Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * deparse.c
4 : * Query deparser for postgres_fdw
5 : *
6 : * This file includes functions that examine query WHERE clauses to see
7 : * whether they're safe to send to the remote server for execution, as
8 : * well as functions to construct the query text to be sent. The latter
9 : * functionality is annoyingly duplicative of ruleutils.c, but there are
10 : * enough special considerations that it seems best to keep this separate.
11 : * One saving grace is that we only need deparse logic for node types that
12 : * we consider safe to send.
13 : *
14 : * We assume that the remote session's search_path is exactly "pg_catalog",
15 : * and thus we need schema-qualify all and only names outside pg_catalog.
16 : *
17 : * We do not consider that it is ever safe to send COLLATE expressions to
18 : * the remote server: it might not have the same collation names we do.
19 : * (Later we might consider it safe to send COLLATE "C", but even that would
20 : * fail on old remote servers.) An expression is considered safe to send
21 : * only if all operator/function input collations used in it are traceable to
22 : * Var(s) of the foreign table. That implies that if the remote server gets
23 : * a different answer than we do, the foreign table's columns are not marked
24 : * with collations that match the remote table's columns, which we can
25 : * consider to be user error.
26 : *
27 : * Portions Copyright (c) 2012-2026, PostgreSQL Global Development Group
28 : *
29 : * IDENTIFICATION
30 : * contrib/postgres_fdw/deparse.c
31 : *
32 : *-------------------------------------------------------------------------
33 : */
34 : #include "postgres.h"
35 :
36 : #include "access/htup_details.h"
37 : #include "access/sysattr.h"
38 : #include "access/table.h"
39 : #include "catalog/pg_aggregate.h"
40 : #include "catalog/pg_authid.h"
41 : #include "catalog/pg_collation.h"
42 : #include "catalog/pg_database.h"
43 : #include "catalog/pg_namespace.h"
44 : #include "catalog/pg_operator.h"
45 : #include "catalog/pg_opfamily.h"
46 : #include "catalog/pg_proc.h"
47 : #include "catalog/pg_ts_config.h"
48 : #include "catalog/pg_ts_dict.h"
49 : #include "catalog/pg_type.h"
50 : #include "commands/defrem.h"
51 : #include "nodes/nodeFuncs.h"
52 : #include "nodes/plannodes.h"
53 : #include "optimizer/optimizer.h"
54 : #include "optimizer/prep.h"
55 : #include "optimizer/tlist.h"
56 : #include "parser/parsetree.h"
57 : #include "postgres_fdw.h"
58 : #include "utils/builtins.h"
59 : #include "utils/lsyscache.h"
60 : #include "utils/rel.h"
61 : #include "utils/syscache.h"
62 : #include "utils/typcache.h"
63 :
64 : /*
65 : * Global context for foreign_expr_walker's search of an expression tree.
66 : */
67 : typedef struct foreign_glob_cxt
68 : {
69 : PlannerInfo *root; /* global planner state */
70 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
71 : Relids relids; /* relids of base relations in the underlying
72 : * scan */
73 : } foreign_glob_cxt;
74 :
75 : /*
76 : * Local (per-tree-level) context for foreign_expr_walker's search.
77 : * This is concerned with identifying collations used in the expression.
78 : */
79 : typedef enum
80 : {
81 : FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
82 : * it has default collation that is not
83 : * traceable to a foreign Var */
84 : FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
85 : FDW_COLLATE_UNSAFE, /* collation is non-default and derives from
86 : * something other than a foreign Var */
87 : } FDWCollateState;
88 :
89 : typedef struct foreign_loc_cxt
90 : {
91 : Oid collation; /* OID of current collation, if any */
92 : FDWCollateState state; /* state of current collation choice */
93 : } foreign_loc_cxt;
94 :
95 : /*
96 : * Context for deparseExpr
97 : */
98 : typedef struct deparse_expr_cxt
99 : {
100 : PlannerInfo *root; /* global planner state */
101 : RelOptInfo *foreignrel; /* the foreign relation we are planning for */
102 : RelOptInfo *scanrel; /* the underlying scan relation. Same as
103 : * foreignrel, when that represents a join or
104 : * a base relation. */
105 : StringInfo buf; /* output buffer to append to */
106 : List **params_list; /* exprs that will become remote Params */
107 : } deparse_expr_cxt;
108 :
109 : #define REL_ALIAS_PREFIX "r"
110 : /* Handy macro to add relation name qualification */
111 : #define ADD_REL_QUALIFIER(buf, varno) \
112 : appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
113 : #define SUBQUERY_REL_ALIAS_PREFIX "s"
114 : #define SUBQUERY_COL_ALIAS_PREFIX "c"
115 :
116 : /*
117 : * Functions to determine whether an expression can be evaluated safely on
118 : * remote server.
119 : */
120 : static bool foreign_expr_walker(Node *node,
121 : foreign_glob_cxt *glob_cxt,
122 : foreign_loc_cxt *outer_cxt,
123 : foreign_loc_cxt *case_arg_cxt);
124 : static char *deparse_type_name(Oid type_oid, int32 typemod);
125 :
126 : /*
127 : * Functions to construct string representation of a node tree.
128 : */
129 : static void deparseTargetList(StringInfo buf,
130 : RangeTblEntry *rte,
131 : Index rtindex,
132 : Relation rel,
133 : bool is_returning,
134 : Bitmapset *attrs_used,
135 : bool qualify_col,
136 : List **retrieved_attrs);
137 : static void deparseExplicitTargetList(List *tlist,
138 : bool is_returning,
139 : List **retrieved_attrs,
140 : deparse_expr_cxt *context);
141 : static void deparseSubqueryTargetList(deparse_expr_cxt *context);
142 : static void deparseReturningList(StringInfo buf, RangeTblEntry *rte,
143 : Index rtindex, Relation rel,
144 : bool trig_after_row,
145 : List *withCheckOptionList,
146 : List *returningList,
147 : List **retrieved_attrs);
148 : static void deparseColumnRef(StringInfo buf, int varno, int varattno,
149 : RangeTblEntry *rte, bool qualify_col);
150 : static void deparseRelation(StringInfo buf, Relation rel);
151 : static void deparseExpr(Expr *node, deparse_expr_cxt *context);
152 : static void deparseVar(Var *node, deparse_expr_cxt *context);
153 : static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype);
154 : static void deparseParam(Param *node, deparse_expr_cxt *context);
155 : static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context);
156 : static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
157 : static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
158 : static bool isPlainForeignVar(Expr *node, deparse_expr_cxt *context);
159 : static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
160 : static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
161 : static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
162 : deparse_expr_cxt *context);
163 : static void deparseRelabelType(RelabelType *node, deparse_expr_cxt *context);
164 : static void deparseArrayCoerceExpr(ArrayCoerceExpr *node, deparse_expr_cxt *context);
165 : static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context);
166 : static void deparseNullTest(NullTest *node, deparse_expr_cxt *context);
167 : static void deparseCaseExpr(CaseExpr *node, deparse_expr_cxt *context);
168 : static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context);
169 : static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
170 : deparse_expr_cxt *context);
171 : static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
172 : deparse_expr_cxt *context);
173 : static void deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
174 : deparse_expr_cxt *context);
175 : static void deparseLockingClause(deparse_expr_cxt *context);
176 : static void appendOrderByClause(List *pathkeys, bool has_final_sort,
177 : deparse_expr_cxt *context);
178 : static void appendLimitClause(deparse_expr_cxt *context);
179 : static void appendConditions(List *exprs, deparse_expr_cxt *context);
180 : static void deparseFromExprForRel(StringInfo buf, PlannerInfo *root,
181 : RelOptInfo *foreignrel, bool use_alias,
182 : Index ignore_rel, List **ignore_conds,
183 : List **additional_conds,
184 : List **params_list);
185 : static void appendWhereClause(List *exprs, List *additional_conds,
186 : deparse_expr_cxt *context);
187 : static void deparseFromExpr(List *quals, deparse_expr_cxt *context);
188 : static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root,
189 : RelOptInfo *foreignrel, bool make_subquery,
190 : Index ignore_rel, List **ignore_conds,
191 : List **additional_conds, List **params_list);
192 : static void deparseAggref(Aggref *node, deparse_expr_cxt *context);
193 : static void appendGroupByClause(List *tlist, deparse_expr_cxt *context);
194 : static void appendOrderBySuffix(Oid sortop, Oid sortcoltype, bool nulls_first,
195 : deparse_expr_cxt *context);
196 : static void appendAggOrderBy(List *orderList, List *targetList,
197 : deparse_expr_cxt *context);
198 : static void appendFunctionName(Oid funcid, deparse_expr_cxt *context);
199 : static Node *deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
200 : deparse_expr_cxt *context);
201 :
202 : /*
203 : * Helper functions
204 : */
205 : static bool is_subquery_var(Var *node, RelOptInfo *foreignrel,
206 : int *relno, int *colno);
207 : static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
208 : int *relno, int *colno);
209 :
210 :
211 : /*
212 : * Examine each qual clause in input_conds, and classify them into two groups,
213 : * which are returned as two lists:
214 : * - remote_conds contains expressions that can be evaluated remotely
215 : * - local_conds contains expressions that can't be evaluated remotely
216 : */
217 : void
218 0 : classifyConditions(PlannerInfo *root,
219 : RelOptInfo *baserel,
220 : List *input_conds,
221 : List **remote_conds,
222 : List **local_conds)
223 : {
224 0 : ListCell *lc;
225 :
226 0 : *remote_conds = NIL;
227 0 : *local_conds = NIL;
228 :
229 0 : foreach(lc, input_conds)
230 : {
231 0 : RestrictInfo *ri = lfirst_node(RestrictInfo, lc);
232 :
233 0 : if (is_foreign_expr(root, baserel, ri->clause))
234 0 : *remote_conds = lappend(*remote_conds, ri);
235 : else
236 0 : *local_conds = lappend(*local_conds, ri);
237 0 : }
238 0 : }
239 :
240 : /*
241 : * Returns true if given expr is safe to evaluate on the foreign server.
242 : */
243 : bool
244 0 : is_foreign_expr(PlannerInfo *root,
245 : RelOptInfo *baserel,
246 : Expr *expr)
247 : {
248 0 : foreign_glob_cxt glob_cxt;
249 0 : foreign_loc_cxt loc_cxt;
250 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
251 :
252 : /*
253 : * Check that the expression consists of nodes that are safe to execute
254 : * remotely.
255 : */
256 0 : glob_cxt.root = root;
257 0 : glob_cxt.foreignrel = baserel;
258 :
259 : /*
260 : * For an upper relation, use relids from its underneath scan relation,
261 : * because the upperrel's own relids currently aren't set to anything
262 : * meaningful by the core code. For other relation, use their own relids.
263 : */
264 0 : if (IS_UPPER_REL(baserel))
265 0 : glob_cxt.relids = fpinfo->outerrel->relids;
266 : else
267 0 : glob_cxt.relids = baserel->relids;
268 0 : loc_cxt.collation = InvalidOid;
269 0 : loc_cxt.state = FDW_COLLATE_NONE;
270 0 : if (!foreign_expr_walker((Node *) expr, &glob_cxt, &loc_cxt, NULL))
271 0 : return false;
272 :
273 : /*
274 : * If the expression has a valid collation that does not arise from a
275 : * foreign var, the expression can not be sent over.
276 : */
277 0 : if (loc_cxt.state == FDW_COLLATE_UNSAFE)
278 0 : return false;
279 :
280 : /*
281 : * An expression which includes any mutable functions can't be sent over
282 : * because its result is not stable. For example, sending now() remote
283 : * side could cause confusion from clock offsets. Future versions might
284 : * be able to make this choice with more granularity. (We check this last
285 : * because it requires a lot of expensive catalog lookups.)
286 : */
287 0 : if (contain_mutable_functions((Node *) expr))
288 0 : return false;
289 :
290 : /* OK to evaluate on the remote server */
291 0 : return true;
292 0 : }
293 :
294 : /*
295 : * Check if expression is safe to execute remotely, and return true if so.
296 : *
297 : * In addition, *outer_cxt is updated with collation information.
298 : *
299 : * case_arg_cxt is NULL if this subexpression is not inside a CASE-with-arg.
300 : * Otherwise, it points to the collation info derived from the arg expression,
301 : * which must be consulted by any CaseTestExpr.
302 : *
303 : * We must check that the expression contains only node types we can deparse,
304 : * that all types/functions/operators are safe to send (they are "shippable"),
305 : * and that all collations used in the expression derive from Vars of the
306 : * foreign table. Because of the latter, the logic is pretty close to
307 : * assign_collations_walker() in parse_collate.c, though we can assume here
308 : * that the given expression is valid. Note function mutability is not
309 : * currently considered here.
310 : */
311 : static bool
312 0 : foreign_expr_walker(Node *node,
313 : foreign_glob_cxt *glob_cxt,
314 : foreign_loc_cxt *outer_cxt,
315 : foreign_loc_cxt *case_arg_cxt)
316 : {
317 0 : bool check_type = true;
318 0 : PgFdwRelationInfo *fpinfo;
319 0 : foreign_loc_cxt inner_cxt;
320 0 : Oid collation;
321 0 : FDWCollateState state;
322 :
323 : /* Need do nothing for empty subexpressions */
324 0 : if (node == NULL)
325 0 : return true;
326 :
327 : /* May need server info from baserel's fdw_private struct */
328 0 : fpinfo = (PgFdwRelationInfo *) (glob_cxt->foreignrel->fdw_private);
329 :
330 : /* Set up inner_cxt for possible recursion to child nodes */
331 0 : inner_cxt.collation = InvalidOid;
332 0 : inner_cxt.state = FDW_COLLATE_NONE;
333 :
334 0 : switch (nodeTag(node))
335 : {
336 : case T_Var:
337 : {
338 0 : Var *var = (Var *) node;
339 :
340 : /*
341 : * If the Var is from the foreign table, we consider its
342 : * collation (if any) safe to use. If it is from another
343 : * table, we treat its collation the same way as we would a
344 : * Param's collation, ie it's not safe for it to have a
345 : * non-default collation.
346 : */
347 0 : if (bms_is_member(var->varno, glob_cxt->relids) &&
348 0 : var->varlevelsup == 0)
349 : {
350 : /* Var belongs to foreign table */
351 :
352 : /*
353 : * System columns other than ctid should not be sent to
354 : * the remote, since we don't make any effort to ensure
355 : * that local and remote values match (tableoid, in
356 : * particular, almost certainly doesn't match).
357 : */
358 0 : if (var->varattno < 0 &&
359 0 : var->varattno != SelfItemPointerAttributeNumber)
360 0 : return false;
361 :
362 : /* Else check the collation */
363 0 : collation = var->varcollid;
364 0 : state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
365 0 : }
366 : else
367 : {
368 : /* Var belongs to some other table */
369 0 : collation = var->varcollid;
370 0 : if (collation == InvalidOid ||
371 0 : collation == DEFAULT_COLLATION_OID)
372 : {
373 : /*
374 : * It's noncollatable, or it's safe to combine with a
375 : * collatable foreign Var, so set state to NONE.
376 : */
377 0 : state = FDW_COLLATE_NONE;
378 0 : }
379 : else
380 : {
381 : /*
382 : * Do not fail right away, since the Var might appear
383 : * in a collation-insensitive context.
384 : */
385 0 : state = FDW_COLLATE_UNSAFE;
386 : }
387 : }
388 0 : }
389 0 : break;
390 : case T_Const:
391 : {
392 0 : Const *c = (Const *) node;
393 :
394 : /*
395 : * Constants of regproc and related types can't be shipped
396 : * unless the referenced object is shippable. But NULL's ok.
397 : * (See also the related code in dependency.c.)
398 : */
399 0 : if (!c->constisnull)
400 : {
401 0 : switch (c->consttype)
402 : {
403 : case REGPROCOID:
404 : case REGPROCEDUREOID:
405 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
406 0 : ProcedureRelationId, fpinfo))
407 0 : return false;
408 0 : break;
409 : case REGOPEROID:
410 : case REGOPERATOROID:
411 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
412 0 : OperatorRelationId, fpinfo))
413 0 : return false;
414 0 : break;
415 : case REGCLASSOID:
416 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
417 0 : RelationRelationId, fpinfo))
418 0 : return false;
419 0 : break;
420 : case REGTYPEOID:
421 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
422 0 : TypeRelationId, fpinfo))
423 0 : return false;
424 0 : break;
425 : case REGCOLLATIONOID:
426 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
427 0 : CollationRelationId, fpinfo))
428 0 : return false;
429 0 : break;
430 : case REGCONFIGOID:
431 :
432 : /*
433 : * For text search objects only, we weaken the
434 : * normal shippability criterion to allow all OIDs
435 : * below FirstNormalObjectId. Without this, none
436 : * of the initdb-installed TS configurations would
437 : * be shippable, which would be quite annoying.
438 : */
439 0 : if (DatumGetObjectId(c->constvalue) >= FirstNormalObjectId &&
440 0 : !is_shippable(DatumGetObjectId(c->constvalue),
441 0 : TSConfigRelationId, fpinfo))
442 0 : return false;
443 0 : break;
444 : case REGDICTIONARYOID:
445 0 : if (DatumGetObjectId(c->constvalue) >= FirstNormalObjectId &&
446 0 : !is_shippable(DatumGetObjectId(c->constvalue),
447 0 : TSDictionaryRelationId, fpinfo))
448 0 : return false;
449 0 : break;
450 : case REGNAMESPACEOID:
451 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
452 0 : NamespaceRelationId, fpinfo))
453 0 : return false;
454 0 : break;
455 : case REGROLEOID:
456 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
457 0 : AuthIdRelationId, fpinfo))
458 0 : return false;
459 0 : break;
460 : case REGDATABASEOID:
461 0 : if (!is_shippable(DatumGetObjectId(c->constvalue),
462 0 : DatabaseRelationId, fpinfo))
463 0 : return false;
464 0 : break;
465 : }
466 0 : }
467 :
468 : /*
469 : * If the constant has nondefault collation, either it's of a
470 : * non-builtin type, or it reflects folding of a CollateExpr.
471 : * It's unsafe to send to the remote unless it's used in a
472 : * non-collation-sensitive context.
473 : */
474 0 : collation = c->constcollid;
475 0 : if (collation == InvalidOid ||
476 0 : collation == DEFAULT_COLLATION_OID)
477 0 : state = FDW_COLLATE_NONE;
478 : else
479 0 : state = FDW_COLLATE_UNSAFE;
480 0 : }
481 0 : break;
482 : case T_Param:
483 : {
484 0 : Param *p = (Param *) node;
485 :
486 : /*
487 : * If it's a MULTIEXPR Param, punt. We can't tell from here
488 : * whether the referenced sublink/subplan contains any remote
489 : * Vars; if it does, handling that is too complicated to
490 : * consider supporting at present. Fortunately, MULTIEXPR
491 : * Params are not reduced to plain PARAM_EXEC until the end of
492 : * planning, so we can easily detect this case. (Normal
493 : * PARAM_EXEC Params are safe to ship because their values
494 : * come from somewhere else in the plan tree; but a MULTIEXPR
495 : * references a sub-select elsewhere in the same targetlist,
496 : * so we'd be on the hook to evaluate it somehow if we wanted
497 : * to handle such cases as direct foreign updates.)
498 : */
499 0 : if (p->paramkind == PARAM_MULTIEXPR)
500 0 : return false;
501 :
502 : /*
503 : * Collation rule is same as for Consts and non-foreign Vars.
504 : */
505 0 : collation = p->paramcollid;
506 0 : if (collation == InvalidOid ||
507 0 : collation == DEFAULT_COLLATION_OID)
508 0 : state = FDW_COLLATE_NONE;
509 : else
510 0 : state = FDW_COLLATE_UNSAFE;
511 0 : }
512 0 : break;
513 : case T_SubscriptingRef:
514 : {
515 0 : SubscriptingRef *sr = (SubscriptingRef *) node;
516 :
517 : /* Assignment should not be in restrictions. */
518 0 : if (sr->refassgnexpr != NULL)
519 0 : return false;
520 :
521 : /*
522 : * Recurse into the remaining subexpressions. The container
523 : * subscripts will not affect collation of the SubscriptingRef
524 : * result, so do those first and reset inner_cxt afterwards.
