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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 : 454276 : 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 : 454276 : QueryDesc *qd = palloc_object(QueryDesc);
78 : :
79 : 454276 : qd->operation = plannedstmt->commandType; /* operation */
80 : 454276 : qd->plannedstmt = plannedstmt; /* plan */
81 : 454276 : qd->sourceText = sourceText; /* query text */
82 : 454276 : qd->snapshot = RegisterSnapshot(snapshot); /* snapshot */
83 : : /* RI check snapshot */
84 : 454276 : qd->crosscheck_snapshot = RegisterSnapshot(crosscheck_snapshot);
85 : 454276 : qd->dest = dest; /* output dest */
86 : 454276 : qd->params = params; /* parameter values passed into query */
87 : 454276 : qd->queryEnv = queryEnv;
88 : 454276 : qd->instrument_options = instrument_options; /* instrumentation wanted? */
89 : :
90 : : /* null these fields until set by ExecutorStart */
91 : 454276 : qd->tupDesc = NULL;
92 : 454276 : qd->estate = NULL;
93 : 454276 : qd->planstate = NULL;
94 : 454276 : qd->totaltime = NULL;
95 : :
96 : : /* not yet executed */
97 : 454276 : qd->already_executed = false;
98 : :
99 : 908552 : return qd;
100 : 454276 : }
101 : :
102 : : /*
103 : : * FreeQueryDesc
104 : : */
105 : : void
106 : 447460 : FreeQueryDesc(QueryDesc *qdesc)
107 : : {
108 : : /* Can't be a live query */
109 [ + - ]: 447460 : Assert(qdesc->estate == NULL);
110 : :
111 : : /* forget our snapshots */
112 : 447460 : UnregisterSnapshot(qdesc->snapshot);
113 : 447460 : UnregisterSnapshot(qdesc->crosscheck_snapshot);
114 : :
115 : : /* Only the QueryDesc itself need be freed */
116 : 447460 : pfree(qdesc);
117 : 447460 : }
118 : :
119 : :
120 : : /*
121 : : * ProcessQuery
122 : : * Execute a single plannable query within a PORTAL_MULTI_QUERY,
123 : : * PORTAL_ONE_RETURNING, or PORTAL_ONE_MOD_WITH portal
124 : : *
125 : : * plan: the plan tree for the query
126 : : * sourceText: the source text of the query
127 : : * params: any parameters needed
128 : : * dest: where to send results
129 : : * qc: where to store the command completion status data.
130 : : *
131 : : * qc may be NULL if caller doesn't want a status string.
132 : : *
133 : : * Must be called in a memory context that will be reset or deleted on
134 : : * error; otherwise the executor's memory usage will be leaked.
135 : : */
136 : : static void
137 : 6613 : ProcessQuery(PlannedStmt *plan,
138 : : const char *sourceText,
139 : : ParamListInfo params,
140 : : QueryEnvironment *queryEnv,
141 : : DestReceiver *dest,
142 : : QueryCompletion *qc)
143 : : {
144 : 6613 : QueryDesc *queryDesc;
145 : :
146 : : /*
147 : : * Create the QueryDesc object
148 : : */
149 : 13226 : queryDesc = CreateQueryDesc(plan, sourceText,
150 : 6613 : GetActiveSnapshot(), InvalidSnapshot,
151 : 6613 : dest, params, queryEnv, 0);
152 : :
153 : : /*
154 : : * Call ExecutorStart to prepare the plan for execution
155 : : */
156 : 6613 : ExecutorStart(queryDesc, 0);
157 : :
158 : : /*
159 : : * Run the plan to completion.
160 : : */
161 : 6613 : ExecutorRun(queryDesc, ForwardScanDirection, 0);
162 : :
163 : : /*
164 : : * Build command completion status data, if caller wants one.
165 : : */
166 [ + + ]: 6613 : if (qc)
167 : : {
168 : 5890 : CommandTag tag;
169 : :
170 [ + + ]: 5890 : if (queryDesc->operation == CMD_SELECT)
171 : 18 : tag = CMDTAG_SELECT;
172 [ + + ]: 5872 : else if (queryDesc->operation == CMD_INSERT)
173 : 4608 : tag = CMDTAG_INSERT;
174 [ + + ]: 1264 : else if (queryDesc->operation == CMD_UPDATE)
175 : 703 : tag = CMDTAG_UPDATE;
176 [ + + ]: 561 : else if (queryDesc->operation == CMD_DELETE)
177 : 398 : tag = CMDTAG_DELETE;
178 [ + - ]: 163 : else if (queryDesc->operation == CMD_MERGE)
179 : 163 : tag = CMDTAG_MERGE;
180 : : else
181 : 0 : tag = CMDTAG_UNKNOWN;
182 : :
183 : 5890 : SetQueryCompletion(qc, tag, queryDesc->estate->es_processed);
184 : 5890 : }
185 : :
186 : : /*
187 : : * Now, we close down all the scans and free allocated resources.
188 : : */
189 : 6613 : ExecutorFinish(queryDesc);
190 : 6613 : ExecutorEnd(queryDesc);
191 : :
192 : 6613 : FreeQueryDesc(queryDesc);
193 : 6613 : }
194 : :
195 : : /*
196 : : * ChoosePortalStrategy
197 : : * Select portal execution strategy given the intended statement list.
198 : : *
199 : : * The list elements can be Querys or PlannedStmts.
200 : : * That's more general than portals need, but plancache.c uses this too.
201 : : *
202 : : * See the comments in portal.h.
203 : : */
204 : : PortalStrategy
205 : 68987 : ChoosePortalStrategy(List *stmts)
206 : : {
207 : 68987 : int nSetTag;
208 : 68987 : ListCell *lc;
209 : :
210 : : /*
211 : : * PORTAL_ONE_SELECT and PORTAL_UTIL_SELECT need only consider the
212 : : * single-statement case, since there are no rewrite rules that can add
213 : : * auxiliary queries to a SELECT or a utility command. PORTAL_ONE_MOD_WITH
214 : : * likewise allows only one top-level statement.
215 : : */
216 [ + + ]: 68987 : if (list_length(stmts) == 1)
217 : : {
218 : 68931 : Node *stmt = (Node *) linitial(stmts);
219 : :
220 [ + + ]: 68931 : if (IsA(stmt, Query))
221 : : {
222 : 9802 : Query *query = (Query *) stmt;
223 : :
224 [ - + ]: 9802 : if (query->canSetTag)
225 : : {
226 [ + + ]: 9802 : if (query->commandType == CMD_SELECT)
227 : : {
228 [ - + ]: 7467 : if (query->hasModifyingCTE)
229 : 0 : return PORTAL_ONE_MOD_WITH;
230 : : else
231 : 7467 : return PORTAL_ONE_SELECT;
232 : : }
233 [ + + ]: 2335 : if (query->commandType == CMD_UTILITY)
234 : : {
235 [ + + ]: 2103 : if (UtilityReturnsTuples(query->utilityStmt))
236 : 1656 : return PORTAL_UTIL_SELECT;
237 : : /* it can't be ONE_RETURNING, so give up */
238 : 447 : return PORTAL_MULTI_QUERY;
239 : : }
240 : 232 : }
241 [ + + ]: 9802 : }
242 [ + - ]: 59129 : else if (IsA(stmt, PlannedStmt))
243 : : {
244 : 59129 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
245 : :
246 [ + + ]: 59129 : if (pstmt->canSetTag)
247 : : {
248 [ + + ]: 59123 : if (pstmt->commandType == CMD_SELECT)
249 : : {
250 [ + + ]: 25086 : if (pstmt->hasModifyingCTE)
251 : 20 : return PORTAL_ONE_MOD_WITH;
252 : : else
253 : 25066 : return PORTAL_ONE_SELECT;
254 : : }
255 [ + + ]: 34037 : if (pstmt->commandType == CMD_UTILITY)
256 : : {
257 [ + + ]: 27602 : if (UtilityReturnsTuples(pstmt->utilityStmt))
258 : 4206 : return PORTAL_UTIL_SELECT;
259 : : /* it can't be ONE_RETURNING, so give up */
260 : 23396 : return PORTAL_MULTI_QUERY;
261 : : }
262 : 6435 : }
263 [ + + ]: 59129 : }
264 : : else
265 [ # # # # ]: 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(stmt));
266 [ + + ]: 68931 : }
267 : :
268 : : /*
269 : : * PORTAL_ONE_RETURNING has to allow auxiliary queries added by rewrite.
270 : : * Choose PORTAL_ONE_RETURNING if there is exactly one canSetTag query and
271 : : * it has a RETURNING list.
