1481 : : portal->strategy == PORTAL_ONE_MOD_WITH ||
1482 : : portal->strategy == PORTAL_UTIL_SELECT);
1483 : :
1484 : : /*
1485 : : * Note: we disallow backwards fetch (including re-fetch of current row)
1486 : : * for NO SCROLL cursors, but we interpret that very loosely: you can use
1487 : : * any of the FetchDirection options, so long as the end result is to move
1488 : : * forwards by at least one row. Currently it's sufficient to check for
1489 : : * NO SCROLL in DoPortalRewind() and in the forward == false path in
1490 : : * PortalRunSelect(); but someday we might prefer to account for that
1491 : : * restriction explicitly here.
1492 : : */
1493 [ + + + + : 34298 : switch (fdirection)
- ]
1494 : : {
1495 : 33794 : case FETCH_FORWARD:
1496 [ + + ]: 33794 : if (count < 0)
1497 : : {
1498 : 2 : fdirection = FETCH_BACKWARD;
1499 : 2 : count = -count;
1500 : : }
1501 : : /* fall out of switch to share code with FETCH_BACKWARD */
1502 : 33794 : break;
1503 : 336 : case FETCH_BACKWARD:
1504 [ + + ]: 336 : if (count < 0)
1505 : : {
1506 : 1 : fdirection = FETCH_FORWARD;
1507 : 1 : count = -count;
1508 : : }
1509 : : /* fall out of switch to share code with FETCH_FORWARD */
1510 : 336 : break;
1511 : 109 : case FETCH_ABSOLUTE:
1512 [ + + ]: 109 : if (count > 0)
1513 : : {
1514 : : /*
1515 : : * Definition: Rewind to start, advance count-1 rows, return
1516 : : * next row (if any).
1517 : : *
1518 : : * In practice, if the goal is less than halfway back to the
1519 : : * start, it's better to scan from where we are.
1520 : : *
1521 : : * Also, if current portalPos is outside the range of "long",
1522 : : * do it the hard way to avoid possible overflow of the count
1523 : : * argument to PortalRunSelect. We must exclude exactly
1524 : : * LONG_MAX, as well, lest the count look like FETCH_ALL.
1525 : : *
1526 : : * In any case, we arrange to fetch the target row going
1527 : : * forwards.
1528 : : */
1529 [ + + ]: 63 : if ((uint64) (count - 1) <= portal->portalPos / 2 ||
1530 [ - + ]: 25 : portal->portalPos >= (uint64) LONG_MAX)
1531 : : {
1532 : 38 : DoPortalRewind(portal);
1533 [ - + ]: 34 : if (count > 1)
1534 : 0 : PortalRunSelect(portal, true, count - 1,
1535 : : None_Receiver);
1536 : : }
1537 : : else
1538 : : {
1539 : 25 : long pos = (long) portal->portalPos;
1540 : :
1541 [ - + ]: 25 : if (portal->atEnd)
1542 : 0 : pos++; /* need one extra fetch if off end */
1543 [ + + ]: 25 : if (count <= pos)
1544 : 8 : PortalRunSelect(portal, false, pos - count + 1,
1545 : : None_Receiver);
1546 [ + + ]: 17 : else if (count > pos + 1)
1547 : 8 : PortalRunSelect(portal, true, count - pos - 1,
1548 : : None_Receiver);
1549 : : }
1550 : 55 : return PortalRunSelect(portal, true, 1L, dest);
1551 : : }
1552 [ + + ]: 46 : else if (count < 0)
1553 : : {
1554 : : /*
1555 : : * Definition: Advance to end, back up abs(count)-1 rows,
1556 : : * return prior row (if any). We could optimize this if we
1557 : : * knew in advance where the end was, but typically we won't.
1558 : : * (Is it worth considering case where count > half of size of
1559 : : * query? We could rewind once we know the size ...)
1560 : : */
1561 : 38 : PortalRunSelect(portal, true, FETCH_ALL, None_Receiver);
1562 [ - + ]: 38 : if (count < -1)
1563 : 0 : PortalRunSelect(portal, false, -count - 1, None_Receiver);
1564 : 38 : return PortalRunSelect(portal, false, 1L, dest);
1565 : : }
1566 : : else
1567 : : {
1568 : : /* count == 0 */
1569 : : /* Rewind to start, return zero rows */
1570 : 8 : DoPortalRewind(portal);
1571 : 8 : return PortalRunSelect(portal, true, 0L, dest);
1572 : : }
1573 : : break;
1574 : 59 : case FETCH_RELATIVE:
1575 [ + + ]: 59 : if (count > 0)
1576 : : {
1577 : : /*
1578 : : * Definition: advance count-1 rows, return next row (if any).