525 : */
526 0 : if (!foreign_expr_walker((Node *) sr->refupperindexpr,
527 0 : glob_cxt, &inner_cxt, case_arg_cxt))
528 0 : return false;
529 0 : inner_cxt.collation = InvalidOid;
530 0 : inner_cxt.state = FDW_COLLATE_NONE;
531 0 : if (!foreign_expr_walker((Node *) sr->reflowerindexpr,
532 0 : glob_cxt, &inner_cxt, case_arg_cxt))
533 0 : return false;
534 0 : inner_cxt.collation = InvalidOid;
535 0 : inner_cxt.state = FDW_COLLATE_NONE;
536 0 : if (!foreign_expr_walker((Node *) sr->refexpr,
537 0 : glob_cxt, &inner_cxt, case_arg_cxt))
538 0 : return false;
539 :
540 : /*
541 : * Container subscripting typically yields same collation as
542 : * refexpr's, but in case it doesn't, use same logic as for
543 : * function nodes.
544 : */
545 0 : collation = sr->refcollid;
546 0 : if (collation == InvalidOid)
547 0 : state = FDW_COLLATE_NONE;
548 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
549 0 : collation == inner_cxt.collation)
550 0 : state = FDW_COLLATE_SAFE;
551 0 : else if (collation == DEFAULT_COLLATION_OID)
552 0 : state = FDW_COLLATE_NONE;
553 : else
554 0 : state = FDW_COLLATE_UNSAFE;
555 0 : }
556 0 : break;
557 : case T_FuncExpr:
558 : {
559 0 : FuncExpr *fe = (FuncExpr *) node;
560 :
561 : /*
562 : * If function used by the expression is not shippable, it
563 : * can't be sent to remote because it might have incompatible
564 : * semantics on remote side.
565 : */
566 0 : if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
567 0 : return false;
568 :
569 : /*
570 : * Recurse to input subexpressions.
571 : */
572 0 : if (!foreign_expr_walker((Node *) fe->args,
573 0 : glob_cxt, &inner_cxt, case_arg_cxt))
574 0 : return false;
575 :
576 : /*
577 : * If function's input collation is not derived from a foreign
578 : * Var, it can't be sent to remote.
579 : */
580 0 : if (fe->inputcollid == InvalidOid)
581 : /* OK, inputs are all noncollatable */ ;
582 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
583 0 : fe->inputcollid != inner_cxt.collation)
584 0 : return false;
585 :
586 : /*
587 : * Detect whether node is introducing a collation not derived
588 : * from a foreign Var. (If so, we just mark it unsafe for now
589 : * rather than immediately returning false, since the parent
590 : * node might not care.)
591 : */
592 0 : collation = fe->funccollid;
593 0 : if (collation == InvalidOid)
594 0 : state = FDW_COLLATE_NONE;
595 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
596 0 : collation == inner_cxt.collation)
597 0 : state = FDW_COLLATE_SAFE;
598 0 : else if (collation == DEFAULT_COLLATION_OID)
599 0 : state = FDW_COLLATE_NONE;
600 : else
601 0 : state = FDW_COLLATE_UNSAFE;
602 0 : }
603 0 : break;
604 : case T_OpExpr:
605 : case T_DistinctExpr: /* struct-equivalent to OpExpr */
606 : {
607 0 : OpExpr *oe = (OpExpr *) node;
608 :
609 : /*
610 : * Similarly, only shippable operators can be sent to remote.
611 : * (If the operator is shippable, we assume its underlying
612 : * function is too.)
613 : */
614 0 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
615 0 : return false;
616 :
617 : /*
618 : * Recurse to input subexpressions.
619 : */
620 0 : if (!foreign_expr_walker((Node *) oe->args,
621 0 : glob_cxt, &inner_cxt, case_arg_cxt))
622 0 : return false;
623 :
624 : /*
625 : * If operator's input collation is not derived from a foreign
626 : * Var, it can't be sent to remote.
627 : */
628 0 : if (oe->inputcollid == InvalidOid)
629 : /* OK, inputs are all noncollatable */ ;
630 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
631 0 : oe->inputcollid != inner_cxt.collation)
632 0 : return false;
633 :
634 : /* Result-collation handling is same as for functions */
635 0 : collation = oe->opcollid;
636 0 : if (collation == InvalidOid)
637 0 : state = FDW_COLLATE_NONE;
638 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
639 0 : collation == inner_cxt.collation)
640 0 : state = FDW_COLLATE_SAFE;
641 0 : else if (collation == DEFAULT_COLLATION_OID)
642 0 : state = FDW_COLLATE_NONE;
643 : else
644 0 : state = FDW_COLLATE_UNSAFE;
645 0 : }
646 0 : break;
647 : case T_ScalarArrayOpExpr:
648 : {
649 0 : ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
650 :
651 : /*
652 : * Again, only shippable operators can be sent to remote.
653 : */
654 0 : if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
655 0 : return false;
656 :
657 : /*
658 : * Recurse to input subexpressions.
659 : */
660 0 : if (!foreign_expr_walker((Node *) oe->args,
661 0 : glob_cxt, &inner_cxt, case_arg_cxt))
662 0 : return false;
663 :
664 : /*
665 : * If operator's input collation is not derived from a foreign
666 : * Var, it can't be sent to remote.
667 : */
668 0 : if (oe->inputcollid == InvalidOid)
669 : /* OK, inputs are all noncollatable */ ;
670 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
671 0 : oe->inputcollid != inner_cxt.collation)
672 0 : return false;
673 :
674 : /* Output is always boolean and so noncollatable. */
675 0 : collation = InvalidOid;
676 0 : state = FDW_COLLATE_NONE;
677 0 : }
678 0 : break;
679 : case T_RelabelType:
680 : {
681 0 : RelabelType *r = (RelabelType *) node;
682 :
683 : /*
684 : * Recurse to input subexpression.
685 : */
686 0 : if (!foreign_expr_walker((Node *) r->arg,
687 0 : glob_cxt, &inner_cxt, case_arg_cxt))
688 0 : return false;
689 :
690 : /*
691 : * RelabelType must not introduce a collation not derived from
692 : * an input foreign Var (same logic as for a real function).
693 : */
694 0 : collation = r->resultcollid;
695 0 : if (collation == InvalidOid)
696 0 : state = FDW_COLLATE_NONE;
697 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
698 0 : collation == inner_cxt.collation)
699 0 : state = FDW_COLLATE_SAFE;
700 0 : else if (collation == DEFAULT_COLLATION_OID)
701 0 : state = FDW_COLLATE_NONE;
702 : else
703 0 : state = FDW_COLLATE_UNSAFE;
704 0 : }
705 0 : break;
706 : case T_ArrayCoerceExpr:
707 : {
708 0 : ArrayCoerceExpr *e = (ArrayCoerceExpr *) node;
709 :
710 : /*
711 : * Recurse to input subexpression.
712 : */
713 0 : if (!foreign_expr_walker((Node *) e->arg,
714 0 : glob_cxt, &inner_cxt, case_arg_cxt))
715 0 : return false;
716 :
717 : /*
718 : * T_ArrayCoerceExpr must not introduce a collation not
719 : * derived from an input foreign Var (same logic as for a
720 : * function).
721 : */
722 0 : collation = e->resultcollid;
723 0 : if (collation == InvalidOid)
724 0 : state = FDW_COLLATE_NONE;
725 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
726 0 : collation == inner_cxt.collation)
727 0 : state = FDW_COLLATE_SAFE;
728 0 : else if (collation == DEFAULT_COLLATION_OID)
729 0 : state = FDW_COLLATE_NONE;
730 : else
731 0 : state = FDW_COLLATE_UNSAFE;
732 0 : }
733 0 : break;
734 : case T_BoolExpr:
735 : {
736 0 : BoolExpr *b = (BoolExpr *) node;
737 :
738 : /*
739 : * Recurse to input subexpressions.
740 : */
741 0 : if (!foreign_expr_walker((Node *) b->args,
742 0 : glob_cxt, &inner_cxt, case_arg_cxt))
743 0 : return false;
744 :
745 : /* Output is always boolean and so noncollatable. */
746 0 : collation = InvalidOid;
747 0 : state = FDW_COLLATE_NONE;
748 0 : }
749 0 : break;
750 : case T_NullTest:
751 : {
752 0 : NullTest *nt = (NullTest *) node;
753 :
754 : /*
755 : * Recurse to input subexpressions.
756 : */
757 0 : if (!foreign_expr_walker((Node *) nt->arg,
758 0 : glob_cxt, &inner_cxt, case_arg_cxt))
759 0 : return false;
760 :
761 : /* Output is always boolean and so noncollatable. */
762 0 : collation = InvalidOid;
763 0 : state = FDW_COLLATE_NONE;
764 0 : }
765 0 : break;
766 : case T_CaseExpr:
767 : {
768 0 : CaseExpr *ce = (CaseExpr *) node;
769 0 : foreign_loc_cxt arg_cxt;
770 0 : foreign_loc_cxt tmp_cxt;
771 0 : ListCell *lc;
772 :
773 : /*
774 : * Recurse to CASE's arg expression, if any. Its collation
775 : * has to be saved aside for use while examining CaseTestExprs
776 : * within the WHEN expressions.
777 : */
778 0 : arg_cxt.collation = InvalidOid;
779 0 : arg_cxt.state = FDW_COLLATE_NONE;
780 0 : if (ce->arg)
781 : {
782 0 : if (!foreign_expr_walker((Node *) ce->arg,
783 0 : glob_cxt, &arg_cxt, case_arg_cxt))
784 0 : return false;
785 0 : }
786 :
787 : /* Examine the CaseWhen subexpressions. */
788 0 : foreach(lc, ce->args)
789 : {
790 0 : CaseWhen *cw = lfirst_node(CaseWhen, lc);
791 :
792 0 : if (ce->arg)
793 : {
794 : /*
795 : * In a CASE-with-arg, the parser should have produced
796 : * WHEN clauses of the form "CaseTestExpr = RHS",
797 : * possibly with an implicit coercion inserted above
798 : * the CaseTestExpr. However in an expression that's
799 : * been through the optimizer, the WHEN clause could
800 : * be almost anything (since the equality operator
801 : * could have been expanded into an inline function).
802 : * In such cases forbid pushdown, because
803 : * deparseCaseExpr can't handle it.
804 : */
805 0 : Node *whenExpr = (Node *) cw->expr;
806 0 : List *opArgs;
807 :
808 0 : if (!IsA(whenExpr, OpExpr))
809 0 : return false;
810 :
811 0 : opArgs = ((OpExpr *) whenExpr)->args;
812 0 : if (list_length(opArgs) != 2 ||
813 0 : !IsA(strip_implicit_coercions(linitial(opArgs)),
814 : CaseTestExpr))
815 0 : return false;
816 0 : }
817 :
818 : /*
819 : * Recurse to WHEN expression, passing down the arg info.
820 : * Its collation doesn't affect the result (really, it
821 : * should be boolean and thus not have a collation).
822 : */
823 0 : tmp_cxt.collation = InvalidOid;
824 0 : tmp_cxt.state = FDW_COLLATE_NONE;
825 0 : if (!foreign_expr_walker((Node *) cw->expr,
826 0 : glob_cxt, &tmp_cxt, &arg_cxt))
827 0 : return false;
828 :
829 : /* Recurse to THEN expression. */
830 0 : if (!foreign_expr_walker((Node *) cw->result,
831 0 : glob_cxt, &inner_cxt, case_arg_cxt))
832 0 : return false;
833 0 : }
834 :
835 : /* Recurse to ELSE expression. */
836 0 : if (!foreign_expr_walker((Node *) ce->defresult,
837 0 : glob_cxt, &inner_cxt, case_arg_cxt))
838 0 : return false;
839 :
840 : /*
841 : * Detect whether node is introducing a collation not derived
842 : * from a foreign Var. (If so, we just mark it unsafe for now
843 : * rather than immediately returning false, since the parent
844 : * node might not care.) This is the same as for function
845 : * nodes, except that the input collation is derived from only
846 : * the THEN and ELSE subexpressions.
847 : */
848 0 : collation = ce->casecollid;
849 0 : if (collation == InvalidOid)
850 0 : state = FDW_COLLATE_NONE;
851 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
852 0 : collation == inner_cxt.collation)
853 0 : state = FDW_COLLATE_SAFE;
854 0 : else if (collation == DEFAULT_COLLATION_OID)
855 0 : state = FDW_COLLATE_NONE;
856 : else
857 0 : state = FDW_COLLATE_UNSAFE;
858 0 : }
859 0 : break;
860 : case T_CaseTestExpr:
861 : {
862 0 : CaseTestExpr *c = (CaseTestExpr *) node;
863 :
864 : /* Punt if we seem not to be inside a CASE arg WHEN. */
865 0 : if (!case_arg_cxt)
866 0 : return false;
867 :
868 : /*
869 : * Otherwise, any nondefault collation attached to the
870 : * CaseTestExpr node must be derived from foreign Var(s) in
871 : * the CASE arg.
872 : */
873 0 : collation = c->collation;
874 0 : if (collation == InvalidOid)
875 0 : state = FDW_COLLATE_NONE;
876 0 : else if (case_arg_cxt->state == FDW_COLLATE_SAFE &&
877 0 : collation == case_arg_cxt->collation)
878 0 : state = FDW_COLLATE_SAFE;
879 0 : else if (collation == DEFAULT_COLLATION_OID)
880 0 : state = FDW_COLLATE_NONE;
881 : else
882 0 : state = FDW_COLLATE_UNSAFE;
883 0 : }
884 0 : break;
885 : case T_ArrayExpr:
886 : {
887 0 : ArrayExpr *a = (ArrayExpr *) node;
888 :
889 : /*
890 : * Recurse to input subexpressions.
891 : */
892 0 : if (!foreign_expr_walker((Node *) a->elements,
893 0 : glob_cxt, &inner_cxt, case_arg_cxt))
894 0 : return false;
895 :
896 : /*
897 : * ArrayExpr must not introduce a collation not derived from
898 : * an input foreign Var (same logic as for a function).
899 : */
900 0 : collation = a->array_collid;
901 0 : if (collation == InvalidOid)
902 0 : state = FDW_COLLATE_NONE;
903 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
904 0 : collation == inner_cxt.collation)
905 0 : state = FDW_COLLATE_SAFE;
906 0 : else if (collation == DEFAULT_COLLATION_OID)
907 0 : state = FDW_COLLATE_NONE;
908 : else
909 0 : state = FDW_COLLATE_UNSAFE;
910 0 : }
911 0 : break;
912 : case T_List:
913 : {
914 0 : List *l = (List *) node;
915 0 : ListCell *lc;
916 :
917 : /*
918 : * Recurse to component subexpressions.
919 : */
920 0 : foreach(lc, l)
921 : {
922 0 : if (!foreign_expr_walker((Node *) lfirst(lc),
923 0 : glob_cxt, &inner_cxt, case_arg_cxt))
924 0 : return false;
925 0 : }
926 :
927 : /*
928 : * When processing a list, collation state just bubbles up
929 : * from the list elements.
930 : */
931 0 : collation = inner_cxt.collation;
932 0 : state = inner_cxt.state;
933 :
934 : /* Don't apply exprType() to the list. */
935 0 : check_type = false;
936 0 : }
937 0 : break;
938 : case T_Aggref:
939 : {
940 0 : Aggref *agg = (Aggref *) node;
941 0 : ListCell *lc;
942 :
943 : /* Not safe to pushdown when not in grouping context */
944 0 : if (!IS_UPPER_REL(glob_cxt->foreignrel))
945 0 : return false;
946 :
947 : /* Only non-split aggregates are pushable. */
948 0 : if (agg->aggsplit != AGGSPLIT_SIMPLE)
949 0 : return false;
950 :
951 : /* As usual, it must be shippable. */
952 0 : if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
953 0 : return false;
954 :
955 : /*
956 : * Recurse to input args. aggdirectargs, aggorder and
957 : * aggdistinct are all present in args, so no need to check
958 : * their shippability explicitly.
959 : */
960 0 : foreach(lc, agg->args)
961 : {
962 0 : Node *n = (Node *) lfirst(lc);
963 :
964 : /* If TargetEntry, extract the expression from it */
965 0 : if (IsA(n, TargetEntry))
966 : {
967 0 : TargetEntry *tle = (TargetEntry *) n;
968 :
969 0 : n = (Node *) tle->expr;
970 0 : }
971 :
972 0 : if (!foreign_expr_walker(n,
973 0 : glob_cxt, &inner_cxt, case_arg_cxt))
974 0 : return false;
975 0 : }
976 :
977 : /*
978 : * For aggorder elements, check whether the sort operator, if
979 : * specified, is shippable or not.
980 : */
981 0 : if (agg->aggorder)
982 : {
983 0 : foreach(lc, agg->aggorder)
984 : {
985 0 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
986 0 : Oid sortcoltype;
987 0 : TypeCacheEntry *typentry;
988 0 : TargetEntry *tle;
989 :
990 0 : tle = get_sortgroupref_tle(srt->tleSortGroupRef,
991 0 : agg->args);
992 0 : sortcoltype = exprType((Node *) tle->expr);
993 0 : typentry = lookup_type_cache(sortcoltype,
994 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
995 : /* Check shippability of non-default sort operator. */
996 0 : if (srt->sortop != typentry->lt_opr &&
997 0 : srt->sortop != typentry->gt_opr &&
998 0 : !is_shippable(srt->sortop, OperatorRelationId,
999 0 : fpinfo))
1000 0 : return false;
1001 0 : }
1002 0 : }
1003 :
1004 : /* Check aggregate filter */
1005 0 : if (!foreign_expr_walker((Node *) agg->aggfilter,
1006 0 : glob_cxt, &inner_cxt, case_arg_cxt))
1007 0 : return false;
1008 :
1009 : /*
1010 : * If aggregate's input collation is not derived from a
1011 : * foreign Var, it can't be sent to remote.
1012 : */
1013 0 : if (agg->inputcollid == InvalidOid)
1014 : /* OK, inputs are all noncollatable */ ;
1015 0 : else if (inner_cxt.state != FDW_COLLATE_SAFE ||
1016 0 : agg->inputcollid != inner_cxt.collation)
1017 0 : return false;
1018 :
1019 : /*
1020 : * Detect whether node is introducing a collation not derived
1021 : * from a foreign Var. (If so, we just mark it unsafe for now
1022 : * rather than immediately returning false, since the parent
1023 : * node might not care.)
1024 : */
1025 0 : collation = agg->aggcollid;
1026 0 : if (collation == InvalidOid)
1027 0 : state = FDW_COLLATE_NONE;
1028 0 : else if (inner_cxt.state == FDW_COLLATE_SAFE &&
1029 0 : collation == inner_cxt.collation)
1030 0 : state = FDW_COLLATE_SAFE;
1031 0 : else if (collation == DEFAULT_COLLATION_OID)
1032 0 : state = FDW_COLLATE_NONE;
1033 : else
1034 0 : state = FDW_COLLATE_UNSAFE;
1035 0 : }
1036 0 : break;
1037 : default:
1038 :
1039 : /*
1040 : * If it's anything else, assume it's unsafe. This list can be
1041 : * expanded later, but don't forget to add deparse support below.
1042 : */
1043 0 : return false;
1044 : }
1045 :
1046 : /*
1047 : * If result type of given expression is not shippable, it can't be sent
1048 : * to remote because it might have incompatible semantics on remote side.
1049 : */
1050 0 : if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
1051 0 : return false;
1052 :
1053 : /*
1054 : * Now, merge my collation information into my parent's state.