272 : : */
273 : 6729 : nSetTag = 0;
274 [ + + + + : 13486 : foreach(lc, stmts)
+ + + + ]
275 : : {
276 : 6757 : Node *stmt = (Node *) lfirst(lc);
277 : :
278 [ + + ]: 6757 : if (IsA(stmt, Query))
279 : : {
280 : 234 : Query *query = (Query *) stmt;
281 : :
282 [ + + ]: 234 : if (query->canSetTag)
283 : : {
284 [ - + ]: 233 : if (++nSetTag > 1)
285 : 0 : return PORTAL_MULTI_QUERY; /* no need to look further */
286 [ + - + + ]: 233 : if (query->commandType == CMD_UTILITY ||
287 : 233 : query->returningList == NIL)
288 : 210 : return PORTAL_MULTI_QUERY; /* no need to look further */
289 : 23 : }
290 [ + + ]: 234 : }
291 [ + - ]: 6523 : else if (IsA(stmt, PlannedStmt))
292 : : {
293 : 6523 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
294 : :
295 [ + + ]: 6523 : if (pstmt->canSetTag)
296 : : {
297 [ - + ]: 6488 : if (++nSetTag > 1)
298 : 0 : return PORTAL_MULTI_QUERY; /* no need to look further */
299 [ + - + + ]: 6488 : if (pstmt->commandType == CMD_UTILITY ||
300 : 6488 : !pstmt->hasReturning)
301 : 6258 : return PORTAL_MULTI_QUERY; /* no need to look further */
302 : 230 : }
303 [ + + ]: 6523 : }
304 : : else
305 [ # # # # ]: 0 : elog(ERROR, "unrecognized node type: %d", (int) nodeTag(stmt));
306 [ + + ]: 6757 : }
307 [ + + ]: 261 : if (nSetTag == 1)
308 : 253 : return PORTAL_ONE_RETURNING;
309 : :
310 : : /* Else, it's the general case... */
311 : 8 : return PORTAL_MULTI_QUERY;
312 : 68987 : }
313 : :
314 : : /*
315 : : * FetchPortalTargetList
316 : : * Given a portal that returns tuples, extract the query targetlist.
317 : : * Returns NIL if the portal doesn't have a determinable targetlist.
318 : : *
319 : : * Note: do not modify the result.
320 : : */
321 : : List *
322 : 27026 : FetchPortalTargetList(Portal portal)
323 : : {
324 : : /* no point in looking if we determined it doesn't return tuples */
325 [ + + ]: 27026 : if (portal->strategy == PORTAL_MULTI_QUERY)
326 : 5 : return NIL;
327 : : /* get the primary statement and find out what it returns */
328 : 27021 : return FetchStatementTargetList((Node *) PortalGetPrimaryStmt(portal));
329 : 27026 : }
330 : :
331 : : /*
332 : : * FetchStatementTargetList
333 : : * Given a statement that returns tuples, extract the query targetlist.
334 : : * Returns NIL if the statement doesn't have a determinable targetlist.
335 : : *
336 : : * This can be applied to a Query or a PlannedStmt.
337 : : * That's more general than portals need, but plancache.c uses this too.
338 : : *
339 : : * Note: do not modify the result.
340 : : *
341 : : * XXX be careful to keep this in sync with UtilityReturnsTuples.
342 : : */
343 : : List *
344 : 27233 : FetchStatementTargetList(Node *stmt)
345 : : {
346 [ + - ]: 27233 : if (stmt == NULL)
347 : 0 : return NIL;
348 [ + + ]: 27233 : if (IsA(stmt, Query))
349 : : {
350 : 212 : Query *query = (Query *) stmt;
351 : :
352 [ + + ]: 212 : if (query->commandType == CMD_UTILITY)
353 : : {
354 : : /* transfer attention to utility statement */
355 : 2 : stmt = query->utilityStmt;
356 : 2 : }
357 : : else
358 : : {
359 [ + + ]: 210 : if (query->commandType == CMD_SELECT)
360 : 208 : return query->targetList;
361 [ + - ]: 2 : if (query->returningList)
362 : 2 : return query->returningList;
363 : 0 : return NIL;
364 : : }
365 [ + + ]: 212 : }
366 [ + + ]: 27023 : if (IsA(stmt, PlannedStmt))
367 : : {
368 : 27021 : PlannedStmt *pstmt = (PlannedStmt *) stmt;
369 : :
370 [ + + ]: 27021 : if (pstmt->commandType == CMD_UTILITY)
371 : : {
372 : : /* transfer attention to utility statement */
373 : 2816 : stmt = pstmt->utilityStmt;
374 : 2816 : }
375 : : else
376 : : {
377 [ + + ]: 24205 : if (pstmt->commandType == CMD_SELECT)
378 : 23995 : return pstmt->planTree->targetlist;
379 [ + - ]: 210 : if (pstmt->hasReturning)
380 : 210 : return pstmt->planTree->targetlist;
381 : 0 : return NIL;
382 : : }
383 [ + + ]: 27021 : }
384 [ + + ]: 2818 : if (IsA(stmt, FetchStmt))
385 : : {
386 : 228 : FetchStmt *fstmt = (FetchStmt *) stmt;
387 : 228 : Portal subportal;
388 : :
389 [ + - ]: 228 : Assert(!fstmt->ismove);
390 : 228 : subportal = GetPortalByName(fstmt->portalname);
391 [ + - ]: 228 : Assert(PortalIsValid(subportal));
392 : 228 : return FetchPortalTargetList(subportal);
393 : 228 : }
394 [ + + ]: 2590 : if (IsA(stmt, ExecuteStmt))
395 : : {
396 : 205 : ExecuteStmt *estmt = (ExecuteStmt *) stmt;
397 : 205 : PreparedStatement *entry;
398 : :
399 : 205 : entry = FetchPreparedStatement(estmt->name, true);
400 : 205 : return FetchPreparedStatementTargetList(entry);
401 : 205 : }
402 : 2385 : return NIL;
403 : 27233 : }
404 : :
405 : : /*
406 : : * PortalStart
407 : : * Prepare a portal for execution.
408 : : *
409 : : * Caller must already have created the portal, done PortalDefineQuery(),
410 : : * and adjusted portal options if needed.
411 : : *
412 : : * If parameters are needed by the query, they must be passed in "params"
413 : : * (caller is responsible for giving them appropriate lifetime).
414 : : *
415 : : * The caller can also provide an initial set of "eflags" to be passed to
416 : : * ExecutorStart (but note these can be modified internally, and they are
417 : : * currently only honored for PORTAL_ONE_SELECT portals). Most callers
418 : : * should simply pass zero.
419 : : *
420 : : * The caller can optionally pass a snapshot to be used; pass InvalidSnapshot
421 : : * for the normal behavior of setting a new snapshot. This parameter is
422 : : * presently ignored for non-PORTAL_ONE_SELECT portals (it's only intended
423 : : * to be used for cursors).
424 : : *
425 : : * On return, portal is ready to accept PortalRun() calls, and the result
426 : : * tupdesc (if any) is known.
427 : : */
428 : : void
429 : 59377 : PortalStart(Portal portal, ParamListInfo params,
430 : : int eflags, Snapshot snapshot)
431 : : {
432 : 59377 : Portal saveActivePortal;
433 : 59377 : ResourceOwner saveResourceOwner;
434 : 59377 : MemoryContext savePortalContext;
435 : 59377 : MemoryContext oldContext;
436 : 59377 : QueryDesc *queryDesc;
437 : 59377 : int myeflags;
438 : :
439 [ + - ]: 59377 : Assert(PortalIsValid(portal));
440 [ + - ]: 59377 : Assert(portal->status == PORTAL_DEFINED);
441 : :
442 : : /*
443 : : * Set up global portal context pointers.
444 : : */
445 : 59377 : saveActivePortal = ActivePortal;
446 : 59377 : saveResourceOwner = CurrentResourceOwner;
447 : 59377 : savePortalContext = PortalContext;
448 [ + + ]: 59377 : PG_TRY();
449 : : {
450 : 59280 : ActivePortal = portal;
451 [ + + ]: 59280 : if (portal->resowner)
452 : 59183 : CurrentResourceOwner = portal->resowner;
453 : 59280 : PortalContext = portal->portalContext;
454 : :
455 : 59280 : oldContext = MemoryContextSwitchTo(PortalContext);
456 : :
457 : : /* Must remember portal param list, if any */
458 : 59280 : portal->portalParams = params;
459 : :
460 : : /*
461 : : * Determine the portal execution strategy
462 : : */
463 : 59280 : portal->strategy = ChoosePortalStrategy(portal->stmts);
464 : :
465 : : /*
466 : : * Fire her up according to the strategy
467 : : */
468 [ + + + + : 59280 : switch (portal->strategy)
+ ]
469 : : {
470 : : case PORTAL_ONE_SELECT:
471 : :
472 : : /* Must set snapshot before starting executor. */
473 [ + + ]: 25066 : if (snapshot)
474 : 1222 : PushActiveSnapshot(snapshot);
475 : : else
476 : 23844 : PushActiveSnapshot(GetTransactionSnapshot());
477 : :
478 : : /*
479 : : * We could remember the snapshot in portal->portalSnapshot,
480 : : * but presently there seems no need to, as this code path
481 : : * cannot be used for non-atomic execution. Hence there can't
482 : : * be any commit/abort that might destroy the snapshot. Since
483 : : * we don't do that, there's also no need to force a
484 : : * non-default nesting level for the snapshot.
485 : : */
486 : :
487 : : /*
488 : : * Create QueryDesc in portal's context; for the moment, set
489 : : * the destination to DestNone.
490 : : */
491 : 50132 : queryDesc = CreateQueryDesc(linitial_node(PlannedStmt, portal->stmts),
492 : 25066 : portal->sourceText,
493 : 25066 : GetActiveSnapshot(),
494 : : InvalidSnapshot,
495 : 25066 : None_Receiver,
496 : 25066 : params,
497 : 25066 : portal->queryEnv,
498 : : 0);
499 : :
500 : : /*
501 : : * If it's a scrollable cursor, executor needs to support
502 : : * REWIND and backwards scan, as well as whatever the caller
503 : : * might've asked for.