1579 : : */
1580 [ + + ]: 26 : if (count > 1)
1581 : 17 : PortalRunSelect(portal, true, count - 1, None_Receiver);
1582 : 26 : return PortalRunSelect(portal, true, 1L, dest);
1583 : : }
1584 [ + + ]: 33 : else if (count < 0)
1585 : : {
1586 : : /*
1587 : : * Definition: back up abs(count)-1 rows, return prior row (if
1588 : : * any).
1589 : : */
1590 [ + + ]: 21 : if (count < -1)
1591 : 12 : PortalRunSelect(portal, false, -count - 1, None_Receiver);
1592 : 21 : return PortalRunSelect(portal, false, 1L, dest);
1593 : : }
1594 : : else
1595 : : {
1596 : : /* count == 0 */
1597 : : /* Same as FETCH FORWARD 0, so fall out of switch */
1598 : 12 : fdirection = FETCH_FORWARD;
1599 : : }
1600 : 12 : break;
1601 : 0 : default:
1602 [ # # ]: 0 : elog(ERROR, "bogus direction");
1603 : : break;
1604 : : }
1605 : :
1606 : : /*
1607 : : * Get here with fdirection == FETCH_FORWARD or FETCH_BACKWARD, and count
1608 : : * >= 0.
1609 : : */
1610 : 34142 : forward = (fdirection == FETCH_FORWARD);
1611 : :
1612 : : /*
1613 : : * Zero count means to re-fetch the current row, if any (per SQL)
1614 : : */
1615 [ + + ]: 34142 : if (count == 0)
1616 : : {
1617 : : bool on_row;
1618 : :
1619 : : /* Are we sitting on a row? */
1620 [ + - + - ]: 12 : on_row = (!portal->atStart && !portal->atEnd);
1621 : :
1622 [ - + ]: 12 : if (dest->mydest == DestNone)
1623 : : {
1624 : : /* MOVE 0 returns 0/1 based on if FETCH 0 would return a row */
1625 : 0 : return on_row ? 1 : 0;
1626 : : }
1627 : : else
1628 : : {
1629 : : /*
1630 : : * If we are sitting on a row, back up one so we can re-fetch it.
1631 : : * If we are not sitting on a row, we still have to start up and
1632 : : * shut down the executor so that the destination is initialized
1633 : : * and shut down correctly; so keep going. To PortalRunSelect,
1634 : : * count == 0 means we will retrieve no row.
1635 : : */
1636 [ + - ]: 12 : if (on_row)
1637 : : {
1638 : 12 : PortalRunSelect(portal, false, 1L, None_Receiver);
1639 : : /* Set up to fetch one row forward */
1640 : 8 : count = 1;
1641 : 8 : forward = true;
1642 : : }
1643 : : }
1644 : : }
1645 : :
1646 : : /*
1647 : : * Optimize MOVE BACKWARD ALL into a Rewind.
1648 : : */
1649 [ + + + + : 34138 : if (!forward && count == FETCH_ALL && dest->mydest == DestNone)
+ + ]
1650 : : {
1651 : 16 : uint64 result = portal->portalPos;
1652 : :
1653 [ + + - + ]: 16 : if (result > 0 && !portal->atEnd)
1654 : 0 : result--;
1655 : 16 : DoPortalRewind(portal);
1656 : 16 : return result;
1657 : : }
1658 : :
1659 : 34122 : return PortalRunSelect(portal, forward, count, dest);
1660 : : }
1661 : :
1662 : : /*
1663 : : * DoPortalRewind - rewind a Portal to starting point
1664 : : */
1665 : : static void
1666 : 62 : DoPortalRewind(Portal portal)
1667 : : {
1668 : : QueryDesc *queryDesc;
1669 : :
1670 : : /*
1671 : : * No work is needed if we've not advanced nor attempted to advance the
1672 : : * cursor (and we don't want to throw a NO SCROLL error in this case).
1673 : : */
1674 [ + + + - ]: 62 : if (portal->atStart && !portal->atEnd)
1675 : 12 : return;
1676 : :
1677 : : /* Otherwise, cursor must allow scrolling */
1678 [ + + ]: 50 : if (portal->cursorOptions & CURSOR_OPT_NO_SCROLL)
1679 [ + - ]: 4 : ereport(ERROR,
1680 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1681 : : errmsg("cursor can only scan forward"),
1682 : : errhint("Declare it with SCROLL option to enable backward scan.")));
1683 : :
1684 : : /* Rewind holdStore, if we have one */
1685 [ + + ]: 46 : if (portal->holdStore)
1686 : : {
1687 : : MemoryContext oldcontext;
1688 : :
1689 : 4 : oldcontext = MemoryContextSwitchTo(portal->holdContext);
1690 : 4 : tuplestore_rescan(portal->holdStore);
1691 : 4 : MemoryContextSwitchTo(oldcontext);
1692 : : }
1693 : :
1694 : : /* Rewind executor, if active */
1695 : 46 : queryDesc = portal->queryDesc;
1696 [ + + ]: 46 : if (queryDesc)
1697 : : {
1698 : 42 : PushActiveSnapshot(queryDesc->snapshot);
1699 : 42 : ExecutorRewind(queryDesc);
1700 : 42 : PopActiveSnapshot();
1701 : : }
1702 : :
1703 : 46 : portal->atStart = true;
1704 : 46 : portal->atEnd = false;
1705 : 46 : portal->portalPos = 0;
1706 : : }
1707 : :
1708 : : /*
1709 : : * PlannedStmtRequiresSnapshot - what it says on the tin
1710 : : */
1711 : : bool
1712 : 300871 : PlannedStmtRequiresSnapshot(PlannedStmt *pstmt)
1713 : : {
1714 : 300871 : Node *utilityStmt = pstmt->utilityStmt;
1715 : :
1716 : : /* If it's not a utility statement, it definitely needs a snapshot */
1717 [ + + ]: 300871 : if (utilityStmt == NULL)
1718 : 50098 : return true;
1719 : :
1720 : : /*
1721 : : * Most utility statements need a snapshot, and the default presumption
1722 : : * about new ones should be that they do too. Hence, enumerate those that
1723 : : * do not need one.