1055 : */
1056 0 : if (state > outer_cxt->state)
1057 : {
1058 : /* Override previous parent state */
1059 0 : outer_cxt->collation = collation;
1060 0 : outer_cxt->state = state;
1061 0 : }
1062 0 : else if (state == outer_cxt->state)
1063 : {
1064 : /* Merge, or detect error if there's a collation conflict */
1065 0 : switch (state)
1066 : {
1067 : case FDW_COLLATE_NONE:
1068 : /* Nothing + nothing is still nothing */
1069 : break;
1070 : case FDW_COLLATE_SAFE:
1071 0 : if (collation != outer_cxt->collation)
1072 : {
1073 : /*
1074 : * Non-default collation always beats default.
1075 : */
1076 0 : if (outer_cxt->collation == DEFAULT_COLLATION_OID)
1077 : {
1078 : /* Override previous parent state */
1079 0 : outer_cxt->collation = collation;
1080 0 : }
1081 0 : else if (collation != DEFAULT_COLLATION_OID)
1082 : {
1083 : /*
1084 : * Conflict; show state as indeterminate. We don't
1085 : * want to "return false" right away, since parent
1086 : * node might not care about collation.
1087 : */
1088 0 : outer_cxt->state = FDW_COLLATE_UNSAFE;
1089 0 : }
1090 0 : }
1091 0 : break;
1092 : case FDW_COLLATE_UNSAFE:
1093 : /* We're still conflicted ... */
1094 : break;
1095 : }
1096 0 : }
1097 :
1098 : /* It looks OK */
1099 0 : return true;
1100 0 : }
1101 :
1102 : /*
1103 : * Returns true if given expr is something we'd have to send the value of
1104 : * to the foreign server.
1105 : *
1106 : * This should return true when the expression is a shippable node that
1107 : * deparseExpr would add to context->params_list. Note that we don't care
1108 : * if the expression *contains* such a node, only whether one appears at top
1109 : * level. We need this to detect cases where setrefs.c would recognize a
1110 : * false match between an fdw_exprs item (which came from the params_list)
1111 : * and an entry in fdw_scan_tlist (which we're considering putting the given
1112 : * expression into).
1113 : */
1114 : bool
1115 0 : is_foreign_param(PlannerInfo *root,
1116 : RelOptInfo *baserel,
1117 : Expr *expr)
1118 : {
1119 0 : if (expr == NULL)
1120 0 : return false;
1121 :
1122 0 : switch (nodeTag(expr))
1123 : {
1124 : case T_Var:
1125 : {
1126 : /* It would have to be sent unless it's a foreign Var */
1127 0 : Var *var = (Var *) expr;
1128 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
1129 0 : Relids relids;
1130 :
1131 0 : if (IS_UPPER_REL(baserel))
1132 0 : relids = fpinfo->outerrel->relids;
1133 : else
1134 0 : relids = baserel->relids;
1135 :
1136 0 : if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
1137 0 : return false; /* foreign Var, so not a param */
1138 : else
1139 0 : return true; /* it'd have to be a param */
1140 : break;
1141 0 : }
1142 : case T_Param:
1143 : /* Params always have to be sent to the foreign server */
1144 0 : return true;
1145 : default:
1146 0 : break;
1147 : }
1148 0 : return false;
1149 0 : }
1150 :
1151 : /*
1152 : * Returns true if it's safe to push down the sort expression described by
1153 : * 'pathkey' to the foreign server.
1154 : */
1155 : bool
1156 0 : is_foreign_pathkey(PlannerInfo *root,
1157 : RelOptInfo *baserel,
1158 : PathKey *pathkey)
1159 : {
1160 0 : EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
1161 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) baserel->fdw_private;
1162 :
1163 : /*
1164 : * is_foreign_expr would detect volatile expressions as well, but checking
1165 : * ec_has_volatile here saves some cycles.
1166 : */
1167 0 : if (pathkey_ec->ec_has_volatile)
1168 0 : return false;
1169 :
1170 : /* can't push down the sort if the pathkey's opfamily is not shippable */
1171 0 : if (!is_shippable(pathkey->pk_opfamily, OperatorFamilyRelationId, fpinfo))
1172 0 : return false;
1173 :
1174 : /* can push if a suitable EC member exists */
1175 0 : return (find_em_for_rel(root, pathkey_ec, baserel) != NULL);
1176 0 : }
1177 :
1178 : /*
1179 : * Convert type OID + typmod info into a type name we can ship to the remote
1180 : * server. Someplace else had better have verified that this type name is
1181 : * expected to be known on the remote end.
1182 : *
1183 : * This is almost just format_type_with_typemod(), except that if left to its
1184 : * own devices, that function will make schema-qualification decisions based
1185 : * on the local search_path, which is wrong. We must schema-qualify all
1186 : * type names that are not in pg_catalog. We assume here that built-in types
1187 : * are all in pg_catalog and need not be qualified; otherwise, qualify.
1188 : */
1189 : static char *
1190 0 : deparse_type_name(Oid type_oid, int32 typemod)
1191 : {
1192 0 : bits16 flags = FORMAT_TYPE_TYPEMOD_GIVEN;
1193 :
1194 0 : if (!is_builtin(type_oid))
1195 0 : flags |= FORMAT_TYPE_FORCE_QUALIFY;
1196 :
1197 0 : return format_type_extended(type_oid, typemod, flags);
1198 0 : }
1199 :
1200 : /*
1201 : * Build the targetlist for given relation to be deparsed as SELECT clause.
1202 : *
1203 : * The output targetlist contains the columns that need to be fetched from the
1204 : * foreign server for the given relation. If foreignrel is an upper relation,
1205 : * then the output targetlist can also contain expressions to be evaluated on
1206 : * foreign server.
1207 : */
1208 : List *
1209 0 : build_tlist_to_deparse(RelOptInfo *foreignrel)
1210 : {
1211 0 : List *tlist = NIL;
1212 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1213 0 : ListCell *lc;
1214 :
1215 : /*
1216 : * For an upper relation, we have already built the target list while
1217 : * checking shippability, so just return that.
1218 : */
1219 0 : if (IS_UPPER_REL(foreignrel))
1220 0 : return fpinfo->grouped_tlist;
1221 :
1222 : /*
1223 : * We require columns specified in foreignrel->reltarget->exprs and those
1224 : * required for evaluating the local conditions.
1225 : */
1226 0 : tlist = add_to_flat_tlist(tlist,
1227 0 : pull_var_clause((Node *) foreignrel->reltarget->exprs,
1228 : PVC_RECURSE_PLACEHOLDERS));
1229 0 : foreach(lc, fpinfo->local_conds)
1230 : {
1231 0 : RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1232 :
1233 0 : tlist = add_to_flat_tlist(tlist,
1234 0 : pull_var_clause((Node *) rinfo->clause,
1235 : PVC_RECURSE_PLACEHOLDERS));
1236 0 : }
1237 :
1238 0 : return tlist;
1239 0 : }
1240 :
1241 : /*
1242 : * Deparse SELECT statement for given relation into buf.
1243 : *
1244 : * tlist contains the list of desired columns to be fetched from foreign server.
1245 : * For a base relation fpinfo->attrs_used is used to construct SELECT clause,
1246 : * hence the tlist is ignored for a base relation.
1247 : *
1248 : * remote_conds is the list of conditions to be deparsed into the WHERE clause
1249 : * (or, in the case of upper relations, into the HAVING clause).
1250 : *
1251 : * If params_list is not NULL, it receives a list of Params and other-relation
1252 : * Vars used in the clauses; these values must be transmitted to the remote
1253 : * server as parameter values.
1254 : *
1255 : * If params_list is NULL, we're generating the query for EXPLAIN purposes,
1256 : * so Params and other-relation Vars should be replaced by dummy values.
1257 : *
1258 : * pathkeys is the list of pathkeys to order the result by.
1259 : *
1260 : * is_subquery is the flag to indicate whether to deparse the specified
1261 : * relation as a subquery.
1262 : *
1263 : * List of columns selected is returned in retrieved_attrs.
1264 : */
1265 : void
1266 0 : deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
1267 : List *tlist, List *remote_conds, List *pathkeys,
1268 : bool has_final_sort, bool has_limit, bool is_subquery,
1269 : List **retrieved_attrs, List **params_list)
1270 : {
1271 0 : deparse_expr_cxt context;
1272 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1273 0 : List *quals;
1274 :
1275 : /*
1276 : * We handle relations for foreign tables, joins between those and upper
1277 : * relations.
1278 : */
1279 0 : Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel) || IS_UPPER_REL(rel));
1280 :
1281 : /* Fill portions of context common to upper, join and base relation */
1282 0 : context.buf = buf;
1283 0 : context.root = root;
1284 0 : context.foreignrel = rel;
1285 0 : context.scanrel = IS_UPPER_REL(rel) ? fpinfo->outerrel : rel;
1286 0 : context.params_list = params_list;
1287 :
1288 : /* Construct SELECT clause */
1289 0 : deparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
1290 :
1291 : /*
1292 : * For upper relations, the WHERE clause is built from the remote
1293 : * conditions of the underlying scan relation; otherwise, we can use the
1294 : * supplied list of remote conditions directly.
1295 : */
1296 0 : if (IS_UPPER_REL(rel))
1297 : {
1298 0 : PgFdwRelationInfo *ofpinfo;
1299 :
1300 0 : ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
1301 0 : quals = ofpinfo->remote_conds;
1302 0 : }
1303 : else
1304 0 : quals = remote_conds;
1305 :
1306 : /* Construct FROM and WHERE clauses */
1307 0 : deparseFromExpr(quals, &context);
1308 :
1309 0 : if (IS_UPPER_REL(rel))
1310 : {
1311 : /* Append GROUP BY clause */
1312 0 : appendGroupByClause(tlist, &context);
1313 :
1314 : /* Append HAVING clause */
1315 0 : if (remote_conds)
1316 : {
1317 0 : appendStringInfoString(buf, " HAVING ");
1318 0 : appendConditions(remote_conds, &context);
1319 0 : }
1320 0 : }
1321 :
1322 : /* Add ORDER BY clause if we found any useful pathkeys */
1323 0 : if (pathkeys)
1324 0 : appendOrderByClause(pathkeys, has_final_sort, &context);
1325 :
1326 : /* Add LIMIT clause if necessary */
1327 0 : if (has_limit)
1328 0 : appendLimitClause(&context);
1329 :
1330 : /* Add any necessary FOR UPDATE/SHARE. */
1331 0 : deparseLockingClause(&context);
1332 0 : }
1333 :
1334 : /*
1335 : * Construct a simple SELECT statement that retrieves desired columns
1336 : * of the specified foreign table, and append it to "buf". The output
1337 : * contains just "SELECT ... ".
1338 : *
1339 : * We also create an integer List of the columns being retrieved, which is
1340 : * returned to *retrieved_attrs, unless we deparse the specified relation
1341 : * as a subquery.
1342 : *
1343 : * tlist is the list of desired columns. is_subquery is the flag to
1344 : * indicate whether to deparse the specified relation as a subquery.
1345 : * Read prologue of deparseSelectStmtForRel() for details.
1346 : */
1347 : static void
1348 0 : deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
1349 : deparse_expr_cxt *context)
1350 : {
1351 0 : StringInfo buf = context->buf;
1352 0 : RelOptInfo *foreignrel = context->foreignrel;
1353 0 : PlannerInfo *root = context->root;
1354 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1355 :
1356 : /*
1357 : * Construct SELECT list
1358 : */
1359 0 : appendStringInfoString(buf, "SELECT ");
1360 :
1361 0 : if (is_subquery)
1362 : {
1363 : /*
1364 : * For a relation that is deparsed as a subquery, emit expressions
1365 : * specified in the relation's reltarget. Note that since this is for
1366 : * the subquery, no need to care about *retrieved_attrs.
1367 : */
1368 0 : deparseSubqueryTargetList(context);
1369 0 : }
1370 0 : else if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
1371 : {
1372 : /*
1373 : * For a join or upper relation the input tlist gives the list of
1374 : * columns required to be fetched from the foreign server.
1375 : */
1376 0 : deparseExplicitTargetList(tlist, false, retrieved_attrs, context);
1377 0 : }
1378 : else
1379 : {
1380 : /*
1381 : * For a base relation fpinfo->attrs_used gives the list of columns
1382 : * required to be fetched from the foreign server.
1383 : */
1384 0 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1385 :
1386 : /*
1387 : * Core code already has some lock on each rel being planned, so we
1388 : * can use NoLock here.
1389 : */
1390 0 : Relation rel = table_open(rte->relid, NoLock);
1391 :
1392 0 : deparseTargetList(buf, rte, foreignrel->relid, rel, false,
1393 0 : fpinfo->attrs_used, false, retrieved_attrs);
1394 0 : table_close(rel, NoLock);
1395 0 : }
1396 0 : }
1397 :
1398 : /*
1399 : * Construct a FROM clause and, if needed, a WHERE clause, and append those to
1400 : * "buf".
1401 : *
1402 : * quals is the list of clauses to be included in the WHERE clause.
1403 : * (These may or may not include RestrictInfo decoration.)
1404 : */
1405 : static void
1406 0 : deparseFromExpr(List *quals, deparse_expr_cxt *context)
1407 : {
1408 0 : StringInfo buf = context->buf;
1409 0 : RelOptInfo *scanrel = context->scanrel;
1410 0 : List *additional_conds = NIL;
1411 :
1412 : /* For upper relations, scanrel must be either a joinrel or a baserel */
1413 0 : Assert(!IS_UPPER_REL(context->foreignrel) ||
1414 : IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
1415 :
1416 : /* Construct FROM clause */
1417 0 : appendStringInfoString(buf, " FROM ");
1418 0 : deparseFromExprForRel(buf, context->root, scanrel,
1419 0 : (bms_membership(scanrel->relids) == BMS_MULTIPLE),
1420 : (Index) 0, NULL, &additional_conds,
1421 0 : context->params_list);
1422 0 : appendWhereClause(quals, additional_conds, context);
1423 0 : if (additional_conds != NIL)
1424 0 : list_free_deep(additional_conds);
1425 0 : }
1426 :
1427 : /*
1428 : * Emit a target list that retrieves the columns specified in attrs_used.
1429 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1430 : * parameter is true only for a RETURNING targetlist.
1431 : *
1432 : * The tlist text is appended to buf, and we also create an integer List
1433 : * of the columns being retrieved, which is returned to *retrieved_attrs.
1434 : *
1435 : * If qualify_col is true, add relation alias before the column name.
1436 : */
1437 : static void
1438 0 : deparseTargetList(StringInfo buf,
1439 : RangeTblEntry *rte,
1440 : Index rtindex,
1441 : Relation rel,
1442 : bool is_returning,
1443 : Bitmapset *attrs_used,
1444 : bool qualify_col,
1445 : List **retrieved_attrs)
1446 : {
1447 0 : TupleDesc tupdesc = RelationGetDescr(rel);
1448 0 : bool have_wholerow;
1449 0 : bool first;
1450 0 : int i;
1451 :
1452 0 : *retrieved_attrs = NIL;
1453 :
1454 : /* If there's a whole-row reference, we'll need all the columns. */
1455 0 : have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
1456 0 : attrs_used);
1457 :
1458 0 : first = true;
1459 0 : for (i = 1; i <= tupdesc->natts; i++)
1460 : {
1461 : /* Ignore dropped attributes. */
1462 0 : if (TupleDescCompactAttr(tupdesc, i - 1)->attisdropped)
1463 0 : continue;
1464 :
1465 0 : if (have_wholerow ||
1466 0 : bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
1467 0 : attrs_used))
1468 : {
1469 0 : if (!first)
1470 0 : appendStringInfoString(buf, ", ");
1471 0 : else if (is_returning)
1472 0 : appendStringInfoString(buf, " RETURNING ");
1473 0 : first = false;
1474 :
1475 0 : deparseColumnRef(buf, rtindex, i, rte, qualify_col);
1476 :
1477 0 : *retrieved_attrs = lappend_int(*retrieved_attrs, i);
1478 0 : }
1479 0 : }
1480 :
1481 : /*
1482 : * Add ctid if needed. We currently don't support retrieving any other
1483 : * system columns.
1484 : */
1485 0 : if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
1486 0 : attrs_used))
1487 : {
1488 0 : if (!first)
1489 0 : appendStringInfoString(buf, ", ");
1490 0 : else if (is_returning)
1491 0 : appendStringInfoString(buf, " RETURNING ");
1492 0 : first = false;
1493 :
1494 0 : if (qualify_col)
1495 0 : ADD_REL_QUALIFIER(buf, rtindex);
1496 0 : appendStringInfoString(buf, "ctid");
1497 :
1498 0 : *retrieved_attrs = lappend_int(*retrieved_attrs,
1499 : SelfItemPointerAttributeNumber);
1500 0 : }
1501 :
1502 : /* Don't generate bad syntax if no undropped columns */
1503 0 : if (first && !is_returning)
1504 0 : appendStringInfoString(buf, "NULL");
1505 0 : }
1506 :
1507 : /*
1508 : * Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
1509 : * given relation (context->scanrel).
1510 : */
1511 : static void
1512 0 : deparseLockingClause(deparse_expr_cxt *context)
1513 : {
1514 0 : StringInfo buf = context->buf;
1515 0 : PlannerInfo *root = context->root;
1516 0 : RelOptInfo *rel = context->scanrel;
1517 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1518 0 : int relid = -1;
1519 :
1520 0 : while ((relid = bms_next_member(rel->relids, relid)) >= 0)
1521 : {
1522 : /*
1523 : * Ignore relation if it appears in a lower subquery. Locking clause
1524 : * for such a relation is included in the subquery if necessary.
1525 : */
1526 0 : if (bms_is_member(relid, fpinfo->lower_subquery_rels))
1527 0 : continue;
1528 :
1529 : /*
1530 : * Add FOR UPDATE/SHARE if appropriate. We apply locking during the
1531 : * initial row fetch, rather than later on as is done for local
1532 : * tables. The extra roundtrips involved in trying to duplicate the
1533 : * local semantics exactly don't seem worthwhile (see also comments
1534 : * for RowMarkType).
1535 : *
1536 : * Note: because we actually run the query as a cursor, this assumes
1537 : * that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
1538 : * before 8.3.
1539 : */
1540 0 : if (bms_is_member(relid, root->all_result_relids) &&
1541 0 : (root->parse->commandType == CMD_UPDATE ||
1542 0 : root->parse->commandType == CMD_DELETE))
1543 : {
1544 : /* Relation is UPDATE/DELETE target, so use FOR UPDATE */
1545 0 : appendStringInfoString(buf, " FOR UPDATE");
1546 :
1547 : /* Add the relation alias if we are here for a join relation */
1548 0 : if (IS_JOIN_REL(rel))
1549 0 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1550 0 : }
1551 : else
1552 : {
1553 0 : PlanRowMark *rc = get_plan_rowmark(root->rowMarks, relid);
1554 :
1555 0 : if (rc)
1556 : {
1557 : /*
1558 : * Relation is specified as a FOR UPDATE/SHARE target, so
1559 : * handle that. (But we could also see LCS_NONE, meaning this
1560 : * isn't a target relation after all.)
1561 : *
1562 : * For now, just ignore any [NO] KEY specification, since (a)
1563 : * it's not clear what that means for a remote table that we
1564 : * don't have complete information about, and (b) it wouldn't
1565 : * work anyway on older remote servers. Likewise, we don't
1566 : * worry about NOWAIT.
1567 : */
1568 0 : switch (rc->strength)
1569 : {
1570 : case LCS_NONE:
1571 : /* No locking needed */
1572 : break;
1573 : case LCS_FORKEYSHARE:
1574 : case LCS_FORSHARE:
1575 0 : appendStringInfoString(buf, " FOR SHARE");
1576 0 : break;
1577 : case LCS_FORNOKEYUPDATE:
1578 : case LCS_FORUPDATE:
1579 0 : appendStringInfoString(buf, " FOR UPDATE");
1580 0 : break;
1581 : }
1582 :
1583 : /* Add the relation alias if we are here for a join relation */
1584 0 : if (bms_membership(rel->relids) == BMS_MULTIPLE &&
1585 0 : rc->strength != LCS_NONE)
1586 0 : appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1587 0 : }
1588 0 : }
1589 : }
1590 0 : }
1591 :
1592 : /*
1593 : * Deparse conditions from the provided list and append them to buf.