504 : : */
505 [ + + ]: 25066 : if (portal->cursorOptions & CURSOR_OPT_SCROLL)
506 : 431 : myeflags = eflags | EXEC_FLAG_REWIND | EXEC_FLAG_BACKWARD;
507 : : else
508 : 24635 : myeflags = eflags;
509 : :
510 : : /*
511 : : * Call ExecutorStart to prepare the plan for execution
512 : : */
513 : 25066 : ExecutorStart(queryDesc, myeflags);
514 : :
515 : : /*
516 : : * This tells PortalCleanup to shut down the executor
517 : : */
518 : 25066 : portal->queryDesc = queryDesc;
519 : :
520 : : /*
521 : : * Remember tuple descriptor (computed by ExecutorStart)
522 : : */
523 : 25066 : portal->tupDesc = queryDesc->tupDesc;
524 : :
525 : : /*
526 : : * Reset cursor position data to "start of query"
527 : : */
528 : 25066 : portal->atStart = true;
529 : 25066 : portal->atEnd = false; /* allow fetches */
530 : 25066 : portal->portalPos = 0;
531 : :
532 : 25066 : PopActiveSnapshot();
533 : 25066 : break;
534 : :
535 : : case PORTAL_ONE_RETURNING:
536 : : case PORTAL_ONE_MOD_WITH:
537 : :
538 : : /*
539 : : * We don't start the executor until we are told to run the
540 : : * portal. We do need to set up the result tupdesc.
541 : : */
542 : : {
543 : 250 : PlannedStmt *pstmt;
544 : :
545 : 250 : pstmt = PortalGetPrimaryStmt(portal);
546 : 250 : portal->tupDesc =
547 : 250 : ExecCleanTypeFromTL(pstmt->planTree->targetlist);
548 : 250 : }
549 : :
550 : : /*
551 : : * Reset cursor position data to "start of query"
552 : : */
553 : 250 : portal->atStart = true;
554 : 250 : portal->atEnd = false; /* allow fetches */
555 : 250 : portal->portalPos = 0;
556 : 250 : break;
557 : :
558 : : case PORTAL_UTIL_SELECT:
559 : :
560 : : /*
561 : : * We don't set snapshot here, because PortalRunUtility will
562 : : * take care of it if needed.
563 : : */
564 : : {
565 : 4206 : PlannedStmt *pstmt = PortalGetPrimaryStmt(portal);
566 : :
567 [ + - ]: 4206 : Assert(pstmt->commandType == CMD_UTILITY);
568 : 4206 : portal->tupDesc = UtilityTupleDescriptor(pstmt->utilityStmt);
569 : 4206 : }
570 : :
571 : : /*
572 : : * Reset cursor position data to "start of query"
573 : : */
574 : 4206 : portal->atStart = true;
575 : 4206 : portal->atEnd = false; /* allow fetches */
576 : 4206 : portal->portalPos = 0;
577 : 4206 : break;
578 : :
579 : : case PORTAL_MULTI_QUERY:
580 : : /* Need do nothing now */
581 : 29661 : portal->tupDesc = NULL;
582 : 29661 : break;
583 : : }
584 : : }
585 : 59377 : PG_CATCH();
586 : : {
587 : : /* Uncaught error while executing portal: mark it dead */
588 : 97 : MarkPortalFailed(portal);
589 : :
590 : : /* Restore global vars and propagate error */
591 : 97 : ActivePortal = saveActivePortal;
592 : 97 : CurrentResourceOwner = saveResourceOwner;
593 : 97 : PortalContext = savePortalContext;
594 : :
595 : 97 : PG_RE_THROW();
596 : : }
597 [ + - ]: 59086 : PG_END_TRY();
598 : :
599 : 59086 : MemoryContextSwitchTo(oldContext);
600 : :
601 : 59086 : ActivePortal = saveActivePortal;
602 : 59086 : CurrentResourceOwner = saveResourceOwner;
603 : 59086 : PortalContext = savePortalContext;
604 : :
605 : 59086 : portal->status = PORTAL_READY;
606 : 59086 : }
607 : :
608 : : /*
609 : : * PortalSetResultFormat
610 : : * Select the format codes for a portal's output.
611 : : *
612 : : * This must be run after PortalStart for a portal that will be read by
613 : : * a DestRemote or DestRemoteExecute destination. It is not presently needed
614 : : * for other destination types.
615 : : *
616 : : * formats[] is the client format request, as per Bind message conventions.
617 : : */
618 : : void
619 : 56505 : PortalSetResultFormat(Portal portal, int nFormats, int16 *formats)
620 : : {
621 : 56505 : int natts;
622 : 56505 : int i;
623 : :
624 : : /* Do nothing if portal won't return tuples */
625 [ + + ]: 56505 : if (portal->tupDesc == NULL)
626 : 29651 : return;
627 : 26854 : natts = portal->tupDesc->natts;
628 : 26854 : portal->formats = (int16 *)
629 : 53708 : MemoryContextAlloc(portal->portalContext,
630 : 26854 : natts * sizeof(int16));
631 [ - + ]: 26854 : if (nFormats > 1)
632 : : {
633 : : /* format specified for each column */
634 [ # # ]: 0 : if (nFormats != natts)
635 [ # # # # ]: 0 : ereport(ERROR,
636 : : (errcode(ERRCODE_PROTOCOL_VIOLATION),
637 : : errmsg("bind message has %d result formats but query has %d columns",
638 : : nFormats, natts)));
639 : 0 : memcpy(portal->formats, formats, natts * sizeof(int16));
640 : 0 : }
641 [ + - ]: 26854 : else if (nFormats > 0)
642 : : {
643 : : /* single format specified, use for all columns */
644 : 26854 : int16 format1 = formats[0];
645 : :
646 [ + + ]: 102226 : for (i = 0; i < natts; i++)
647 : 75372 : portal->formats[i] = format1;
648 : 26854 : }
649 : : else
650 : : {
651 : : /* use default format for all columns */
652 [ # # ]: 0 : for (i = 0; i < natts; i++)
653 : 0 : portal->formats[i] = 0;
654 : : }
655 [ - + ]: 56505 : }
656 : :
657 : : /*
658 : : * PortalRun
659 : : * Run a portal's query or queries.
660 : : *
661 : : * count <= 0 is interpreted as a no-op: the destination gets started up
662 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
663 : : * interpreted as "all rows". Note that count is ignored in multi-query
664 : : * situations, where we always run the portal to completion.
665 : : *
666 : : * isTopLevel: true if query is being executed at backend "top level"
667 : : * (that is, directly from a client command message)
668 : : *
669 : : * dest: where to send output of primary (canSetTag) query
670 : : *
671 : : * altdest: where to send output of non-primary queries
672 : : *
673 : : * qc: where to store command completion status data.
674 : : * May be NULL if caller doesn't want status data.
675 : : *
676 : : * Returns true if the portal's execution is complete, false if it was
677 : : * suspended due to exhaustion of the count parameter.
678 : : */
679 : : bool
680 : 63253 : PortalRun(Portal portal, long count, bool isTopLevel,
681 : : DestReceiver *dest, DestReceiver *altdest,
682 : : QueryCompletion *qc)
683 : : {
684 : 63253 : bool result;
685 : 63253 : uint64 nprocessed;
686 : 63253 : ResourceOwner saveTopTransactionResourceOwner;
687 : 63253 : MemoryContext saveTopTransactionContext;
688 : 63253 : Portal saveActivePortal;
689 : 63253 : ResourceOwner saveResourceOwner;
690 : 63253 : MemoryContext savePortalContext;
691 : 63253 : MemoryContext saveMemoryContext;
692 : :
693 [ + - ]: 63253 : Assert(PortalIsValid(portal));
694 : :
695 : 63253 : TRACE_POSTGRESQL_QUERY_EXECUTE_START();
696 : :
697 : : /* Initialize empty completion data */
698 [ + + ]: 63253 : if (qc)
699 : 56727 : InitializeQueryCompletion(qc);
700 : :
701 [ - + # # ]: 63253 : if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
702 : : {
703 [ # # # # ]: 0 : elog(DEBUG3, "PortalRun");
704 : : /* PORTAL_MULTI_QUERY logs its own stats per query */
705 : 0 : ResetUsage();
706 : 0 : }
707 : :
708 : : /*
709 : : * Check for improper portal use, and mark portal active.
710 : : */
711 : 63253 : MarkPortalActive(portal);
712 : :
713 : : /*
714 : : * Set up global portal context pointers.
715 : : *
716 : : * We have to play a special game here to support utility commands like
717 : : * VACUUM and CLUSTER, which internally start and commit transactions.
718 : : * When we are called to execute such a command, CurrentResourceOwner will
719 : : * be pointing to the TopTransactionResourceOwner --- which will be
720 : : * destroyed and replaced in the course of the internal commit and
721 : : * restart. So we need to be prepared to restore it as pointing to the
722 : : * exit-time TopTransactionResourceOwner. (Ain't that ugly? This idea of
723 : : * internally starting whole new transactions is not good.)
724 : : * CurrentMemoryContext has a similar problem, but the other pointers we
725 : : * save here will be NULL or pointing to longer-lived objects.
726 : : */
727 : 63253 : saveTopTransactionResourceOwner = TopTransactionResourceOwner;
728 : 63253 : saveTopTransactionContext = TopTransactionContext;
729 : 63253 : saveActivePortal = ActivePortal;
730 : 63253 : saveResourceOwner = CurrentResourceOwner;
731 : 63253 : savePortalContext = PortalContext;
732 : 63253 : saveMemoryContext = CurrentMemoryContext;
733 [ + + ]: 63253 : PG_TRY();
734 : : {
735 : 58988 : ActivePortal = portal;
736 [ + + ]: 58988 : if (portal->resowner)
737 : 56727 : CurrentResourceOwner = portal->resowner;
738 : 58988 : PortalContext = portal->portalContext;
739 : :
740 : 58988 : MemoryContextSwitchTo(PortalContext);
741 : :
742 [ + + - ]: 58988 : switch (portal->strategy)
743 : : {
744 : : case PORTAL_ONE_SELECT:
745 : : case PORTAL_ONE_RETURNING:
746 : : case PORTAL_ONE_MOD_WITH:
747 : : case PORTAL_UTIL_SELECT:
748 : :
749 : : /*
750 : : * If we have not yet run the command, do so, storing its
751 : : * results in the portal's tuplestore. But we don't do that
752 : : * for the PORTAL_ONE_SELECT case.
