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deparse.c
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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) 2012-2023, 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_namespace.h"
43 #include "catalog/pg_operator.h"
44 #include "catalog/pg_opfamily.h"
45 #include "catalog/pg_proc.h"
46 #include "catalog/pg_ts_config.h"
47 #include "catalog/pg_ts_dict.h"
48 #include "catalog/pg_type.h"
49 #include "commands/defrem.h"
50 #include "nodes/makefuncs.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 #include "commands/tablecmds.h"
64 
65 /*
66  * Global context for foreign_expr_walker's search of an expression tree.
67  */
68 typedef struct foreign_glob_cxt
69 {
70  PlannerInfo *root; /* global planner state */
71  RelOptInfo *foreignrel; /* the foreign relation we are planning for */
72  Relids relids; /* relids of base relations in the underlying
73  * scan */
74 } foreign_glob_cxt;
75 
76 /*
77  * Local (per-tree-level) context for foreign_expr_walker's search.
78  * This is concerned with identifying collations used in the expression.
79  */
80 typedef enum
81 {
82  FDW_COLLATE_NONE, /* expression is of a noncollatable type, or
83  * it has default collation that is not
84  * traceable to a foreign Var */
85  FDW_COLLATE_SAFE, /* collation derives from a foreign Var */
86  FDW_COLLATE_UNSAFE /* collation is non-default and derives from
87  * something other than a foreign Var */
88 } FDWCollateState;
89 
90 typedef struct foreign_loc_cxt
91 {
92  Oid collation; /* OID of current collation, if any */
93  FDWCollateState state; /* state of current collation choice */
94 } foreign_loc_cxt;
95 
96 /*
97  * Context for deparseExpr
98  */
99 typedef struct deparse_expr_cxt
100 {
101  PlannerInfo *root; /* global planner state */
102  RelOptInfo *foreignrel; /* the foreign relation we are planning for */
103  RelOptInfo *scanrel; /* the underlying scan relation. Same as
104  * foreignrel, when that represents a join or
105  * a base relation. */
106  StringInfo buf; /* output buffer to append to */
107  List **params_list; /* exprs that will become remote Params */
108 } deparse_expr_cxt;
109 
110 #define REL_ALIAS_PREFIX "r"
111 /* Handy macro to add relation name qualification */
112 #define ADD_REL_QUALIFIER(buf, varno) \
113  appendStringInfo((buf), "%s%d.", REL_ALIAS_PREFIX, (varno))
114 #define SUBQUERY_REL_ALIAS_PREFIX "s"
115 #define SUBQUERY_COL_ALIAS_PREFIX "c"
116 
117 /*
118  * Functions to determine whether an expression can be evaluated safely on
119  * remote server.
120  */
121 static bool foreign_expr_walker(Node *node,
122  foreign_glob_cxt *glob_cxt,
123  foreign_loc_cxt *outer_cxt,
124  foreign_loc_cxt *case_arg_cxt);
125 static char *deparse_type_name(Oid type_oid, int32 typemod);
126 
127 /*
128  * Functions to construct string representation of a node tree.
129  */
130 static void deparseTargetList(StringInfo buf,
131  RangeTblEntry *rte,
132  Index rtindex,
133  Relation rel,
134  bool is_returning,
135  Bitmapset *attrs_used,
136  bool qualify_col,
137  List **retrieved_attrs);
138 static void deparseExplicitTargetList(List *tlist,
139  bool is_returning,
140  List **retrieved_attrs,
141  deparse_expr_cxt *context);
142 static void deparseSubqueryTargetList(deparse_expr_cxt *context);
143 static void deparseReturningList(StringInfo buf, RangeTblEntry *rte,
144  Index rtindex, Relation rel,
145  bool trig_after_row,
146  List *withCheckOptionList,
147  List *returningList,
148  List **retrieved_attrs);
149 static void deparseColumnRef(StringInfo buf, int varno, int varattno,
150  RangeTblEntry *rte, bool qualify_col);
151 static void deparseRelation(StringInfo buf, Relation rel);
152 static void deparseExpr(Expr *node, deparse_expr_cxt *context);
153 static void deparseVar(Var *node, deparse_expr_cxt *context);
154 static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype);
155 static void deparseParam(Param *node, deparse_expr_cxt *context);
156 static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context);
157 static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context);
158 static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context);
159 static bool isPlainForeignVar(Expr *node, deparse_expr_cxt *context);
160 static void deparseOperatorName(StringInfo buf, Form_pg_operator opform);
161 static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context);
162 static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node,
163  deparse_expr_cxt *context);
164 static void deparseRelabelType(RelabelType *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 **params_list);
184 static void deparseFromExpr(List *quals, deparse_expr_cxt *context);
185 static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root,
186  RelOptInfo *foreignrel, bool make_subquery,
187  Index ignore_rel, List **ignore_conds, List **params_list);
188 static void deparseAggref(Aggref *node, deparse_expr_cxt *context);
189 static void appendGroupByClause(List *tlist, deparse_expr_cxt *context);
190 static void appendOrderBySuffix(Oid sortop, Oid sortcoltype, bool nulls_first,
191  deparse_expr_cxt *context);
192 static void appendAggOrderBy(List *orderList, List *targetList,
193  deparse_expr_cxt *context);
194 static void appendFunctionName(Oid funcid, deparse_expr_cxt *context);
195 static Node *deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
196  deparse_expr_cxt *context);
197 
198 /*
199  * Helper functions
200  */
201 static bool is_subquery_var(Var *node, RelOptInfo *foreignrel,
202  int *relno, int *colno);
203 static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
204  int *relno, int *colno);
205 
206 
207 /*
208  * Examine each qual clause in input_conds, and classify them into two groups,
209  * which are returned as two lists:
210  * - remote_conds contains expressions that can be evaluated remotely
211  * - local_conds contains expressions that can't be evaluated remotely
212  */
213 void
214 classifyConditions(PlannerInfo *root,
215  RelOptInfo *baserel,
216  List *input_conds,
217  List **remote_conds,
218  List **local_conds)
219 {
220  ListCell *lc;
221 
222  *remote_conds = NIL;
223  *local_conds = NIL;
224 
225  foreach(lc, input_conds)
226  {
227  RestrictInfo *ri = lfirst_node(RestrictInfo, lc);
228 
229  if (is_foreign_expr(root, baserel, ri->clause))
230  *remote_conds = lappend(*remote_conds, ri);
231  else
232  *local_conds = lappend(*local_conds, ri);
233  }
234 }
235 
236 /*
237  * Returns true if given expr is safe to evaluate on the foreign server.
238  */
239 bool
240 is_foreign_expr(PlannerInfo *root,
241  RelOptInfo *baserel,
242  Expr *expr)
243 {
244  foreign_glob_cxt glob_cxt;
245  foreign_loc_cxt loc_cxt;
246  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
247 
248  /*
249  * Check that the expression consists of nodes that are safe to execute
250  * remotely.
251  */
252  glob_cxt.root = root;
253  glob_cxt.foreignrel = baserel;
254 
255  /*
256  * For an upper relation, use relids from its underneath scan relation,
257  * because the upperrel's own relids currently aren't set to anything
258  * meaningful by the core code. For other relation, use their own relids.
259  */
260  if (IS_UPPER_REL(baserel))
261  glob_cxt.relids = fpinfo->outerrel->relids;
262  else
263  glob_cxt.relids = baserel->relids;
264  loc_cxt.collation = InvalidOid;
265  loc_cxt.state = FDW_COLLATE_NONE;
266  if (!foreign_expr_walker((Node *) expr, &glob_cxt, &loc_cxt, NULL))
267  return false;
268 
269  /*
270  * If the expression has a valid collation that does not arise from a
271  * foreign var, the expression can not be sent over.
272  */
273  if (loc_cxt.state == FDW_COLLATE_UNSAFE)
274  return false;
275 
276  /*
277  * An expression which includes any mutable functions can't be sent over
278  * because its result is not stable. For example, sending now() remote
279  * side could cause confusion from clock offsets. Future versions might
280  * be able to make this choice with more granularity. (We check this last
281  * because it requires a lot of expensive catalog lookups.)
282  */
283  if (contain_mutable_functions((Node *) expr))
284  return false;
285 
286  /* OK to evaluate on the remote server */
287  return true;
288 }
289 
290 /*
291  * Check if expression is safe to execute remotely, and return true if so.
292  *
293  * In addition, *outer_cxt is updated with collation information.
294  *
295  * case_arg_cxt is NULL if this subexpression is not inside a CASE-with-arg.
296  * Otherwise, it points to the collation info derived from the arg expression,
297  * which must be consulted by any CaseTestExpr.
298  *
299  * We must check that the expression contains only node types we can deparse,
300  * that all types/functions/operators are safe to send (they are "shippable"),
301  * and that all collations used in the expression derive from Vars of the
302  * foreign table. Because of the latter, the logic is pretty close to
303  * assign_collations_walker() in parse_collate.c, though we can assume here
304  * that the given expression is valid. Note function mutability is not
305  * currently considered here.
306  */
307 static bool
308 foreign_expr_walker(Node *node,
309  foreign_glob_cxt *glob_cxt,
310  foreign_loc_cxt *outer_cxt,
311  foreign_loc_cxt *case_arg_cxt)
312 {
313  bool check_type = true;
314  PgFdwRelationInfo *fpinfo;
315  foreign_loc_cxt inner_cxt;
316  Oid collation;
317  FDWCollateState state;
318 
319  /* Need do nothing for empty subexpressions */
320  if (node == NULL)
321  return true;
322 
323  /* May need server info from baserel's fdw_private struct */
324  fpinfo = (PgFdwRelationInfo *) (glob_cxt->foreignrel->fdw_private);
325 
326  /* Set up inner_cxt for possible recursion to child nodes */
327  inner_cxt.collation = InvalidOid;
328  inner_cxt.state = FDW_COLLATE_NONE;
329 
330  switch (nodeTag(node))
331  {
332  case T_Var:
333  {
334  Var *var = (Var *) node;
335 
336  /*
337  * If the Var is from the foreign table, we consider its
338  * collation (if any) safe to use. If it is from another
339  * table, we treat its collation the same way as we would a
340  * Param's collation, ie it's not safe for it to have a
341  * non-default collation.
