Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * prepare.c
4 : * Prepareable SQL statements via PREPARE, EXECUTE and DEALLOCATE
5 : *
6 : * This module also implements storage of prepared statements that are
7 : * accessed via the extended FE/BE query protocol.
8 : *
9 : *
10 : * Copyright (c) 2002-2024, PostgreSQL Global Development Group
11 : *
12 : * IDENTIFICATION
13 : * src/backend/commands/prepare.c
14 : *
15 : *-------------------------------------------------------------------------
16 : */
17 : #include "postgres.h"
18 :
19 : #include <limits.h>
20 :
21 : #include "access/xact.h"
22 : #include "catalog/pg_type.h"
23 : #include "commands/createas.h"
24 : #include "commands/prepare.h"
25 : #include "funcapi.h"
26 : #include "nodes/nodeFuncs.h"
27 : #include "parser/parse_coerce.h"
28 : #include "parser/parse_collate.h"
29 : #include "parser/parse_expr.h"
30 : #include "parser/parse_type.h"
31 : #include "tcop/pquery.h"
32 : #include "tcop/utility.h"
33 : #include "utils/builtins.h"
34 : #include "utils/snapmgr.h"
35 : #include "utils/timestamp.h"
36 :
37 :
38 : /*
39 : * The hash table in which prepared queries are stored. This is
40 : * per-backend: query plans are not shared between backends.
41 : * The keys for this hash table are the arguments to PREPARE and EXECUTE
42 : * (statement names); the entries are PreparedStatement structs.
43 : */
44 : static HTAB *prepared_queries = NULL;
45 :
46 : static void InitQueryHashTable(void);
47 : static ParamListInfo EvaluateParams(ParseState *pstate,
48 : PreparedStatement *pstmt, List *params,
49 : EState *estate);
50 : static Datum build_regtype_array(Oid *param_types, int num_params);
51 :
52 : /*
53 : * Implements the 'PREPARE' utility statement.
54 : */
55 : void
56 1668 : PrepareQuery(ParseState *pstate, PrepareStmt *stmt,
57 : int stmt_location, int stmt_len)
58 : {
59 : RawStmt *rawstmt;
60 : CachedPlanSource *plansource;
61 1668 : Oid *argtypes = NULL;
62 : int nargs;
63 : List *query_list;
64 :
65 : /*
66 : * Disallow empty-string statement name (conflicts with protocol-level
67 : * unnamed statement).
68 : */
69 1668 : if (!stmt->name || stmt->name[0] == '\0')
70 0 : ereport(ERROR,
71 : (errcode(ERRCODE_INVALID_PSTATEMENT_DEFINITION),
72 : errmsg("invalid statement name: must not be empty")));
73 :
74 : /*
75 : * Need to wrap the contained statement in a RawStmt node to pass it to
76 : * parse analysis.
77 : */
78 1668 : rawstmt = makeNode(RawStmt);
79 1668 : rawstmt->stmt = stmt->query;
80 1668 : rawstmt->stmt_location = stmt_location;
81 1668 : rawstmt->stmt_len = stmt_len;
82 :
83 : /*
84 : * Create the CachedPlanSource before we do parse analysis, since it needs
85 : * to see the unmodified raw parse tree.
86 : */
87 1668 : plansource = CreateCachedPlan(rawstmt, pstate->p_sourcetext,
88 : CreateCommandTag(stmt->query));
89 :
90 : /* Transform list of TypeNames to array of type OIDs */
91 1668 : nargs = list_length(stmt->argtypes);
92 :
93 1668 : if (nargs)
94 : {
95 : int i;
96 : ListCell *l;
97 :
98 1398 : argtypes = palloc_array(Oid, nargs);
99 1398 : i = 0;
100 :
101 2954 : foreach(l, stmt->argtypes)
102 : {
103 1562 : TypeName *tn = lfirst(l);
104 1562 : Oid toid = typenameTypeId(pstate, tn);
105 :
106 1556 : argtypes[i++] = toid;
107 : }
108 : }
109 :
110 : /*
111 : * Analyze the statement using these parameter types (any parameters
112 : * passed in from above us will not be visible to it), allowing
113 : * information about unknown parameters to be deduced from context.