753 : : */
754 [ + + - + ]: 29327 : if (portal->strategy != PORTAL_ONE_SELECT && !portal->holdStore)
755 : 3106 : FillPortalStore(portal, isTopLevel);
756 : :
757 : : /*
758 : : * Now fetch desired portion of results.
759 : : */
760 : 29327 : nprocessed = PortalRunSelect(portal, true, count, dest);
761 : :
762 : : /*
763 : : * If the portal result contains a command tag and the caller
764 : : * gave us a pointer to store it, copy it and update the
765 : : * rowcount.
766 : : */
767 [ + + + - ]: 29327 : if (qc && portal->qc.commandTag != CMDTAG_UNKNOWN)
768 : : {
769 : 26064 : CopyQueryCompletion(qc, &portal->qc);
770 : 26064 : qc->nprocessed = nprocessed;
771 : 26064 : }
772 : :
773 : : /* Mark portal not active */
774 : 29327 : portal->status = PORTAL_READY;
775 : :
776 : : /*
777 : : * Since it's a forward fetch, say DONE iff atEnd is now true.
778 : : */
779 : 29327 : result = portal->atEnd;
780 : 29327 : break;
781 : :
782 : : case PORTAL_MULTI_QUERY:
783 : 59322 : PortalRunMulti(portal, isTopLevel, false,
784 : 29661 : dest, altdest, qc);
785 : :
786 : : /* Prevent portal's commands from being re-executed */
787 : 29661 : MarkPortalDone(portal);
788 : :
789 : : /* Always complete at end of RunMulti */
790 : 29661 : result = true;
791 : 29661 : break;
792 : :
793 : : default:
794 [ # # # # ]: 0 : elog(ERROR, "unrecognized portal strategy: %d",
795 : : (int) portal->strategy);
796 : 0 : result = false; /* keep compiler quiet */
797 : 0 : break;
798 : : }
799 : : }
800 : 56727 : PG_CATCH();
801 : : {
802 : : /* Uncaught error while executing portal: mark it dead */
803 : 4265 : MarkPortalFailed(portal);
804 : :
805 : : /* Restore global vars and propagate error */
806 [ + + ]: 4265 : if (saveMemoryContext == saveTopTransactionContext)
807 : 4219 : MemoryContextSwitchTo(TopTransactionContext);
808 : : else
809 : 46 : MemoryContextSwitchTo(saveMemoryContext);
810 : 4265 : ActivePortal = saveActivePortal;
811 [ + + ]: 4265 : if (saveResourceOwner == saveTopTransactionResourceOwner)
812 : 4224 : CurrentResourceOwner = TopTransactionResourceOwner;
813 : : else
814 : 41 : CurrentResourceOwner = saveResourceOwner;
815 : 4265 : PortalContext = savePortalContext;
816 : :
817 : 4265 : PG_RE_THROW();
818 : : }
819 [ + - ]: 52462 : PG_END_TRY();
820 : :
821 [ + + ]: 52462 : if (saveMemoryContext == saveTopTransactionContext)
822 : 51495 : MemoryContextSwitchTo(TopTransactionContext);
823 : : else
824 : 967 : MemoryContextSwitchTo(saveMemoryContext);
825 : 52462 : ActivePortal = saveActivePortal;
826 [ + + ]: 52462 : if (saveResourceOwner == saveTopTransactionResourceOwner)
827 : 51588 : CurrentResourceOwner = TopTransactionResourceOwner;
828 : : else
829 : 874 : CurrentResourceOwner = saveResourceOwner;
830 : 52462 : PortalContext = savePortalContext;
831 : :
832 [ - + # # ]: 52462 : if (log_executor_stats && portal->strategy != PORTAL_MULTI_QUERY)
833 : 0 : ShowUsage("EXECUTOR STATISTICS");
834 : :
835 : 52462 : TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
836 : :
837 : 104924 : return result;
838 : 52462 : }
839 : :
840 : : /*
841 : : * PortalRunSelect
842 : : * Execute a portal's query in PORTAL_ONE_SELECT mode, and also
843 : : * when fetching from a completed holdStore in PORTAL_ONE_RETURNING,
844 : : * PORTAL_ONE_MOD_WITH, and PORTAL_UTIL_SELECT cases.
845 : : *
846 : : * This handles simple N-rows-forward-or-backward cases. For more complex
847 : : * nonsequential access to a portal, see PortalRunFetch.
848 : : *
849 : : * count <= 0 is interpreted as a no-op: the destination gets started up
850 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
851 : : * interpreted as "all rows". (cf FetchStmt.howMany)
852 : : *
853 : : * Caller must already have validated the Portal and done appropriate
854 : : * setup (cf. PortalRun).
855 : : *
856 : : * Returns number of rows processed (suitable for use in result tag)
857 : : */
858 : : static uint64
859 : 34787 : PortalRunSelect(Portal portal,
860 : : bool forward,
861 : : long count,
862 : : DestReceiver *dest)
863 : : {
864 : 34787 : QueryDesc *queryDesc;
865 : 34787 : ScanDirection direction;
866 : 34787 : uint64 nprocessed;
867 : :
868 : : /*
869 : : * NB: queryDesc will be NULL if we are fetching from a held cursor or a
870 : : * completed utility query; can't use it in that path.
871 : : */
872 : 34787 : queryDesc = portal->queryDesc;
873 : :
874 : : /* Caller messed up if we have neither a ready query nor held data. */
875 [ + + + - ]: 34787 : Assert(queryDesc || portal->holdStore);
876 : :
877 : : /*
878 : : * Force the queryDesc destination to the right thing. This supports
879 : : * MOVE, for example, which will pass in dest = DestNone. This is okay to
880 : : * change as long as we do it on every fetch. (The Executor must not
881 : : * assume that dest never changes.)
882 : : */
883 [ + + ]: 34787 : if (queryDesc)
884 : 26419 : queryDesc->dest = dest;
885 : :
886 : : /*
887 : : * Determine which direction to go in, and check to see if we're already
888 : : * at the end of the available tuples in that direction. If so, set the
889 : : * direction to NoMovement to avoid trying to fetch any tuples. (This
890 : : * check exists because not all plan node types are robust about being
891 : : * called again if they've already returned NULL once.) Then call the
892 : : * executor (we must not skip this, because the destination needs to see a
893 : : * setup and shutdown even if no tuples are available). Finally, update
894 : : * the portal position state depending on the number of tuples that were
895 : : * retrieved.
896 : : */
897 [ + + ]: 34787 : if (forward)
898 : : {
899 [ + + + + ]: 34687 : if (portal->atEnd || count <= 0)
900 : : {
901 : 547 : direction = NoMovementScanDirection;
902 : 547 : count = 0; /* don't pass negative count to executor */
903 : 547 : }
904 : : else
905 : 34140 : direction = ForwardScanDirection;
906 : :
907 : : /* In the executor, zero count processes all rows */
908 [ + + ]: 34687 : if (count == FETCH_ALL)
909 : 27056 : count = 0;
910 : :
911 [ + + ]: 34687 : if (portal->holdStore)
912 : 8365 : nprocessed = RunFromStore(portal, direction, (uint64) count, dest);
913 : : else
914 : : {
915 : 26322 : PushActiveSnapshot(queryDesc->snapshot);
916 : 26322 : ExecutorRun(queryDesc, direction, (uint64) count);
917 : 26322 : nprocessed = queryDesc->estate->es_processed;
918 : 26322 : PopActiveSnapshot();
919 : : }
920 : :
921 [ + + ]: 34687 : if (!ScanDirectionIsNoMovement(direction))
922 : : {
923 [ + + ]: 33194 : if (nprocessed > 0)
924 : 27259 : portal->atStart = false; /* OK to go backward now */
925 [ + + + + ]: 33194 : if (count == 0 || nprocessed < (uint64) count)
926 : 28073 : portal->atEnd = true; /* we retrieved 'em all */
927 : 33194 : portal->portalPos += nprocessed;
928 : 33194 : }
929 : 34687 : }
930 : : else
931 : : {
932 [ + + ]: 100 : if (portal->cursorOptions & CURSOR_OPT_NO_SCROLL)
933 [ + - + - ]: 4 : ereport(ERROR,
934 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
935 : : errmsg("cursor can only scan forward"),
936 : : errhint("Declare it with SCROLL option to enable backward scan.")));
937 : :
938 [ + + - + ]: 96 : if (portal->atStart || count <= 0)
939 : : {
940 : 12 : direction = NoMovementScanDirection;
941 : 12 : count = 0; /* don't pass negative count to executor */
942 : 12 : }
943 : : else
944 : 84 : direction = BackwardScanDirection;
945 : :
946 : : /* In the executor, zero count processes all rows */
947 [ + + ]: 96 : if (count == FETCH_ALL)
948 : 10 : count = 0;
949 : :
950 [ + + ]: 96 : if (portal->holdStore)
951 : 2 : nprocessed = RunFromStore(portal, direction, (uint64) count, dest);
952 : : else
953 : : {
954 : 94 : PushActiveSnapshot(queryDesc->snapshot);
955 : 94 : ExecutorRun(queryDesc, direction, (uint64) count);
956 : 94 : nprocessed = queryDesc->estate->es_processed;
957 : 94 : PopActiveSnapshot();
958 : : }
959 : :
960 [ + + ]: 96 : if (!ScanDirectionIsNoMovement(direction))
961 : : {
962 [ + + + + ]: 84 : if (nprocessed > 0 && portal->atEnd)
963 : : {
964 : 25 : portal->atEnd = false; /* OK to go forward now */
965 : 25 : portal->portalPos++; /* adjust for endpoint case */
966 : 25 : }
967 [ + + + + ]: 84 : if (count == 0 || nprocessed < (uint64) count)
968 : : {
969 : 31 : portal->atStart = true; /* we retrieved 'em all */
970 : 31 : portal->portalPos = 0;
971 : 31 : }
972 : : else
973 : : {
974 : 53 : portal->portalPos -= nprocessed;
975 : : }
976 : 84 : }
977 : : }
978 : :
979 : 69566 : return nprocessed;
980 : 34783 : }
981 : :
982 : : /*
983 : : * FillPortalStore
984 : : * Run the query and load result tuples into the portal's tuple store.
