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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * preptlist.c
4 : : * Routines to preprocess the parse tree target list
5 : : *
6 : : * For an INSERT, the targetlist must contain an entry for each attribute of
7 : : * the target relation in the correct order.
8 : : *
9 : : * For an UPDATE, the targetlist just contains the expressions for the new
10 : : * column values.
11 : : *
12 : : * For UPDATE and DELETE queries, the targetlist must also contain "junk"
13 : : * tlist entries needed to allow the executor to identify the rows to be
14 : : * updated or deleted; for example, the ctid of a heap row. (The planner
15 : : * adds these; they're not in what we receive from the parser/rewriter.)
16 : : *
17 : : * For all query types, there can be additional junk tlist entries, such as
18 : : * sort keys, Vars needed for a RETURNING list, and row ID information needed
19 : : * for SELECT FOR UPDATE locking and/or EvalPlanQual checking.
20 : : *
21 : : * The query rewrite phase also does preprocessing of the targetlist (see
22 : : * rewriteTargetListIU). The division of labor between here and there is
23 : : * partially historical, but it's not entirely arbitrary. The stuff done
24 : : * here is closely connected to physical access to tables, whereas the
25 : : * rewriter's work is more concerned with SQL semantics.
26 : : *
27 : : *
28 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
29 : : * Portions Copyright (c) 1994, Regents of the University of California
30 : : *
31 : : * IDENTIFICATION
32 : : * src/backend/optimizer/prep/preptlist.c
33 : : *
34 : : *-------------------------------------------------------------------------
35 : : */
36 : :
37 : : #include "postgres.h"
38 : :
39 : : #include "access/table.h"
40 : : #include "nodes/makefuncs.h"
41 : : #include "optimizer/appendinfo.h"
42 : : #include "optimizer/optimizer.h"
43 : : #include "optimizer/prep.h"
44 : : #include "optimizer/tlist.h"
45 : : #include "parser/parse_coerce.h"
46 : : #include "parser/parsetree.h"
47 : : #include "utils/lsyscache.h"
48 : : #include "utils/rel.h"
49 : :
50 : : static List *expand_insert_targetlist(PlannerInfo *root, List *tlist,
51 : : Relation rel);
52 : :
53 : :
54 : : /*
55 : : * preprocess_targetlist
56 : : * Driver for preprocessing the parse tree targetlist.
57 : : *
58 : : * The preprocessed targetlist is returned in root->processed_tlist.
59 : : * Also, if this is an UPDATE, we return a list of target column numbers
60 : : * in root->update_colnos. (Resnos in processed_tlist will be consecutive,
61 : : * so do not look at that to find out which columns are targets!)
62 : : */
63 : : void
64 : 50852 : preprocess_targetlist(PlannerInfo *root)
65 : : {
66 : 50852 : Query *parse = root->parse;
67 : 50852 : int result_relation = parse->resultRelation;
68 : 50852 : List *range_table = parse->rtable;
69 : 50852 : CmdType command_type = parse->commandType;
70 : 50852 : RangeTblEntry *target_rte = NULL;
71 : 50852 : Relation target_relation = NULL;
72 : 50852 : List *tlist;
73 : 50852 : ListCell *lc;
74 : :
75 : : /*
76 : : * If there is a result relation, open it so we can look for missing
77 : : * columns and so on. We assume that previous code already acquired at
78 : : * least AccessShareLock on the relation, so we need no lock here.
79 : : */
80 [ + + ]: 50852 : if (result_relation)
81 : : {
82 : 7234 : target_rte = rt_fetch(result_relation, range_table);
83 : :
84 : : /*
85 : : * Sanity check: it'd better be a real relation not, say, a subquery.
86 : : * Else parser or rewriter messed up.
87 : : */
88 [ + - ]: 7234 : if (target_rte->rtekind != RTE_RELATION)
89 [ # # # # ]: 0 : elog(ERROR, "result relation must be a regular relation");
90 : :
91 : 7234 : target_relation = table_open(target_rte->relid, NoLock);
92 : 7234 : }
93 : : else
94 [ + - ]: 43618 : Assert(command_type == CMD_SELECT);
95 : :
96 : : /*
97 : : * In an INSERT, the executor expects the targetlist to match the exact
98 : : * order of the target table's attributes, including entries for
99 : : * attributes not mentioned in the source query.