114 : * Rewrite the query. The result could be 0, 1, or many queries.
115 : */
116 1662 : query_list = pg_analyze_and_rewrite_varparams(rawstmt, pstate->p_sourcetext,
117 : &argtypes, &nargs, NULL);
118 :
119 : /* Finish filling in the CachedPlanSource */
120 1662 : CompleteCachedPlan(plansource,
121 : query_list,
122 : NULL,
123 : argtypes,
124 : nargs,
125 : NULL,
126 : NULL,
127 : CURSOR_OPT_PARALLEL_OK, /* allow parallel mode */
128 : true); /* fixed result */
129 :
130 : /*
131 : * Save the results.
132 : */
133 1662 : StorePreparedStatement(stmt->name,
134 : plansource,
135 : true);
136 1656 : }
137 :
138 : /*
139 : * ExecuteQuery --- implement the 'EXECUTE' utility statement.
140 : *
141 : * This code also supports CREATE TABLE ... AS EXECUTE. That case is
142 : * indicated by passing a non-null intoClause. The DestReceiver is already
143 : * set up correctly for CREATE TABLE AS, but we still have to make a few
144 : * other adjustments here.
145 : */
146 : void
147 11362 : ExecuteQuery(ParseState *pstate,
148 : ExecuteStmt *stmt, IntoClause *intoClause,
149 : ParamListInfo params,
150 : DestReceiver *dest, QueryCompletion *qc)
151 : {
152 : PreparedStatement *entry;
153 : CachedPlan *cplan;
154 : List *plan_list;
155 11362 : ParamListInfo paramLI = NULL;
156 11362 : EState *estate = NULL;
157 : Portal portal;
158 : char *query_string;
159 : int eflags;
160 : long count;
161 :
162 : /* Look it up in the hash table */
163 11362 : entry = FetchPreparedStatement(stmt->name, true);
164 :
165 : /* Shouldn't find a non-fixed-result cached plan */
166 11362 : if (!entry->plansource->fixed_result)
167 0 : elog(ERROR, "EXECUTE does not support variable-result cached plans");
168 :
169 : /* Evaluate parameters, if any */
170 11362 : if (entry->plansource->num_params > 0)
171 : {
172 : /*
173 : * Need an EState to evaluate parameters; must not delete it till end
174 : * of query, in case parameters are pass-by-reference. Note that the
175 : * passed-in "params" could possibly be referenced in the parameter
176 : * expressions.
177 : */
178 10450 : estate = CreateExecutorState();
179 10450 : estate->es_param_list_info = params;
180 10450 : paramLI = EvaluateParams(pstate, entry, stmt->params, estate);
181 : }
182 :
183 : /* Create a new portal to run the query in */
184 11326 : portal = CreateNewPortal();
185 : /* Don't display the portal in pg_cursors, it is for internal use only */
186 11326 : portal->visible = false;
187 :
188 : /* Copy the plan's saved query string into the portal's memory */
189 11326 : query_string = MemoryContextStrdup(portal->portalContext,
190 11326 : entry->plansource->query_string);
191 :
192 : /* Replan if needed, and increment plan refcount for portal */
193 11326 : cplan = GetCachedPlan(entry->plansource, paramLI, NULL, NULL);
194 11296 : plan_list = cplan->stmt_list;
195 :
196 : /*
197 : * DO NOT add any logic that could possibly throw an error between
198 : * GetCachedPlan and PortalDefineQuery, or you'll leak the plan refcount.
199 : */
200 11296 : PortalDefineQuery(portal,
201 : NULL,
202 : query_string,
203 11296 : entry->plansource->commandTag,
204 : plan_list,
205 : cplan);
206 :
207 : /*
208 : * For CREATE TABLE ... AS EXECUTE, we must verify that the prepared
209 : * statement is one that produces tuples. Currently we insist that it be
210 : * a plain old SELECT. In future we might consider supporting other
211 : * things such as INSERT ... RETURNING, but there are a couple of issues
212 : * to be settled first, notably how WITH NO DATA should be handled in such
213 : * a case (do we really want to suppress execution?) and how to pass down
214 : * the OID-determining eflags (PortalStart won't handle them in such a
215 : * case, and for that matter it's not clear the executor will either).