342  */
343  if (bms_is_member(var->varno, glob_cxt->relids) &&
344  var->varlevelsup == 0)
345  {
346  /* Var belongs to foreign table */
347 
348  /*
349  * System columns other than ctid should not be sent to
350  * the remote, since we don't make any effort to ensure
351  * that local and remote values match (tableoid, in
352  * particular, almost certainly doesn't match).
353  */
354  if (var->varattno < 0 &&
355  var->varattno != SelfItemPointerAttributeNumber)
356  return false;
357 
358  /* Else check the collation */
359  collation = var->varcollid;
360  state = OidIsValid(collation) ? FDW_COLLATE_SAFE : FDW_COLLATE_NONE;
361  }
362  else
363  {
364  /* Var belongs to some other table */
365  collation = var->varcollid;
366  if (collation == InvalidOid ||
367  collation == DEFAULT_COLLATION_OID)
368  {
369  /*
370  * It's noncollatable, or it's safe to combine with a
371  * collatable foreign Var, so set state to NONE.
372  */
373  state = FDW_COLLATE_NONE;
374  }
375  else
376  {
377  /*
378  * Do not fail right away, since the Var might appear
379  * in a collation-insensitive context.
380  */
381  state = FDW_COLLATE_UNSAFE;
382  }
383  }
384  }
385  break;
386  case T_Const:
387  {
388  Const *c = (Const *) node;
389 
390  /*
391  * Constants of regproc and related types can't be shipped
392  * unless the referenced object is shippable. But NULL's ok.
393  * (See also the related code in dependency.c.)
394  */
395  if (!c->constisnull)
396  {
397  switch (c->consttype)
398  {
399  case REGPROCOID:
400  case REGPROCEDUREOID:
401  if (!is_shippable(DatumGetObjectId(c->constvalue),
402  ProcedureRelationId, fpinfo))
403  return false;
404  break;
405  case REGOPEROID:
406  case REGOPERATOROID:
407  if (!is_shippable(DatumGetObjectId(c->constvalue),
408  OperatorRelationId, fpinfo))
409  return false;
410  break;
411  case REGCLASSOID:
412  if (!is_shippable(DatumGetObjectId(c->constvalue),
413  RelationRelationId, fpinfo))
414  return false;
415  break;
416  case REGTYPEOID:
417  if (!is_shippable(DatumGetObjectId(c->constvalue),
418  TypeRelationId, fpinfo))
419  return false;
420  break;
421  case REGCOLLATIONOID:
422  if (!is_shippable(DatumGetObjectId(c->constvalue),
423  CollationRelationId, fpinfo))
424  return false;
425  break;
426  case REGCONFIGOID:
427 
428  /*
429  * For text search objects only, we weaken the
430  * normal shippability criterion to allow all OIDs
431  * below FirstNormalObjectId. Without this, none
432  * of the initdb-installed TS configurations would
433  * be shippable, which would be quite annoying.
434  */
435  if (DatumGetObjectId(c->constvalue) >= FirstNormalObjectId &&
436  !is_shippable(DatumGetObjectId(c->constvalue),
437  TSConfigRelationId, fpinfo))
438  return false;
439  break;
440  case REGDICTIONARYOID:
441  if (DatumGetObjectId(c->constvalue) >= FirstNormalObjectId &&
442  !is_shippable(DatumGetObjectId(c->constvalue),
443  TSDictionaryRelationId, fpinfo))
444  return false;
445  break;
446  case REGNAMESPACEOID:
447  if (!is_shippable(DatumGetObjectId(c->constvalue),
448  NamespaceRelationId, fpinfo))
449  return false;
450  break;
451  case REGROLEOID:
452  if (!is_shippable(DatumGetObjectId(c->constvalue),
453  AuthIdRelationId, fpinfo))
454  return false;
455  break;
456  }
457  }
458 
459  /*
460  * If the constant has nondefault collation, either it's of a
461  * non-builtin type, or it reflects folding of a CollateExpr.
462  * It's unsafe to send to the remote unless it's used in a
463  * non-collation-sensitive context.
464  */
465  collation = c->constcollid;
466  if (collation == InvalidOid ||
467  collation == DEFAULT_COLLATION_OID)
468  state = FDW_COLLATE_NONE;
469  else
470  state = FDW_COLLATE_UNSAFE;
471  }
472  break;
473  case T_Param:
474  {
475  Param *p = (Param *) node;
476 
477  /*
478  * If it's a MULTIEXPR Param, punt. We can't tell from here
479  * whether the referenced sublink/subplan contains any remote
480  * Vars; if it does, handling that is too complicated to
481  * consider supporting at present. Fortunately, MULTIEXPR
482  * Params are not reduced to plain PARAM_EXEC until the end of
483  * planning, so we can easily detect this case. (Normal
484  * PARAM_EXEC Params are safe to ship because their values
485  * come from somewhere else in the plan tree; but a MULTIEXPR
486  * references a sub-select elsewhere in the same targetlist,
487  * so we'd be on the hook to evaluate it somehow if we wanted
488  * to handle such cases as direct foreign updates.)
489  */
490  if (p->paramkind == PARAM_MULTIEXPR)
491  return false;
492 
493  /*
494  * Collation rule is same as for Consts and non-foreign Vars.
495  */
496  collation = p->paramcollid;
497  if (collation == InvalidOid ||
498  collation == DEFAULT_COLLATION_OID)
499  state = FDW_COLLATE_NONE;
500  else
501  state = FDW_COLLATE_UNSAFE;
502  }
503  break;
504  case T_SubscriptingRef:
505  {
506  SubscriptingRef *sr = (SubscriptingRef *) node;
507 
508  /* Assignment should not be in restrictions. */
509  if (sr->refassgnexpr != NULL)
510  return false;
511 
512  /*
513  * Recurse into the remaining subexpressions. The container
514  * subscripts will not affect collation of the SubscriptingRef
515  * result, so do those first and reset inner_cxt afterwards.
516  */
517  if (!foreign_expr_walker((Node *) sr->refupperindexpr,
518  glob_cxt, &inner_cxt, case_arg_cxt))
519  return false;
520  inner_cxt.collation = InvalidOid;
521  inner_cxt.state = FDW_COLLATE_NONE;
522  if (!foreign_expr_walker((Node *) sr->reflowerindexpr,
523  glob_cxt, &inner_cxt, case_arg_cxt))
524  return false;
525  inner_cxt.collation = InvalidOid;
526  inner_cxt.state = FDW_COLLATE_NONE;
527  if (!foreign_expr_walker((Node *) sr->refexpr,
528  glob_cxt, &inner_cxt, case_arg_cxt))
529  return false;
530 
531  /*
532  * Container subscripting typically yields same collation as
533  * refexpr's, but in case it doesn't, use same logic as for
534  * function nodes.
535  */
536  collation = sr->refcollid;
537  if (collation == InvalidOid)
538  state = FDW_COLLATE_NONE;
539  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
540  collation == inner_cxt.collation)
541  state = FDW_COLLATE_SAFE;
542  else if (collation == DEFAULT_COLLATION_OID)
543  state = FDW_COLLATE_NONE;
544  else
545  state = FDW_COLLATE_UNSAFE;
546  }
547  break;
548  case T_FuncExpr:
549  {
550  FuncExpr *fe = (FuncExpr *) node;
551 
552  /*
553  * If function used by the expression is not shippable, it
554  * can't be sent to remote because it might have incompatible
555  * semantics on remote side.
556  */
557  if (!is_shippable(fe->funcid, ProcedureRelationId, fpinfo))
558  return false;
559 
560  /*
561  * Recurse to input subexpressions.
562  */
563  if (!foreign_expr_walker((Node *) fe->args,
564  glob_cxt, &inner_cxt, case_arg_cxt))
565  return false;
566 
567  /*
568  * If function's input collation is not derived from a foreign
569  * Var, it can't be sent to remote.
570  */
571  if (fe->inputcollid == InvalidOid)
572  /* OK, inputs are all noncollatable */ ;
573  else if (inner_cxt.state != FDW_COLLATE_SAFE ||
574  fe->inputcollid != inner_cxt.collation)
575  return false;
576 
577  /*
578  * Detect whether node is introducing a collation not derived
579  * from a foreign Var. (If so, we just mark it unsafe for now
580  * rather than immediately returning false, since the parent
581  * node might not care.)
582  */
583  collation = fe->funccollid;
584  if (collation == InvalidOid)
585  state = FDW_COLLATE_NONE;
586  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
587  collation == inner_cxt.collation)
588  state = FDW_COLLATE_SAFE;
589  else if (collation == DEFAULT_COLLATION_OID)
590  state = FDW_COLLATE_NONE;
591  else
592  state = FDW_COLLATE_UNSAFE;
593  }
594  break;
595  case T_OpExpr:
596  case T_DistinctExpr: /* struct-equivalent to OpExpr */
597  {
598  OpExpr *oe = (OpExpr *) node;
599 
600  /*
601  * Similarly, only shippable operators can be sent to remote.
602  * (If the operator is shippable, we assume its underlying
603  * function is too.)
604  */
605  if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
606  return false;
607 
608  /*
609  * Recurse to input subexpressions.
610  */
611  if (!foreign_expr_walker((Node *) oe->args,
612  glob_cxt, &inner_cxt, case_arg_cxt))
613  return false;
614 
615  /*
616  * If operator's input collation is not derived from a foreign
617  * Var, it can't be sent to remote.
618  */
619  if (oe->inputcollid == InvalidOid)
620  /* OK, inputs are all noncollatable */ ;
621  else if (inner_cxt.state != FDW_COLLATE_SAFE ||
622  oe->inputcollid != inner_cxt.collation)
623  return false;
624 
625  /* Result-collation handling is same as for functions */
626  collation = oe->opcollid;
627  if (collation == InvalidOid)
628  state = FDW_COLLATE_NONE;
629  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
630  collation == inner_cxt.collation)
631  state = FDW_COLLATE_SAFE;
632  else if (collation == DEFAULT_COLLATION_OID)
633  state = FDW_COLLATE_NONE;
634  else
635  state = FDW_COLLATE_UNSAFE;
636  }
637  break;
638  case T_ScalarArrayOpExpr:
639  {
640  ScalarArrayOpExpr *oe = (ScalarArrayOpExpr *) node;
641 
642  /*
643  * Again, only shippable operators can be sent to remote.