1594 : *
1595 : * The conditions in the list are assumed to be ANDed. This function is used to
1596 : * deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
1597 : *
1598 : * Depending on the caller, the list elements might be either RestrictInfos
1599 : * or bare clauses.
1600 : */
1601 : static void
1602 0 : appendConditions(List *exprs, deparse_expr_cxt *context)
1603 : {
1604 0 : int nestlevel;
1605 0 : ListCell *lc;
1606 0 : bool is_first = true;
1607 0 : StringInfo buf = context->buf;
1608 :
1609 : /* Make sure any constants in the exprs are printed portably */
1610 0 : nestlevel = set_transmission_modes();
1611 :
1612 0 : foreach(lc, exprs)
1613 : {
1614 0 : Expr *expr = (Expr *) lfirst(lc);
1615 :
1616 : /* Extract clause from RestrictInfo, if required */
1617 0 : if (IsA(expr, RestrictInfo))
1618 0 : expr = ((RestrictInfo *) expr)->clause;
1619 :
1620 : /* Connect expressions with "AND" and parenthesize each condition. */
1621 0 : if (!is_first)
1622 0 : appendStringInfoString(buf, " AND ");
1623 :
1624 0 : appendStringInfoChar(buf, '(');
1625 0 : deparseExpr(expr, context);
1626 0 : appendStringInfoChar(buf, ')');
1627 :
1628 0 : is_first = false;
1629 0 : }
1630 :
1631 0 : reset_transmission_modes(nestlevel);
1632 0 : }
1633 :
1634 : /*
1635 : * Append WHERE clause, containing conditions from exprs and additional_conds,
1636 : * to context->buf.
1637 : */
1638 : static void
1639 0 : appendWhereClause(List *exprs, List *additional_conds, deparse_expr_cxt *context)
1640 : {
1641 0 : StringInfo buf = context->buf;
1642 0 : bool need_and = false;
1643 0 : ListCell *lc;
1644 :
1645 0 : if (exprs != NIL || additional_conds != NIL)
1646 0 : appendStringInfoString(buf, " WHERE ");
1647 :
1648 : /*
1649 : * If there are some filters, append them.
1650 : */
1651 0 : if (exprs != NIL)
1652 : {
1653 0 : appendConditions(exprs, context);
1654 0 : need_and = true;
1655 0 : }
1656 :
1657 : /*
1658 : * If there are some EXISTS conditions, coming from SEMI-JOINS, append
1659 : * them.
1660 : */
1661 0 : foreach(lc, additional_conds)
1662 : {
1663 0 : if (need_and)
1664 0 : appendStringInfoString(buf, " AND ");
1665 0 : appendStringInfoString(buf, (char *) lfirst(lc));
1666 0 : need_and = true;
1667 0 : }
1668 0 : }
1669 :
1670 : /* Output join name for given join type */
1671 : const char *
1672 0 : get_jointype_name(JoinType jointype)
1673 : {
1674 0 : switch (jointype)
1675 : {
1676 : case JOIN_INNER:
1677 0 : return "INNER";
1678 :
1679 : case JOIN_LEFT:
1680 0 : return "LEFT";
1681 :
1682 : case JOIN_RIGHT:
1683 0 : return "RIGHT";
1684 :
1685 : case JOIN_FULL:
1686 0 : return "FULL";
1687 :
1688 : case JOIN_SEMI:
1689 0 : return "SEMI";
1690 :
1691 : default:
1692 : /* Shouldn't come here, but protect from buggy code. */
1693 0 : elog(ERROR, "unsupported join type %d", jointype);
1694 0 : }
1695 :
1696 : /* Keep compiler happy */
1697 0 : return NULL;
1698 0 : }
1699 :
1700 : /*
1701 : * Deparse given targetlist and append it to context->buf.
1702 : *
1703 : * tlist is list of TargetEntry's which in turn contain Var nodes.
1704 : *
1705 : * retrieved_attrs is the list of continuously increasing integers starting
1706 : * from 1. It has same number of entries as tlist.
1707 : *
1708 : * This is used for both SELECT and RETURNING targetlists; the is_returning
1709 : * parameter is true only for a RETURNING targetlist.
1710 : */
1711 : static void
1712 0 : deparseExplicitTargetList(List *tlist,
1713 : bool is_returning,
1714 : List **retrieved_attrs,
1715 : deparse_expr_cxt *context)
1716 : {
1717 0 : ListCell *lc;
1718 0 : StringInfo buf = context->buf;
1719 0 : int i = 0;
1720 :
1721 0 : *retrieved_attrs = NIL;
1722 :
1723 0 : foreach(lc, tlist)
1724 : {
1725 0 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
1726 :
1727 0 : if (i > 0)
1728 0 : appendStringInfoString(buf, ", ");
1729 0 : else if (is_returning)
1730 0 : appendStringInfoString(buf, " RETURNING ");
1731 :
1732 0 : deparseExpr((Expr *) tle->expr, context);
1733 :
1734 0 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
1735 0 : i++;
1736 0 : }
1737 :
1738 0 : if (i == 0 && !is_returning)
1739 0 : appendStringInfoString(buf, "NULL");
1740 0 : }
1741 :
1742 : /*
1743 : * Emit expressions specified in the given relation's reltarget.
1744 : *
1745 : * This is used for deparsing the given relation as a subquery.
1746 : */
1747 : static void
1748 0 : deparseSubqueryTargetList(deparse_expr_cxt *context)
1749 : {
1750 0 : StringInfo buf = context->buf;
1751 0 : RelOptInfo *foreignrel = context->foreignrel;
1752 0 : bool first;
1753 0 : ListCell *lc;
1754 :
1755 : /* Should only be called in these cases. */
1756 0 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1757 :
1758 0 : first = true;
1759 0 : foreach(lc, foreignrel->reltarget->exprs)
1760 : {
1761 0 : Node *node = (Node *) lfirst(lc);
1762 :
1763 0 : if (!first)
1764 0 : appendStringInfoString(buf, ", ");
1765 0 : first = false;
1766 :
1767 0 : deparseExpr((Expr *) node, context);
1768 0 : }
1769 :
1770 : /* Don't generate bad syntax if no expressions */
1771 0 : if (first)
1772 0 : appendStringInfoString(buf, "NULL");
1773 0 : }
1774 :
1775 : /*
1776 : * Construct FROM clause for given relation
1777 : *
1778 : * The function constructs ... JOIN ... ON ... for join relation. For a base
1779 : * relation it just returns schema-qualified tablename, with the appropriate
1780 : * alias if so requested.
1781 : *
1782 : * 'ignore_rel' is either zero or the RT index of a target relation. In the
1783 : * latter case the function constructs FROM clause of UPDATE or USING clause
1784 : * of DELETE; it deparses the join relation as if the relation never contained
1785 : * the target relation, and creates a List of conditions to be deparsed into
1786 : * the top-level WHERE clause, which is returned to *ignore_conds.
1787 : *
1788 : * 'additional_conds' is a pointer to a list of strings to be appended to
1789 : * the WHERE clause, coming from lower-level SEMI-JOINs.
1790 : */
1791 : static void
1792 0 : deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1793 : bool use_alias, Index ignore_rel, List **ignore_conds,
1794 : List **additional_conds, List **params_list)
1795 : {
1796 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1797 :
1798 0 : if (IS_JOIN_REL(foreignrel))
1799 : {
1800 0 : StringInfoData join_sql_o;
1801 0 : StringInfoData join_sql_i;
1802 0 : RelOptInfo *outerrel = fpinfo->outerrel;
1803 0 : RelOptInfo *innerrel = fpinfo->innerrel;
1804 0 : bool outerrel_is_target = false;
1805 0 : bool innerrel_is_target = false;
1806 0 : List *additional_conds_i = NIL;
1807 0 : List *additional_conds_o = NIL;
1808 :
1809 0 : if (ignore_rel > 0 && bms_is_member(ignore_rel, foreignrel->relids))
1810 : {
1811 : /*
1812 : * If this is an inner join, add joinclauses to *ignore_conds and
1813 : * set it to empty so that those can be deparsed into the WHERE
1814 : * clause. Note that since the target relation can never be
1815 : * within the nullable side of an outer join, those could safely
1816 : * be pulled up into the WHERE clause (see foreign_join_ok()).
1817 : * Note also that since the target relation is only inner-joined
1818 : * to any other relation in the query, all conditions in the join
1819 : * tree mentioning the target relation could be deparsed into the
1820 : * WHERE clause by doing this recursively.
1821 : */
1822 0 : if (fpinfo->jointype == JOIN_INNER)
1823 : {
1824 0 : *ignore_conds = list_concat(*ignore_conds,
1825 0 : fpinfo->joinclauses);
1826 0 : fpinfo->joinclauses = NIL;
1827 0 : }
1828 :
1829 : /*
1830 : * Check if either of the input relations is the target relation.
1831 : */
1832 0 : if (outerrel->relid == ignore_rel)
1833 0 : outerrel_is_target = true;
1834 0 : else if (innerrel->relid == ignore_rel)
1835 0 : innerrel_is_target = true;
1836 0 : }
1837 :
1838 : /* Deparse outer relation if not the target relation. */
1839 0 : if (!outerrel_is_target)
1840 : {
1841 0 : initStringInfo(&join_sql_o);
1842 0 : deparseRangeTblRef(&join_sql_o, root, outerrel,
1843 0 : fpinfo->make_outerrel_subquery,
1844 0 : ignore_rel, ignore_conds, &additional_conds_o,
1845 0 : params_list);
1846 :
1847 : /*
1848 : * If inner relation is the target relation, skip deparsing it.
1849 : * Note that since the join of the target relation with any other
1850 : * relation in the query is an inner join and can never be within
1851 : * the nullable side of an outer join, the join could be
1852 : * interchanged with higher-level joins (cf. identity 1 on outer
1853 : * join reordering shown in src/backend/optimizer/README), which
1854 : * means it's safe to skip the target-relation deparsing here.
1855 : */
1856 0 : if (innerrel_is_target)
1857 : {
1858 0 : Assert(fpinfo->jointype == JOIN_INNER);
1859 0 : Assert(fpinfo->joinclauses == NIL);
1860 0 : appendBinaryStringInfo(buf, join_sql_o.data, join_sql_o.len);
1861 : /* Pass EXISTS conditions to upper level */
1862 0 : if (additional_conds_o != NIL)
1863 : {
1864 0 : Assert(*additional_conds == NIL);
1865 0 : *additional_conds = additional_conds_o;
1866 0 : }
1867 0 : return;
1868 : }
1869 0 : }
1870 :
1871 : /* Deparse inner relation if not the target relation. */
1872 0 : if (!innerrel_is_target)
1873 : {
1874 0 : initStringInfo(&join_sql_i);
1875 0 : deparseRangeTblRef(&join_sql_i, root, innerrel,
1876 0 : fpinfo->make_innerrel_subquery,
1877 0 : ignore_rel, ignore_conds, &additional_conds_i,
1878 0 : params_list);
1879 :
1880 : /*
1881 : * SEMI-JOIN is deparsed as the EXISTS subquery. It references
1882 : * outer and inner relations, so it should be evaluated as the
1883 : * condition in the upper-level WHERE clause. We deparse the
1884 : * condition and pass it to upper level callers as an
1885 : * additional_conds list. Upper level callers are responsible for
1886 : * inserting conditions from the list where appropriate.
1887 : */
1888 0 : if (fpinfo->jointype == JOIN_SEMI)
1889 : {
1890 0 : deparse_expr_cxt context;
1891 0 : StringInfoData str;
1892 :
1893 : /* Construct deparsed condition from this SEMI-JOIN */
1894 0 : initStringInfo(&str);
1895 0 : appendStringInfo(&str, "EXISTS (SELECT NULL FROM %s",
1896 0 : join_sql_i.data);
1897 :
1898 0 : context.buf = &str;
1899 0 : context.foreignrel = foreignrel;
1900 0 : context.scanrel = foreignrel;
1901 0 : context.root = root;
1902 0 : context.params_list = params_list;
1903 :
1904 : /*
1905 : * Append SEMI-JOIN clauses and EXISTS conditions from lower
1906 : * levels to the current EXISTS subquery
1907 : */
1908 0 : appendWhereClause(fpinfo->joinclauses, additional_conds_i, &context);
1909 :
1910 : /*
1911 : * EXISTS conditions, coming from lower join levels, have just
1912 : * been processed.
1913 : */
1914 0 : if (additional_conds_i != NIL)
1915 : {
1916 0 : list_free_deep(additional_conds_i);
1917 0 : additional_conds_i = NIL;
1918 0 : }
1919 :
1920 : /* Close parentheses for EXISTS subquery */
1921 0 : appendStringInfoChar(&str, ')');
1922 :
1923 0 : *additional_conds = lappend(*additional_conds, str.data);
1924 0 : }
1925 :
1926 : /*
1927 : * If outer relation is the target relation, skip deparsing it.
1928 : * See the above note about safety.
1929 : */
1930 0 : if (outerrel_is_target)
1931 : {
1932 0 : Assert(fpinfo->jointype == JOIN_INNER);
1933 0 : Assert(fpinfo->joinclauses == NIL);
1934 0 : appendBinaryStringInfo(buf, join_sql_i.data, join_sql_i.len);
1935 : /* Pass EXISTS conditions to the upper call */
1936 0 : if (additional_conds_i != NIL)
1937 : {
1938 0 : Assert(*additional_conds == NIL);
1939 0 : *additional_conds = additional_conds_i;
1940 0 : }
1941 0 : return;
1942 : }
1943 0 : }
1944 :
1945 : /* Neither of the relations is the target relation. */
1946 0 : Assert(!outerrel_is_target && !innerrel_is_target);
1947 :
1948 : /*
1949 : * For semijoin FROM clause is deparsed as an outer relation. An inner
1950 : * relation and join clauses are converted to EXISTS condition and
1951 : * passed to the upper level.
1952 : */
1953 0 : if (fpinfo->jointype == JOIN_SEMI)
1954 : {
1955 0 : appendBinaryStringInfo(buf, join_sql_o.data, join_sql_o.len);
1956 0 : }
1957 : else
1958 : {
1959 : /*
1960 : * For a join relation FROM clause, entry is deparsed as
1961 : *
1962 : * ((outer relation) <join type> (inner relation) ON
1963 : * (joinclauses))
1964 : */
1965 0 : appendStringInfo(buf, "(%s %s JOIN %s ON ", join_sql_o.data,
1966 0 : get_jointype_name(fpinfo->jointype), join_sql_i.data);
1967 :
1968 : /* Append join clause; (TRUE) if no join clause */
1969 0 : if (fpinfo->joinclauses)
1970 : {
1971 0 : deparse_expr_cxt context;
1972 :
1973 0 : context.buf = buf;
1974 0 : context.foreignrel = foreignrel;
1975 0 : context.scanrel = foreignrel;
1976 0 : context.root = root;
1977 0 : context.params_list = params_list;
1978 :
1979 0 : appendStringInfoChar(buf, '(');
1980 0 : appendConditions(fpinfo->joinclauses, &context);
1981 0 : appendStringInfoChar(buf, ')');
1982 0 : }
1983 : else
1984 0 : appendStringInfoString(buf, "(TRUE)");
1985 :
1986 : /* End the FROM clause entry. */
1987 0 : appendStringInfoChar(buf, ')');
1988 : }
1989 :
1990 : /*
1991 : * Construct additional_conds to be passed to the upper caller from
1992 : * current level additional_conds and additional_conds, coming from
1993 : * inner and outer rels.
1994 : */
1995 0 : if (additional_conds_o != NIL)
1996 : {
1997 0 : *additional_conds = list_concat(*additional_conds,
1998 0 : additional_conds_o);
1999 0 : list_free(additional_conds_o);
2000 0 : }
2001 :
2002 0 : if (additional_conds_i != NIL)
2003 : {
2004 0 : *additional_conds = list_concat(*additional_conds,
2005 0 : additional_conds_i);
2006 0 : list_free(additional_conds_i);
2007 0 : }
2008 0 : }
2009 : else
2010 : {
2011 0 : RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
2012 :
2013 : /*
2014 : * Core code already has some lock on each rel being planned, so we
2015 : * can use NoLock here.
2016 : */
2017 0 : Relation rel = table_open(rte->relid, NoLock);
2018 :
2019 0 : deparseRelation(buf, rel);
2020 :
2021 : /*
2022 : * Add a unique alias to avoid any conflict in relation names due to
2023 : * pulled up subqueries in the query being built for a pushed down
2024 : * join.
2025 : */
2026 0 : if (use_alias)
2027 0 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, foreignrel->relid);
2028 :
2029 0 : table_close(rel, NoLock);
2030 0 : }
2031 0 : }
2032 :
2033 : /*
2034 : * Append FROM clause entry for the given relation into buf.
2035 : * Conditions from lower-level SEMI-JOINs are appended to additional_conds
2036 : * and should be added to upper level WHERE clause.
2037 : */
2038 : static void
2039 0 : deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
2040 : bool make_subquery, Index ignore_rel, List **ignore_conds,
2041 : List **additional_conds, List **params_list)
2042 : {
2043 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
2044 :
2045 : /* Should only be called in these cases. */
2046 0 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
2047 :
2048 0 : Assert(fpinfo->local_conds == NIL);
2049 :
2050 : /* If make_subquery is true, deparse the relation as a subquery. */
2051 0 : if (make_subquery)
2052 : {
2053 0 : List *retrieved_attrs;
2054 0 : int ncols;
2055 :
2056 : /*
2057 : * The given relation shouldn't contain the target relation, because
2058 : * this should only happen for input relations for a full join, and
2059 : * such relations can never contain an UPDATE/DELETE target.
2060 : */
2061 0 : Assert(ignore_rel == 0 ||
2062 : !bms_is_member(ignore_rel, foreignrel->relids));
2063 :
2064 : /* Deparse the subquery representing the relation. */
2065 0 : appendStringInfoChar(buf, '(');
2066 0 : deparseSelectStmtForRel(buf, root, foreignrel, NIL,
2067 0 : fpinfo->remote_conds, NIL,
2068 : false, false, true,
2069 0 : &retrieved_attrs, params_list);
2070 0 : appendStringInfoChar(buf, ')');
2071 :
2072 : /* Append the relation alias. */
2073 0 : appendStringInfo(buf, " %s%d", SUBQUERY_REL_ALIAS_PREFIX,
2074 0 : fpinfo->relation_index);
2075 :
2076 : /*
2077 : * Append the column aliases if needed. Note that the subquery emits
2078 : * expressions specified in the relation's reltarget (see
2079 : * deparseSubqueryTargetList).
2080 : */
2081 0 : ncols = list_length(foreignrel->reltarget->exprs);
2082 0 : if (ncols > 0)
2083 : {
2084 0 : int i;
2085 :
2086 0 : appendStringInfoChar(buf, '(');
2087 0 : for (i = 1; i <= ncols; i++)
2088 : {
2089 0 : if (i > 1)
2090 0 : appendStringInfoString(buf, ", ");
2091 :
2092 0 : appendStringInfo(buf, "%s%d", SUBQUERY_COL_ALIAS_PREFIX, i);
2093 0 : }
2094 0 : appendStringInfoChar(buf, ')');
2095 0 : }
2096 0 : }
2097 : else
2098 0 : deparseFromExprForRel(buf, root, foreignrel, true, ignore_rel,
2099 0 : ignore_conds, additional_conds,
2100 0 : params_list);
2101 0 : }
2102 :
2103 : /*
2104 : * deparse remote INSERT statement
2105 : *
2106 : * The statement text is appended to buf, and we also create an integer List
2107 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
2108 : * which is returned to *retrieved_attrs.
2109 : *
2110 : * This also stores end position of the VALUES clause, so that we can rebuild
2111 : * an INSERT for a batch of rows later.