985 : : *
986 : : * This is used for PORTAL_ONE_RETURNING, PORTAL_ONE_MOD_WITH, and
987 : : * PORTAL_UTIL_SELECT cases only.
988 : : */
989 : : static void
990 : 4452 : FillPortalStore(Portal portal, bool isTopLevel)
991 : : {
992 : 4452 : DestReceiver *treceiver;
993 : 4452 : QueryCompletion qc;
994 : :
995 : 4452 : InitializeQueryCompletion(&qc);
996 : 4452 : PortalCreateHoldStore(portal);
997 : 4452 : treceiver = CreateDestReceiver(DestTuplestore);
998 : 8904 : SetTuplestoreDestReceiverParams(treceiver,
999 : 4452 : portal->holdStore,
1000 : 4452 : portal->holdContext,
1001 : : false,
1002 : : NULL,
1003 : : NULL);
1004 : :
1005 [ + + - ]: 4452 : switch (portal->strategy)
1006 : : {
1007 : : case PORTAL_ONE_RETURNING:
1008 : : case PORTAL_ONE_MOD_WITH:
1009 : :
1010 : : /*
1011 : : * Run the portal to completion just as for the default
1012 : : * PORTAL_MULTI_QUERY case, but send the primary query's output to
1013 : : * the tuplestore. Auxiliary query outputs are discarded. Set the
1014 : : * portal's holdSnapshot to the snapshot used (or a copy of it).
1015 : : */
1016 : 500 : PortalRunMulti(portal, isTopLevel, true,
1017 : 250 : treceiver, None_Receiver, &qc);
1018 : 250 : break;
1019 : :
1020 : : case PORTAL_UTIL_SELECT:
1021 : 8404 : PortalRunUtility(portal, linitial_node(PlannedStmt, portal->stmts),
1022 : 4202 : isTopLevel, true, treceiver, &qc);
1023 : 4202 : break;
1024 : :
1025 : : default:
1026 [ # # # # ]: 0 : elog(ERROR, "unsupported portal strategy: %d",
1027 : : (int) portal->strategy);
1028 : 0 : break;
1029 : : }
1030 : :
1031 : : /* Override portal completion data with actual command results */
1032 [ + + ]: 4452 : if (qc.commandTag != CMDTAG_UNKNOWN)
1033 : 662 : CopyQueryCompletion(&portal->qc, &qc);
1034 : :
1035 : 4452 : treceiver->rDestroy(treceiver);
1036 : 4452 : }
1037 : :
1038 : : /*
1039 : : * RunFromStore
1040 : : * Fetch tuples from the portal's tuple store.
1041 : : *
1042 : : * Calling conventions are similar to ExecutorRun, except that we
1043 : : * do not depend on having a queryDesc or estate. Therefore we return the
1044 : : * number of tuples processed as the result, not in estate->es_processed.
1045 : : *
1046 : : * One difference from ExecutorRun is that the destination receiver functions
1047 : : * are run in the caller's memory context (since we have no estate). Watch
1048 : : * out for memory leaks.
1049 : : */
1050 : : static uint64
1051 : 8367 : RunFromStore(Portal portal, ScanDirection direction, uint64 count,
1052 : : DestReceiver *dest)
1053 : : {
1054 : 8367 : uint64 current_tuple_count = 0;
1055 : 8367 : TupleTableSlot *slot;
1056 : :
1057 : 8367 : slot = MakeSingleTupleTableSlot(portal->tupDesc, &TTSOpsMinimalTuple);
1058 : :
1059 : 8367 : dest->rStartup(dest, CMD_SELECT, portal->tupDesc);
1060 : :
1061 [ + + ]: 8367 : if (ScanDirectionIsNoMovement(direction))
1062 : : {
1063 : : /* do nothing except start/stop the destination */
1064 : 427 : }
1065 : : else
1066 : : {
1067 : 7940 : bool forward = ScanDirectionIsForward(direction);
1068 : :
1069 : 42505 : for (;;)
1070 : : {
1071 : 42505 : MemoryContext oldcontext;
1072 : 42505 : bool ok;
1073 : :
1074 : 42505 : oldcontext = MemoryContextSwitchTo(portal->holdContext);
1075 : :
1076 : 85010 : ok = tuplestore_gettupleslot(portal->holdStore, forward, false,
1077 : 42505 : slot);
1078 : :
1079 : 42505 : MemoryContextSwitchTo(oldcontext);
1080 : :
1081 [ + + ]: 42505 : if (!ok)
1082 : 4396 : break;
1083 : :
1084 : : /*
1085 : : * If we are not able to send the tuple, we assume the destination
1086 : : * has closed and no more tuples can be sent. If that's the case,
1087 : : * end the loop.
1088 : : */
1089 [ + - ]: 38109 : if (!dest->receiveSlot(slot, dest))
1090 : 0 : break;
1091 : :
1092 : 38109 : ExecClearTuple(slot);
1093 : :
1094 : : /*
1095 : : * check our tuple count.. if we've processed the proper number
1096 : : * then quit, else loop again and process more tuples. Zero count
1097 : : * means no limit.
1098 : : */
1099 : 38109 : current_tuple_count++;
1100 [ + + + + ]: 38109 : if (count && count == current_tuple_count)
1101 : 3544 : break;
1102 [ - + + ]: 42505 : }
1103 : 7940 : }
1104 : :
1105 : 8367 : dest->rShutdown(dest);
1106 : :
1107 : 8367 : ExecDropSingleTupleTableSlot(slot);
1108 : :
1109 : 16734 : return current_tuple_count;
1110 : 8367 : }
1111 : :
1112 : : /*
1113 : : * PortalRunUtility
1114 : : * Execute a utility statement inside a portal.
1115 : : */
1116 : : static void
1117 : 27598 : PortalRunUtility(Portal portal, PlannedStmt *pstmt,
1118 : : bool isTopLevel, bool setHoldSnapshot,
1119 : : DestReceiver *dest, QueryCompletion *qc)
1120 : : {
1121 : : /*
1122 : : * Set snapshot if utility stmt needs one.
1123 : : */
1124 [ + + ]: 27598 : if (PlannedStmtRequiresSnapshot(pstmt))
1125 : : {
1126 : 22728 : Snapshot snapshot = GetTransactionSnapshot();
1127 : :
1128 : : /* If told to, register the snapshot we're using and save in portal */
1129 [ + + ]: 22728 : if (setHoldSnapshot)
1130 : : {
1131 : 3849 : snapshot = RegisterSnapshot(snapshot);
1132 : 3849 : portal->holdSnapshot = snapshot;
1133 : 3849 : }
1134 : :
1135 : : /*
1136 : : * In any case, make the snapshot active and remember it in portal.
1137 : : * Because the portal now references the snapshot, we must tell
1138 : : * snapmgr.c that the snapshot belongs to the portal's transaction
1139 : : * level, else we risk portalSnapshot becoming a dangling pointer.
1140 : : */
1141 : 22728 : PushActiveSnapshotWithLevel(snapshot, portal->createLevel);
1142 : : /* PushActiveSnapshotWithLevel might have copied the snapshot */
1143 : 22728 : portal->portalSnapshot = GetActiveSnapshot();
1144 : 22728 : }
1145 : : else
1146 : 4870 : portal->portalSnapshot = NULL;
1147 : :
1148 : 55196 : ProcessUtility(pstmt,
1149 : 27598 : portal->sourceText,
1150 : 27598 : (portal->cplan != NULL), /* protect tree if in plancache */
1151 : 27598 : isTopLevel ? PROCESS_UTILITY_TOPLEVEL : PROCESS_UTILITY_QUERY,
1152 : 27598 : portal->portalParams,
1153 : 27598 : portal->queryEnv,
1154 : 27598 : dest,
1155 : 27598 : qc);
1156 : :
1157 : : /* Some utility statements may change context on us */
1158 : 27598 : MemoryContextSwitchTo(portal->portalContext);
1159 : :
1160 : : /*
1161 : : * Some utility commands (e.g., VACUUM, WAIT FOR) pop the ActiveSnapshot
1162 : : * stack from under us, so don't complain if it's now empty. Otherwise,
1163 : : * our snapshot should be the top one; pop it. Note that this could be a
1164 : : * different snapshot from the one we made above; see
1165 : : * EnsurePortalSnapshotExists.