644  */
645  if (!is_shippable(oe->opno, OperatorRelationId, fpinfo))
646  return false;
647 
648  /*
649  * Recurse to input subexpressions.
650  */
651  if (!foreign_expr_walker((Node *) oe->args,
652  glob_cxt, &inner_cxt, case_arg_cxt))
653  return false;
654 
655  /*
656  * If operator's input collation is not derived from a foreign
657  * Var, it can't be sent to remote.
658  */
659  if (oe->inputcollid == InvalidOid)
660  /* OK, inputs are all noncollatable */ ;
661  else if (inner_cxt.state != FDW_COLLATE_SAFE ||
662  oe->inputcollid != inner_cxt.collation)
663  return false;
664 
665  /* Output is always boolean and so noncollatable. */
666  collation = InvalidOid;
667  state = FDW_COLLATE_NONE;
668  }
669  break;
670  case T_RelabelType:
671  {
672  RelabelType *r = (RelabelType *) node;
673 
674  /*
675  * Recurse to input subexpression.
676  */
677  if (!foreign_expr_walker((Node *) r->arg,
678  glob_cxt, &inner_cxt, case_arg_cxt))
679  return false;
680 
681  /*
682  * RelabelType must not introduce a collation not derived from
683  * an input foreign Var (same logic as for a real function).
684  */
685  collation = r->resultcollid;
686  if (collation == InvalidOid)
687  state = FDW_COLLATE_NONE;
688  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
689  collation == inner_cxt.collation)
690  state = FDW_COLLATE_SAFE;
691  else if (collation == DEFAULT_COLLATION_OID)
692  state = FDW_COLLATE_NONE;
693  else
694  state = FDW_COLLATE_UNSAFE;
695  }
696  break;
697  case T_BoolExpr:
698  {
699  BoolExpr *b = (BoolExpr *) node;
700 
701  /*
702  * Recurse to input subexpressions.
703  */
704  if (!foreign_expr_walker((Node *) b->args,
705  glob_cxt, &inner_cxt, case_arg_cxt))
706  return false;
707 
708  /* Output is always boolean and so noncollatable. */
709  collation = InvalidOid;
710  state = FDW_COLLATE_NONE;
711  }
712  break;
713  case T_NullTest:
714  {
715  NullTest *nt = (NullTest *) node;
716 
717  /*
718  * Recurse to input subexpressions.
719  */
720  if (!foreign_expr_walker((Node *) nt->arg,
721  glob_cxt, &inner_cxt, case_arg_cxt))
722  return false;
723 
724  /* Output is always boolean and so noncollatable. */
725  collation = InvalidOid;
726  state = FDW_COLLATE_NONE;
727  }
728  break;
729  case T_CaseExpr:
730  {
731  CaseExpr *ce = (CaseExpr *) node;
732  foreign_loc_cxt arg_cxt;
733  foreign_loc_cxt tmp_cxt;
734  ListCell *lc;
735 
736  /*
737  * Recurse to CASE's arg expression, if any. Its collation
738  * has to be saved aside for use while examining CaseTestExprs
739  * within the WHEN expressions.
740  */
741  arg_cxt.collation = InvalidOid;
742  arg_cxt.state = FDW_COLLATE_NONE;
743  if (ce->arg)
744  {
745  if (!foreign_expr_walker((Node *) ce->arg,
746  glob_cxt, &arg_cxt, case_arg_cxt))
747  return false;
748  }
749 
750  /* Examine the CaseWhen subexpressions. */
751  foreach(lc, ce->args)
752  {
753  CaseWhen *cw = lfirst_node(CaseWhen, lc);
754 
755  if (ce->arg)
756  {
757  /*
758  * In a CASE-with-arg, the parser should have produced
759  * WHEN clauses of the form "CaseTestExpr = RHS",
760  * possibly with an implicit coercion inserted above
761  * the CaseTestExpr. However in an expression that's
762  * been through the optimizer, the WHEN clause could
763  * be almost anything (since the equality operator
764  * could have been expanded into an inline function).
765  * In such cases forbid pushdown, because
766  * deparseCaseExpr can't handle it.
767  */
768  Node *whenExpr = (Node *) cw->expr;
769  List *opArgs;
770 
771  if (!IsA(whenExpr, OpExpr))
772  return false;
773 
774  opArgs = ((OpExpr *) whenExpr)->args;
775  if (list_length(opArgs) != 2 ||
776  !IsA(strip_implicit_coercions(linitial(opArgs)),
777  CaseTestExpr))
778  return false;
779  }
780 
781  /*
782  * Recurse to WHEN expression, passing down the arg info.
783  * Its collation doesn't affect the result (really, it
784  * should be boolean and thus not have a collation).
785  */
786  tmp_cxt.collation = InvalidOid;
787  tmp_cxt.state = FDW_COLLATE_NONE;
788  if (!foreign_expr_walker((Node *) cw->expr,
789  glob_cxt, &tmp_cxt, &arg_cxt))
790  return false;
791 
792  /* Recurse to THEN expression. */
793  if (!foreign_expr_walker((Node *) cw->result,
794  glob_cxt, &inner_cxt, case_arg_cxt))
795  return false;
796  }
797 
798  /* Recurse to ELSE expression. */
799  if (!foreign_expr_walker((Node *) ce->defresult,
800  glob_cxt, &inner_cxt, case_arg_cxt))
801  return false;
802 
803  /*
804  * Detect whether node is introducing a collation not derived
805  * from a foreign Var. (If so, we just mark it unsafe for now
806  * rather than immediately returning false, since the parent
807  * node might not care.) This is the same as for function
808  * nodes, except that the input collation is derived from only
809  * the THEN and ELSE subexpressions.
810  */
811  collation = ce->casecollid;
812  if (collation == InvalidOid)
813  state = FDW_COLLATE_NONE;
814  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
815  collation == inner_cxt.collation)
816  state = FDW_COLLATE_SAFE;
817  else if (collation == DEFAULT_COLLATION_OID)
818  state = FDW_COLLATE_NONE;
819  else
820  state = FDW_COLLATE_UNSAFE;
821  }
822  break;
823  case T_CaseTestExpr:
824  {
825  CaseTestExpr *c = (CaseTestExpr *) node;
826 
827  /* Punt if we seem not to be inside a CASE arg WHEN. */
828  if (!case_arg_cxt)
829  return false;
830 
831  /*
832  * Otherwise, any nondefault collation attached to the
833  * CaseTestExpr node must be derived from foreign Var(s) in
834  * the CASE arg.
835  */
836  collation = c->collation;
837  if (collation == InvalidOid)
838  state = FDW_COLLATE_NONE;
839  else if (case_arg_cxt->state == FDW_COLLATE_SAFE &&
840  collation == case_arg_cxt->collation)
841  state = FDW_COLLATE_SAFE;
842  else if (collation == DEFAULT_COLLATION_OID)
843  state = FDW_COLLATE_NONE;
844  else
845  state = FDW_COLLATE_UNSAFE;
846  }
847  break;
848  case T_ArrayExpr:
849  {
850  ArrayExpr *a = (ArrayExpr *) node;
851 
852  /*
853  * Recurse to input subexpressions.
854  */
855  if (!foreign_expr_walker((Node *) a->elements,
856  glob_cxt, &inner_cxt, case_arg_cxt))
857  return false;
858 
859  /*
860  * ArrayExpr must not introduce a collation not derived from
861  * an input foreign Var (same logic as for a function).
862  */
863  collation = a->array_collid;
864  if (collation == InvalidOid)
865  state = FDW_COLLATE_NONE;
866  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
867  collation == inner_cxt.collation)
868  state = FDW_COLLATE_SAFE;
869  else if (collation == DEFAULT_COLLATION_OID)
870  state = FDW_COLLATE_NONE;
871  else
872  state = FDW_COLLATE_UNSAFE;
873  }
874  break;
875  case T_List:
876  {
877  List *l = (List *) node;
878  ListCell *lc;
879 
880  /*
881  * Recurse to component subexpressions.
882  */
883  foreach(lc, l)
884  {
885  if (!foreign_expr_walker((Node *) lfirst(lc),
886  glob_cxt, &inner_cxt, case_arg_cxt))
887  return false;
888  }
889 
890  /*
891  * When processing a list, collation state just bubbles up
892  * from the list elements.
893  */
894  collation = inner_cxt.collation;
895  state = inner_cxt.state;
896 
897  /* Don't apply exprType() to the list. */
898  check_type = false;
899  }
900  break;
901  case T_Aggref:
902  {
903  Aggref *agg = (Aggref *) node;
904  ListCell *lc;
905 
906  /* Not safe to pushdown when not in grouping context */
907  if (!IS_UPPER_REL(glob_cxt->foreignrel))
908  return false;
909 
910  /* Only non-split aggregates are pushable. */
911  if (agg->aggsplit != AGGSPLIT_SIMPLE)
912  return false;
913 
914  /* As usual, it must be shippable. */
915  if (!is_shippable(agg->aggfnoid, ProcedureRelationId, fpinfo))
916  return false;
917 
918  /*
919  * Recurse to input args. aggdirectargs, aggorder and
920  * aggdistinct are all present in args, so no need to check
921  * their shippability explicitly.
922  */
923  foreach(lc, agg->args)
924  {
925  Node *n = (Node *) lfirst(lc);
926 
927  /* If TargetEntry, extract the expression from it */
928  if (IsA(n, TargetEntry))
929  {
930  TargetEntry *tle = (TargetEntry *) n;
931 
932  n = (Node *) tle->expr;
933  }
934 
935  if (!foreign_expr_walker(n,
936  glob_cxt, &inner_cxt, case_arg_cxt))
937  return false;
938  }
939 
940  /*
941  * For aggorder elements, check whether the sort operator, if
942  * specified, is shippable or not.