2112 : */
2113 : void
2114 0 : deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
2115 : Index rtindex, Relation rel,
2116 : List *targetAttrs, bool doNothing,
2117 : List *withCheckOptionList, List *returningList,
2118 : List **retrieved_attrs, int *values_end_len)
2119 : {
2120 0 : TupleDesc tupdesc = RelationGetDescr(rel);
2121 0 : AttrNumber pindex;
2122 0 : bool first;
2123 0 : ListCell *lc;
2124 :
2125 0 : appendStringInfoString(buf, "INSERT INTO ");
2126 0 : deparseRelation(buf, rel);
2127 :
2128 0 : if (targetAttrs)
2129 : {
2130 0 : appendStringInfoChar(buf, '(');
2131 :
2132 0 : first = true;
2133 0 : foreach(lc, targetAttrs)
2134 : {
2135 0 : int attnum = lfirst_int(lc);
2136 :
2137 0 : if (!first)
2138 0 : appendStringInfoString(buf, ", ");
2139 0 : first = false;
2140 :
2141 0 : deparseColumnRef(buf, rtindex, attnum, rte, false);
2142 0 : }
2143 :
2144 0 : appendStringInfoString(buf, ") VALUES (");
2145 :
2146 0 : pindex = 1;
2147 0 : first = true;
2148 0 : foreach(lc, targetAttrs)
2149 : {
2150 0 : int attnum = lfirst_int(lc);
2151 0 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
2152 :
2153 0 : if (!first)
2154 0 : appendStringInfoString(buf, ", ");
2155 0 : first = false;
2156 :
2157 0 : if (attr->attgenerated)
2158 0 : appendStringInfoString(buf, "DEFAULT");
2159 : else
2160 : {
2161 0 : appendStringInfo(buf, "$%d", pindex);
2162 0 : pindex++;
2163 : }
2164 0 : }
2165 :
2166 0 : appendStringInfoChar(buf, ')');
2167 0 : }
2168 : else
2169 0 : appendStringInfoString(buf, " DEFAULT VALUES");
2170 0 : *values_end_len = buf->len;
2171 :
2172 0 : if (doNothing)
2173 0 : appendStringInfoString(buf, " ON CONFLICT DO NOTHING");
2174 :
2175 0 : deparseReturningList(buf, rte, rtindex, rel,
2176 0 : rel->trigdesc && rel->trigdesc->trig_insert_after_row,
2177 0 : withCheckOptionList, returningList, retrieved_attrs);
2178 0 : }
2179 :
2180 : /*
2181 : * rebuild remote INSERT statement
2182 : *
2183 : * Provided a number of rows in a batch, builds INSERT statement with the
2184 : * right number of parameters.
2185 : */
2186 : void
2187 0 : rebuildInsertSql(StringInfo buf, Relation rel,
2188 : char *orig_query, List *target_attrs,
2189 : int values_end_len, int num_params,
2190 : int num_rows)
2191 : {
2192 0 : TupleDesc tupdesc = RelationGetDescr(rel);
2193 0 : int i;
2194 0 : int pindex;
2195 0 : bool first;
2196 0 : ListCell *lc;
2197 :
2198 : /* Make sure the values_end_len is sensible */
2199 0 : Assert((values_end_len > 0) && (values_end_len <= strlen(orig_query)));
2200 :
2201 : /* Copy up to the end of the first record from the original query */
2202 0 : appendBinaryStringInfo(buf, orig_query, values_end_len);
2203 :
2204 : /*
2205 : * Add records to VALUES clause (we already have parameters for the first
2206 : * row, so start at the right offset).
2207 : */
2208 0 : pindex = num_params + 1;
2209 0 : for (i = 0; i < num_rows; i++)
2210 : {
2211 0 : appendStringInfoString(buf, ", (");
2212 :
2213 0 : first = true;
2214 0 : foreach(lc, target_attrs)
2215 : {
2216 0 : int attnum = lfirst_int(lc);
2217 0 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
2218 :
2219 0 : if (!first)
2220 0 : appendStringInfoString(buf, ", ");
2221 0 : first = false;
2222 :
2223 0 : if (attr->attgenerated)
2224 0 : appendStringInfoString(buf, "DEFAULT");
2225 : else
2226 : {
2227 0 : appendStringInfo(buf, "$%d", pindex);
2228 0 : pindex++;
2229 : }
2230 0 : }
2231 :
2232 0 : appendStringInfoChar(buf, ')');
2233 0 : }
2234 :
2235 : /* Copy stuff after VALUES clause from the original query */
2236 0 : appendStringInfoString(buf, orig_query + values_end_len);
2237 0 : }
2238 :
2239 : /*
2240 : * deparse remote UPDATE statement
2241 : *
2242 : * The statement text is appended to buf, and we also create an integer List
2243 : * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
2244 : * which is returned to *retrieved_attrs.
2245 : */
2246 : void
2247 0 : deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
2248 : Index rtindex, Relation rel,
2249 : List *targetAttrs,
2250 : List *withCheckOptionList, List *returningList,
2251 : List **retrieved_attrs)
2252 : {
2253 0 : TupleDesc tupdesc = RelationGetDescr(rel);
2254 0 : AttrNumber pindex;
2255 0 : bool first;
2256 0 : ListCell *lc;
2257 :
2258 0 : appendStringInfoString(buf, "UPDATE ");
2259 0 : deparseRelation(buf, rel);
2260 0 : appendStringInfoString(buf, " SET ");
2261 :
2262 0 : pindex = 2; /* ctid is always the first param */
2263 0 : first = true;
2264 0 : foreach(lc, targetAttrs)
2265 : {
2266 0 : int attnum = lfirst_int(lc);
2267 0 : CompactAttribute *attr = TupleDescCompactAttr(tupdesc, attnum - 1);
2268 :
2269 0 : if (!first)
2270 0 : appendStringInfoString(buf, ", ");
2271 0 : first = false;
2272 :
2273 0 : deparseColumnRef(buf, rtindex, attnum, rte, false);
2274 0 : if (attr->attgenerated)
2275 0 : appendStringInfoString(buf, " = DEFAULT");
2276 : else
2277 : {
2278 0 : appendStringInfo(buf, " = $%d", pindex);
2279 0 : pindex++;
2280 : }
2281 0 : }
2282 0 : appendStringInfoString(buf, " WHERE ctid = $1");
2283 :
2284 0 : deparseReturningList(buf, rte, rtindex, rel,
2285 0 : rel->trigdesc && rel->trigdesc->trig_update_after_row,
2286 0 : withCheckOptionList, returningList, retrieved_attrs);
2287 0 : }
2288 :
2289 : /*
2290 : * deparse remote UPDATE statement
2291 : *
2292 : * 'buf' is the output buffer to append the statement to
2293 : * 'rtindex' is the RT index of the associated target relation
2294 : * 'rel' is the relation descriptor for the target relation
2295 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
2296 : * containing all base relations in the query
2297 : * 'targetlist' is the tlist of the underlying foreign-scan plan node
2298 : * (note that this only contains new-value expressions and junk attrs)
2299 : * 'targetAttrs' is the target columns of the UPDATE
2300 : * 'remote_conds' is the qual clauses that must be evaluated remotely
2301 : * '*params_list' is an output list of exprs that will become remote Params
2302 : * 'returningList' is the RETURNING targetlist
2303 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
2304 : * by RETURNING (if any)
2305 : */
2306 : void
2307 0 : deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
2308 : Index rtindex, Relation rel,
2309 : RelOptInfo *foreignrel,
2310 : List *targetlist,
2311 : List *targetAttrs,
2312 : List *remote_conds,
2313 : List **params_list,
2314 : List *returningList,
2315 : List **retrieved_attrs)
2316 : {
2317 0 : deparse_expr_cxt context;
2318 0 : int nestlevel;
2319 0 : bool first;
2320 0 : RangeTblEntry *rte = planner_rt_fetch(rtindex, root);
2321 0 : ListCell *lc,
2322 : *lc2;
2323 0 : List *additional_conds = NIL;
2324 :
2325 : /* Set up context struct for recursion */
2326 0 : context.root = root;
2327 0 : context.foreignrel = foreignrel;
2328 0 : context.scanrel = foreignrel;
2329 0 : context.buf = buf;
2330 0 : context.params_list = params_list;
2331 :
2332 0 : appendStringInfoString(buf, "UPDATE ");
2333 0 : deparseRelation(buf, rel);
2334 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2335 0 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
2336 0 : appendStringInfoString(buf, " SET ");
2337 :
2338 : /* Make sure any constants in the exprs are printed portably */
2339 0 : nestlevel = set_transmission_modes();
2340 :
2341 0 : first = true;
2342 0 : forboth(lc, targetlist, lc2, targetAttrs)
2343 : {
2344 0 : TargetEntry *tle = lfirst_node(TargetEntry, lc);
2345 0 : int attnum = lfirst_int(lc2);
2346 :
2347 : /* update's new-value expressions shouldn't be resjunk */
2348 0 : Assert(!tle->resjunk);
2349 :
2350 0 : if (!first)
2351 0 : appendStringInfoString(buf, ", ");
2352 0 : first = false;
2353 :
2354 0 : deparseColumnRef(buf, rtindex, attnum, rte, false);
2355 0 : appendStringInfoString(buf, " = ");
2356 0 : deparseExpr((Expr *) tle->expr, &context);
2357 0 : }
2358 :
2359 0 : reset_transmission_modes(nestlevel);
2360 :
2361 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2362 : {
2363 0 : List *ignore_conds = NIL;
2364 :
2365 :
2366 0 : appendStringInfoString(buf, " FROM ");
2367 0 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
2368 0 : &ignore_conds, &additional_conds, params_list);
2369 0 : remote_conds = list_concat(remote_conds, ignore_conds);
2370 0 : }
2371 :
2372 0 : appendWhereClause(remote_conds, additional_conds, &context);
2373 :
2374 0 : if (additional_conds != NIL)
2375 0 : list_free_deep(additional_conds);
2376 :
2377 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2378 0 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
2379 : &context);
2380 : else
2381 0 : deparseReturningList(buf, rte, rtindex, rel, false,
2382 0 : NIL, returningList, retrieved_attrs);
2383 0 : }
2384 :
2385 : /*
2386 : * deparse remote DELETE statement
2387 : *
2388 : * The statement text is appended to buf, and we also create an integer List
2389 : * of the columns being retrieved by RETURNING (if any), which is returned
2390 : * to *retrieved_attrs.
2391 : */
2392 : void
2393 0 : deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
2394 : Index rtindex, Relation rel,
2395 : List *returningList,
2396 : List **retrieved_attrs)
2397 : {
2398 0 : appendStringInfoString(buf, "DELETE FROM ");
2399 0 : deparseRelation(buf, rel);
2400 0 : appendStringInfoString(buf, " WHERE ctid = $1");
2401 :
2402 0 : deparseReturningList(buf, rte, rtindex, rel,
2403 0 : rel->trigdesc && rel->trigdesc->trig_delete_after_row,
2404 0 : NIL, returningList, retrieved_attrs);
2405 0 : }
2406 :
2407 : /*
2408 : * deparse remote DELETE statement
2409 : *
2410 : * 'buf' is the output buffer to append the statement to
2411 : * 'rtindex' is the RT index of the associated target relation
2412 : * 'rel' is the relation descriptor for the target relation
2413 : * 'foreignrel' is the RelOptInfo for the target relation or the join relation
2414 : * containing all base relations in the query
2415 : * 'remote_conds' is the qual clauses that must be evaluated remotely
2416 : * '*params_list' is an output list of exprs that will become remote Params
2417 : * 'returningList' is the RETURNING targetlist
2418 : * '*retrieved_attrs' is an output list of integers of columns being retrieved
2419 : * by RETURNING (if any)
2420 : */
2421 : void
2422 0 : deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
2423 : Index rtindex, Relation rel,
2424 : RelOptInfo *foreignrel,
2425 : List *remote_conds,
2426 : List **params_list,
2427 : List *returningList,
2428 : List **retrieved_attrs)
2429 : {
2430 0 : deparse_expr_cxt context;
2431 0 : List *additional_conds = NIL;
2432 :
2433 : /* Set up context struct for recursion */
2434 0 : context.root = root;
2435 0 : context.foreignrel = foreignrel;
2436 0 : context.scanrel = foreignrel;
2437 0 : context.buf = buf;
2438 0 : context.params_list = params_list;
2439 :
2440 0 : appendStringInfoString(buf, "DELETE FROM ");
2441 0 : deparseRelation(buf, rel);
2442 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2443 0 : appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
2444 :
2445 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2446 : {
2447 0 : List *ignore_conds = NIL;
2448 :
2449 0 : appendStringInfoString(buf, " USING ");
2450 0 : deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
2451 0 : &ignore_conds, &additional_conds, params_list);
2452 0 : remote_conds = list_concat(remote_conds, ignore_conds);
2453 0 : }
2454 :
2455 0 : appendWhereClause(remote_conds, additional_conds, &context);
2456 :
2457 0 : if (additional_conds != NIL)
2458 0 : list_free_deep(additional_conds);
2459 :
2460 0 : if (foreignrel->reloptkind == RELOPT_JOINREL)
2461 0 : deparseExplicitTargetList(returningList, true, retrieved_attrs,
2462 : &context);
2463 : else
2464 0 : deparseReturningList(buf, planner_rt_fetch(rtindex, root),
2465 0 : rtindex, rel, false,
2466 0 : NIL, returningList, retrieved_attrs);
2467 0 : }
2468 :
2469 : /*
2470 : * Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
2471 : */
2472 : static void
2473 0 : deparseReturningList(StringInfo buf, RangeTblEntry *rte,
2474 : Index rtindex, Relation rel,
2475 : bool trig_after_row,
2476 : List *withCheckOptionList,
2477 : List *returningList,
2478 : List **retrieved_attrs)
2479 : {
2480 0 : Bitmapset *attrs_used = NULL;
2481 :
2482 0 : if (trig_after_row)
2483 : {
2484 : /* whole-row reference acquires all non-system columns */
2485 0 : attrs_used =
2486 0 : bms_make_singleton(0 - FirstLowInvalidHeapAttributeNumber);
2487 0 : }
2488 :
2489 0 : if (withCheckOptionList != NIL)
2490 : {
2491 : /*
2492 : * We need the attrs, non-system and system, mentioned in the local
2493 : * query's WITH CHECK OPTION list.
2494 : *
2495 : * Note: we do this to ensure that WCO constraints will be evaluated
2496 : * on the data actually inserted/updated on the remote side, which
2497 : * might differ from the data supplied by the core code, for example
2498 : * as a result of remote triggers.
2499 : */
2500 0 : pull_varattnos((Node *) withCheckOptionList, rtindex,
2501 : &attrs_used);
2502 0 : }
2503 :
2504 0 : if (returningList != NIL)
2505 : {
2506 : /*
2507 : * We need the attrs, non-system and system, mentioned in the local
2508 : * query's RETURNING list.
2509 : */
2510 0 : pull_varattnos((Node *) returningList, rtindex,
2511 : &attrs_used);
2512 0 : }
2513 :
2514 0 : if (attrs_used != NULL)
2515 0 : deparseTargetList(buf, rte, rtindex, rel, true, attrs_used, false,
2516 0 : retrieved_attrs);
2517 : else
2518 0 : *retrieved_attrs = NIL;
2519 0 : }
2520 :
2521 : /*
2522 : * Construct SELECT statement to acquire size in blocks of given relation.
2523 : *
2524 : * Note: we use local definition of block size, not remote definition.
2525 : * This is perhaps debatable.
2526 : *
2527 : * Note: pg_relation_size() exists in 8.1 and later.
2528 : */
2529 : void
2530 0 : deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
2531 : {
2532 0 : StringInfoData relname;
2533 :
2534 : /* We'll need the remote relation name as a literal. */
2535 0 : initStringInfo(&relname);
2536 0 : deparseRelation(&relname, rel);
2537 :
2538 0 : appendStringInfoString(buf, "SELECT pg_catalog.pg_relation_size(");
2539 0 : deparseStringLiteral(buf, relname.data);
2540 0 : appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
2541 0 : }
2542 :
2543 : /*
2544 : * Construct SELECT statement to acquire the number of rows and the relkind of
2545 : * a relation.
2546 : *
2547 : * Note: we just return the remote server's reltuples value, which might
2548 : * be off a good deal, but it doesn't seem worth working harder. See
2549 : * comments in postgresAcquireSampleRowsFunc.
2550 : */
2551 : void
2552 0 : deparseAnalyzeInfoSql(StringInfo buf, Relation rel)
2553 : {
2554 0 : StringInfoData relname;
2555 :
2556 : /* We'll need the remote relation name as a literal. */
2557 0 : initStringInfo(&relname);
2558 0 : deparseRelation(&relname, rel);
2559 :
2560 0 : appendStringInfoString(buf, "SELECT reltuples, relkind FROM pg_catalog.pg_class WHERE oid = ");
2561 0 : deparseStringLiteral(buf, relname.data);
2562 0 : appendStringInfoString(buf, "::pg_catalog.regclass");
2563 0 : }
2564 :
2565 : /*
2566 : * Construct SELECT statement to acquire sample rows of given relation.
2567 : *
2568 : * SELECT command is appended to buf, and list of columns retrieved
2569 : * is returned to *retrieved_attrs.
2570 : *
2571 : * We only support sampling methods we can decide based on server version.
2572 : * Allowing custom TSM modules (like tsm_system_rows) might be useful, but it
2573 : * would require detecting which extensions are installed, to allow automatic
2574 : * fall-back. Moreover, the methods may use different parameters like number
2575 : * of rows (and not sampling rate). So we leave this for future improvements.
2576 : *
2577 : * Using random() to sample rows on the remote server has the advantage that
2578 : * this works on all PostgreSQL versions (unlike TABLESAMPLE), and that it
2579 : * does the sampling on the remote side (without transferring everything and
2580 : * then discarding most rows).
2581 : *
2582 : * The disadvantage is that we still have to read all rows and evaluate the
2583 : * random(), while TABLESAMPLE (at least with the "system" method) may skip.
2584 : * It's not that different from the "bernoulli" method, though.
2585 : *
2586 : * We could also do "ORDER BY random() LIMIT x", which would always pick
2587 : * the expected number of rows, but it requires sorting so it may be much
2588 : * more expensive (particularly on large tables, which is what the
2589 : * remote sampling is meant to improve).
2590 : */
2591 : void
2592 0 : deparseAnalyzeSql(StringInfo buf, Relation rel,
2593 : PgFdwSamplingMethod sample_method, double sample_frac,
2594 : List **retrieved_attrs)
2595 : {
2596 0 : Oid relid = RelationGetRelid(rel);
2597 0 : TupleDesc tupdesc = RelationGetDescr(rel);
2598 0 : int i;
2599 0 : char *colname;
2600 0 : List *options;
2601 0 : ListCell *lc;
2602 0 : bool first = true;
2603 :
2604 0 : *retrieved_attrs = NIL;
2605 :
2606 0 : appendStringInfoString(buf, "SELECT ");
2607 0 : for (i = 0; i < tupdesc->natts; i++)
2608 : {
2609 : /* Ignore dropped columns. */
2610 0 : if (TupleDescAttr(tupdesc, i)->attisdropped)
2611 0 : continue;
2612 :
2613 0 : if (!first)
2614 0 : appendStringInfoString(buf, ", ");
2615 0 : first = false;
2616 :
2617 : /* Use attribute name or column_name option. */
2618 0 : colname = NameStr(TupleDescAttr(tupdesc, i)->attname);
2619 0 : options = GetForeignColumnOptions(relid, i + 1);
2620 :
2621 0 : foreach(lc, options)
2622 : {
2623 0 : DefElem *def = (DefElem *) lfirst(lc);
2624 :
2625 0 : if (strcmp(def->defname, "column_name") == 0)
2626 : {
2627 0 : colname = defGetString(def);
2628 0 : break;
2629 : }
2630 0 : }
2631 :
2632 0 : appendStringInfoString(buf, quote_identifier(colname));
2633 :
2634 0 : *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
2635 0 : }
2636 :
2637 : /* Don't generate bad syntax for zero-column relation. */
2638 0 : if (first)
2639 0 : appendStringInfoString(buf, "NULL");
2640 :
2641 : /*
2642 : * Construct FROM clause, and perhaps WHERE clause too, depending on the
2643 : * selected sampling method.