100 : : *
101 : : * In an UPDATE, we don't rearrange the tlist order, but we need to make a
102 : : * separate list of the target attribute numbers, in tlist order, and then
103 : : * renumber the processed_tlist entries to be consecutive.
104 : : */
105 : 50852 : tlist = parse->targetList;
106 [ + + ]: 50852 : if (command_type == CMD_INSERT)
107 : 5327 : tlist = expand_insert_targetlist(root, tlist, target_relation);
108 [ + + ]: 45525 : else if (command_type == CMD_UPDATE)
109 : 1130 : root->update_colnos = extract_update_targetlist_colnos(tlist);
110 : :
111 : : /*
112 : : * For non-inherited UPDATE/DELETE/MERGE, register any junk column(s)
113 : : * needed to allow the executor to identify the rows to be updated or
114 : : * deleted. In the inheritance case, we do nothing now, leaving this to
115 : : * be dealt with when expand_inherited_rtentry() makes the leaf target
116 : : * relations. (But there might not be any leaf target relations, in which
117 : : * case we must do this in distribute_row_identity_vars().)
118 : : */
119 [ + + + + ]: 50852 : if ((command_type == CMD_UPDATE || command_type == CMD_DELETE ||
120 [ + + ]: 50852 : command_type == CMD_MERGE) &&
121 : 50852 : !target_rte->inh)
122 : : {
123 : : /* row-identity logic expects to add stuff to processed_tlist */
124 : 1532 : root->processed_tlist = tlist;
125 : 3064 : add_row_identity_columns(root, result_relation,
126 : 1532 : target_rte, target_relation);
127 : 1532 : tlist = root->processed_tlist;
128 : 1532 : }
129 : :
130 : : /*
131 : : * For MERGE we also need to handle the target list for each INSERT and
132 : : * UPDATE action separately. In addition, we examine the qual of each
133 : : * action and add any Vars there (other than those of the target rel) to
134 : : * the subplan targetlist.
135 : : */
136 [ + + ]: 50852 : if (command_type == CMD_MERGE)
137 : : {
138 : 273 : ListCell *l;
139 : 273 : List *vars;
140 : :
141 : : /*
142 : : * For MERGE, handle targetlist of each MergeAction separately. Give
143 : : * the same treatment to MergeAction->targetList as we would have
144 : : * given to a regular INSERT. For UPDATE, collect the column numbers
145 : : * being modified.
146 : : */
147 [ + - + + : 678 : foreach(l, parse->mergeActionList)
+ + ]
148 : : {
149 : 405 : MergeAction *action = (MergeAction *) lfirst(l);
150 : 405 : ListCell *l2;
151 : :
152 [ + + ]: 405 : if (action->commandType == CMD_INSERT)
153 : 266 : action->targetList = expand_insert_targetlist(root,
154 : 133 : action->targetList,
155 : 133 : target_relation);
156 [ + + ]: 272 : else if (action->commandType == CMD_UPDATE)
157 : 185 : action->updateColnos =
158 : 185 : extract_update_targetlist_colnos(action->targetList);
159 : :
160 : : /*
161 : : * Add resjunk entries for any Vars and PlaceHolderVars used in
162 : : * each action's targetlist and WHEN condition that belong to
163 : : * relations other than the target. We don't expect to see any
164 : : * aggregates or window functions here.