943  */
944  if (agg->aggorder)
945  {
946  foreach(lc, agg->aggorder)
947  {
948  SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
949  Oid sortcoltype;
950  TypeCacheEntry *typentry;
951  TargetEntry *tle;
952 
953  tle = get_sortgroupref_tle(srt->tleSortGroupRef,
954  agg->args);
955  sortcoltype = exprType((Node *) tle->expr);
956  typentry = lookup_type_cache(sortcoltype,
957  TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
958  /* Check shippability of non-default sort operator. */
959  if (srt->sortop != typentry->lt_opr &&
960  srt->sortop != typentry->gt_opr &&
961  !is_shippable(srt->sortop, OperatorRelationId,
962  fpinfo))
963  return false;
964  }
965  }
966 
967  /* Check aggregate filter */
968  if (!foreign_expr_walker((Node *) agg->aggfilter,
969  glob_cxt, &inner_cxt, case_arg_cxt))
970  return false;
971 
972  /*
973  * If aggregate's input collation is not derived from a
974  * foreign Var, it can't be sent to remote.
975  */
976  if (agg->inputcollid == InvalidOid)
977  /* OK, inputs are all noncollatable */ ;
978  else if (inner_cxt.state != FDW_COLLATE_SAFE ||
979  agg->inputcollid != inner_cxt.collation)
980  return false;
981 
982  /*
983  * Detect whether node is introducing a collation not derived
984  * from a foreign Var. (If so, we just mark it unsafe for now
985  * rather than immediately returning false, since the parent
986  * node might not care.)
987  */
988  collation = agg->aggcollid;
989  if (collation == InvalidOid)
990  state = FDW_COLLATE_NONE;
991  else if (inner_cxt.state == FDW_COLLATE_SAFE &&
992  collation == inner_cxt.collation)
993  state = FDW_COLLATE_SAFE;
994  else if (collation == DEFAULT_COLLATION_OID)
995  state = FDW_COLLATE_NONE;
996  else
997  state = FDW_COLLATE_UNSAFE;
998  }
999  break;
1000  default:
1001 
1002  /*
1003  * If it's anything else, assume it's unsafe. This list can be
1004  * expanded later, but don't forget to add deparse support below.
1005  */
1006  return false;
1007  }
1008 
1009  /*
1010  * If result type of given expression is not shippable, it can't be sent
1011  * to remote because it might have incompatible semantics on remote side.
1012  */
1013  if (check_type && !is_shippable(exprType(node), TypeRelationId, fpinfo))
1014  return false;
1015 
1016  /*
1017  * Now, merge my collation information into my parent's state.
1018  */
1019  if (state > outer_cxt->state)
1020  {
1021  /* Override previous parent state */
1022  outer_cxt->collation = collation;
1023  outer_cxt->state = state;
1024  }
1025  else if (state == outer_cxt->state)
1026  {
1027  /* Merge, or detect error if there's a collation conflict */
1028  switch (state)
1029  {
1030  case FDW_COLLATE_NONE:
1031  /* Nothing + nothing is still nothing */
1032  break;
1033  case FDW_COLLATE_SAFE:
1034  if (collation != outer_cxt->collation)
1035  {
1036  /*
1037  * Non-default collation always beats default.
1038  */
1039  if (outer_cxt->collation == DEFAULT_COLLATION_OID)
1040  {
1041  /* Override previous parent state */
1042  outer_cxt->collation = collation;
1043  }
1044  else if (collation != DEFAULT_COLLATION_OID)
1045  {
1046  /*
1047  * Conflict; show state as indeterminate. We don't
1048  * want to "return false" right away, since parent
1049  * node might not care about collation.
1050  */
1051  outer_cxt->state = FDW_COLLATE_UNSAFE;
1052  }
1053  }
1054  break;
1055  case FDW_COLLATE_UNSAFE:
1056  /* We're still conflicted ... */
1057  break;
1058  }
1059  }
1060 
1061  /* It looks OK */
1062  return true;
1063 }
1064 
1065 /*
1066  * Returns true if given expr is something we'd have to send the value of
1067  * to the foreign server.
1068  *
1069  * This should return true when the expression is a shippable node that
1070  * deparseExpr would add to context->params_list. Note that we don't care
1071  * if the expression *contains* such a node, only whether one appears at top
1072  * level. We need this to detect cases where setrefs.c would recognize a
1073  * false match between an fdw_exprs item (which came from the params_list)
1074  * and an entry in fdw_scan_tlist (which we're considering putting the given
1075  * expression into).
1076  */
1077 bool
1078 is_foreign_param(PlannerInfo *root,
1079  RelOptInfo *baserel,
1080  Expr *expr)
1081 {
1082  if (expr == NULL)
1083  return false;
1084 
1085  switch (nodeTag(expr))
1086  {
1087  case T_Var:
1088  {
1089  /* It would have to be sent unless it's a foreign Var */
1090  Var *var = (Var *) expr;
1091  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) (baserel->fdw_private);
1092  Relids relids;
1093 
1094  if (IS_UPPER_REL(baserel))
1095  relids = fpinfo->outerrel->relids;
1096  else
1097  relids = baserel->relids;
1098 
1099  if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
1100  return false; /* foreign Var, so not a param */
1101  else
1102  return true; /* it'd have to be a param */
1103  break;
1104  }
1105  case T_Param:
1106  /* Params always have to be sent to the foreign server */
1107  return true;
1108  default:
1109  break;
1110  }
1111  return false;
1112 }
1113 
1114 /*
1115  * Returns true if it's safe to push down the sort expression described by
1116  * 'pathkey' to the foreign server.
1117  */
1118 bool
1119 is_foreign_pathkey(PlannerInfo *root,
1120  RelOptInfo *baserel,
1121  PathKey *pathkey)
1122 {
1123  EquivalenceClass *pathkey_ec = pathkey->pk_eclass;
1124  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) baserel->fdw_private;
1125 
1126  /*
1127  * is_foreign_expr would detect volatile expressions as well, but checking
1128  * ec_has_volatile here saves some cycles.
1129  */
1130  if (pathkey_ec->ec_has_volatile)
1131  return false;
1132 
1133  /* can't push down the sort if the pathkey's opfamily is not shippable */
1134  if (!is_shippable(pathkey->pk_opfamily, OperatorFamilyRelationId, fpinfo))
1135  return false;
1136 
1137  /* can push if a suitable EC member exists */
1138  return (find_em_for_rel(root, pathkey_ec, baserel) != NULL);
1139 }
1140 
1141 /*
1142  * Convert type OID + typmod info into a type name we can ship to the remote
1143  * server. Someplace else had better have verified that this type name is
1144  * expected to be known on the remote end.
1145  *
1146  * This is almost just format_type_with_typemod(), except that if left to its
1147  * own devices, that function will make schema-qualification decisions based
1148  * on the local search_path, which is wrong. We must schema-qualify all
1149  * type names that are not in pg_catalog. We assume here that built-in types
1150  * are all in pg_catalog and need not be qualified; otherwise, qualify.
1151  */
1152 static char *
1153 deparse_type_name(Oid type_oid, int32 typemod)
1154 {
1155  bits16 flags = FORMAT_TYPE_TYPEMOD_GIVEN;
1156 
1157  if (!is_builtin(type_oid))
1158  flags |= FORMAT_TYPE_FORCE_QUALIFY;
1159 
1160  return format_type_extended(type_oid, typemod, flags);
1161 }
1162 
1163 /*
1164  * Build the targetlist for given relation to be deparsed as SELECT clause.
1165  *
1166  * The output targetlist contains the columns that need to be fetched from the
1167  * foreign server for the given relation. If foreignrel is an upper relation,
1168  * then the output targetlist can also contain expressions to be evaluated on
1169  * foreign server.
1170  */
1171 List *
1172 build_tlist_to_deparse(RelOptInfo *foreignrel)
1173 {
1174  List *tlist = NIL;
1175  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1176  ListCell *lc;
1177 
1178  /*
1179  * For an upper relation, we have already built the target list while
1180  * checking shippability, so just return that.
1181  */
1182  if (IS_UPPER_REL(foreignrel))
1183  return fpinfo->grouped_tlist;
1184 
1185  /*
1186  * We require columns specified in foreignrel->reltarget->exprs and those
1187  * required for evaluating the local conditions.
1188  */
1189  tlist = add_to_flat_tlist(tlist,
1190  pull_var_clause((Node *) foreignrel->reltarget->exprs,
1191  PVC_RECURSE_PLACEHOLDERS));
1192  foreach(lc, fpinfo->local_conds)
1193  {
1194  RestrictInfo *rinfo = lfirst_node(RestrictInfo, lc);
1195 
1196  tlist = add_to_flat_tlist(tlist,
1197  pull_var_clause((Node *) rinfo->clause,
1198  PVC_RECURSE_PLACEHOLDERS));
1199  }
1200 
1201  return tlist;
1202 }
1203 
1204 /*
1205  * Deparse SELECT statement for given relation into buf.
1206  *
1207  * tlist contains the list of desired columns to be fetched from foreign server.
1208  * For a base relation fpinfo->attrs_used is used to construct SELECT clause,
1209  * hence the tlist is ignored for a base relation.
1210  *
1211  * remote_conds is the list of conditions to be deparsed into the WHERE clause
1212  * (or, in the case of upper relations, into the HAVING clause).
1213  *
1214  * If params_list is not NULL, it receives a list of Params and other-relation
1215  * Vars used in the clauses; these values must be transmitted to the remote
1216  * server as parameter values.
1217  *
1218  * If params_list is NULL, we're generating the query for EXPLAIN purposes,
1219  * so Params and other-relation Vars should be replaced by dummy values.
1220  *
1221  * pathkeys is the list of pathkeys to order the result by.
1222  *
1223  * is_subquery is the flag to indicate whether to deparse the specified
1224  * relation as a subquery.
1225  *
1226  * List of columns selected is returned in retrieved_attrs.
1227  */
1228 void
1229 deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel,
1230  List *tlist, List *remote_conds, List *pathkeys,
1231  bool has_final_sort, bool has_limit, bool is_subquery,
1232  List **retrieved_attrs, List **params_list)
1233 {
1234  deparse_expr_cxt context;
1235  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1236  List *quals;
1237 
1238  /*
1239  * We handle relations for foreign tables, joins between those and upper
1240  * relations.