2644 : */
2645 0 : appendStringInfoString(buf, " FROM ");
2646 0 : deparseRelation(buf, rel);
2647 :
2648 0 : switch (sample_method)
2649 : {
2650 : case ANALYZE_SAMPLE_OFF:
2651 : /* nothing to do here */
2652 : break;
2653 :
2654 : case ANALYZE_SAMPLE_RANDOM:
2655 0 : appendStringInfo(buf, " WHERE pg_catalog.random() < %f", sample_frac);
2656 0 : break;
2657 :
2658 : case ANALYZE_SAMPLE_SYSTEM:
2659 0 : appendStringInfo(buf, " TABLESAMPLE SYSTEM(%f)", (100.0 * sample_frac));
2660 0 : break;
2661 :
2662 : case ANALYZE_SAMPLE_BERNOULLI:
2663 0 : appendStringInfo(buf, " TABLESAMPLE BERNOULLI(%f)", (100.0 * sample_frac));
2664 0 : break;
2665 :
2666 : case ANALYZE_SAMPLE_AUTO:
2667 : /* should have been resolved into actual method */
2668 0 : elog(ERROR, "unexpected sampling method");
2669 0 : break;
2670 : }
2671 0 : }
2672 :
2673 : /*
2674 : * Construct a simple "TRUNCATE rel" statement
2675 : */
2676 : void
2677 0 : deparseTruncateSql(StringInfo buf,
2678 : List *rels,
2679 : DropBehavior behavior,
2680 : bool restart_seqs)
2681 : {
2682 0 : ListCell *cell;
2683 :
2684 0 : appendStringInfoString(buf, "TRUNCATE ");
2685 :
2686 0 : foreach(cell, rels)
2687 : {
2688 0 : Relation rel = lfirst(cell);
2689 :
2690 0 : if (cell != list_head(rels))
2691 0 : appendStringInfoString(buf, ", ");
2692 :
2693 0 : deparseRelation(buf, rel);
2694 0 : }
2695 :
2696 0 : appendStringInfo(buf, " %s IDENTITY",
2697 0 : restart_seqs ? "RESTART" : "CONTINUE");
2698 :
2699 0 : if (behavior == DROP_RESTRICT)
2700 0 : appendStringInfoString(buf, " RESTRICT");
2701 0 : else if (behavior == DROP_CASCADE)
2702 0 : appendStringInfoString(buf, " CASCADE");
2703 0 : }
2704 :
2705 : /*
2706 : * Construct name to use for given column, and emit it into buf.
2707 : * If it has a column_name FDW option, use that instead of attribute name.
2708 : *
2709 : * If qualify_col is true, qualify column name with the alias of relation.
2710 : */
2711 : static void
2712 0 : deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte,
2713 : bool qualify_col)
2714 : {
2715 : /* We support fetching the remote side's CTID and OID. */
2716 0 : if (varattno == SelfItemPointerAttributeNumber)
2717 : {
2718 0 : if (qualify_col)
2719 0 : ADD_REL_QUALIFIER(buf, varno);
2720 0 : appendStringInfoString(buf, "ctid");
2721 0 : }
2722 0 : else if (varattno < 0)
2723 : {
2724 : /*
2725 : * All other system attributes are fetched as 0, except for table OID,
2726 : * which is fetched as the local table OID. However, we must be
2727 : * careful; the table could be beneath an outer join, in which case it
2728 : * must go to NULL whenever the rest of the row does.
2729 : */
2730 0 : Oid fetchval = 0;
2731 :
2732 0 : if (varattno == TableOidAttributeNumber)
2733 0 : fetchval = rte->relid;
2734 :
2735 0 : if (qualify_col)
2736 : {
2737 0 : appendStringInfoString(buf, "CASE WHEN (");
2738 0 : ADD_REL_QUALIFIER(buf, varno);
2739 0 : appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
2740 0 : }
2741 : else
2742 0 : appendStringInfo(buf, "%u", fetchval);
2743 0 : }
2744 0 : else if (varattno == 0)
2745 : {
2746 : /* Whole row reference */
2747 0 : Relation rel;
2748 0 : Bitmapset *attrs_used;
2749 :
2750 : /* Required only to be passed down to deparseTargetList(). */
2751 0 : List *retrieved_attrs;
2752 :
2753 : /*
2754 : * The lock on the relation will be held by upper callers, so it's
2755 : * fine to open it with no lock here.
2756 : */
2757 0 : rel = table_open(rte->relid, NoLock);
2758 :
2759 : /*
2760 : * The local name of the foreign table can not be recognized by the
2761 : * foreign server and the table it references on foreign server might
2762 : * have different column ordering or different columns than those
2763 : * declared locally. Hence we have to deparse whole-row reference as
2764 : * ROW(columns referenced locally). Construct this by deparsing a
2765 : * "whole row" attribute.
2766 : */
2767 0 : attrs_used = bms_add_member(NULL,
2768 : 0 - FirstLowInvalidHeapAttributeNumber);
2769 :
2770 : /*
2771 : * In case the whole-row reference is under an outer join then it has
2772 : * to go NULL whenever the rest of the row goes NULL. Deparsing a join
2773 : * query would always involve multiple relations, thus qualify_col
2774 : * would be true.
2775 : */
2776 0 : if (qualify_col)
2777 : {
2778 0 : appendStringInfoString(buf, "CASE WHEN (");
2779 0 : ADD_REL_QUALIFIER(buf, varno);
2780 0 : appendStringInfoString(buf, "*)::text IS NOT NULL THEN ");
2781 0 : }
2782 :
2783 0 : appendStringInfoString(buf, "ROW(");
2784 0 : deparseTargetList(buf, rte, varno, rel, false, attrs_used, qualify_col,
2785 : &retrieved_attrs);
2786 0 : appendStringInfoChar(buf, ')');
2787 :
2788 : /* Complete the CASE WHEN statement started above. */
2789 0 : if (qualify_col)
2790 0 : appendStringInfoString(buf, " END");
2791 :
2792 0 : table_close(rel, NoLock);
2793 0 : bms_free(attrs_used);
2794 0 : }
2795 : else
2796 : {
2797 0 : char *colname = NULL;
2798 0 : List *options;
2799 0 : ListCell *lc;
2800 :
2801 : /* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
2802 0 : Assert(!IS_SPECIAL_VARNO(varno));
2803 :
2804 : /*
2805 : * If it's a column of a foreign table, and it has the column_name FDW
2806 : * option, use that value.
2807 : */
2808 0 : options = GetForeignColumnOptions(rte->relid, varattno);
2809 0 : foreach(lc, options)
2810 : {
2811 0 : DefElem *def = (DefElem *) lfirst(lc);
2812 :
2813 0 : if (strcmp(def->defname, "column_name") == 0)
2814 : {
2815 0 : colname = defGetString(def);
2816 0 : break;
2817 : }
2818 0 : }
2819 :
2820 : /*
2821 : * If it's a column of a regular table or it doesn't have column_name
2822 : * FDW option, use attribute name.
2823 : */
2824 0 : if (colname == NULL)
2825 0 : colname = get_attname(rte->relid, varattno, false);
2826 :
2827 0 : if (qualify_col)
2828 0 : ADD_REL_QUALIFIER(buf, varno);
2829 :
2830 0 : appendStringInfoString(buf, quote_identifier(colname));
2831 0 : }
2832 0 : }
2833 :
2834 : /*
2835 : * Append remote name of specified foreign table to buf.
2836 : * Use value of table_name FDW option (if any) instead of relation's name.
2837 : * Similarly, schema_name FDW option overrides schema name.
2838 : */
2839 : static void
2840 0 : deparseRelation(StringInfo buf, Relation rel)
2841 : {
2842 0 : ForeignTable *table;
2843 0 : const char *nspname = NULL;
2844 0 : const char *relname = NULL;
2845 0 : ListCell *lc;
2846 :
2847 : /* obtain additional catalog information. */
2848 0 : table = GetForeignTable(RelationGetRelid(rel));
2849 :
2850 : /*
2851 : * Use value of FDW options if any, instead of the name of object itself.
2852 : */
2853 0 : foreach(lc, table->options)
2854 : {
2855 0 : DefElem *def = (DefElem *) lfirst(lc);
2856 :
2857 0 : if (strcmp(def->defname, "schema_name") == 0)
2858 0 : nspname = defGetString(def);
2859 0 : else if (strcmp(def->defname, "table_name") == 0)
2860 0 : relname = defGetString(def);
2861 0 : }
2862 :
2863 : /*
2864 : * Note: we could skip printing the schema name if it's pg_catalog, but
2865 : * that doesn't seem worth the trouble.
2866 : */
2867 0 : if (nspname == NULL)
2868 0 : nspname = get_namespace_name(RelationGetNamespace(rel));
2869 0 : if (relname == NULL)
2870 0 : relname = RelationGetRelationName(rel);
2871 :
2872 0 : appendStringInfo(buf, "%s.%s",
2873 0 : quote_identifier(nspname), quote_identifier(relname));
2874 0 : }
2875 :
2876 : /*
2877 : * Append a SQL string literal representing "val" to buf.
2878 : */
2879 : void
2880 0 : deparseStringLiteral(StringInfo buf, const char *val)
2881 : {
2882 0 : const char *valptr;
2883 :
2884 : /*
2885 : * Rather than making assumptions about the remote server's value of
2886 : * standard_conforming_strings, always use E'foo' syntax if there are any
2887 : * backslashes. This will fail on remote servers before 8.1, but those
2888 : * are long out of support.
2889 : */
2890 0 : if (strchr(val, '\\') != NULL)
2891 0 : appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
2892 0 : appendStringInfoChar(buf, '\'');
2893 0 : for (valptr = val; *valptr; valptr++)
2894 : {
2895 0 : char ch = *valptr;
2896 :
2897 0 : if (SQL_STR_DOUBLE(ch, true))
2898 0 : appendStringInfoChar(buf, ch);
2899 0 : appendStringInfoChar(buf, ch);
2900 0 : }
2901 0 : appendStringInfoChar(buf, '\'');
2902 0 : }
2903 :
2904 : /*
2905 : * Deparse given expression into context->buf.
2906 : *
2907 : * This function must support all the same node types that foreign_expr_walker
2908 : * accepts.
2909 : *
2910 : * Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
2911 : * scheme: anything more complex than a Var, Const, function call or cast
2912 : * should be self-parenthesized.
2913 : */
2914 : static void
2915 0 : deparseExpr(Expr *node, deparse_expr_cxt *context)
2916 : {
2917 0 : if (node == NULL)
2918 0 : return;
2919 :
2920 0 : switch (nodeTag(node))
2921 : {
2922 : case T_Var:
2923 0 : deparseVar((Var *) node, context);
2924 0 : break;
2925 : case T_Const:
2926 0 : deparseConst((Const *) node, context, 0);
2927 0 : break;
2928 : case T_Param:
2929 0 : deparseParam((Param *) node, context);
2930 0 : break;
2931 : case T_SubscriptingRef:
2932 0 : deparseSubscriptingRef((SubscriptingRef *) node, context);
2933 0 : break;
2934 : case T_FuncExpr:
2935 0 : deparseFuncExpr((FuncExpr *) node, context);
2936 0 : break;
2937 : case T_OpExpr:
2938 0 : deparseOpExpr((OpExpr *) node, context);
2939 0 : break;
2940 : case T_DistinctExpr:
2941 0 : deparseDistinctExpr((DistinctExpr *) node, context);
2942 0 : break;
2943 : case T_ScalarArrayOpExpr:
2944 0 : deparseScalarArrayOpExpr((ScalarArrayOpExpr *) node, context);
2945 0 : break;
2946 : case T_RelabelType:
2947 0 : deparseRelabelType((RelabelType *) node, context);
2948 0 : break;
2949 : case T_ArrayCoerceExpr:
2950 0 : deparseArrayCoerceExpr((ArrayCoerceExpr *) node, context);
2951 0 : break;
2952 : case T_BoolExpr:
2953 0 : deparseBoolExpr((BoolExpr *) node, context);
2954 0 : break;
2955 : case T_NullTest:
2956 0 : deparseNullTest((NullTest *) node, context);
2957 0 : break;
2958 : case T_CaseExpr:
2959 0 : deparseCaseExpr((CaseExpr *) node, context);
2960 0 : break;
2961 : case T_ArrayExpr:
2962 0 : deparseArrayExpr((ArrayExpr *) node, context);
2963 0 : break;
2964 : case T_Aggref:
2965 0 : deparseAggref((Aggref *) node, context);
2966 0 : break;
2967 : default:
2968 0 : elog(ERROR, "unsupported expression type for deparse: %d",
2969 : (int) nodeTag(node));
2970 0 : break;
2971 : }
2972 0 : }
2973 :
2974 : /*
2975 : * Deparse given Var node into context->buf.
2976 : *
2977 : * If the Var belongs to the foreign relation, just print its remote name.
2978 : * Otherwise, it's effectively a Param (and will in fact be a Param at
2979 : * run time). Handle it the same way we handle plain Params --- see
2980 : * deparseParam for comments.
2981 : */
2982 : static void
2983 0 : deparseVar(Var *node, deparse_expr_cxt *context)
2984 : {
2985 0 : Relids relids = context->scanrel->relids;
2986 0 : int relno;
2987 0 : int colno;
2988 :
2989 : /* Qualify columns when multiple relations are involved. */
2990 0 : bool qualify_col = (bms_membership(relids) == BMS_MULTIPLE);
2991 :
2992 : /*
2993 : * If the Var belongs to the foreign relation that is deparsed as a
2994 : * subquery, use the relation and column alias to the Var provided by the
2995 : * subquery, instead of the remote name.
2996 : */
2997 0 : if (is_subquery_var(node, context->scanrel, &relno, &colno))
2998 : {
2999 0 : appendStringInfo(context->buf, "%s%d.%s%d",
3000 0 : SUBQUERY_REL_ALIAS_PREFIX, relno,
3001 0 : SUBQUERY_COL_ALIAS_PREFIX, colno);
3002 0 : return;
3003 : }
3004 :
3005 0 : if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
3006 0 : deparseColumnRef(context->buf, node->varno, node->varattno,
3007 0 : planner_rt_fetch(node->varno, context->root),
3008 0 : qualify_col);
3009 : else
3010 : {
3011 : /* Treat like a Param */
3012 0 : if (context->params_list)
3013 : {
3014 0 : int pindex = 0;
3015 0 : ListCell *lc;
3016 :
3017 : /* find its index in params_list */
3018 0 : foreach(lc, *context->params_list)
3019 : {
3020 0 : pindex++;
3021 0 : if (equal(node, (Node *) lfirst(lc)))
3022 0 : break;
3023 0 : }
3024 0 : if (lc == NULL)
3025 : {
3026 : /* not in list, so add it */
3027 0 : pindex++;
3028 0 : *context->params_list = lappend(*context->params_list, node);
3029 0 : }
3030 :
3031 0 : printRemoteParam(pindex, node->vartype, node->vartypmod, context);
3032 0 : }
3033 : else
3034 : {
3035 0 : printRemotePlaceholder(node->vartype, node->vartypmod, context);
3036 : }
3037 : }
3038 0 : }
3039 :
3040 : /*
3041 : * Deparse given constant value into context->buf.
3042 : *
3043 : * This function has to be kept in sync with ruleutils.c's get_const_expr.
3044 : *
3045 : * As in that function, showtype can be -1 to never show "::typename"
3046 : * decoration, +1 to always show it, or 0 to show it only if the constant
3047 : * wouldn't be assumed to be the right type by default.
3048 : *
3049 : * In addition, this code allows showtype to be -2 to indicate that we should
3050 : * not show "::typename" decoration if the constant is printed as an untyped
3051 : * literal or NULL (while in other cases, behaving as for showtype == 0).
3052 : */
3053 : static void
3054 0 : deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
3055 : {
3056 0 : StringInfo buf = context->buf;
3057 0 : Oid typoutput;
3058 0 : bool typIsVarlena;
3059 0 : char *extval;
3060 0 : bool isfloat = false;
3061 0 : bool isstring = false;
3062 0 : bool needlabel;
3063 :
3064 0 : if (node->constisnull)
3065 : {
3066 0 : appendStringInfoString(buf, "NULL");
3067 0 : if (showtype >= 0)
3068 0 : appendStringInfo(buf, "::%s",
3069 0 : deparse_type_name(node->consttype,
3070 0 : node->consttypmod));
3071 0 : return;
3072 : }
3073 :
3074 0 : getTypeOutputInfo(node->consttype,
3075 : &typoutput, &typIsVarlena);
3076 0 : extval = OidOutputFunctionCall(typoutput, node->constvalue);
3077 :
3078 0 : switch (node->consttype)
3079 : {
3080 : case INT2OID:
3081 : case INT4OID:
3082 : case INT8OID:
3083 : case OIDOID:
3084 : case FLOAT4OID:
3085 : case FLOAT8OID:
3086 : case NUMERICOID:
3087 : {
3088 : /*
3089 : * No need to quote unless it's a special value such as 'NaN'.
3090 : * See comments in get_const_expr().
3091 : */
3092 0 : if (strspn(extval, "0123456789+-eE.") == strlen(extval))
3093 : {
3094 0 : if (extval[0] == '+' || extval[0] == '-')
3095 0 : appendStringInfo(buf, "(%s)", extval);
3096 : else
3097 0 : appendStringInfoString(buf, extval);
3098 0 : if (strcspn(extval, "eE.") != strlen(extval))
3099 0 : isfloat = true; /* it looks like a float */
3100 0 : }
3101 : else
3102 0 : appendStringInfo(buf, "'%s'", extval);
3103 : }
3104 0 : break;
3105 : case BITOID:
3106 : case VARBITOID:
3107 0 : appendStringInfo(buf, "B'%s'", extval);
3108 0 : break;
3109 : case BOOLOID:
3110 0 : if (strcmp(extval, "t") == 0)
3111 0 : appendStringInfoString(buf, "true");
3112 : else
3113 0 : appendStringInfoString(buf, "false");
3114 0 : break;
3115 : default:
3116 0 : deparseStringLiteral(buf, extval);
3117 0 : isstring = true;
3118 0 : break;
3119 : }
3120 :
3121 0 : pfree(extval);
3122 :
3123 0 : if (showtype == -1)
3124 0 : return; /* never print type label */
3125 :
3126 : /*
3127 : * For showtype == 0, append ::typename unless the constant will be
3128 : * implicitly typed as the right type when it is read in.
3129 : *
3130 : * XXX this code has to be kept in sync with the behavior of the parser,
3131 : * especially make_const.
3132 : */
3133 0 : switch (node->consttype)
3134 : {
3135 : case BOOLOID:
3136 : case INT4OID:
3137 : case UNKNOWNOID:
3138 0 : needlabel = false;
3139 0 : break;
3140 : case NUMERICOID:
3141 0 : needlabel = !isfloat || (node->consttypmod >= 0);
3142 0 : break;
3143 : default:
3144 0 : if (showtype == -2)
3145 : {
3146 : /* label unless we printed it as an untyped string */
3147 0 : needlabel = !isstring;
3148 0 : }
3149 : else
3150 0 : needlabel = true;
3151 0 : break;
3152 : }
3153 0 : if (needlabel || showtype > 0)
3154 0 : appendStringInfo(buf, "::%s",
3155 0 : deparse_type_name(node->consttype,
3156 0 : node->consttypmod));
3157 0 : }
3158 :
3159 : /*
3160 : * Deparse given Param node.
3161 : *
3162 : * If we're generating the query "for real", add the Param to
3163 : * context->params_list if it's not already present, and then use its index
3164 : * in that list as the remote parameter number. During EXPLAIN, there's
3165 : * no need to identify a parameter number.