165 : : */
166 : 405 : vars = pull_var_clause((Node *)
167 : 810 : list_concat_copy((List *) action->qual,
168 : 405 : action->targetList),
169 : : PVC_INCLUDE_PLACEHOLDERS);
170 [ + + + + : 896 : foreach(l2, vars)
+ + ]
171 : : {
172 : 491 : Var *var = (Var *) lfirst(l2);
173 : 491 : TargetEntry *tle;
174 : :
175 [ + + + + ]: 491 : if (IsA(var, Var) && var->varno == result_relation)
176 : 215 : continue; /* don't need it */
177 : :
178 [ + + ]: 276 : if (tlist_member((Expr *) var, tlist))
179 : 72 : continue; /* already got it */
180 : :
181 : 408 : tle = makeTargetEntry((Expr *) var,
182 : 204 : list_length(tlist) + 1,
183 : : NULL, true);
184 : 204 : tlist = lappend(tlist, tle);
185 [ + + ]: 491 : }
186 : 405 : list_free(vars);
187 : 405 : }
188 : :
189 : : /*
190 : : * Add resjunk entries for any Vars and PlaceHolderVars used in the
191 : : * join condition that belong to relations other than the target. We
192 : : * don't expect to see any aggregates or window functions here.
193 : : */
194 : 273 : vars = pull_var_clause(parse->mergeJoinCondition,
195 : : PVC_INCLUDE_PLACEHOLDERS);
196 [ + + + + : 332 : foreach(l, vars)
+ + ]
197 : : {
198 : 59 : Var *var = (Var *) lfirst(l);
199 : 59 : TargetEntry *tle;
200 : :
201 [ + + + + ]: 59 : if (IsA(var, Var) && var->varno == result_relation)
202 : 20 : continue; /* don't need it */
203 : :
204 [ + + ]: 39 : if (tlist_member((Expr *) var, tlist))
205 : 15 : continue; /* already got it */
206 : :
207 : 48 : tle = makeTargetEntry((Expr *) var,
208 : 24 : list_length(tlist) + 1,
209 : : NULL, true);
210 : 24 : tlist = lappend(tlist, tle);
211 [ + + ]: 59 : }
212 : 273 : }
213 : :
214 : : /*
215 : : * Add necessary junk columns for rowmarked rels. These values are needed
216 : : * for locking of rels selected FOR UPDATE/SHARE, and to do EvalPlanQual
217 : : * rechecking. See comments for PlanRowMark in plannodes.h. If you
218 : : * change this stanza, see also expand_inherited_rtentry(), which has to
219 : : * be able to add on junk columns equivalent to these.
220 : : *
221 : : * (Someday it might be useful to fold these resjunk columns into the
222 : : * row-identity-column management used for UPDATE/DELETE. Today is not
223 : : * that day, however. One notable issue is that it seems important that
224 : : * the whole-row Vars made here use the real table rowtype, not RECORD, so
225 : : * that conversion to/from child relations' rowtypes will happen. Also,
226 : : * since these entries don't potentially bloat with more and more child
227 : : * relations, there's not really much need for column sharing.)
228 : : */
229 [ + + + + : 52059 : foreach(lc, root->rowMarks)
+ + ]
230 : : {
231 : 1207 : PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
232 : 1207 : Var *var;
233 : 1207 : char resname[32];
234 : 1207 : TargetEntry *tle;
235 : :
236 : : /* child rels use the same junk attrs as their parents */
237 [ - + ]: 1207 : if (rc->rti != rc->prti)
238 : 0 : continue;
239 : :
240 [ + + ]: 1207 : if (rc->allMarkTypes & ~(1 << ROW_MARK_COPY))
241 : : {
242 : : /* Need to fetch TID */
243 : 1132 : var = makeVar(rc->rti,
244 : : SelfItemPointerAttributeNumber,
245 : : TIDOID,
246 : : -1,
247 : : InvalidOid,
248 : : 0);
249 : 1132 : snprintf(resname, sizeof(resname), "ctid%u", rc->rowmarkId);
250 : 2264 : tle = makeTargetEntry((Expr *) var,