1241  */
1242  Assert(IS_JOIN_REL(rel) || IS_SIMPLE_REL(rel) || IS_UPPER_REL(rel));
1243 
1244  /* Fill portions of context common to upper, join and base relation */
1245  context.buf = buf;
1246  context.root = root;
1247  context.foreignrel = rel;
1248  context.scanrel = IS_UPPER_REL(rel) ? fpinfo->outerrel : rel;
1249  context.params_list = params_list;
1250 
1251  /* Construct SELECT clause */
1252  deparseSelectSql(tlist, is_subquery, retrieved_attrs, &context);
1253 
1254  /*
1255  * For upper relations, the WHERE clause is built from the remote
1256  * conditions of the underlying scan relation; otherwise, we can use the
1257  * supplied list of remote conditions directly.
1258  */
1259  if (IS_UPPER_REL(rel))
1260  {
1261  PgFdwRelationInfo *ofpinfo;
1262 
1263  ofpinfo = (PgFdwRelationInfo *) fpinfo->outerrel->fdw_private;
1264  quals = ofpinfo->remote_conds;
1265  }
1266  else
1267  quals = remote_conds;
1268 
1269  /* Construct FROM and WHERE clauses */
1270  deparseFromExpr(quals, &context);
1271 
1272  if (IS_UPPER_REL(rel))
1273  {
1274  /* Append GROUP BY clause */
1275  appendGroupByClause(tlist, &context);
1276 
1277  /* Append HAVING clause */
1278  if (remote_conds)
1279  {
1280  appendStringInfoString(buf, " HAVING ");
1281  appendConditions(remote_conds, &context);
1282  }
1283  }
1284 
1285  /* Add ORDER BY clause if we found any useful pathkeys */
1286  if (pathkeys)
1287  appendOrderByClause(pathkeys, has_final_sort, &context);
1288 
1289  /* Add LIMIT clause if necessary */
1290  if (has_limit)
1291  appendLimitClause(&context);
1292 
1293  /* Add any necessary FOR UPDATE/SHARE. */
1294  deparseLockingClause(&context);
1295 }
1296 
1297 /*
1298  * Construct a simple SELECT statement that retrieves desired columns
1299  * of the specified foreign table, and append it to "buf". The output
1300  * contains just "SELECT ... ".
1301  *
1302  * We also create an integer List of the columns being retrieved, which is
1303  * returned to *retrieved_attrs, unless we deparse the specified relation
1304  * as a subquery.
1305  *
1306  * tlist is the list of desired columns. is_subquery is the flag to
1307  * indicate whether to deparse the specified relation as a subquery.
1308  * Read prologue of deparseSelectStmtForRel() for details.
1309  */
1310 static void
1311 deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs,
1312  deparse_expr_cxt *context)
1313 {
1314  StringInfo buf = context->buf;
1315  RelOptInfo *foreignrel = context->foreignrel;
1316  PlannerInfo *root = context->root;
1317  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1318 
1319  /*
1320  * Construct SELECT list
1321  */
1322  appendStringInfoString(buf, "SELECT ");
1323 
1324  if (is_subquery)
1325  {
1326  /*
1327  * For a relation that is deparsed as a subquery, emit expressions
1328  * specified in the relation's reltarget. Note that since this is for
1329  * the subquery, no need to care about *retrieved_attrs.
1330  */
1331  deparseSubqueryTargetList(context);
1332  }
1333  else if (IS_JOIN_REL(foreignrel) || IS_UPPER_REL(foreignrel))
1334  {
1335  /*
1336  * For a join or upper relation the input tlist gives the list of
1337  * columns required to be fetched from the foreign server.
1338  */
1339  deparseExplicitTargetList(tlist, false, retrieved_attrs, context);
1340  }
1341  else
1342  {
1343  /*
1344  * For a base relation fpinfo->attrs_used gives the list of columns
1345  * required to be fetched from the foreign server.
1346  */
1347  RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1348 
1349  /*
1350  * Core code already has some lock on each rel being planned, so we
1351  * can use NoLock here.
1352  */
1353  Relation rel = table_open(rte->relid, NoLock);
1354 
1355  deparseTargetList(buf, rte, foreignrel->relid, rel, false,
1356  fpinfo->attrs_used, false, retrieved_attrs);
1357  table_close(rel, NoLock);
1358  }
1359 }
1360 
1361 /*
1362  * Construct a FROM clause and, if needed, a WHERE clause, and append those to
1363  * "buf".
1364  *
1365  * quals is the list of clauses to be included in the WHERE clause.
1366  * (These may or may not include RestrictInfo decoration.)
1367  */
1368 static void
1369 deparseFromExpr(List *quals, deparse_expr_cxt *context)
1370 {
1371  StringInfo buf = context->buf;
1372  RelOptInfo *scanrel = context->scanrel;
1373 
1374  /* For upper relations, scanrel must be either a joinrel or a baserel */
1375  Assert(!IS_UPPER_REL(context->foreignrel) ||
1376  IS_JOIN_REL(scanrel) || IS_SIMPLE_REL(scanrel));
1377 
1378  /* Construct FROM clause */
1379  appendStringInfoString(buf, " FROM ");
1380  deparseFromExprForRel(buf, context->root, scanrel,
1381  (bms_membership(scanrel->relids) == BMS_MULTIPLE),
1382  (Index) 0, NULL, context->params_list);
1383 
1384  /* Construct WHERE clause */
1385  if (quals != NIL)
1386  {
1387  appendStringInfoString(buf, " WHERE ");
1388  appendConditions(quals, context);
1389  }
1390 }
1391 
1392 /*
1393  * Emit a target list that retrieves the columns specified in attrs_used.
1394  * This is used for both SELECT and RETURNING targetlists; the is_returning
1395  * parameter is true only for a RETURNING targetlist.
1396  *
1397  * The tlist text is appended to buf, and we also create an integer List
1398  * of the columns being retrieved, which is returned to *retrieved_attrs.
1399  *
1400  * If qualify_col is true, add relation alias before the column name.
1401  */
1402 static void
1403 deparseTargetList(StringInfo buf,
1404  RangeTblEntry *rte,
1405  Index rtindex,
1406  Relation rel,
1407  bool is_returning,
1408  Bitmapset *attrs_used,
1409  bool qualify_col,
1410  List **retrieved_attrs)
1411 {
1412  TupleDesc tupdesc = RelationGetDescr(rel);
1413  bool have_wholerow;
1414  bool first;
1415  int i;
1416 
1417  *retrieved_attrs = NIL;
1418 
1419  /* If there's a whole-row reference, we'll need all the columns. */
1420  have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber,
1421  attrs_used);
1422 
1423  first = true;
1424  for (i = 1; i <= tupdesc->natts; i++)
1425  {
1426  Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
1427 
1428  /* Ignore dropped attributes. */
1429  if (attr->attisdropped)
1430  continue;
1431 
1432  if (have_wholerow ||
1433  bms_is_member(i - FirstLowInvalidHeapAttributeNumber,
1434  attrs_used))
1435  {
1436  if (!first)
1437  appendStringInfoString(buf, ", ");
1438  else if (is_returning)
1439  appendStringInfoString(buf, " RETURNING ");
1440  first = false;
1441 
1442  deparseColumnRef(buf, rtindex, i, rte, qualify_col);
1443 
1444  *retrieved_attrs = lappend_int(*retrieved_attrs, i);
1445  }
1446  }
1447 
1448  /*
1449  * Add ctid if needed. We currently don't support retrieving any other
1450  * system columns.
1451  */
1452  if (bms_is_member(SelfItemPointerAttributeNumber - FirstLowInvalidHeapAttributeNumber,
1453  attrs_used))
1454  {
1455  if (!first)
1456  appendStringInfoString(buf, ", ");
1457  else if (is_returning)
1458  appendStringInfoString(buf, " RETURNING ");
1459  first = false;
1460 
1461  if (qualify_col)
1462  ADD_REL_QUALIFIER(buf, rtindex);
1463  appendStringInfoString(buf, "ctid");
1464 
1465  *retrieved_attrs = lappend_int(*retrieved_attrs,
1466  SelfItemPointerAttributeNumber);
1467  }
1468 
1469  /* Don't generate bad syntax if no undropped columns */
1470  if (first && !is_returning)
1471  appendStringInfoString(buf, "NULL");
1472 }
1473 
1474 /*
1475  * Deparse the appropriate locking clause (FOR UPDATE or FOR SHARE) for a
1476  * given relation (context->scanrel).
1477  */
1478 static void
1479 deparseLockingClause(deparse_expr_cxt *context)
1480 {
1481  StringInfo buf = context->buf;
1482  PlannerInfo *root = context->root;
1483  RelOptInfo *rel = context->scanrel;
1484  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) rel->fdw_private;
1485  int relid = -1;
1486 
1487  while ((relid = bms_next_member(rel->relids, relid)) >= 0)
1488  {
1489  /*
1490  * Ignore relation if it appears in a lower subquery. Locking clause
1491  * for such a relation is included in the subquery if necessary.
1492  */
1493  if (bms_is_member(relid, fpinfo->lower_subquery_rels))
1494  continue;
1495 
1496  /*
1497  * Add FOR UPDATE/SHARE if appropriate. We apply locking during the
1498  * initial row fetch, rather than later on as is done for local
1499  * tables. The extra roundtrips involved in trying to duplicate the
1500  * local semantics exactly don't seem worthwhile (see also comments
1501  * for RowMarkType).
1502  *
1503  * Note: because we actually run the query as a cursor, this assumes
1504  * that DECLARE CURSOR ... FOR UPDATE is supported, which it isn't
1505  * before 8.3.
1506  */
1507  if (bms_is_member(relid, root->all_result_relids) &&
1508  (root->parse->commandType == CMD_UPDATE ||
1509  root->parse->commandType == CMD_DELETE))
1510  {
1511  /* Relation is UPDATE/DELETE target, so use FOR UPDATE */
1512  appendStringInfoString(buf, " FOR UPDATE");
1513 
1514  /* Add the relation alias if we are here for a join relation */
1515  if (IS_JOIN_REL(rel))
1516  appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1517  }
1518  else
1519  {
1520  PlanRowMark *rc = get_plan_rowmark(root->rowMarks, relid);
1521 
1522  if (rc)
1523  {
1524  /*
1525  * Relation is specified as a FOR UPDATE/SHARE target, so
1526  * handle that. (But we could also see LCS_NONE, meaning this
1527  * isn't a target relation after all.)
1528  *
1529  * For now, just ignore any [NO] KEY specification, since (a)
1530  * it's not clear what that means for a remote table that we
1531  * don't have complete information about, and (b) it wouldn't
1532  * work anyway on older remote servers. Likewise, we don't
1533  * worry about NOWAIT.