3166 : */
3167 : static void
3168 0 : deparseParam(Param *node, deparse_expr_cxt *context)
3169 : {
3170 0 : if (context->params_list)
3171 : {
3172 0 : int pindex = 0;
3173 0 : ListCell *lc;
3174 :
3175 : /* find its index in params_list */
3176 0 : foreach(lc, *context->params_list)
3177 : {
3178 0 : pindex++;
3179 0 : if (equal(node, (Node *) lfirst(lc)))
3180 0 : break;
3181 0 : }
3182 0 : if (lc == NULL)
3183 : {
3184 : /* not in list, so add it */
3185 0 : pindex++;
3186 0 : *context->params_list = lappend(*context->params_list, node);
3187 0 : }
3188 :
3189 0 : printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
3190 0 : }
3191 : else
3192 : {
3193 0 : printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
3194 : }
3195 0 : }
3196 :
3197 : /*
3198 : * Deparse a container subscript expression.
3199 : */
3200 : static void
3201 0 : deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context)
3202 : {
3203 0 : StringInfo buf = context->buf;
3204 0 : ListCell *lowlist_item;
3205 0 : ListCell *uplist_item;
3206 :
3207 : /* Always parenthesize the expression. */
3208 0 : appendStringInfoChar(buf, '(');
3209 :
3210 : /*
3211 : * Deparse referenced array expression first. If that expression includes
3212 : * a cast, we have to parenthesize to prevent the array subscript from
3213 : * being taken as typename decoration. We can avoid that in the typical
3214 : * case of subscripting a Var, but otherwise do it.
3215 : */
3216 0 : if (IsA(node->refexpr, Var))
3217 0 : deparseExpr(node->refexpr, context);
3218 : else
3219 : {
3220 0 : appendStringInfoChar(buf, '(');
3221 0 : deparseExpr(node->refexpr, context);
3222 0 : appendStringInfoChar(buf, ')');
3223 : }
3224 :
3225 : /* Deparse subscript expressions. */
3226 0 : lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
3227 0 : foreach(uplist_item, node->refupperindexpr)
3228 : {
3229 0 : appendStringInfoChar(buf, '[');
3230 0 : if (lowlist_item)
3231 : {
3232 0 : deparseExpr(lfirst(lowlist_item), context);
3233 0 : appendStringInfoChar(buf, ':');
3234 0 : lowlist_item = lnext(node->reflowerindexpr, lowlist_item);
3235 0 : }
3236 0 : deparseExpr(lfirst(uplist_item), context);
3237 0 : appendStringInfoChar(buf, ']');
3238 0 : }
3239 :
3240 0 : appendStringInfoChar(buf, ')');
3241 0 : }
3242 :
3243 : /*
3244 : * Deparse a function call.
3245 : */
3246 : static void
3247 0 : deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
3248 : {
3249 0 : StringInfo buf = context->buf;
3250 0 : bool use_variadic;
3251 0 : bool first;
3252 0 : ListCell *arg;
3253 :
3254 : /*
3255 : * If the function call came from an implicit coercion, then just show the
3256 : * first argument.
3257 : */
3258 0 : if (node->funcformat == COERCE_IMPLICIT_CAST)
3259 : {
3260 0 : deparseExpr((Expr *) linitial(node->args), context);
3261 0 : return;
3262 : }
3263 :
3264 : /*
3265 : * If the function call came from a cast, then show the first argument
3266 : * plus an explicit cast operation.
3267 : */
3268 0 : if (node->funcformat == COERCE_EXPLICIT_CAST)
3269 : {
3270 0 : Oid rettype = node->funcresulttype;
3271 0 : int32 coercedTypmod;
3272 :
3273 : /* Get the typmod if this is a length-coercion function */
3274 0 : (void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
3275 :
3276 0 : deparseExpr((Expr *) linitial(node->args), context);
3277 0 : appendStringInfo(buf, "::%s",
3278 0 : deparse_type_name(rettype, coercedTypmod));
3279 : return;
3280 0 : }
3281 :
3282 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
3283 0 : use_variadic = node->funcvariadic;
3284 :
3285 : /*
3286 : * Normal function: display as proname(args).
3287 : */
3288 0 : appendFunctionName(node->funcid, context);
3289 0 : appendStringInfoChar(buf, '(');
3290 :
3291 : /* ... and all the arguments */
3292 0 : first = true;
3293 0 : foreach(arg, node->args)
3294 : {
3295 0 : if (!first)
3296 0 : appendStringInfoString(buf, ", ");
3297 0 : if (use_variadic && lnext(node->args, arg) == NULL)
3298 0 : appendStringInfoString(buf, "VARIADIC ");
3299 0 : deparseExpr((Expr *) lfirst(arg), context);
3300 0 : first = false;
3301 0 : }
3302 0 : appendStringInfoChar(buf, ')');
3303 0 : }
3304 :
3305 : /*
3306 : * Deparse given operator expression. To avoid problems around
3307 : * priority of operations, we always parenthesize the arguments.
3308 : */
3309 : static void
3310 0 : deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
3311 : {
3312 0 : StringInfo buf = context->buf;
3313 0 : HeapTuple tuple;
3314 0 : Form_pg_operator form;
3315 0 : Expr *right;
3316 0 : bool canSuppressRightConstCast = false;
3317 0 : char oprkind;
3318 :
3319 : /* Retrieve information about the operator from system catalog. */
3320 0 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
3321 0 : if (!HeapTupleIsValid(tuple))
3322 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
3323 0 : form = (Form_pg_operator) GETSTRUCT(tuple);
3324 0 : oprkind = form->oprkind;
3325 :
3326 : /* Sanity check. */
3327 0 : Assert((oprkind == 'l' && list_length(node->args) == 1) ||
3328 : (oprkind == 'b' && list_length(node->args) == 2));
3329 :
3330 0 : right = llast(node->args);
3331 :
3332 : /* Always parenthesize the expression. */
3333 0 : appendStringInfoChar(buf, '(');
3334 :
3335 : /* Deparse left operand, if any. */
3336 0 : if (oprkind == 'b')
3337 : {
3338 0 : Expr *left = linitial(node->args);
3339 0 : Oid leftType = exprType((Node *) left);
3340 0 : Oid rightType = exprType((Node *) right);
3341 0 : bool canSuppressLeftConstCast = false;
3342 :
3343 : /*
3344 : * When considering a binary operator, if one operand is a Const that
3345 : * can be printed as a bare string literal or NULL (i.e., it will look
3346 : * like type UNKNOWN to the remote parser), the Const normally
3347 : * receives an explicit cast to the operator's input type. However,
3348 : * in Const-to-Var comparisons where both operands are of the same
3349 : * type, we prefer to suppress the explicit cast, leaving the Const's
3350 : * type resolution up to the remote parser. The remote's resolution
3351 : * heuristic will assume that an unknown input type being compared to
3352 : * a known input type is of that known type as well.
3353 : *
3354 : * This hack allows some cases to succeed where a remote column is
3355 : * declared with a different type in the local (foreign) table. By
3356 : * emitting "foreigncol = 'foo'" not "foreigncol = 'foo'::text" or the
3357 : * like, we allow the remote parser to pick an "=" operator that's
3358 : * compatible with whatever type the remote column really is, such as
3359 : * an enum.
3360 : *
3361 : * We allow cast suppression to happen only when the other operand is
3362 : * a plain foreign Var. Although the remote's unknown-type heuristic
3363 : * would apply to other cases just as well, we would be taking a
3364 : * bigger risk that the inferred type is something unexpected. With
3365 : * this restriction, if anything goes wrong it's the user's fault for
3366 : * not declaring the local column with the same type as the remote
3367 : * column.
3368 : */
3369 0 : if (leftType == rightType)
3370 : {
3371 0 : if (IsA(left, Const))
3372 0 : canSuppressLeftConstCast = isPlainForeignVar(right, context);
3373 0 : else if (IsA(right, Const))
3374 0 : canSuppressRightConstCast = isPlainForeignVar(left, context);
3375 0 : }
3376 :
3377 0 : if (canSuppressLeftConstCast)
3378 0 : deparseConst((Const *) left, context, -2);
3379 : else
3380 0 : deparseExpr(left, context);
3381 :
3382 0 : appendStringInfoChar(buf, ' ');
3383 0 : }
3384 :
3385 : /* Deparse operator name. */
3386 0 : deparseOperatorName(buf, form);
3387 :
3388 : /* Deparse right operand. */
3389 0 : appendStringInfoChar(buf, ' ');
3390 :
3391 0 : if (canSuppressRightConstCast)
3392 0 : deparseConst((Const *) right, context, -2);
3393 : else
3394 0 : deparseExpr(right, context);
3395 :
3396 0 : appendStringInfoChar(buf, ')');
3397 :
3398 0 : ReleaseSysCache(tuple);
3399 0 : }
3400 :
3401 : /*
3402 : * Will "node" deparse as a plain foreign Var?
3403 : */
3404 : static bool
3405 0 : isPlainForeignVar(Expr *node, deparse_expr_cxt *context)
3406 : {
3407 : /*
3408 : * We allow the foreign Var to have an implicit RelabelType, mainly so
3409 : * that this'll work with varchar columns. Note that deparseRelabelType
3410 : * will not print such a cast, so we're not breaking the restriction that
3411 : * the expression print as a plain Var. We won't risk it for an implicit
3412 : * cast that requires a function, nor for non-implicit RelabelType; such
3413 : * cases seem too likely to involve semantics changes compared to what
3414 : * would happen on the remote side.
3415 : */
3416 0 : if (IsA(node, RelabelType) &&
3417 0 : ((RelabelType *) node)->relabelformat == COERCE_IMPLICIT_CAST)
3418 0 : node = ((RelabelType *) node)->arg;
3419 :
3420 0 : if (IsA(node, Var))
3421 : {
3422 : /*
3423 : * The Var must be one that'll deparse as a foreign column reference
3424 : * (cf. deparseVar).
3425 : */
3426 0 : Var *var = (Var *) node;
3427 0 : Relids relids = context->scanrel->relids;
3428 :
3429 0 : if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
3430 0 : return true;
3431 0 : }
3432 :
3433 0 : return false;
3434 0 : }
3435 :
3436 : /*
3437 : * Print the name of an operator.
3438 : */
3439 : static void
3440 0 : deparseOperatorName(StringInfo buf, Form_pg_operator opform)
3441 : {
3442 0 : char *opname;
3443 :
3444 : /* opname is not a SQL identifier, so we should not quote it. */
3445 0 : opname = NameStr(opform->oprname);
3446 :
3447 : /* Print schema name only if it's not pg_catalog */
3448 0 : if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
3449 : {
3450 0 : const char *opnspname;
3451 :
3452 0 : opnspname = get_namespace_name(opform->oprnamespace);
3453 : /* Print fully qualified operator name. */
3454 0 : appendStringInfo(buf, "OPERATOR(%s.%s)",
3455 0 : quote_identifier(opnspname), opname);
3456 0 : }
3457 : else
3458 : {
3459 : /* Just print operator name. */
3460 0 : appendStringInfoString(buf, opname);
3461 : }
3462 0 : }
3463 :
3464 : /*
3465 : * Deparse IS DISTINCT FROM.
3466 : */
3467 : static void
3468 0 : deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
3469 : {
3470 0 : StringInfo buf = context->buf;
3471 :
3472 0 : Assert(list_length(node->args) == 2);
3473 :
3474 0 : appendStringInfoChar(buf, '(');
3475 0 : deparseExpr(linitial(node->args), context);
3476 0 : appendStringInfoString(buf, " IS DISTINCT FROM ");
3477 0 : deparseExpr(lsecond(node->args), context);
3478 0 : appendStringInfoChar(buf, ')');
3479 0 : }
3480 :
3481 : /*
3482 : * Deparse given ScalarArrayOpExpr expression. To avoid problems
3483 : * around priority of operations, we always parenthesize the arguments.
3484 : */
3485 : static void
3486 0 : deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
3487 : {
3488 0 : StringInfo buf = context->buf;
3489 0 : HeapTuple tuple;
3490 0 : Form_pg_operator form;
3491 0 : Expr *arg1;
3492 0 : Expr *arg2;
3493 :
3494 : /* Retrieve information about the operator from system catalog. */
3495 0 : tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
3496 0 : if (!HeapTupleIsValid(tuple))
3497 0 : elog(ERROR, "cache lookup failed for operator %u", node->opno);
3498 0 : form = (Form_pg_operator) GETSTRUCT(tuple);
3499 :
3500 : /* Sanity check. */
3501 0 : Assert(list_length(node->args) == 2);
3502 :
3503 : /* Always parenthesize the expression. */
3504 0 : appendStringInfoChar(buf, '(');
3505 :
3506 : /* Deparse left operand. */
3507 0 : arg1 = linitial(node->args);
3508 0 : deparseExpr(arg1, context);
3509 0 : appendStringInfoChar(buf, ' ');
3510 :
3511 : /* Deparse operator name plus decoration. */
3512 0 : deparseOperatorName(buf, form);
3513 0 : appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
3514 :
3515 : /* Deparse right operand. */
3516 0 : arg2 = lsecond(node->args);
3517 0 : deparseExpr(arg2, context);
3518 :
3519 0 : appendStringInfoChar(buf, ')');
3520 :
3521 : /* Always parenthesize the expression. */
3522 0 : appendStringInfoChar(buf, ')');
3523 :
3524 0 : ReleaseSysCache(tuple);
3525 0 : }
3526 :
3527 : /*
3528 : * Deparse a RelabelType (binary-compatible cast) node.
3529 : */
3530 : static void
3531 0 : deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
3532 : {
3533 0 : deparseExpr(node->arg, context);
3534 0 : if (node->relabelformat != COERCE_IMPLICIT_CAST)
3535 0 : appendStringInfo(context->buf, "::%s",
3536 0 : deparse_type_name(node->resulttype,
3537 0 : node->resulttypmod));
3538 0 : }
3539 :
3540 : /*
3541 : * Deparse an ArrayCoerceExpr (array-type conversion) node.
3542 : */
3543 : static void
3544 0 : deparseArrayCoerceExpr(ArrayCoerceExpr *node, deparse_expr_cxt *context)
3545 : {
3546 0 : deparseExpr(node->arg, context);
3547 :
3548 : /*
3549 : * No difference how to deparse explicit cast, but if we omit implicit
3550 : * cast in the query, it'll be more user-friendly
3551 : */
3552 0 : if (node->coerceformat != COERCE_IMPLICIT_CAST)
3553 0 : appendStringInfo(context->buf, "::%s",
3554 0 : deparse_type_name(node->resulttype,
3555 0 : node->resulttypmod));
3556 0 : }
3557 :
3558 : /*
3559 : * Deparse a BoolExpr node.
3560 : */
3561 : static void
3562 0 : deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
3563 : {
3564 0 : StringInfo buf = context->buf;
3565 0 : const char *op = NULL; /* keep compiler quiet */
3566 0 : bool first;
3567 0 : ListCell *lc;
3568 :
3569 0 : switch (node->boolop)
3570 : {
3571 : case AND_EXPR:
3572 0 : op = "AND";
3573 0 : break;
3574 : case OR_EXPR:
3575 0 : op = "OR";
3576 0 : break;
3577 : case NOT_EXPR:
3578 0 : appendStringInfoString(buf, "(NOT ");
3579 0 : deparseExpr(linitial(node->args), context);
3580 0 : appendStringInfoChar(buf, ')');
3581 0 : return;
3582 : }
3583 :
3584 0 : appendStringInfoChar(buf, '(');
3585 0 : first = true;
3586 0 : foreach(lc, node->args)
3587 : {
3588 0 : if (!first)
3589 0 : appendStringInfo(buf, " %s ", op);
3590 0 : deparseExpr((Expr *) lfirst(lc), context);
3591 0 : first = false;
3592 0 : }
3593 0 : appendStringInfoChar(buf, ')');
3594 0 : }
3595 :
3596 : /*
3597 : * Deparse IS [NOT] NULL expression.
3598 : */
3599 : static void
3600 0 : deparseNullTest(NullTest *node, deparse_expr_cxt *context)
3601 : {
3602 0 : StringInfo buf = context->buf;
3603 :
3604 0 : appendStringInfoChar(buf, '(');
3605 0 : deparseExpr(node->arg, context);
3606 :
3607 : /*
3608 : * For scalar inputs, we prefer to print as IS [NOT] NULL, which is
3609 : * shorter and traditional. If it's a rowtype input but we're applying a
3610 : * scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
3611 : * correct.
3612 : */
3613 0 : if (node->argisrow || !type_is_rowtype(exprType((Node *) node->arg)))
3614 : {
3615 0 : if (node->nulltesttype == IS_NULL)
3616 0 : appendStringInfoString(buf, " IS NULL)");
3617 : else
3618 0 : appendStringInfoString(buf, " IS NOT NULL)");
3619 0 : }
3620 : else
3621 : {
3622 0 : if (node->nulltesttype == IS_NULL)
3623 0 : appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
3624 : else
3625 0 : appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
3626 : }
3627 0 : }
3628 :
3629 : /*
3630 : * Deparse CASE expression
3631 : */
3632 : static void
3633 0 : deparseCaseExpr(CaseExpr *node, deparse_expr_cxt *context)
3634 : {
3635 0 : StringInfo buf = context->buf;
3636 0 : ListCell *lc;
3637 :
3638 0 : appendStringInfoString(buf, "(CASE");
3639 :
3640 : /* If this is a CASE arg WHEN then emit the arg expression */
3641 0 : if (node->arg != NULL)
3642 : {
3643 0 : appendStringInfoChar(buf, ' ');
3644 0 : deparseExpr(node->arg, context);
3645 0 : }
3646 :
3647 : /* Add each condition/result of the CASE clause */
3648 0 : foreach(lc, node->args)
3649 : {
3650 0 : CaseWhen *whenclause = (CaseWhen *) lfirst(lc);
3651 :
3652 : /* WHEN */
3653 0 : appendStringInfoString(buf, " WHEN ");
3654 0 : if (node->arg == NULL) /* CASE WHEN */
3655 0 : deparseExpr(whenclause->expr, context);
3656 : else /* CASE arg WHEN */
3657 : {
3658 : /* Ignore the CaseTestExpr and equality operator. */
3659 0 : deparseExpr(lsecond(castNode(OpExpr, whenclause->expr)->args),
3660 0 : context);
3661 : }
3662 :
3663 : /* THEN */
3664 0 : appendStringInfoString(buf, " THEN ");
3665 0 : deparseExpr(whenclause->result, context);
3666 0 : }
3667 :
3668 : /* add ELSE if present */
3669 0 : if (node->defresult != NULL)
3670 : {
3671 0 : appendStringInfoString(buf, " ELSE ");
3672 0 : deparseExpr(node->defresult, context);
3673 0 : }
3674 :
3675 : /* append END */
3676 0 : appendStringInfoString(buf, " END)");
3677 0 : }
3678 :
3679 : /*
3680 : * Deparse ARRAY[...] construct.
3681 : */
3682 : static void
3683 0 : deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
3684 : {
3685 0 : StringInfo buf = context->buf;
3686 0 : bool first = true;
3687 0 : ListCell *lc;
3688 :
3689 0 : appendStringInfoString(buf, "ARRAY[");
3690 0 : foreach(lc, node->elements)
3691 : {
3692 0 : if (!first)
3693 0 : appendStringInfoString(buf, ", ");
3694 0 : deparseExpr(lfirst(lc), context);
3695 0 : first = false;
3696 0 : }
3697 0 : appendStringInfoChar(buf, ']');
3698 :
3699 : /* If the array is empty, we need an explicit cast to the array type. */
3700 0 : if (node->elements == NIL)
3701 0 : appendStringInfo(buf, "::%s",
3702 0 : deparse_type_name(node->array_typeid, -1));
3703 0 : }
3704 :
3705 : /*
3706 : * Deparse an Aggref node.