251 : 1132 : list_length(tlist) + 1,
252 : 1132 : pstrdup(resname),
253 : : true);
254 : 1132 : tlist = lappend(tlist, tle);
255 : 1132 : }
256 [ + + ]: 1207 : if (rc->allMarkTypes & (1 << ROW_MARK_COPY))
257 : : {
258 : : /* Need the whole row as a junk var */
259 : 150 : var = makeWholeRowVar(rt_fetch(rc->rti, range_table),
260 : 75 : rc->rti,
261 : : 0,
262 : : false);
263 : 75 : snprintf(resname, sizeof(resname), "wholerow%u", rc->rowmarkId);
264 : 150 : tle = makeTargetEntry((Expr *) var,
265 : 75 : list_length(tlist) + 1,
266 : 75 : pstrdup(resname),
267 : : true);
268 : 75 : tlist = lappend(tlist, tle);
269 : 75 : }
270 : :
271 : : /* If parent of inheritance tree, always fetch the tableoid too. */
272 [ + - ]: 1207 : if (rc->isParent)
273 : : {
274 : 0 : var = makeVar(rc->rti,
275 : : TableOidAttributeNumber,
276 : : OIDOID,
277 : : -1,
278 : : InvalidOid,
279 : : 0);
280 : 0 : snprintf(resname, sizeof(resname), "tableoid%u", rc->rowmarkId);
281 : 0 : tle = makeTargetEntry((Expr *) var,
282 : 0 : list_length(tlist) + 1,
283 : 0 : pstrdup(resname),
284 : : true);
285 : 0 : tlist = lappend(tlist, tle);
286 : 0 : }
287 [ - + ]: 1207 : }
288 : :
289 : : /*
290 : : * If the query has a RETURNING list, add resjunk entries for any Vars
291 : : * used in RETURNING that belong to other relations. We need to do this
292 : : * to make these Vars available for the RETURNING calculation. Vars that
293 : : * belong to the result rel don't need to be added, because they will be
294 : : * made to refer to the actual heap tuple.
295 : : */
296 [ + + + + ]: 50852 : if (parse->returningList && list_length(parse->rtable) > 1)
297 : : {
298 : 239 : List *vars;
299 : 239 : ListCell *l;
300 : :
301 : 239 : vars = pull_var_clause((Node *) parse->returningList,
302 : : PVC_RECURSE_AGGREGATES |
303 : : PVC_RECURSE_WINDOWFUNCS |
304 : : PVC_INCLUDE_PLACEHOLDERS);
305 [ + + + + : 1142 : foreach(l, vars)
+ + ]
306 : : {
307 : 903 : Var *var = (Var *) lfirst(l);
308 : 903 : TargetEntry *tle;
309 : :
310 [ + - + + ]: 903 : if (IsA(var, Var) &&
311 : 903 : var->varno == result_relation)
312 : 812 : continue; /* don't need it */
313 : :
314 [ + + ]: 91 : if (tlist_member((Expr *) var, tlist))
315 : 37 : continue; /* already got it */
316 : :
317 : 108 : tle = makeTargetEntry((Expr *) var,
318 : 54 : list_length(tlist) + 1,
319 : : NULL,
320 : : true);
321 : :
322 : 54 : tlist = lappend(tlist, tle);
323 [ + + ]: 903 : }
324 : 239 : list_free(vars);
325 : 239 : }
326 : :
327 : 50852 : root->processed_tlist = tlist;
328 : :
329 [ + + ]: 50852 : if (target_relation)
330 : 7234 : table_close(target_relation, NoLock);
331 : 50852 : }
332 : :
333 : : /*
334 : : * extract_update_targetlist_colnos
335 : : * Extract a list of the target-table column numbers that
336 : : * an UPDATE's targetlist wants to assign to, then renumber.
337 : : *
338 : : * The convention in the parser and rewriter is that the resnos in an
339 : : * UPDATE's non-resjunk TLE entries are the target column numbers
340 : : * to assign to. Here, we extract that info into a separate list, and
341 : : * then convert the tlist to the sequential-numbering convention that's
342 : : * used by all other query types.
343 : : *
344 : : * This is also applied to the tlist associated with INSERT ... ON CONFLICT
345 : : * ... UPDATE, although not till much later in planning.