1166 : : */
1167 [ + + - + ]: 27598 : if (portal->portalSnapshot != NULL && ActiveSnapshotSet())
1168 : : {
1169 [ + - ]: 19934 : Assert(portal->portalSnapshot == GetActiveSnapshot());
1170 : 19934 : PopActiveSnapshot();
1171 : 19934 : }
1172 : 27598 : portal->portalSnapshot = NULL;
1173 : 27598 : }
1174 : :
1175 : : /*
1176 : : * PortalRunMulti
1177 : : * Execute a portal's queries in the general case (multi queries
1178 : : * or non-SELECT-like queries)
1179 : : */
1180 : : static void
1181 : 26628 : PortalRunMulti(Portal portal,
1182 : : bool isTopLevel, bool setHoldSnapshot,
1183 : : DestReceiver *dest, DestReceiver *altdest,
1184 : : QueryCompletion *qc)
1185 : : {
1186 : 26628 : bool active_snapshot_set = false;
1187 : 26628 : ListCell *stmtlist_item;
1188 : :
1189 : : /*
1190 : : * If the destination is DestRemoteExecute, change to DestNone. The
1191 : : * reason is that the client won't be expecting any tuples, and indeed has
1192 : : * no way to know what they are, since there is no provision for Describe
1193 : : * to send a RowDescription message when this portal execution strategy is
1194 : : * in effect. This presently will only affect SELECT commands added to
1195 : : * non-SELECT queries by rewrite rules: such commands will be executed,
1196 : : * but the results will be discarded unless you use "simple Query"
1197 : : * protocol.
1198 : : */
1199 [ + + ]: 26628 : if (dest->mydest == DestRemoteExecute)
1200 : 22 : dest = None_Receiver;
1201 [ + + ]: 26628 : if (altdest->mydest == DestRemoteExecute)
1202 : 22 : altdest = None_Receiver;
1203 : :
1204 : : /*
1205 : : * Loop to handle the individual queries generated from a single parsetree
1206 : : * by analysis and rewrite.
1207 : : */
1208 [ + - + + : 56637 : foreach(stmtlist_item, portal->stmts)
+ + ]
1209 : : {
1210 : 30009 : PlannedStmt *pstmt = lfirst_node(PlannedStmt, stmtlist_item);
1211 : :
1212 : : /*
1213 : : * If we got a cancel signal in prior command, quit
1214 : : */
1215 [ + - ]: 30009 : CHECK_FOR_INTERRUPTS();
1216 : :
1217 [ + + ]: 30009 : if (pstmt->utilityStmt == NULL)
1218 : : {
1219 : : /*
1220 : : * process a plannable query.
1221 : : */
1222 : 6613 : TRACE_POSTGRESQL_QUERY_EXECUTE_START();
1223 : :
1224 [ + - ]: 6613 : if (log_executor_stats)
1225 : 0 : ResetUsage();
1226 : :
1227 : : /*
1228 : : * Must always have a snapshot for plannable queries. First time
1229 : : * through, take a new snapshot; for subsequent queries in the
1230 : : * same portal, just update the snapshot's copy of the command
1231 : : * counter.
1232 : : */
1233 [ + + ]: 6613 : if (!active_snapshot_set)
1234 : : {
1235 : 6515 : Snapshot snapshot = GetTransactionSnapshot();
1236 : :
1237 : : /* If told to, register the snapshot and save in portal */
1238 [ + + ]: 6515 : if (setHoldSnapshot)
1239 : : {
1240 : 250 : snapshot = RegisterSnapshot(snapshot);
1241 : 250 : portal->holdSnapshot = snapshot;
1242 : 250 : }
1243 : :
1244 : : /*
1245 : : * We can't have the holdSnapshot also be the active one,
1246 : : * because UpdateActiveSnapshotCommandId would complain. So
1247 : : * force an extra snapshot copy. Plain PushActiveSnapshot
1248 : : * would have copied the transaction snapshot anyway, so this
1249 : : * only adds a copy step when setHoldSnapshot is true. (It's
1250 : : * okay for the command ID of the active snapshot to diverge
1251 : : * from what holdSnapshot has.)
1252 : : */
1253 : 6515 : PushCopiedSnapshot(snapshot);
1254 : :
1255 : : /*
1256 : : * As for PORTAL_ONE_SELECT portals, it does not seem
1257 : : * necessary to maintain portal->portalSnapshot here.
1258 : : */
1259 : :
1260 : 6515 : active_snapshot_set = true;
1261 : 6515 : }
1262 : : else
1263 : 98 : UpdateActiveSnapshotCommandId();
1264 : :
1265 [ + + ]: 6613 : if (pstmt->canSetTag)
1266 : : {
1267 : : /* statement can set tag string */
1268 : 13016 : ProcessQuery(pstmt,
1269 : 6508 : portal->sourceText,
1270 : 6508 : portal->portalParams,
1271 : 6508 : portal->queryEnv,
1272 : 6508 : dest, qc);
1273 : 6508 : }
1274 : : else
1275 : : {
1276 : : /* stmt added by rewrite cannot set tag */
1277 : 210 : ProcessQuery(pstmt,
1278 : 105 : portal->sourceText,
1279 : 105 : portal->portalParams,
1280 : 105 : portal->queryEnv,
1281 : 105 : altdest, NULL);
1282 : : }
1283 : :
1284 [ + - ]: 6613 : if (log_executor_stats)
1285 : 0 : ShowUsage("EXECUTOR STATISTICS");
1286 : :
1287 : 6613 : TRACE_POSTGRESQL_QUERY_EXECUTE_DONE();
1288 : 6613 : }
1289 : : else
1290 : : {
1291 : : /*
1292 : : * process utility functions (create, destroy, etc..)
1293 : : *
1294 : : * We must not set a snapshot here for utility commands (if one is
1295 : : * needed, PortalRunUtility will do it). If a utility command is
1296 : : * alone in a portal then everything's fine. The only case where
1297 : : * a utility command can be part of a longer list is that rules
1298 : : * are allowed to include NotifyStmt. NotifyStmt doesn't care
1299 : : * whether it has a snapshot or not, so we just leave the current
1300 : : * snapshot alone if we have one.
1301 : : */
1302 [ + - ]: 23396 : if (pstmt->canSetTag)
1303 : : {
1304 [ + - ]: 23396 : Assert(!active_snapshot_set);
1305 : : /* statement can set tag string */
1306 : 46792 : PortalRunUtility(portal, pstmt, isTopLevel, false,
1307 : 23396 : dest, qc);
1308 : 23396 : }
1309 : : else
1310 : : {
1311 [ # # ]: 0 : Assert(IsA(pstmt->utilityStmt, NotifyStmt));
1312 : : /* stmt added by rewrite cannot set tag */
1313 : 0 : PortalRunUtility(portal, pstmt, isTopLevel, false,
1314 : 0 : altdest, NULL);
1315 : : }
1316 : : }
1317 : :
1318 : : /*
1319 : : * Clear subsidiary contexts to recover temporary memory.
1320 : : */
1321 [ + - ]: 30009 : Assert(portal->portalContext == CurrentMemoryContext);
1322 : :
1323 : 30009 : MemoryContextDeleteChildren(portal->portalContext);
1324 : :
1325 : : /*
1326 : : * Avoid crashing if portal->stmts has been reset. This can only
1327 : : * occur if a CALL or DO utility statement executed an internal
1328 : : * COMMIT/ROLLBACK (cf PortalReleaseCachedPlan). The CALL or DO must
1329 : : * have been the only statement in the portal, so there's nothing left
1330 : : * for us to do; but we don't want to dereference a now-dangling list
1331 : : * pointer.
1332 : : */
1333 [ + - ]: 30009 : if (portal->stmts == NIL)
1334 : 0 : break;
1335 : :
1336 : : /*
1337 : : * Increment command counter between queries, but not after the last
1338 : : * one.
1339 : : */
1340 [ + + ]: 30009 : if (lnext(portal->stmts, stmtlist_item) != NULL)
1341 : 98 : CommandCounterIncrement();
1342 [ - + ]: 30009 : }
1343 : :
1344 : : /* Pop the snapshot if we pushed one. */
1345 [ + + ]: 26628 : if (active_snapshot_set)
1346 : 5733 : PopActiveSnapshot();
1347 : :
1348 : : /*
1349 : : * If a command tag was requested and we did not fill in a run-time-
1350 : : * determined tag above, copy the parse-time tag from the Portal. (There
1351 : : * might not be any tag there either, in edge cases such as empty prepared
1352 : : * statements. That's OK.)
1353 : : */
1354 [ + - ]: 26628 : if (qc &&
1355 [ + + - + ]: 26628 : qc->commandTag == CMDTAG_UNKNOWN &&
1356 : 20401 : portal->qc.commandTag != CMDTAG_UNKNOWN)
1357 : 20401 : CopyQueryCompletion(qc, &portal->qc);
1358 : 26628 : }
1359 : :
1360 : : /*
1361 : : * PortalRunFetch
1362 : : * Variant form of PortalRun that supports SQL FETCH directions.
1363 : : *
1364 : : * Note: we presently assume that no callers of this want isTopLevel = true.
1365 : : *
1366 : : * count <= 0 is interpreted as a no-op: the destination gets started up
1367 : : * and shut down, but nothing else happens. Also, count == FETCH_ALL is
1368 : : * interpreted as "all rows". (cf FetchStmt.howMany)
1369 : : *
1370 : : * Returns number of rows processed (suitable for use in result tag)
1371 : : */
1372 : : uint64
1373 : 7775 : PortalRunFetch(Portal portal,
1374 : : FetchDirection fdirection,
1375 : : long count,
1376 : : DestReceiver *dest)
1377 : : {
1378 : 7775 : uint64 result;
1379 : 7775 : Portal saveActivePortal;
1380 : 7775 : ResourceOwner saveResourceOwner;
1381 : 7775 : MemoryContext savePortalContext;
1382 : 7775 : MemoryContext oldContext;
1383 : :
1384 [ + - ]: 7775 : Assert(PortalIsValid(portal));
1385 : :
1386 : : /*
1387 : : * Check for improper portal use, and mark portal active.