216 : *
217 : * For CREATE TABLE ... AS EXECUTE, we also have to ensure that the proper
218 : * eflags and fetch count are passed to PortalStart/PortalRun.
219 : */
220 11296 : if (intoClause)
221 : {
222 : PlannedStmt *pstmt;
223 :
224 42 : if (list_length(plan_list) != 1)
225 0 : ereport(ERROR,
226 : (errcode(ERRCODE_WRONG_OBJECT_TYPE),
227 : errmsg("prepared statement is not a SELECT")));
228 42 : pstmt = linitial_node(PlannedStmt, plan_list);
229 42 : if (pstmt->commandType != CMD_SELECT)
230 0 : ereport(ERROR,
231 : (errcode(ERRCODE_WRONG_OBJECT_TYPE),
232 : errmsg("prepared statement is not a SELECT")));
233 :
234 : /* Set appropriate eflags */
235 42 : eflags = GetIntoRelEFlags(intoClause);
236 :
237 : /* And tell PortalRun whether to run to completion or not */
238 42 : if (intoClause->skipData)
239 12 : count = 0;
240 : else
241 30 : count = FETCH_ALL;
242 : }
243 : else
244 : {
245 : /* Plain old EXECUTE */
246 11254 : eflags = 0;
247 11254 : count = FETCH_ALL;
248 : }
249 :
250 : /*
251 : * Run the portal as appropriate.
252 : */
253 11296 : PortalStart(portal, paramLI, eflags, GetActiveSnapshot());
254 :
255 11296 : (void) PortalRun(portal, count, false, true, dest, dest, qc);
256 :
257 11264 : PortalDrop(portal, false);
258 :
259 11264 : if (estate)
260 10378 : FreeExecutorState(estate);
261 :
262 : /* No need to pfree other memory, MemoryContext will be reset */
263 11264 : }
264 :
265 : /*
266 : * EvaluateParams: evaluate a list of parameters.
267 : *
268 : * pstate: parse state
269 : * pstmt: statement we are getting parameters for.
270 : * params: list of given parameter expressions (raw parser output!)
271 : * estate: executor state to use.
272 : *
273 : * Returns a filled-in ParamListInfo -- this can later be passed to
274 : * CreateQueryDesc(), which allows the executor to make use of the parameters
275 : * during query execution.
276 : */
277 : static ParamListInfo
278 10694 : EvaluateParams(ParseState *pstate, PreparedStatement *pstmt, List *params,
279 : EState *estate)
280 : {
281 10694 : Oid *param_types = pstmt->plansource->param_types;
282 10694 : int num_params = pstmt->plansource->num_params;
283 10694 : int nparams = list_length(params);
284 : ParamListInfo paramLI;
285 : List *exprstates;
286 : ListCell *l;
287 : int i;
288 :
289 10694 : if (nparams != num_params)
290 12 : ereport(ERROR,
291 : (errcode(ERRCODE_SYNTAX_ERROR),
292 : errmsg("wrong number of parameters for prepared statement \"%s\"",
293 : pstmt->stmt_name),
294 : errdetail("Expected %d parameters but got %d.",
295 : num_params, nparams)));
296 :
297 : /* Quick exit if no parameters */
298 10682 : if (num_params == 0)
299 0 : return NULL;
300 :
301 : /*
302 : * We have to run parse analysis for the expressions. Since the parser is
303 : * not cool about scribbling on its input, copy first.