346 : : */
347 : : List *
348 : 1599 : extract_update_targetlist_colnos(List *tlist)
349 : : {
350 : 1599 : List *update_colnos = NIL;
351 : 1599 : AttrNumber nextresno = 1;
352 : 1599 : ListCell *lc;
353 : :
354 [ + + + + : 3436 : foreach(lc, tlist)
+ + ]
355 : : {
356 : 1837 : TargetEntry *tle = (TargetEntry *) lfirst(lc);
357 : :
358 [ + + ]: 1837 : if (!tle->resjunk)
359 : 1791 : update_colnos = lappend_int(update_colnos, tle->resno);
360 : 1837 : tle->resno = nextresno++;
361 : 1837 : }
362 : 3198 : return update_colnos;
363 : 1599 : }
364 : :
365 : :
366 : : /*****************************************************************************
367 : : *
368 : : * TARGETLIST EXPANSION
369 : : *
370 : : *****************************************************************************/
371 : :
372 : : /*
373 : : * expand_insert_targetlist
374 : : * Given a target list as generated by the parser and a result relation,
375 : : * add targetlist entries for any missing attributes, and ensure the
376 : : * non-junk attributes appear in proper field order.
377 : : *
378 : : * Once upon a time we also did more or less this with UPDATE targetlists,
379 : : * but now this code is only applied to INSERT targetlists.
380 : : */
381 : : static List *
382 : 5460 : expand_insert_targetlist(PlannerInfo *root, List *tlist, Relation rel)
383 : : {
384 : 5460 : List *new_tlist = NIL;
385 : 5460 : ListCell *tlist_item;
386 : 5460 : int attrno,
387 : : numattrs;
388 : :
389 : 5460 : tlist_item = list_head(tlist);
390 : :
391 : : /*
392 : : * The rewriter should have already ensured that the TLEs are in correct
393 : : * order; but we have to insert TLEs for any missing attributes.
394 : : *
395 : : * Scan the tuple description in the relation's relcache entry to make
396 : : * sure we have all the user attributes in the right order.
397 : : */
398 : 5460 : numattrs = RelationGetNumberOfAttributes(rel);
399 : :
400 [ + + ]: 19691 : for (attrno = 1; attrno <= numattrs; attrno++)
401 : : {
402 : 14231 : Form_pg_attribute att_tup = TupleDescAttr(rel->rd_att, attrno - 1);
403 : 14231 : TargetEntry *new_tle = NULL;
404 : :
405 [ + + ]: 14231 : if (tlist_item != NULL)
406 : : {
407 : 13589 : TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);
408 : :
409 [ + - + + ]: 13589 : if (!old_tle->resjunk && old_tle->resno == attrno)
410 : : {
411 : 12159 : new_tle = old_tle;
412 : 12159 : tlist_item = lnext(tlist, tlist_item);
413 : 12159 : }
414 : 13589 : }
415 : :
416 [ + + ]: 14231 : if (new_tle == NULL)
417 : : {
418 : : /*
419 : : * Didn't find a matching tlist entry, so make one.
420 : : *
421 : : * INSERTs should insert NULL in this case. (We assume the
422 : : * rewriter would have inserted any available non-NULL default
423 : : * value.) Also, normally we must apply any domain constraints
424 : : * that might exist --- this is to catch domain NOT NULL.
425 : : *
426 : : * When generating a NULL constant for a dropped column, we label
427 : : * it INT4 (any other guaranteed-to-exist datatype would do as
428 : : * well). We can't label it with the dropped column's datatype
429 : : * since that might not exist anymore. It does not really matter
430 : : * what we claim the type is, since NULL is NULL --- its
431 : : * representation is datatype-independent. This could perhaps
432 : : * confuse code comparing the finished plan to the target
433 : : * relation, however.
434 : : *
435 : : * Another exception is that if the column is generated, the value
436 : : * we produce here will be ignored, and we don't want to risk
437 : : * throwing an error. So in that case we *don't* want to apply
438 : : * domain constraints, so we must produce a NULL of the base type.
439 : : * Again, code comparing the finished plan to the target relation
440 : : * must account for this.