1724 : : *
1725 : : * Transaction control, LOCK, and SET must *not* set a snapshot, since
1726 : : * they need to be executable at the start of a transaction-snapshot-mode
1727 : : * transaction without freezing a snapshot. By extension we allow SHOW
1728 : : * not to set a snapshot. The other stmts listed are just efficiency
1729 : : * hacks. Beware of listing anything that can modify the database --- if,
1730 : : * say, it has to update an index with expressions that invoke
1731 : : * user-defined functions, then it had better have a snapshot.
1732 : : */
1733 [ + + ]: 250773 : if (IsA(utilityStmt, TransactionStmt) ||
1734 [ + + ]: 223429 : IsA(utilityStmt, LockStmt) ||
1735 [ + + ]: 222833 : IsA(utilityStmt, VariableSetStmt) ||
1736 [ + + ]: 197427 : IsA(utilityStmt, VariableShowStmt) ||
1737 [ + + ]: 196868 : IsA(utilityStmt, ConstraintsSetStmt) ||
1738 : : /* efficiency hacks from here down */
1739 [ + + ]: 196797 : IsA(utilityStmt, FetchStmt) ||
1740 [ + + ]: 192350 : IsA(utilityStmt, ListenStmt) ||
1741 [ + + ]: 192298 : IsA(utilityStmt, NotifyStmt) ||
1742 [ + + ]: 192236 : IsA(utilityStmt, UnlistenStmt) ||
1743 [ + + ]: 192174 : IsA(utilityStmt, CheckPointStmt) ||
1744 [ + + ]: 191707 : IsA(utilityStmt, WaitStmt))
1745 : 59320 : return false;
1746 : :
1747 : 191453 : return true;
1748 : : }
1749 : :
1750 : : /*
1751 : : * EnsurePortalSnapshotExists - recreate Portal-level snapshot, if needed
1752 : : *
1753 : : * Generally, we will have an active snapshot whenever we are executing
1754 : : * inside a Portal, unless the Portal's query is one of the utility
1755 : : * statements exempted from that rule (see PlannedStmtRequiresSnapshot).
1756 : : * However, procedures and DO blocks can commit or abort the transaction,
1757 : : * and thereby destroy all snapshots. This function can be called to
1758 : : * re-establish the Portal-level snapshot when none exists.
1759 : : */
1760 : : void
1761 : 281217 : EnsurePortalSnapshotExists(void)
1762 : : {
1763 : : Portal portal;
1764 : :
1765 : : /*
1766 : : * Nothing to do if a snapshot is set. (We take it on faith that the
1767 : : * outermost active snapshot belongs to some Portal; or if there is no
1768 : : * Portal, it's somebody else's responsibility to manage things.)
1769 : : */
1770 [ + + ]: 281217 : if (ActiveSnapshotSet())
1771 : 278969 : return;
1772 : :
1773 : : /* Otherwise, we'd better have an active Portal */
1774 : 2248 : portal = ActivePortal;
1775 [ - + ]: 2248 : if (unlikely(portal == NULL))
1776 [ # # ]: 0 : elog(ERROR, "cannot execute SQL without an outer snapshot or portal");
1777 : : Assert(portal->portalSnapshot == NULL);
1778 : :
1779 : : /*
1780 : : * Create a new snapshot, make it active, and remember it in portal.
1781 : : * Because the portal now references the snapshot, we must tell snapmgr.c
1782 : : * that the snapshot belongs to the portal's transaction level, else we
1783 : : * risk portalSnapshot becoming a dangling pointer.
1784 : : */
1785 : 2248 : PushActiveSnapshotWithLevel(GetTransactionSnapshot(), portal->createLevel);
1786 : : /* PushActiveSnapshotWithLevel might have copied the snapshot */
1787 : 2248 : portal->portalSnapshot = GetActiveSnapshot();
1788 : : }
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