304 : */
305 10682 : params = copyObject(params);
306 :
307 10682 : i = 0;
308 21674 : foreach(l, params)
309 : {
310 11004 : Node *expr = lfirst(l);
311 11004 : Oid expected_type_id = param_types[i];
312 : Oid given_type_id;
313 :
314 11004 : expr = transformExpr(pstate, expr, EXPR_KIND_EXECUTE_PARAMETER);
315 :
316 11004 : given_type_id = exprType(expr);
317 :
318 11004 : expr = coerce_to_target_type(pstate, expr, given_type_id,
319 : expected_type_id, -1,
320 : COERCION_ASSIGNMENT,
321 : COERCE_IMPLICIT_CAST,
322 : -1);
323 :
324 10998 : if (expr == NULL)
325 6 : ereport(ERROR,
326 : (errcode(ERRCODE_DATATYPE_MISMATCH),
327 : errmsg("parameter $%d of type %s cannot be coerced to the expected type %s",
328 : i + 1,
329 : format_type_be(given_type_id),
330 : format_type_be(expected_type_id)),
331 : errhint("You will need to rewrite or cast the expression."),
332 : parser_errposition(pstate, exprLocation(lfirst(l)))));
333 :
334 : /* Take care of collations in the finished expression. */
335 10992 : assign_expr_collations(pstate, expr);
336 :
337 10992 : lfirst(l) = expr;
338 10992 : i++;
339 : }
340 :
341 : /* Prepare the expressions for execution */
342 10670 : exprstates = ExecPrepareExprList(params, estate);
343 :
344 10670 : paramLI = makeParamList(num_params);
345 :
346 10670 : i = 0;
347 21638 : foreach(l, exprstates)
348 : {
349 10980 : ExprState *n = (ExprState *) lfirst(l);
350 10980 : ParamExternData *prm = ¶mLI->params[i];
351 :
352 10980 : prm->ptype = param_types[i];
353 10980 : prm->pflags = PARAM_FLAG_CONST;
354 10980 : prm->value = ExecEvalExprSwitchContext(n,
355 10980 : GetPerTupleExprContext(estate),
356 : &prm->isnull);
357 :
358 10968 : i++;
359 : }
360 :
361 10658 : return paramLI;
362 : }
363 :
364 :
365 : /*
366 : * Initialize query hash table upon first use.
367 : */
368 : static void
369 946 : InitQueryHashTable(void)
370 : {
371 : HASHCTL hash_ctl;
372 :
373 946 : hash_ctl.keysize = NAMEDATALEN;
374 946 : hash_ctl.entrysize = sizeof(PreparedStatement);
375 :
376 946 : prepared_queries = hash_create("Prepared Queries",
377 : 32,
378 : &hash_ctl,
379 : HASH_ELEM | HASH_STRINGS);
380 946 : }
381 :
382 : /*
383 : * Store all the data pertaining to a query in the hash table using
384 : * the specified key. The passed CachedPlanSource should be "unsaved"
385 : * in case we get an error here; we'll save it once we've created the hash
386 : * table entry.
387 : */
388 : void
389 5910 : StorePreparedStatement(const char *stmt_name,
390 : CachedPlanSource *plansource,
391 : bool from_sql)
392 : {
393 : PreparedStatement *entry;
394 5910 : TimestampTz cur_ts = GetCurrentStatementStartTimestamp();
395 : bool found;
396 :
397 : /* Initialize the hash table, if necessary */
398 5910 : if (!prepared_queries)
399 946 : InitQueryHashTable();
400 :
401 : /* Add entry to hash table */
402 5910 : entry = (PreparedStatement *) hash_search(prepared_queries,
403 : stmt_name,
404 : HASH_ENTER,
405 : &found);
406 :
407 : /* Shouldn't get a duplicate entry */
408 5910 : if (found)
409 6 : ereport(ERROR,
410 : (errcode(ERRCODE_DUPLICATE_PSTATEMENT),
411 : errmsg("prepared statement \"%s\" already exists",
412 : stmt_name)));
413 :
414 : /* Fill in the hash table entry */
415 5904 : entry->plansource = plansource;
416 5904 : entry->from_sql = from_sql;
417 5904 : entry->prepare_time = cur_ts;
418 :
419 : /* Now it's safe to move the CachedPlanSource to permanent memory */
420 5904 : SaveCachedPlan(plansource);
421 5904 : }
422 :
423 : /*
424 : * Lookup an existing query in the hash table. If the query does not
425 : * actually exist, throw ereport(ERROR) or return NULL per second parameter.
426 : *
427 : * Note: this does not force the referenced plancache entry to be valid,
428 : * since not all callers care.
429 : */
430 : PreparedStatement *
431 74542 : FetchPreparedStatement(const char *stmt_name, bool throwError)
432 : {
433 : PreparedStatement *entry;
434 :
435 : /*
436 : * If the hash table hasn't been initialized, it can't be storing
437 : * anything, therefore it couldn't possibly store our plan.