3707 : */
3708 : static void
3709 0 : deparseAggref(Aggref *node, deparse_expr_cxt *context)
3710 : {
3711 0 : StringInfo buf = context->buf;
3712 0 : bool use_variadic;
3713 :
3714 : /* Only basic, non-split aggregation accepted. */
3715 0 : Assert(node->aggsplit == AGGSPLIT_SIMPLE);
3716 :
3717 : /* Check if need to print VARIADIC (cf. ruleutils.c) */
3718 0 : use_variadic = node->aggvariadic;
3719 :
3720 : /* Find aggregate name from aggfnoid which is a pg_proc entry */
3721 0 : appendFunctionName(node->aggfnoid, context);
3722 0 : appendStringInfoChar(buf, '(');
3723 :
3724 : /* Add DISTINCT */
3725 0 : appendStringInfoString(buf, (node->aggdistinct != NIL) ? "DISTINCT " : "");
3726 :
3727 0 : if (AGGKIND_IS_ORDERED_SET(node->aggkind))
3728 : {
3729 : /* Add WITHIN GROUP (ORDER BY ..) */
3730 0 : ListCell *arg;
3731 0 : bool first = true;
3732 :
3733 0 : Assert(!node->aggvariadic);
3734 0 : Assert(node->aggorder != NIL);
3735 :
3736 0 : foreach(arg, node->aggdirectargs)
3737 : {
3738 0 : if (!first)
3739 0 : appendStringInfoString(buf, ", ");
3740 0 : first = false;
3741 :
3742 0 : deparseExpr((Expr *) lfirst(arg), context);
3743 0 : }
3744 :
3745 0 : appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
3746 0 : appendAggOrderBy(node->aggorder, node->args, context);
3747 0 : }
3748 : else
3749 : {
3750 : /* aggstar can be set only in zero-argument aggregates */
3751 0 : if (node->aggstar)
3752 0 : appendStringInfoChar(buf, '*');
3753 : else
3754 : {
3755 0 : ListCell *arg;
3756 0 : bool first = true;
3757 :
3758 : /* Add all the arguments */
3759 0 : foreach(arg, node->args)
3760 : {
3761 0 : TargetEntry *tle = (TargetEntry *) lfirst(arg);
3762 0 : Node *n = (Node *) tle->expr;
3763 :
3764 0 : if (tle->resjunk)
3765 0 : continue;
3766 :
3767 0 : if (!first)
3768 0 : appendStringInfoString(buf, ", ");
3769 0 : first = false;
3770 :
3771 : /* Add VARIADIC */
3772 0 : if (use_variadic && lnext(node->args, arg) == NULL)
3773 0 : appendStringInfoString(buf, "VARIADIC ");
3774 :
3775 0 : deparseExpr((Expr *) n, context);
3776 0 : }
3777 0 : }
3778 :
3779 : /* Add ORDER BY */
3780 0 : if (node->aggorder != NIL)
3781 : {
3782 0 : appendStringInfoString(buf, " ORDER BY ");
3783 0 : appendAggOrderBy(node->aggorder, node->args, context);
3784 0 : }
3785 : }
3786 :
3787 : /* Add FILTER (WHERE ..) */
3788 0 : if (node->aggfilter != NULL)
3789 : {
3790 0 : appendStringInfoString(buf, ") FILTER (WHERE ");
3791 0 : deparseExpr((Expr *) node->aggfilter, context);
3792 0 : }
3793 :
3794 0 : appendStringInfoChar(buf, ')');
3795 0 : }
3796 :
3797 : /*
3798 : * Append ORDER BY within aggregate function.
3799 : */
3800 : static void
3801 0 : appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
3802 : {
3803 0 : StringInfo buf = context->buf;
3804 0 : ListCell *lc;
3805 0 : bool first = true;
3806 :
3807 0 : foreach(lc, orderList)
3808 : {
3809 0 : SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
3810 0 : Node *sortexpr;
3811 :
3812 0 : if (!first)
3813 0 : appendStringInfoString(buf, ", ");
3814 0 : first = false;
3815 :
3816 : /* Deparse the sort expression proper. */
3817 0 : sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList,
3818 0 : false, context);
3819 : /* Add decoration as needed. */
3820 0 : appendOrderBySuffix(srt->sortop, exprType(sortexpr), srt->nulls_first,
3821 0 : context);
3822 0 : }
3823 0 : }
3824 :
3825 : /*
3826 : * Append the ASC, DESC, USING <OPERATOR> and NULLS FIRST / NULLS LAST parts
3827 : * of an ORDER BY clause.
3828 : */
3829 : static void
3830 0 : appendOrderBySuffix(Oid sortop, Oid sortcoltype, bool nulls_first,
3831 : deparse_expr_cxt *context)
3832 : {
3833 0 : StringInfo buf = context->buf;
3834 0 : TypeCacheEntry *typentry;
3835 :
3836 : /* See whether operator is default < or > for sort expr's datatype. */
3837 0 : typentry = lookup_type_cache(sortcoltype,
3838 : TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
3839 :
3840 0 : if (sortop == typentry->lt_opr)
3841 0 : appendStringInfoString(buf, " ASC");
3842 0 : else if (sortop == typentry->gt_opr)
3843 0 : appendStringInfoString(buf, " DESC");
3844 : else
3845 : {
3846 0 : HeapTuple opertup;
3847 0 : Form_pg_operator operform;
3848 :
3849 0 : appendStringInfoString(buf, " USING ");
3850 :
3851 : /* Append operator name. */
3852 0 : opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(sortop));
3853 0 : if (!HeapTupleIsValid(opertup))
3854 0 : elog(ERROR, "cache lookup failed for operator %u", sortop);
3855 0 : operform = (Form_pg_operator) GETSTRUCT(opertup);
3856 0 : deparseOperatorName(buf, operform);
3857 0 : ReleaseSysCache(opertup);
3858 0 : }
3859 :
3860 0 : if (nulls_first)
3861 0 : appendStringInfoString(buf, " NULLS FIRST");
3862 : else
3863 0 : appendStringInfoString(buf, " NULLS LAST");
3864 0 : }
3865 :
3866 : /*
3867 : * Print the representation of a parameter to be sent to the remote side.
3868 : *
3869 : * Note: we always label the Param's type explicitly rather than relying on
3870 : * transmitting a numeric type OID in PQsendQueryParams(). This allows us to
3871 : * avoid assuming that types have the same OIDs on the remote side as they
3872 : * do locally --- they need only have the same names.
3873 : */
3874 : static void
3875 0 : printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
3876 : deparse_expr_cxt *context)
3877 : {
3878 0 : StringInfo buf = context->buf;
3879 0 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3880 :
3881 0 : appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
3882 0 : }
3883 :
3884 : /*
3885 : * Print the representation of a placeholder for a parameter that will be
3886 : * sent to the remote side at execution time.
3887 : *
3888 : * This is used when we're just trying to EXPLAIN the remote query.
3889 : * We don't have the actual value of the runtime parameter yet, and we don't
3890 : * want the remote planner to generate a plan that depends on such a value
3891 : * anyway. Thus, we can't do something simple like "$1::paramtype".
3892 : * Instead, we emit "((SELECT null::paramtype)::paramtype)".
3893 : * In all extant versions of Postgres, the planner will see that as an unknown
3894 : * constant value, which is what we want. This might need adjustment if we
3895 : * ever make the planner flatten scalar subqueries. Note: the reason for the
3896 : * apparently useless outer cast is to ensure that the representation as a
3897 : * whole will be parsed as an a_expr and not a select_with_parens; the latter
3898 : * would do the wrong thing in the context "x = ANY(...)".
3899 : */
3900 : static void
3901 0 : printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
3902 : deparse_expr_cxt *context)
3903 : {
3904 0 : StringInfo buf = context->buf;
3905 0 : char *ptypename = deparse_type_name(paramtype, paramtypmod);
3906 :
3907 0 : appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
3908 0 : }
3909 :
3910 : /*
3911 : * Deparse GROUP BY clause.
3912 : */
3913 : static void
3914 0 : appendGroupByClause(List *tlist, deparse_expr_cxt *context)
3915 : {
3916 0 : StringInfo buf = context->buf;
3917 0 : Query *query = context->root->parse;
3918 0 : ListCell *lc;
3919 0 : bool first = true;
3920 :
3921 : /* Nothing to be done, if there's no GROUP BY clause in the query. */
3922 0 : if (!query->groupClause)
3923 0 : return;
3924 :
3925 0 : appendStringInfoString(buf, " GROUP BY ");
3926 :
3927 : /*
3928 : * Queries with grouping sets are not pushed down, so we don't expect
3929 : * grouping sets here.
3930 : */
3931 0 : Assert(!query->groupingSets);
3932 :
3933 : /*
3934 : * We intentionally print query->groupClause not processed_groupClause,
3935 : * leaving it to the remote planner to get rid of any redundant GROUP BY
3936 : * items again. This is necessary in case processed_groupClause reduced
3937 : * to empty, and in any case the redundancy situation on the remote might
3938 : * be different than what we think here.
3939 : */
3940 0 : foreach(lc, query->groupClause)
3941 : {
3942 0 : SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
3943 :
3944 0 : if (!first)
3945 0 : appendStringInfoString(buf, ", ");
3946 0 : first = false;
3947 :
3948 0 : deparseSortGroupClause(grp->tleSortGroupRef, tlist, true, context);
3949 0 : }
3950 0 : }
3951 :
3952 : /*
3953 : * Deparse ORDER BY clause defined by the given pathkeys.
3954 : *
3955 : * The clause should use Vars from context->scanrel if !has_final_sort,
3956 : * or from context->foreignrel's targetlist if has_final_sort.
3957 : *
3958 : * We find a suitable pathkey expression (some earlier step
3959 : * should have verified that there is one) and deparse it.
3960 : */
3961 : static void
3962 0 : appendOrderByClause(List *pathkeys, bool has_final_sort,
3963 : deparse_expr_cxt *context)
3964 : {
3965 0 : ListCell *lcell;
3966 0 : int nestlevel;
3967 0 : StringInfo buf = context->buf;
3968 0 : bool gotone = false;
3969 :
3970 : /* Make sure any constants in the exprs are printed portably */
3971 0 : nestlevel = set_transmission_modes();
3972 :
3973 0 : foreach(lcell, pathkeys)
3974 : {
3975 0 : PathKey *pathkey = lfirst(lcell);
3976 0 : EquivalenceMember *em;
3977 0 : Expr *em_expr;
3978 0 : Oid oprid;
3979 :
3980 0 : if (has_final_sort)
3981 : {
3982 : /*
3983 : * By construction, context->foreignrel is the input relation to
3984 : * the final sort.
3985 : */
3986 0 : em = find_em_for_rel_target(context->root,
3987 0 : pathkey->pk_eclass,
3988 0 : context->foreignrel);
3989 0 : }
3990 : else
3991 0 : em = find_em_for_rel(context->root,
3992 0 : pathkey->pk_eclass,
3993 0 : context->scanrel);
3994 :
3995 : /*
3996 : * We don't expect any error here; it would mean that shippability
3997 : * wasn't verified earlier. For the same reason, we don't recheck
3998 : * shippability of the sort operator.
3999 : */
4000 0 : if (em == NULL)
4001 0 : elog(ERROR, "could not find pathkey item to sort");
4002 :
4003 0 : em_expr = em->em_expr;
4004 :
4005 : /*
4006 : * If the member is a Const expression then we needn't add it to the
4007 : * ORDER BY clause. This can happen in UNION ALL queries where the
4008 : * union child targetlist has a Const. Adding these would be
4009 : * wasteful, but also, for INT columns, an integer literal would be
4010 : * seen as an ordinal column position rather than a value to sort by.
4011 : * deparseConst() does have code to handle this, but it seems less
4012 : * effort on all accounts just to skip these for ORDER BY clauses.
4013 : */
4014 0 : if (IsA(em_expr, Const))
4015 0 : continue;
4016 :
4017 0 : if (!gotone)
4018 : {
4019 0 : appendStringInfoString(buf, " ORDER BY ");
4020 0 : gotone = true;
4021 0 : }
4022 : else
4023 0 : appendStringInfoString(buf, ", ");
4024 :
4025 : /*
4026 : * Lookup the operator corresponding to the compare type in the
4027 : * opclass. The datatype used by the opfamily is not necessarily the
4028 : * same as the expression type (for array types for example).
4029 : */
4030 0 : oprid = get_opfamily_member_for_cmptype(pathkey->pk_opfamily,
4031 0 : em->em_datatype,
4032 0 : em->em_datatype,
4033 0 : pathkey->pk_cmptype);
4034 0 : if (!OidIsValid(oprid))
4035 0 : elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
4036 : pathkey->pk_cmptype, em->em_datatype, em->em_datatype,
4037 : pathkey->pk_opfamily);
4038 :
4039 0 : deparseExpr(em_expr, context);
4040 :
4041 : /*
4042 : * Here we need to use the expression's actual type to discover
4043 : * whether the desired operator will be the default or not.
4044 : */
4045 0 : appendOrderBySuffix(oprid, exprType((Node *) em_expr),
4046 0 : pathkey->pk_nulls_first, context);
4047 :
4048 0 : }
4049 0 : reset_transmission_modes(nestlevel);
4050 0 : }
4051 :
4052 : /*
4053 : * Deparse LIMIT/OFFSET clause.
4054 : */
4055 : static void
4056 0 : appendLimitClause(deparse_expr_cxt *context)
4057 : {
4058 0 : PlannerInfo *root = context->root;
4059 0 : StringInfo buf = context->buf;
4060 0 : int nestlevel;
4061 :
4062 : /* Make sure any constants in the exprs are printed portably */
4063 0 : nestlevel = set_transmission_modes();
4064 :
4065 0 : if (root->parse->limitCount)
4066 : {
4067 0 : appendStringInfoString(buf, " LIMIT ");
4068 0 : deparseExpr((Expr *) root->parse->limitCount, context);
4069 0 : }
4070 0 : if (root->parse->limitOffset)
4071 : {
4072 0 : appendStringInfoString(buf, " OFFSET ");
4073 0 : deparseExpr((Expr *) root->parse->limitOffset, context);
4074 0 : }
4075 :
4076 0 : reset_transmission_modes(nestlevel);
4077 0 : }
4078 :
4079 : /*
4080 : * appendFunctionName
4081 : * Deparses function name from given function oid.
4082 : */
4083 : static void
4084 0 : appendFunctionName(Oid funcid, deparse_expr_cxt *context)
4085 : {
4086 0 : StringInfo buf = context->buf;
4087 0 : HeapTuple proctup;
4088 0 : Form_pg_proc procform;
4089 0 : const char *proname;
4090 :
4091 0 : proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
4092 0 : if (!HeapTupleIsValid(proctup))
4093 0 : elog(ERROR, "cache lookup failed for function %u", funcid);
4094 0 : procform = (Form_pg_proc) GETSTRUCT(proctup);
4095 :
4096 : /* Print schema name only if it's not pg_catalog */
4097 0 : if (procform->pronamespace != PG_CATALOG_NAMESPACE)
4098 : {
4099 0 : const char *schemaname;
4100 :
4101 0 : schemaname = get_namespace_name(procform->pronamespace);
4102 0 : appendStringInfo(buf, "%s.", quote_identifier(schemaname));
4103 0 : }
4104 :
4105 : /* Always print the function name */
4106 0 : proname = NameStr(procform->proname);
4107 0 : appendStringInfoString(buf, quote_identifier(proname));
4108 :
4109 0 : ReleaseSysCache(proctup);
4110 0 : }
4111 :
4112 : /*
4113 : * Appends a sort or group clause.
4114 : *
4115 : * Like get_rule_sortgroupclause(), returns the expression tree, so caller
4116 : * need not find it again.
4117 : */
4118 : static Node *
4119 0 : deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
4120 : deparse_expr_cxt *context)
4121 : {
4122 0 : StringInfo buf = context->buf;
4123 0 : TargetEntry *tle;
4124 0 : Expr *expr;
4125 :
4126 0 : tle = get_sortgroupref_tle(ref, tlist);
4127 0 : expr = tle->expr;
4128 :
4129 0 : if (force_colno)
4130 : {
4131 : /* Use column-number form when requested by caller. */
4132 0 : Assert(!tle->resjunk);
4133 0 : appendStringInfo(buf, "%d", tle->resno);
4134 0 : }
4135 0 : else if (expr && IsA(expr, Const))
4136 : {
4137 : /*
4138 : * Force a typecast here so that we don't emit something like "GROUP
4139 : * BY 2", which will be misconstrued as a column position rather than
4140 : * a constant.
4141 : */
4142 0 : deparseConst((Const *) expr, context, 1);
4143 0 : }
4144 0 : else if (!expr || IsA(expr, Var))
4145 0 : deparseExpr(expr, context);
4146 : else
4147 : {
4148 : /* Always parenthesize the expression. */
4149 0 : appendStringInfoChar(buf, '(');
4150 0 : deparseExpr(expr, context);
4151 0 : appendStringInfoChar(buf, ')');
4152 : }
4153 :
4154 0 : return (Node *) expr;
4155 0 : }
4156 :
4157 :
4158 : /*
4159 : * Returns true if given Var is deparsed as a subquery output column, in
4160 : * which case, *relno and *colno are set to the IDs for the relation and
4161 : * column alias to the Var provided by the subquery.
4162 : */
4163 : static bool
4164 0 : is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
4165 : {
4166 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
4167 0 : RelOptInfo *outerrel = fpinfo->outerrel;
4168 0 : RelOptInfo *innerrel = fpinfo->innerrel;
4169 :
4170 : /* Should only be called in these cases. */
4171 0 : Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
4172 :
4173 : /*
4174 : * If the given relation isn't a join relation, it doesn't have any lower
4175 : * subqueries, so the Var isn't a subquery output column.
4176 : */
4177 0 : if (!IS_JOIN_REL(foreignrel))
4178 0 : return false;
4179 :
4180 : /*
4181 : * If the Var doesn't belong to any lower subqueries, it isn't a subquery
4182 : * output column.
4183 : */
4184 0 : if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
4185 0 : return false;
4186 :
4187 0 : if (bms_is_member(node->varno, outerrel->relids))
4188 : {
4189 : /*
4190 : * If outer relation is deparsed as a subquery, the Var is an output
4191 : * column of the subquery; get the IDs for the relation/column alias.
4192 : */
4193 0 : if (fpinfo->make_outerrel_subquery)
4194 : {
4195 0 : get_relation_column_alias_ids(node, outerrel, relno, colno);
4196 0 : return true;
4197 : }
4198 :
4199 : /* Otherwise, recurse into the outer relation. */
4200 0 : return is_subquery_var(node, outerrel, relno, colno);
4201 : }
4202 : else
4203 : {
4204 0 : Assert(bms_is_member(node->varno, innerrel->relids));
4205 :
4206 : /*
4207 : * If inner relation is deparsed as a subquery, the Var is an output
4208 : * column of the subquery; get the IDs for the relation/column alias.
4209 : */
4210 0 : if (fpinfo->make_innerrel_subquery)
4211 : {
4212 0 : get_relation_column_alias_ids(node, innerrel, relno, colno);
4213 0 : return true;
4214 : }
4215 :
4216 : /* Otherwise, recurse into the inner relation. */
4217 0 : return is_subquery_var(node, innerrel, relno, colno);
4218 : }
4219 0 : }
4220 :
4221 : /*
4222 : * Get the IDs for the relation and column alias to given Var belonging to
4223 : * given relation, which are returned into *relno and *colno.
4224 : */
4225 : static void
4226 0 : get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
4227 : int *relno, int *colno)
4228 : {
4229 0 : PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
4230 0 : int i;
4231 0 : ListCell *lc;
4232 :
4233 : /* Get the relation alias ID */
4234 0 : *relno = fpinfo->relation_index;
4235 :
4236 : /* Get the column alias ID */
4237 0 : i = 1;
4238 0 : foreach(lc, foreignrel->reltarget->exprs)
4239 : {
4240 0 : Var *tlvar = (Var *) lfirst(lc);
4241 :
4242 : /*
4243 : * Match reltarget entries only on varno/varattno. Ideally there
4244 : * would be some cross-check on varnullingrels, but it's unclear what
4245 : * to do exactly; we don't have enough context to know what that value
4246 : * should be.
4247 : */
4248 0 : if (IsA(tlvar, Var) &&
4249 0 : tlvar->varno == node->varno &&
4250 0 : tlvar->varattno == node->varattno)
4251 : {
4252 0 : *colno = i;
4253 0 : return;
4254 : }
4255 0 : i++;
4256 0 : }
4257 :
4258 : /* Shouldn't get here */
4259 0 : elog(ERROR, "unexpected expression in subquery output");
4260 0 : }
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