1534  */
1535  switch (rc->strength)
1536  {
1537  case LCS_NONE:
1538  /* No locking needed */
1539  break;
1540  case LCS_FORKEYSHARE:
1541  case LCS_FORSHARE:
1542  appendStringInfoString(buf, " FOR SHARE");
1543  break;
1544  case LCS_FORNOKEYUPDATE:
1545  case LCS_FORUPDATE:
1546  appendStringInfoString(buf, " FOR UPDATE");
1547  break;
1548  }
1549 
1550  /* Add the relation alias if we are here for a join relation */
1551  if (bms_membership(rel->relids) == BMS_MULTIPLE &&
1552  rc->strength != LCS_NONE)
1553  appendStringInfo(buf, " OF %s%d", REL_ALIAS_PREFIX, relid);
1554  }
1555  }
1556  }
1557 }
1558 
1559 /*
1560  * Deparse conditions from the provided list and append them to buf.
1561  *
1562  * The conditions in the list are assumed to be ANDed. This function is used to
1563  * deparse WHERE clauses, JOIN .. ON clauses and HAVING clauses.
1564  *
1565  * Depending on the caller, the list elements might be either RestrictInfos
1566  * or bare clauses.
1567  */
1568 static void
1569 appendConditions(List *exprs, deparse_expr_cxt *context)
1570 {
1571  int nestlevel;
1572  ListCell *lc;
1573  bool is_first = true;
1574  StringInfo buf = context->buf;
1575 
1576  /* Make sure any constants in the exprs are printed portably */
1577  nestlevel = set_transmission_modes();
1578 
1579  foreach(lc, exprs)
1580  {
1581  Expr *expr = (Expr *) lfirst(lc);
1582 
1583  /* Extract clause from RestrictInfo, if required */
1584  if (IsA(expr, RestrictInfo))
1585  expr = ((RestrictInfo *) expr)->clause;
1586 
1587  /* Connect expressions with "AND" and parenthesize each condition. */
1588  if (!is_first)
1589  appendStringInfoString(buf, " AND ");
1590 
1591  appendStringInfoChar(buf, '(');
1592  deparseExpr(expr, context);
1593  appendStringInfoChar(buf, ')');
1594 
1595  is_first = false;
1596  }
1597 
1598  reset_transmission_modes(nestlevel);
1599 }
1600 
1601 /* Output join name for given join type */
1602 const char *
1603 get_jointype_name(JoinType jointype)
1604 {
1605  switch (jointype)
1606  {
1607  case JOIN_INNER:
1608  return "INNER";
1609 
1610  case JOIN_LEFT:
1611  return "LEFT";
1612 
1613  case JOIN_RIGHT:
1614  return "RIGHT";
1615 
1616  case JOIN_FULL:
1617  return "FULL";
1618 
1619  default:
1620  /* Shouldn't come here, but protect from buggy code. */
1621  elog(ERROR, "unsupported join type %d", jointype);
1622  }
1623 
1624  /* Keep compiler happy */
1625  return NULL;
1626 }
1627 
1628 /*
1629  * Deparse given targetlist and append it to context->buf.
1630  *
1631  * tlist is list of TargetEntry's which in turn contain Var nodes.
1632  *
1633  * retrieved_attrs is the list of continuously increasing integers starting
1634  * from 1. It has same number of entries as tlist.
1635  *
1636  * This is used for both SELECT and RETURNING targetlists; the is_returning
1637  * parameter is true only for a RETURNING targetlist.
1638  */
1639 static void
1640 deparseExplicitTargetList(List *tlist,
1641  bool is_returning,
1642  List **retrieved_attrs,
1643  deparse_expr_cxt *context)
1644 {
1645  ListCell *lc;
1646  StringInfo buf = context->buf;
1647  int i = 0;
1648 
1649  *retrieved_attrs = NIL;
1650 
1651  foreach(lc, tlist)
1652  {
1653  TargetEntry *tle = lfirst_node(TargetEntry, lc);
1654 
1655  if (i > 0)
1656  appendStringInfoString(buf, ", ");
1657  else if (is_returning)
1658  appendStringInfoString(buf, " RETURNING ");
1659 
1660  deparseExpr((Expr *) tle->expr, context);
1661 
1662  *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
1663  i++;
1664  }
1665 
1666  if (i == 0 && !is_returning)
1667  appendStringInfoString(buf, "NULL");
1668 }
1669 
1670 /*
1671  * Emit expressions specified in the given relation's reltarget.
1672  *
1673  * This is used for deparsing the given relation as a subquery.
1674  */
1675 static void
1676 deparseSubqueryTargetList(deparse_expr_cxt *context)
1677 {
1678  StringInfo buf = context->buf;
1679  RelOptInfo *foreignrel = context->foreignrel;
1680  bool first;
1681  ListCell *lc;
1682 
1683  /* Should only be called in these cases. */
1684  Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1685 
1686  first = true;
1687  foreach(lc, foreignrel->reltarget->exprs)
1688  {
1689  Node *node = (Node *) lfirst(lc);
1690 
1691  if (!first)
1692  appendStringInfoString(buf, ", ");
1693  first = false;
1694 
1695  deparseExpr((Expr *) node, context);
1696  }
1697 
1698  /* Don't generate bad syntax if no expressions */
1699  if (first)
1700  appendStringInfoString(buf, "NULL");
1701 }
1702 
1703 /*
1704  * Construct FROM clause for given relation
1705  *
1706  * The function constructs ... JOIN ... ON ... for join relation. For a base
1707  * relation it just returns schema-qualified tablename, with the appropriate
1708  * alias if so requested.
1709  *
1710  * 'ignore_rel' is either zero or the RT index of a target relation. In the
1711  * latter case the function constructs FROM clause of UPDATE or USING clause
1712  * of DELETE; it deparses the join relation as if the relation never contained
1713  * the target relation, and creates a List of conditions to be deparsed into
1714  * the top-level WHERE clause, which is returned to *ignore_conds.
1715  */
1716 static void
1717 deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1718  bool use_alias, Index ignore_rel, List **ignore_conds,
1719  List **params_list)
1720 {
1721  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1722 
1723  if (IS_JOIN_REL(foreignrel))
1724  {
1725  StringInfoData join_sql_o;
1726  StringInfoData join_sql_i;
1727  RelOptInfo *outerrel = fpinfo->outerrel;
1728  RelOptInfo *innerrel = fpinfo->innerrel;
1729  bool outerrel_is_target = false;
1730  bool innerrel_is_target = false;
1731 
1732  if (ignore_rel > 0 && bms_is_member(ignore_rel, foreignrel->relids))
1733  {
1734  /*
1735  * If this is an inner join, add joinclauses to *ignore_conds and
1736  * set it to empty so that those can be deparsed into the WHERE
1737  * clause. Note that since the target relation can never be
1738  * within the nullable side of an outer join, those could safely
1739  * be pulled up into the WHERE clause (see foreign_join_ok()).
1740  * Note also that since the target relation is only inner-joined
1741  * to any other relation in the query, all conditions in the join
1742  * tree mentioning the target relation could be deparsed into the
1743  * WHERE clause by doing this recursively.
1744  */
1745  if (fpinfo->jointype == JOIN_INNER)
1746  {
1747  *ignore_conds = list_concat(*ignore_conds,
1748  fpinfo->joinclauses);
1749  fpinfo->joinclauses = NIL;
1750  }
1751 
1752  /*
1753  * Check if either of the input relations is the target relation.
1754  */
1755  if (outerrel->relid == ignore_rel)
1756  outerrel_is_target = true;
1757  else if (innerrel->relid == ignore_rel)
1758  innerrel_is_target = true;
1759  }
1760 
1761  /* Deparse outer relation if not the target relation. */
1762  if (!outerrel_is_target)
1763  {
1764  initStringInfo(&join_sql_o);
1765  deparseRangeTblRef(&join_sql_o, root, outerrel,
1766  fpinfo->make_outerrel_subquery,
1767  ignore_rel, ignore_conds, params_list);
1768 
1769  /*
1770  * If inner relation is the target relation, skip deparsing it.
1771  * Note that since the join of the target relation with any other
1772  * relation in the query is an inner join and can never be within
1773  * the nullable side of an outer join, the join could be
1774  * interchanged with higher-level joins (cf. identity 1 on outer
1775  * join reordering shown in src/backend/optimizer/README), which
1776  * means it's safe to skip the target-relation deparsing here.
1777  */
1778  if (innerrel_is_target)
1779  {
1780  Assert(fpinfo->jointype == JOIN_INNER);
1781  Assert(fpinfo->joinclauses == NIL);
1782  appendBinaryStringInfo(buf, join_sql_o.data, join_sql_o.len);
1783  return;
1784  }
1785  }
1786 
1787  /* Deparse inner relation if not the target relation. */
1788  if (!innerrel_is_target)
1789  {
1790  initStringInfo(&join_sql_i);
1791  deparseRangeTblRef(&join_sql_i, root, innerrel,
1792  fpinfo->make_innerrel_subquery,
1793  ignore_rel, ignore_conds, params_list);
1794 
1795  /*
1796  * If outer relation is the target relation, skip deparsing it.
1797  * See the above note about safety.
1798  */
1799  if (outerrel_is_target)
1800  {
1801  Assert(fpinfo->jointype == JOIN_INNER);
1802  Assert(fpinfo->joinclauses == NIL);
1803  appendBinaryStringInfo(buf, join_sql_i.data, join_sql_i.len);
1804  return;
1805  }
1806  }
1807 
1808  /* Neither of the relations is the target relation. */
1809  Assert(!outerrel_is_target && !innerrel_is_target);
1810 
1811  /*
1812  * For a join relation FROM clause entry is deparsed as
1813  *
1814  * ((outer relation) <join type> (inner relation) ON (joinclauses))
1815  */
1816  appendStringInfo(buf, "(%s %s JOIN %s ON ", join_sql_o.data,
1817  get_jointype_name(fpinfo->jointype), join_sql_i.data);
1818 
1819  /* Append join clause; (TRUE) if no join clause */
1820  if (fpinfo->joinclauses)
1821  {
1822  deparse_expr_cxt context;
1823 
1824  context.buf = buf;
1825  context.foreignrel = foreignrel;
1826  context.scanrel = foreignrel;
1827  context.root = root;
1828  context.params_list = params_list;
1829 
1830  appendStringInfoChar(buf, '(');
1831  appendConditions(fpinfo->joinclauses, &context);
1832  appendStringInfoChar(buf, ')');
1833  }
1834  else
1835  appendStringInfoString(buf, "(TRUE)");
1836 
1837  /* End the FROM clause entry. */
1838  appendStringInfoChar(buf, ')');
1839  }
1840  else
1841  {
1842  RangeTblEntry *rte = planner_rt_fetch(foreignrel->relid, root);
1843 
1844  /*
1845  * Core code already has some lock on each rel being planned, so we
1846  * can use NoLock here.