438 : */
439 74542 : if (prepared_queries)
440 74540 : entry = (PreparedStatement *) hash_search(prepared_queries,
441 : stmt_name,
442 : HASH_FIND,
443 : NULL);
444 : else
445 2 : entry = NULL;
446 :
447 74542 : if (!entry && throwError)
448 4 : ereport(ERROR,
449 : (errcode(ERRCODE_UNDEFINED_PSTATEMENT),
450 : errmsg("prepared statement \"%s\" does not exist",
451 : stmt_name)));
452 :
453 74538 : return entry;
454 : }
455 :
456 : /*
457 : * Given a prepared statement, determine the result tupledesc it will
458 : * produce. Returns NULL if the execution will not return tuples.
459 : *
460 : * Note: the result is created or copied into current memory context.
461 : */
462 : TupleDesc
463 11206 : FetchPreparedStatementResultDesc(PreparedStatement *stmt)
464 : {
465 : /*
466 : * Since we don't allow prepared statements' result tupdescs to change,
467 : * there's no need to worry about revalidating the cached plan here.
468 : */
469 : Assert(stmt->plansource->fixed_result);
470 11206 : if (stmt->plansource->resultDesc)
471 11206 : return CreateTupleDescCopy(stmt->plansource->resultDesc);
472 : else
473 0 : return NULL;
474 : }
475 :
476 : /*
477 : * Given a prepared statement that returns tuples, extract the query
478 : * targetlist. Returns NIL if the statement doesn't have a determinable
479 : * targetlist.
480 : *
481 : * Note: this is pretty ugly, but since it's only used in corner cases like
482 : * Describe Statement on an EXECUTE command, we don't worry too much about
483 : * efficiency.
484 : */
485 : List *
486 11138 : FetchPreparedStatementTargetList(PreparedStatement *stmt)
487 : {
488 : List *tlist;
489 :
490 : /* Get the plan's primary targetlist */
491 11138 : tlist = CachedPlanGetTargetList(stmt->plansource, NULL);
492 :
493 : /* Copy into caller's context in case plan gets invalidated */
494 11138 : return copyObject(tlist);
495 : }
496 :
497 : /*
498 : * Implements the 'DEALLOCATE' utility statement: deletes the
499 : * specified plan from storage.
500 : */
501 : void
502 4034 : DeallocateQuery(DeallocateStmt *stmt)
503 : {
504 4034 : if (stmt->name)
505 3984 : DropPreparedStatement(stmt->name, true);
506 : else
507 50 : DropAllPreparedStatements();
508 4034 : }
509 :
510 : /*
511 : * Internal version of DEALLOCATE
512 : *
513 : * If showError is false, dropping a nonexistent statement is a no-op.
514 : */
515 : void
516 3988 : DropPreparedStatement(const char *stmt_name, bool showError)
517 : {
518 : PreparedStatement *entry;
519 :
520 : /* Find the query's hash table entry; raise error if wanted */
521 3988 : entry = FetchPreparedStatement(stmt_name, showError);
522 :
523 3988 : if (entry)
524 : {
525 : /* Release the plancache entry */
526 3986 : DropCachedPlan(entry->plansource);
527 :
528 : /* Now we can remove the hash table entry */
529 3986 : hash_search(prepared_queries, entry->stmt_name, HASH_REMOVE, NULL);
530 : }
531 3988 : }
532 :
533 : /*
534 : * Drop all cached statements.
535 : */
536 : void
537 56 : DropAllPreparedStatements(void)
538 : {
539 : HASH_SEQ_STATUS seq;
540 : PreparedStatement *entry;
541 :
542 : /* nothing cached */
543 56 : if (!prepared_queries)
544 0 : return;
545 :
546 : /* walk over cache */
547 56 : hash_seq_init(&seq, prepared_queries);
548 122 : while ((entry = hash_seq_search(&seq)) != NULL)
549 : {
550 : /* Release the plancache entry */
551 66 : DropCachedPlan(entry->plansource);
552 :
553 : /* Now we can remove the hash table entry */
554 66 : hash_search(prepared_queries, entry->stmt_name, HASH_REMOVE, NULL);
555 : }
556 : }
557 :
558 : /*
559 : * Implements the 'EXPLAIN EXECUTE' utility statement.