1388 : : */
1389 : 7775 : MarkPortalActive(portal);
1390 : :
1391 : : /*
1392 : : * Set up global portal context pointers.
1393 : : */
1394 : 7775 : saveActivePortal = ActivePortal;
1395 : 7775 : saveResourceOwner = CurrentResourceOwner;
1396 : 7775 : savePortalContext = PortalContext;
1397 [ + + ]: 7775 : PG_TRY();
1398 : : {
1399 : 7765 : ActivePortal = portal;
1400 [ + + ]: 7765 : if (portal->resowner)
1401 : 7755 : CurrentResourceOwner = portal->resowner;
1402 : 7765 : PortalContext = portal->portalContext;
1403 : :
1404 : 7765 : oldContext = MemoryContextSwitchTo(PortalContext);
1405 : :
1406 [ + + - ]: 7765 : switch (portal->strategy)
1407 : : {
1408 : : case PORTAL_ONE_SELECT:
1409 : 2454 : result = DoPortalRunFetch(portal, fdirection, count, dest);
1410 : 2454 : break;
1411 : :
1412 : : case PORTAL_ONE_RETURNING:
1413 : : case PORTAL_ONE_MOD_WITH:
1414 : : case PORTAL_UTIL_SELECT:
1415 : :
1416 : : /*
1417 : : * If we have not yet run the command, do so, storing its
1418 : : * results in the portal's tuplestore.
1419 : : */
1420 [ + + ]: 5311 : if (!portal->holdStore)
1421 : 1346 : FillPortalStore(portal, false /* isTopLevel */ );
1422 : :
1423 : : /*
1424 : : * Now fetch desired portion of results.
1425 : : */
1426 : 5311 : result = DoPortalRunFetch(portal, fdirection, count, dest);
1427 : 5311 : break;
1428 : :
1429 : : default:
1430 [ # # # # ]: 0 : elog(ERROR, "unsupported portal strategy");
1431 : 0 : result = 0; /* keep compiler quiet */
1432 : 0 : break;
1433 : : }
1434 : : }
1435 : 7775 : PG_CATCH();
1436 : : {
1437 : : /* Uncaught error while executing portal: mark it dead */
1438 : 10 : MarkPortalFailed(portal);
1439 : :
1440 : : /* Restore global vars and propagate error */
1441 : 10 : ActivePortal = saveActivePortal;
1442 : 10 : CurrentResourceOwner = saveResourceOwner;
1443 : 10 : PortalContext = savePortalContext;
1444 : :
1445 : 10 : PG_RE_THROW();
1446 : : }
1447 [ + - ]: 7765 : PG_END_TRY();
1448 : :
1449 : 7765 : MemoryContextSwitchTo(oldContext);
1450 : :
1451 : : /* Mark portal not active */
1452 : 7765 : portal->status = PORTAL_READY;
1453 : :
1454 : 7765 : ActivePortal = saveActivePortal;
1455 : 7765 : CurrentResourceOwner = saveResourceOwner;
1456 : 7765 : PortalContext = savePortalContext;
1457 : :
1458 : 15530 : return result;
1459 : 7765 : }
1460 : :
1461 : : /*
1462 : : * DoPortalRunFetch
1463 : : * Guts of PortalRunFetch --- the portal context is already set up
1464 : : *
1465 : : * Here, count < 0 typically reverses the direction. Also, count == FETCH_ALL
1466 : : * is interpreted as "all rows". (cf FetchStmt.howMany)
1467 : : *
1468 : : * Returns number of rows processed (suitable for use in result tag)
1469 : : */
1470 : : static uint64
1471 : 7764 : DoPortalRunFetch(Portal portal,
1472 : : FetchDirection fdirection,
1473 : : long count,
1474 : : DestReceiver *dest)
1475 : : {
1476 : 7764 : bool forward;
1477 : :
1478 [ + + + - : 7764 : Assert(portal->strategy == PORTAL_ONE_SELECT ||
+ - + - ]
1479 : : portal->strategy == PORTAL_ONE_RETURNING ||
1480 : : portal->strategy == PORTAL_ONE_MOD_WITH ||
1481 : : portal->strategy == PORTAL_UTIL_SELECT);
1482 : :
1483 : : /*
1484 : : * Note: we disallow backwards fetch (including re-fetch of current row)
1485 : : * for NO SCROLL cursors, but we interpret that very loosely: you can use
1486 : : * any of the FetchDirection options, so long as the end result is to move
1487 : : * forwards by at least one row. Currently it's sufficient to check for
1488 : : * NO SCROLL in DoPortalRewind() and in the forward == false path in
1489 : : * PortalRunSelect(); but someday we might prefer to account for that
1490 : : * restriction explicitly here.
1491 : : */
1492 [ + + + + : 7764 : switch (fdirection)
- ]
1493 : : {
1494 : : case FETCH_FORWARD:
1495 [ + - ]: 7645 : if (count < 0)
1496 : : {
1497 : 0 : fdirection = FETCH_BACKWARD;
1498 : 0 : count = -count;
1499 : 0 : }
1500 : : /* fall out of switch to share code with FETCH_BACKWARD */
1501 : 7645 : break;
1502 : : case FETCH_BACKWARD:
1503 [ + - ]: 82 : if (count < 0)
1504 : : {
1505 : 0 : fdirection = FETCH_FORWARD;
1506 : 0 : count = -count;
1507 : 0 : }
1508 : : /* fall out of switch to share code with FETCH_FORWARD */
1509 : 82 : break;
1510 : : case FETCH_ABSOLUTE:
1511 [ + + ]: 23 : if (count > 0)
1512 : : {
1513 : : /*
1514 : : * Definition: Rewind to start, advance count-1 rows, return
1515 : : * next row (if any).
1516 : : *
1517 : : * In practice, if the goal is less than halfway back to the
1518 : : * start, it's better to scan from where we are.
1519 : : *
1520 : : * Also, if current portalPos is outside the range of "long",
1521 : : * do it the hard way to avoid possible overflow of the count
1522 : : * argument to PortalRunSelect. We must exclude exactly
1523 : : * LONG_MAX, as well, lest the count look like FETCH_ALL.
1524 : : *
1525 : : * In any case, we arrange to fetch the target row going
1526 : : * forwards.
1527 : : */
1528 [ + + - + ]: 14 : if ((uint64) (count - 1) <= portal->portalPos / 2 ||
1529 : 6 : portal->portalPos >= (uint64) LONG_MAX)
1530 : : {
1531 : 8 : DoPortalRewind(portal);
1532 [ + - ]: 8 : if (count > 1)
1533 : 0 : PortalRunSelect(portal, true, count - 1,
1534 : 0 : None_Receiver);
1535 : 8 : }
1536 : : else
1537 : : {
1538 : 6 : long pos = (long) portal->portalPos;
1539 : :
1540 [ + - ]: 6 : if (portal->atEnd)
1541 : 0 : pos++; /* need one extra fetch if off end */
1542 [ + + ]: 6 : if (count <= pos)
1543 : 4 : PortalRunSelect(portal, false, pos - count + 1,
1544 : 2 : None_Receiver);
1545 [ + + ]: 4 : else if (count > pos + 1)
1546 : 4 : PortalRunSelect(portal, true, count - pos - 1,
1547 : 2 : None_Receiver);
1548 : 6 : }
1549 : 14 : return PortalRunSelect(portal, true, 1L, dest);
1550 : : }
1551 [ - + ]: 9 : else if (count < 0)
1552 : : {
1553 : : /*
1554 : : * Definition: Advance to end, back up abs(count)-1 rows,
1555 : : * return prior row (if any). We could optimize this if we
1556 : : * knew in advance where the end was, but typically we won't.
1557 : : * (Is it worth considering case where count > half of size of
1558 : : * query? We could rewind once we know the size ...)
1559 : : */
1560 : 9 : PortalRunSelect(portal, true, FETCH_ALL, None_Receiver);
1561 [ + - ]: 9 : if (count < -1)
1562 : 0 : PortalRunSelect(portal, false, -count - 1, None_Receiver);
1563 : 9 : return PortalRunSelect(portal, false, 1L, dest);
1564 : : }
1565 : : else
1566 : : {
1567 : : /* count == 0 */
1568 : : /* Rewind to start, return zero rows */
1569 : 0 : DoPortalRewind(portal);
1570 : 0 : return PortalRunSelect(portal, true, 0L, dest);
1571 : : }
1572 : : break;
1573 : : case FETCH_RELATIVE:
1574 [ + + ]: 14 : if (count > 0)
1575 : : {
1576 : : /*
1577 : : * Definition: advance count-1 rows, return next row (if any).
1578 : : */
1579 [ + + ]: 6 : if (count > 1)
1580 : 4 : PortalRunSelect(portal, true, count - 1, None_Receiver);
1581 : 6 : return PortalRunSelect(portal, true, 1L, dest);
1582 : : }
1583 [ + + ]: 8 : else if (count < 0)
1584 : : {
1585 : : /*
1586 : : * Definition: back up abs(count)-1 rows, return prior row (if
1587 : : * any).