1847  */
1848  Relation rel = table_open(rte->relid, NoLock);
1849 
1850  deparseRelation(buf, rel);
1851 
1852  /*
1853  * Add a unique alias to avoid any conflict in relation names due to
1854  * pulled up subqueries in the query being built for a pushed down
1855  * join.
1856  */
1857  if (use_alias)
1858  appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, foreignrel->relid);
1859 
1860  table_close(rel, NoLock);
1861  }
1862 }
1863 
1864 /*
1865  * Append FROM clause entry for the given relation into buf.
1866  */
1867 static void
1868 deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel,
1869  bool make_subquery, Index ignore_rel, List **ignore_conds,
1870  List **params_list)
1871 {
1872  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
1873 
1874  /* Should only be called in these cases. */
1875  Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
1876 
1877  Assert(fpinfo->local_conds == NIL);
1878 
1879  /* If make_subquery is true, deparse the relation as a subquery. */
1880  if (make_subquery)
1881  {
1882  List *retrieved_attrs;
1883  int ncols;
1884 
1885  /*
1886  * The given relation shouldn't contain the target relation, because
1887  * this should only happen for input relations for a full join, and
1888  * such relations can never contain an UPDATE/DELETE target.
1889  */
1890  Assert(ignore_rel == 0 ||
1891  !bms_is_member(ignore_rel, foreignrel->relids));
1892 
1893  /* Deparse the subquery representing the relation. */
1894  appendStringInfoChar(buf, '(');
1895  deparseSelectStmtForRel(buf, root, foreignrel, NIL,
1896  fpinfo->remote_conds, NIL,
1897  false, false, true,
1898  &retrieved_attrs, params_list);
1899  appendStringInfoChar(buf, ')');
1900 
1901  /* Append the relation alias. */
1902  appendStringInfo(buf, " %s%d", SUBQUERY_REL_ALIAS_PREFIX,
1903  fpinfo->relation_index);
1904 
1905  /*
1906  * Append the column aliases if needed. Note that the subquery emits
1907  * expressions specified in the relation's reltarget (see
1908  * deparseSubqueryTargetList).
1909  */
1910  ncols = list_length(foreignrel->reltarget->exprs);
1911  if (ncols > 0)
1912  {
1913  int i;
1914 
1915  appendStringInfoChar(buf, '(');
1916  for (i = 1; i <= ncols; i++)
1917  {
1918  if (i > 1)
1919  appendStringInfoString(buf, ", ");
1920 
1921  appendStringInfo(buf, "%s%d", SUBQUERY_COL_ALIAS_PREFIX, i);
1922  }
1923  appendStringInfoChar(buf, ')');
1924  }
1925  }
1926  else
1927  deparseFromExprForRel(buf, root, foreignrel, true, ignore_rel,
1928  ignore_conds, params_list);
1929 }
1930 
1931 /*
1932  * deparse remote INSERT statement
1933  *
1934  * The statement text is appended to buf, and we also create an integer List
1935  * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
1936  * which is returned to *retrieved_attrs.
1937  *
1938  * This also stores end position of the VALUES clause, so that we can rebuild
1939  * an INSERT for a batch of rows later.
1940  */
1941 void
1942 deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
1943  Index rtindex, Relation rel,
1944  List *targetAttrs, bool doNothing,
1945  List *withCheckOptionList, List *returningList,
1946  List **retrieved_attrs, int *values_end_len)
1947 {
1948  TupleDesc tupdesc = RelationGetDescr(rel);
1949  AttrNumber pindex;
1950  bool first;
1951  ListCell *lc;
1952 
1953  appendStringInfoString(buf, "INSERT INTO ");
1954  deparseRelation(buf, rel);
1955 
1956  if (targetAttrs)
1957  {
1958  appendStringInfoChar(buf, '(');
1959 
1960  first = true;
1961  foreach(lc, targetAttrs)
1962  {
1963  int attnum = lfirst_int(lc);
1964 
1965  if (!first)
1966  appendStringInfoString(buf, ", ");
1967  first = false;
1968 
1969  deparseColumnRef(buf, rtindex, attnum, rte, false);
1970  }
1971 
1972  appendStringInfoString(buf, ") VALUES (");
1973 
1974  pindex = 1;
1975  first = true;
1976  foreach(lc, targetAttrs)
1977  {
1978  int attnum = lfirst_int(lc);
1979  Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
1980 
1981  if (!first)
1982  appendStringInfoString(buf, ", ");
1983  first = false;
1984 
1985  if (attr->attgenerated)
1986  appendStringInfoString(buf, "DEFAULT");
1987  else
1988  {
1989  appendStringInfo(buf, "$%d", pindex);
1990  pindex++;
1991  }
1992  }
1993 
1994  appendStringInfoChar(buf, ')');
1995  }
1996  else
1997  appendStringInfoString(buf, " DEFAULT VALUES");
1998  *values_end_len = buf->len;
1999 
2000  if (doNothing)
2001  appendStringInfoString(buf, " ON CONFLICT DO NOTHING");
2002 
2003  deparseReturningList(buf, rte, rtindex, rel,
2004  rel->trigdesc && rel->trigdesc->trig_insert_after_row,
2005  withCheckOptionList, returningList, retrieved_attrs);
2006 }
2007 
2008 /*
2009  * rebuild remote INSERT statement
2010  *
2011  * Provided a number of rows in a batch, builds INSERT statement with the
2012  * right number of parameters.
2013  */
2014 void
2015 rebuildInsertSql(StringInfo buf, Relation rel,
2016  char *orig_query, List *target_attrs,
2017  int values_end_len, int num_params,
2018  int num_rows)
2019 {
2020  TupleDesc tupdesc = RelationGetDescr(rel);
2021  int i;
2022  int pindex;
2023  bool first;
2024  ListCell *lc;
2025 
2026  /* Make sure the values_end_len is sensible */
2027  Assert((values_end_len > 0) && (values_end_len <= strlen(orig_query)));
2028 
2029  /* Copy up to the end of the first record from the original query */
2030  appendBinaryStringInfo(buf, orig_query, values_end_len);
2031 
2032  /*
2033  * Add records to VALUES clause (we already have parameters for the first
2034  * row, so start at the right offset).
2035  */
2036  pindex = num_params + 1;
2037  for (i = 0; i < num_rows; i++)
2038  {
2039  appendStringInfoString(buf, ", (");
2040 
2041  first = true;
2042  foreach(lc, target_attrs)
2043  {
2044  int attnum = lfirst_int(lc);
2045  Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
2046 
2047  if (!first)
2048  appendStringInfoString(buf, ", ");
2049  first = false;
2050 
2051  if (attr->attgenerated)
2052  appendStringInfoString(buf, "DEFAULT");
2053  else
2054  {
2055  appendStringInfo(buf, "$%d", pindex);
2056  pindex++;
2057  }
2058  }
2059 
2060  appendStringInfoChar(buf, ')');
2061  }
2062 
2063  /* Copy stuff after VALUES clause from the original query */
2064  appendStringInfoString(buf, orig_query + values_end_len);
2065 }
2066 
2067 /*
2068  * deparse remote UPDATE statement
2069  *
2070  * The statement text is appended to buf, and we also create an integer List
2071  * of the columns being retrieved by WITH CHECK OPTION or RETURNING (if any),
2072  * which is returned to *retrieved_attrs.