560 : *
561 : * "into" is NULL unless we are doing EXPLAIN CREATE TABLE AS EXECUTE,
562 : * in which case executing the query should result in creating that table.
563 : *
564 : * Note: the passed-in queryString is that of the EXPLAIN EXECUTE,
565 : * not the original PREPARE; we get the latter string from the plancache.
566 : */
567 : void
568 374 : ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
569 : const char *queryString, ParamListInfo params,
570 : QueryEnvironment *queryEnv)
571 : {
572 : PreparedStatement *entry;
573 : const char *query_string;
574 : CachedPlan *cplan;
575 : List *plan_list;
576 : ListCell *p;
577 374 : ParamListInfo paramLI = NULL;
578 374 : EState *estate = NULL;
579 : instr_time planstart;
580 : instr_time planduration;
581 : BufferUsage bufusage_start,
582 : bufusage;
583 : MemoryContextCounters mem_counters;
584 374 : MemoryContext planner_ctx = NULL;
585 374 : MemoryContext saved_ctx = NULL;
586 :
587 374 : if (es->memory)
588 : {
589 : /* See ExplainOneQuery about this */
590 : Assert(IsA(CurrentMemoryContext, AllocSetContext));
591 6 : planner_ctx = AllocSetContextCreate(CurrentMemoryContext,
592 : "explain analyze planner context",
593 : ALLOCSET_DEFAULT_SIZES);
594 6 : saved_ctx = MemoryContextSwitchTo(planner_ctx);
595 : }
596 :
597 374 : if (es->buffers)
598 0 : bufusage_start = pgBufferUsage;
599 374 : INSTR_TIME_SET_CURRENT(planstart);
600 :
601 : /* Look it up in the hash table */
602 374 : entry = FetchPreparedStatement(execstmt->name, true);
603 :
604 : /* Shouldn't find a non-fixed-result cached plan */
605 374 : if (!entry->plansource->fixed_result)
606 0 : elog(ERROR, "EXPLAIN EXECUTE does not support variable-result cached plans");
607 :
608 374 : query_string = entry->plansource->query_string;
609 :
610 : /* Evaluate parameters, if any */
611 374 : if (entry->plansource->num_params)
612 : {
613 : ParseState *pstate;
614 :
615 244 : pstate = make_parsestate(NULL);
616 244 : pstate->p_sourcetext = queryString;
617 :
618 : /*
619 : * Need an EState to evaluate parameters; must not delete it till end
620 : * of query, in case parameters are pass-by-reference. Note that the
621 : * passed-in "params" could possibly be referenced in the parameter
622 : * expressions.
623 : */
624 244 : estate = CreateExecutorState();
625 244 : estate->es_param_list_info = params;
626 :
627 244 : paramLI = EvaluateParams(pstate, entry, execstmt->params, estate);
628 : }
629 :
630 : /* Replan if needed, and acquire a transient refcount */
631 374 : cplan = GetCachedPlan(entry->plansource, paramLI,
632 : CurrentResourceOwner, queryEnv);
633 :
634 374 : INSTR_TIME_SET_CURRENT(planduration);
635 374 : INSTR_TIME_SUBTRACT(planduration, planstart);
636 :
637 374 : if (es->memory)
638 : {
639 6 : MemoryContextSwitchTo(saved_ctx);
640 6 : MemoryContextMemConsumed(planner_ctx, &mem_counters);
641 : }
642 :
643 : /* calc differences of buffer counters. */
644 374 : if (es->buffers)
645 : {
646 0 : memset(&bufusage, 0, sizeof(BufferUsage));
647 0 : BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
648 : }
649 :
650 374 : plan_list = cplan->stmt_list;
651 :
652 : /* Explain each query */
653 748 : foreach(p, plan_list)
654 : {
655 374 : PlannedStmt *pstmt = lfirst_node(PlannedStmt, p);
656 :
657 374 : if (pstmt->commandType != CMD_UTILITY)
658 748 : ExplainOnePlan(pstmt, into, es, query_string, paramLI, queryEnv,
659 374 : &planduration, (es->buffers ? &bufusage : NULL),
660 374 : es->memory ? &mem_counters : NULL);
661 : else
662 0 : ExplainOneUtility(pstmt->utilityStmt, into, es, query_string,
663 : paramLI, queryEnv);
664 :
665 : /* No need for CommandCounterIncrement, as ExplainOnePlan did it */
666 :
667 : /* Separate plans with an appropriate separator */
668 374 : if (lnext(plan_list, p) != NULL)
669 0 : ExplainSeparatePlans(es);
670 : }
671 :
672 374 : if (estate)
673 244 : FreeExecutorState(estate);
674 :
675 374 : ReleaseCachedPlan(cplan, CurrentResourceOwner);
676 374 : }
677 :
678 : /*
679 : * This set returning function reads all the prepared statements and
680 : * returns a set of (name, statement, prepare_time, param_types, from_sql,
681 : * generic_plans, custom_plans).