1588 : : */
1589 [ + + ]: 5 : if (count < -1)
1590 : 3 : PortalRunSelect(portal, false, -count - 1, None_Receiver);
1591 : 5 : return PortalRunSelect(portal, false, 1L, dest);
1592 : : }
1593 : : else
1594 : : {
1595 : : /* count == 0 */
1596 : : /* Same as FETCH FORWARD 0, so fall out of switch */
1597 : 3 : fdirection = FETCH_FORWARD;
1598 : : }
1599 : 3 : break;
1600 : : default:
1601 [ # # # # ]: 0 : elog(ERROR, "bogus direction");
1602 : 0 : break;
1603 : : }
1604 : :
1605 : : /*
1606 : : * Get here with fdirection == FETCH_FORWARD or FETCH_BACKWARD, and count
1607 : : * >= 0.
1608 : : */
1609 : 7730 : forward = (fdirection == FETCH_FORWARD);
1610 : :
1611 : : /*
1612 : : * Zero count means to re-fetch the current row, if any (per SQL)
1613 : : */
1614 [ + + ]: 7730 : if (count == 0)
1615 : : {
1616 : 4 : bool on_row;
1617 : :
1618 : : /* Are we sitting on a row? */
1619 [ + + ]: 4 : on_row = (!portal->atStart && !portal->atEnd);
1620 : :
1621 [ + - ]: 4 : if (dest->mydest == DestNone)
1622 : : {
1623 : : /* MOVE 0 returns 0/1 based on if FETCH 0 would return a row */
1624 : 0 : return on_row ? 1 : 0;
1625 : : }
1626 : : else
1627 : : {
1628 : : /*
1629 : : * If we are sitting on a row, back up one so we can re-fetch it.
1630 : : * If we are not sitting on a row, we still have to start up and
1631 : : * shut down the executor so that the destination is initialized
1632 : : * and shut down correctly; so keep going. To PortalRunSelect,
1633 : : * count == 0 means we will retrieve no row.
1634 : : */
1635 [ + + ]: 4 : if (on_row)
1636 : : {
1637 : 3 : PortalRunSelect(portal, false, 1L, None_Receiver);
1638 : : /* Set up to fetch one row forward */
1639 : 3 : count = 1;
1640 : 3 : forward = true;
1641 : 3 : }
1642 : : }
1643 [ - + ]: 2 : }
1644 : :
1645 : : /*
1646 : : * Optimize MOVE BACKWARD ALL into a Rewind.
1647 : : */
1648 [ + + + + : 7728 : if (!forward && count == FETCH_ALL && dest->mydest == DestNone)
+ + ]
1649 : : {
1650 : 4 : uint64 result = portal->portalPos;
1651 : :
1652 [ + + + - ]: 4 : if (result > 0 && !portal->atEnd)
1653 : 0 : result--;
1654 : 4 : DoPortalRewind(portal);
1655 : 4 : return result;
1656 : 4 : }
1657 : :
1658 : 7724 : return PortalRunSelect(portal, forward, count, dest);
1659 : 7762 : }
1660 : :
1661 : : /*
1662 : : * DoPortalRewind - rewind a Portal to starting point
1663 : : */
1664 : : static void
1665 : 13 : DoPortalRewind(Portal portal)
1666 : : {
1667 : 13 : QueryDesc *queryDesc;
1668 : :
1669 : : /*
1670 : : * No work is needed if we've not advanced nor attempted to advance the
1671 : : * cursor (and we don't want to throw a NO SCROLL error in this case).
1672 : : */
1673 [ + + - + ]: 13 : if (portal->atStart && !portal->atEnd)
1674 : 3 : return;
1675 : :
1676 : : /* Otherwise, cursor must allow scrolling */
1677 [ + + ]: 10 : if (portal->cursorOptions & CURSOR_OPT_NO_SCROLL)
1678 [ + - + - ]: 1 : ereport(ERROR,
1679 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
1680 : : errmsg("cursor can only scan forward"),
1681 : : errhint("Declare it with SCROLL option to enable backward scan.")));
1682 : :
1683 : : /* Rewind holdStore, if we have one */
1684 [ + + ]: 9 : if (portal->holdStore)
1685 : : {
1686 : 1 : MemoryContext oldcontext;
1687 : :
1688 : 1 : oldcontext = MemoryContextSwitchTo(portal->holdContext);
1689 : 1 : tuplestore_rescan(portal->holdStore);
1690 : 1 : MemoryContextSwitchTo(oldcontext);
1691 : 1 : }
1692 : :
1693 : : /* Rewind executor, if active */
1694 : 9 : queryDesc = portal->queryDesc;
1695 [ + + ]: 9 : if (queryDesc)
1696 : : {
1697 : 8 : PushActiveSnapshot(queryDesc->snapshot);
1698 : 8 : ExecutorRewind(queryDesc);
1699 : 8 : PopActiveSnapshot();
1700 : 8 : }
1701 : :
1702 : 9 : portal->atStart = true;
1703 : 9 : portal->atEnd = false;
1704 : 9 : portal->portalPos = 0;
1705 [ - + ]: 12 : }
1706 : :
1707 : : /*
1708 : : * PlannedStmtRequiresSnapshot - what it says on the tin
1709 : : */
1710 : : bool
1711 : 441245 : PlannedStmtRequiresSnapshot(PlannedStmt *pstmt)
1712 : : {
1713 : 441245 : Node *utilityStmt = pstmt->utilityStmt;
1714 : :
1715 : : /* If it's not a utility statement, it definitely needs a snapshot */
1716 [ + + ]: 441245 : if (utilityStmt == NULL)
1717 : 411157 : return true;
1718 : :
1719 : : /*
1720 : : * Most utility statements need a snapshot, and the default presumption
1721 : : * about new ones should be that they do too. Hence, enumerate those that
1722 : : * do not need one.
1723 : : *
1724 : : * Transaction control, LOCK, and SET must *not* set a snapshot, since
1725 : : * they need to be executable at the start of a transaction-snapshot-mode
1726 : : * transaction without freezing a snapshot. By extension we allow SHOW
1727 : : * not to set a snapshot. The other stmts listed are just efficiency
1728 : : * hacks. Beware of listing anything that can modify the database --- if,
1729 : : * say, it has to update an index with expressions that invoke
1730 : : * user-defined functions, then it had better have a snapshot.
1731 : : */
1732 [ + + ]: 30088 : if (IsA(utilityStmt, TransactionStmt) ||
1733 [ + + ]: 28287 : IsA(utilityStmt, LockStmt) ||
1734 [ + + ]: 28225 : IsA(utilityStmt, VariableSetStmt) ||
1735 [ + + ]: 23824 : IsA(utilityStmt, VariableShowStmt) ||
1736 [ + + ]: 23708 : IsA(utilityStmt, ConstraintsSetStmt) ||
1737 : : /* efficiency hacks from here down */
1738 [ + + ]: 23692 : IsA(utilityStmt, FetchStmt) ||
1739 [ + + ]: 23154 : IsA(utilityStmt, ListenStmt) ||
1740 [ + + ]: 23152 : IsA(utilityStmt, NotifyStmt) ||
1741 [ + + ]: 23151 : IsA(utilityStmt, UnlistenStmt) ||
1742 [ + + - + ]: 23149 : IsA(utilityStmt, CheckPointStmt) ||
1743 : 23140 : IsA(utilityStmt, WaitStmt))
1744 : 6948 : return false;
1745 : :
1746 : 23140 : return true;
1747 : 441245 : }
1748 : :
1749 : : /*
1750 : : * EnsurePortalSnapshotExists - recreate Portal-level snapshot, if needed
1751 : : *
1752 : : * Generally, we will have an active snapshot whenever we are executing
1753 : : * inside a Portal, unless the Portal's query is one of the utility
1754 : : * statements exempted from that rule (see PlannedStmtRequiresSnapshot).
1755 : : * However, procedures and DO blocks can commit or abort the transaction,
1756 : : * and thereby destroy all snapshots. This function can be called to
1757 : : * re-establish the Portal-level snapshot when none exists.
1758 : : */
1759 : : void
1760 : 453987 : EnsurePortalSnapshotExists(void)
1761 : : {
1762 : 453987 : Portal portal;
1763 : :
1764 : : /*
1765 : : * Nothing to do if a snapshot is set. (We take it on faith that the
1766 : : * outermost active snapshot belongs to some Portal; or if there is no
1767 : : * Portal, it's somebody else's responsibility to manage things.)
1768 : : */
1769 [ + + ]: 453987 : if (ActiveSnapshotSet())
1770 : 453970 : return;
1771 : :
1772 : : /* Otherwise, we'd better have an active Portal */
1773 : 17 : portal = ActivePortal;
1774 [ + - ]: 17 : if (unlikely(portal == NULL))
1775 [ # # # # ]: 0 : elog(ERROR, "cannot execute SQL without an outer snapshot or portal");
1776 [ + - ]: 17 : Assert(portal->portalSnapshot == NULL);
1777 : :
1778 : : /*
1779 : : * Create a new snapshot, make it active, and remember it in portal.
1780 : : * Because the portal now references the snapshot, we must tell snapmgr.c
1781 : : * that the snapshot belongs to the portal's transaction level, else we
1782 : : * risk portalSnapshot becoming a dangling pointer.
1783 : : */
1784 : 17 : PushActiveSnapshotWithLevel(GetTransactionSnapshot(), portal->createLevel);
1785 : : /* PushActiveSnapshotWithLevel might have copied the snapshot */
1786 : 17 : portal->portalSnapshot = GetActiveSnapshot();
1787 [ - + ]: 453987 : }
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