441 : : */
442 : 2072 : Node *new_expr;
443 : :
444 [ + + ]: 2072 : if (att_tup->attisdropped)
445 : : {
446 : : /* Insert NULL for dropped column */
447 : 89 : new_expr = (Node *) makeConst(INT4OID,
448 : : -1,
449 : : InvalidOid,
450 : : sizeof(int32),
451 : : (Datum) 0,
452 : : true, /* isnull */
453 : : true /* byval */ );
454 : 89 : }
455 [ + + ]: 1983 : else if (att_tup->attgenerated)
456 : : {
457 : : /* Generated column, insert a NULL of the base type */
458 : 151 : Oid baseTypeId = att_tup->atttypid;
459 : 151 : int32 baseTypeMod = att_tup->atttypmod;
460 : :
461 : 151 : baseTypeId = getBaseTypeAndTypmod(baseTypeId, &baseTypeMod);
462 : 302 : new_expr = (Node *) makeConst(baseTypeId,
463 : 151 : baseTypeMod,
464 : 151 : att_tup->attcollation,
465 : 151 : att_tup->attlen,
466 : : (Datum) 0,
467 : : true, /* isnull */
468 : 151 : att_tup->attbyval);
469 : 151 : }
470 : : else
471 : : {
472 : : /* Normal column, insert a NULL of the column datatype */
473 : 3664 : new_expr = coerce_null_to_domain(att_tup->atttypid,
474 : 1832 : att_tup->atttypmod,
475 : 1832 : att_tup->attcollation,
476 : 1832 : att_tup->attlen,
477 : 1832 : att_tup->attbyval);
478 : : /* Must run expression preprocessing on any non-const nodes */
479 [ + + ]: 1832 : if (!IsA(new_expr, Const))
480 : 11 : new_expr = eval_const_expressions(root, new_expr);
481 : : }
482 : :
483 : 4144 : new_tle = makeTargetEntry((Expr *) new_expr,
484 : 2072 : attrno,
485 : 2072 : pstrdup(NameStr(att_tup->attname)),
486 : : false);
487 : 2072 : }
488 : :
489 : 14231 : new_tlist = lappend(new_tlist, new_tle);
490 : 14231 : }
491 : :
492 : : /*
493 : : * The remaining tlist entries should be resjunk; append them all to the
494 : : * end of the new tlist, making sure they have resnos higher than the last
495 : : * real attribute. (Note: although the rewriter already did such
496 : : * renumbering, we have to do it again here in case we added NULL entries
497 : : * above.)
498 : : */
499 [ - + ]: 5460 : while (tlist_item)
500 : : {
501 : 0 : TargetEntry *old_tle = (TargetEntry *) lfirst(tlist_item);
502 : :
503 [ # # ]: 0 : if (!old_tle->resjunk)
504 [ # # # # ]: 0 : elog(ERROR, "targetlist is not sorted correctly");
505 : : /* Get the resno right, but don't copy unnecessarily */
506 [ # # ]: 0 : if (old_tle->resno != attrno)
507 : : {
508 : 0 : old_tle = flatCopyTargetEntry(old_tle);
509 : 0 : old_tle->resno = attrno;
510 : 0 : }
511 : 0 : new_tlist = lappend(new_tlist, old_tle);
512 : 0 : attrno++;
513 : 0 : tlist_item = lnext(tlist, tlist_item);
514 : 0 : }
515 : :
516 : 10920 : return new_tlist;
517 : 5460 : }
518 : :
519 : :
520 : : /*
521 : : * Locate PlanRowMark for given RT index, or return NULL if none
522 : : *
523 : : * This probably ought to be elsewhere, but there's no very good place
524 : : */
525 : : PlanRowMark *
526 : 2274 : get_plan_rowmark(List *rowmarks, Index rtindex)
527 : : {
528 : 2274 : ListCell *l;
529 : :
530 [ + + + + : 2587 : foreach(l, rowmarks)
+ + + + ]
531 : : {
532 : 313 : PlanRowMark *rc = (PlanRowMark *) lfirst(l);
533 : :
534 [ + + ]: 313 : if (rc->rti == rtindex)
535 : 213 : return rc;
536 [ + + ]: 313 : }
537 : 2061 : return NULL;
538 : 2274 : }
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