682 : */
683 : Datum
684 96 : pg_prepared_statement(PG_FUNCTION_ARGS)
685 : {
686 96 : ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
687 :
688 : /*
689 : * We put all the tuples into a tuplestore in one scan of the hashtable.
690 : * This avoids any issue of the hashtable possibly changing between calls.
691 : */
692 96 : InitMaterializedSRF(fcinfo, 0);
693 :
694 : /* hash table might be uninitialized */
695 96 : if (prepared_queries)
696 : {
697 : HASH_SEQ_STATUS hash_seq;
698 : PreparedStatement *prep_stmt;
699 :
700 84 : hash_seq_init(&hash_seq, prepared_queries);
701 366 : while ((prep_stmt = hash_seq_search(&hash_seq)) != NULL)
702 : {
703 : TupleDesc result_desc;
704 : Datum values[8];
705 282 : bool nulls[8] = {0};
706 :
707 282 : result_desc = prep_stmt->plansource->resultDesc;
708 :
709 282 : values[0] = CStringGetTextDatum(prep_stmt->stmt_name);
710 282 : values[1] = CStringGetTextDatum(prep_stmt->plansource->query_string);
711 282 : values[2] = TimestampTzGetDatum(prep_stmt->prepare_time);
712 564 : values[3] = build_regtype_array(prep_stmt->plansource->param_types,
713 282 : prep_stmt->plansource->num_params);
714 282 : if (result_desc)
715 : {
716 : Oid *result_types;
717 :
718 276 : result_types = palloc_array(Oid, result_desc->natts);
719 948 : for (int i = 0; i < result_desc->natts; i++)
720 672 : result_types[i] = result_desc->attrs[i].atttypid;
721 276 : values[4] = build_regtype_array(result_types, result_desc->natts);
722 : }
723 : else
724 : {
725 : /* no result descriptor (for example, DML statement) */
726 6 : nulls[4] = true;
727 : }
728 282 : values[5] = BoolGetDatum(prep_stmt->from_sql);
729 282 : values[6] = Int64GetDatumFast(prep_stmt->plansource->num_generic_plans);
730 282 : values[7] = Int64GetDatumFast(prep_stmt->plansource->num_custom_plans);
731 :
732 282 : tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
733 : values, nulls);
734 : }
735 : }
736 :
737 96 : return (Datum) 0;
738 : }
739 :
740 : /*
741 : * This utility function takes a C array of Oids, and returns a Datum
742 : * pointing to a one-dimensional Postgres array of regtypes. An empty
743 : * array is returned as a zero-element array, not NULL.
744 : */
745 : static Datum
746 558 : build_regtype_array(Oid *param_types, int num_params)
747 : {
748 : Datum *tmp_ary;
749 : ArrayType *result;
750 : int i;
751 :
752 558 : tmp_ary = palloc_array(Datum, num_params);
753 :
754 1380 : for (i = 0; i < num_params; i++)
755 822 : tmp_ary[i] = ObjectIdGetDatum(param_types[i]);
756 :
757 558 : result = construct_array_builtin(tmp_ary, num_params, REGTYPEOID);
758 558 : return PointerGetDatum(result);
759 : }
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