2073  */
2074 void
2075 deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
2076  Index rtindex, Relation rel,
2077  List *targetAttrs,
2078  List *withCheckOptionList, List *returningList,
2079  List **retrieved_attrs)
2080 {
2081  TupleDesc tupdesc = RelationGetDescr(rel);
2082  AttrNumber pindex;
2083  bool first;
2084  ListCell *lc;
2085 
2086  appendStringInfoString(buf, "UPDATE ");
2087  deparseRelation(buf, rel);
2088  appendStringInfoString(buf, " SET ");
2089 
2090  pindex = 2; /* ctid is always the first param */
2091  first = true;
2092  foreach(lc, targetAttrs)
2093  {
2094  int attnum = lfirst_int(lc);
2095  Form_pg_attribute attr = TupleDescAttr(tupdesc, attnum - 1);
2096 
2097  if (!first)
2098  appendStringInfoString(buf, ", ");
2099  first = false;
2100 
2101  deparseColumnRef(buf, rtindex, attnum, rte, false);
2102  if (attr->attgenerated)
2103  appendStringInfoString(buf, " = DEFAULT");
2104  else
2105  {
2106  appendStringInfo(buf, " = $%d", pindex);
2107  pindex++;
2108  }
2109  }
2110  appendStringInfoString(buf, " WHERE ctid = $1");
2111 
2112  deparseReturningList(buf, rte, rtindex, rel,
2113  rel->trigdesc && rel->trigdesc->trig_update_after_row,
2114  withCheckOptionList, returningList, retrieved_attrs);
2115 }
2116 
2117 /*
2118  * deparse remote UPDATE statement
2119  *
2120  * 'buf' is the output buffer to append the statement to
2121  * 'rtindex' is the RT index of the associated target relation
2122  * 'rel' is the relation descriptor for the target relation
2123  * 'foreignrel' is the RelOptInfo for the target relation or the join relation
2124  * containing all base relations in the query
2125  * 'targetlist' is the tlist of the underlying foreign-scan plan node
2126  * (note that this only contains new-value expressions and junk attrs)
2127  * 'targetAttrs' is the target columns of the UPDATE
2128  * 'remote_conds' is the qual clauses that must be evaluated remotely
2129  * '*params_list' is an output list of exprs that will become remote Params
2130  * 'returningList' is the RETURNING targetlist
2131  * '*retrieved_attrs' is an output list of integers of columns being retrieved
2132  * by RETURNING (if any)
2133  */
2134 void
2135 deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
2136  Index rtindex, Relation rel,
2137  RelOptInfo *foreignrel,
2138  List *targetlist,
2139  List *targetAttrs,
2140  List *remote_conds,
2141  List **params_list,
2142  List *returningList,
2143  List **retrieved_attrs)
2144 {
2145  deparse_expr_cxt context;
2146  int nestlevel;
2147  bool first;
2148  RangeTblEntry *rte = planner_rt_fetch(rtindex, root);
2149  ListCell *lc,
2150  *lc2;
2151 
2152  /* Set up context struct for recursion */
2153  context.root = root;
2154  context.foreignrel = foreignrel;
2155  context.scanrel = foreignrel;
2156  context.buf = buf;
2157  context.params_list = params_list;
2158 
2159  appendStringInfoString(buf, "UPDATE ");
2160  deparseRelation(buf, rel);
2161  if (foreignrel->reloptkind == RELOPT_JOINREL)
2162  appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
2163  appendStringInfoString(buf, " SET ");
2164 
2165  /* Make sure any constants in the exprs are printed portably */
2166  nestlevel = set_transmission_modes();
2167 
2168  first = true;
2169  forboth(lc, targetlist, lc2, targetAttrs)
2170  {
2171  TargetEntry *tle = lfirst_node(TargetEntry, lc);
2172  int attnum = lfirst_int(lc2);
2173 
2174  /* update's new-value expressions shouldn't be resjunk */
2175  Assert(!tle->resjunk);
2176 
2177  if (!first)
2178  appendStringInfoString(buf, ", ");
2179  first = false;
2180 
2181  deparseColumnRef(buf, rtindex, attnum, rte, false);
2182  appendStringInfoString(buf, " = ");
2183  deparseExpr((Expr *) tle->expr, &context);
2184  }
2185 
2186  reset_transmission_modes(nestlevel);
2187 
2188  if (foreignrel->reloptkind == RELOPT_JOINREL)
2189  {
2190  List *ignore_conds = NIL;
2191 
2192  appendStringInfoString(buf, " FROM ");
2193  deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
2194  &ignore_conds, params_list);
2195  remote_conds = list_concat(remote_conds, ignore_conds);
2196  }
2197 
2198  if (remote_conds)
2199  {
2200  appendStringInfoString(buf, " WHERE ");
2201  appendConditions(remote_conds, &context);
2202  }
2203 
2204  if (foreignrel->reloptkind == RELOPT_JOINREL)
2205  deparseExplicitTargetList(returningList, true, retrieved_attrs,
2206  &context);
2207  else
2208  deparseReturningList(buf, rte, rtindex, rel, false,
2209  NIL, returningList, retrieved_attrs);
2210 }
2211 
2212 /*
2213  * deparse remote DELETE statement
2214  *
2215  * The statement text is appended to buf, and we also create an integer List
2216  * of the columns being retrieved by RETURNING (if any), which is returned
2217  * to *retrieved_attrs.
2218  */
2219 void
2220 deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
2221  Index rtindex, Relation rel,
2222  List *returningList,
2223  List **retrieved_attrs)
2224 {
2225  appendStringInfoString(buf, "DELETE FROM ");
2226  deparseRelation(buf, rel);
2227  appendStringInfoString(buf, " WHERE ctid = $1");
2228 
2229  deparseReturningList(buf, rte, rtindex, rel,
2230  rel->trigdesc && rel->trigdesc->trig_delete_after_row,
2231  NIL, returningList, retrieved_attrs);
2232 }
2233 
2234 /*
2235  * deparse remote DELETE statement
2236  *
2237  * 'buf' is the output buffer to append the statement to
2238  * 'rtindex' is the RT index of the associated target relation
2239  * 'rel' is the relation descriptor for the target relation
2240  * 'foreignrel' is the RelOptInfo for the target relation or the join relation
2241  * containing all base relations in the query
2242  * 'remote_conds' is the qual clauses that must be evaluated remotely
2243  * '*params_list' is an output list of exprs that will become remote Params
2244  * 'returningList' is the RETURNING targetlist
2245  * '*retrieved_attrs' is an output list of integers of columns being retrieved
2246  * by RETURNING (if any)
2247  */
2248 void
2249 deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
2250  Index rtindex, Relation rel,
2251  RelOptInfo *foreignrel,
2252  List *remote_conds,
2253  List **params_list,
2254  List *returningList,
2255  List **retrieved_attrs)
2256 {
2257  deparse_expr_cxt context;
2258 
2259  /* Set up context struct for recursion */
2260  context.root = root;
2261  context.foreignrel = foreignrel;
2262  context.scanrel = foreignrel;
2263  context.buf = buf;
2264  context.params_list = params_list;
2265 
2266  appendStringInfoString(buf, "DELETE FROM ");
2267  deparseRelation(buf, rel);
2268  if (foreignrel->reloptkind == RELOPT_JOINREL)
2269  appendStringInfo(buf, " %s%d", REL_ALIAS_PREFIX, rtindex);
2270 
2271  if (foreignrel->reloptkind == RELOPT_JOINREL)
2272  {
2273  List *ignore_conds = NIL;
2274 
2275  appendStringInfoString(buf, " USING ");
2276  deparseFromExprForRel(buf, root, foreignrel, true, rtindex,
2277  &ignore_conds, params_list);
2278  remote_conds = list_concat(remote_conds, ignore_conds);
2279  }
2280 
2281  if (remote_conds)
2282  {
2283  appendStringInfoString(buf, " WHERE ");
2284  appendConditions(remote_conds, &context);
2285  }
2286 
2287  if (foreignrel->reloptkind == RELOPT_JOINREL)
2288  deparseExplicitTargetList(returningList, true, retrieved_attrs,
2289  &context);
2290  else
2291  deparseReturningList(buf, planner_rt_fetch(rtindex, root),
2292  rtindex, rel, false,
2293  NIL, returningList, retrieved_attrs);
2294 }
2295 
2296 /*
2297  * Add a RETURNING clause, if needed, to an INSERT/UPDATE/DELETE.
2298  */
2299 static void
2300 deparseReturningList(StringInfo buf, RangeTblEntry *rte,
2301  Index rtindex, Relation rel,
2302  bool trig_after_row,
2303  List *withCheckOptionList,
2304  List *returningList,
2305  List **retrieved_attrs)
2306 {
2307  Bitmapset *attrs_used = NULL;
2308 
2309  if (trig_after_row)
2310  {
2311  /* whole-row reference acquires all non-system columns */
2312  attrs_used =
2313  bms_make_singleton(0 - FirstLowInvalidHeapAttributeNumber);
2314  }
2315 
2316  if (withCheckOptionList != NIL)
2317  {
2318  /*
2319  * We need the attrs, non-system and system, mentioned in the local
2320  * query's WITH CHECK OPTION list.
2321  *
2322  * Note: we do this to ensure that WCO constraints will be evaluated
2323  * on the data actually inserted/updated on the remote side, which
2324  * might differ from the data supplied by the core code, for example
2325  * as a result of remote triggers.
2326  */
2327  pull_varattnos((Node *) withCheckOptionList, rtindex,
2328  &attrs_used);
2329  }
2330 
2331  if (returningList != NIL)
2332  {
2333  /*
2334  * We need the attrs, non-system and system, mentioned in the local
2335  * query's RETURNING list.
2336  */
2337  pull_varattnos((Node *) returningList, rtindex,
2338  &attrs_used);
2339  }
2340 
2341  if (attrs_used != NULL)
2342  deparseTargetList(buf, rte, rtindex, rel, true, attrs_used, false,
2343  retrieved_attrs);
2344  else
2345  *retrieved_attrs = NIL;
2346 }
2347 
2348 /*
2349  * Construct SELECT statement to acquire size in blocks of given relation.
2350  *
2351  * Note: we use local definition of block size, not remote definition.
2352  * This is perhaps debatable.
2353  *
2354  * Note: pg_relation_size() exists in 8.1 and later.
2355  */
2356 void
2357 deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
2358 {
2359  StringInfoData relname;
2360 
2361  /* We'll need the remote relation name as a literal. */
2362  initStringInfo(&relname);
2363  deparseRelation(&relname, rel);
2364 
2365  appendStringInfoString(buf, "SELECT pg_catalog.pg_relation_size(");
2366  deparseStringLiteral(buf, relname.data);
2367  appendStringInfo(buf, "::pg_catalog.regclass) / %d", BLCKSZ);
2368 }
2369 
2370 /*
2371  * Construct SELECT statement to acquire the number of rows and the relkind of
2372  * a relation.
2373  *
2374  * Note: we just return the remote server's reltuples value, which might
2375  * be off a good deal, but it doesn't seem worth working harder. See
2376  * comments in postgresAcquireSampleRowsFunc.
2377  */
2378 void
2379 deparseAnalyzeInfoSql(StringInfo buf, Relation rel)
2380 {
2381  StringInfoData relname;
2382 
2383  /* We'll need the remote relation name as a literal. */
2384  initStringInfo(&relname);
2385  deparseRelation(&relname, rel);
2386 
2387  appendStringInfoString(buf, "SELECT reltuples, relkind FROM pg_catalog.pg_class WHERE oid = ");
2388  deparseStringLiteral(buf, relname.data);
2389  appendStringInfoString(buf, "::pg_catalog.regclass");
2390 }
2391 
2392 /*
2393  * Construct SELECT statement to acquire sample rows of given relation.
2394  *
2395  * SELECT command is appended to buf, and list of columns retrieved
2396  * is returned to *retrieved_attrs.
2397  *
2398  * We only support sampling methods we can decide based on server version.
2399  * Allowing custom TSM modules (like tsm_system_rows) might be useful, but it
2400  * would require detecting which extensions are installed, to allow automatic
2401  * fall-back. Moreover, the methods may use different parameters like number
2402  * of rows (and not sampling rate). So we leave this for future improvements.
2403  *
2404  * Using random() to sample rows on the remote server has the advantage that
2405  * this works on all PostgreSQL versions (unlike TABLESAMPLE), and that it
2406  * does the sampling on the remote side (without transferring everything and
2407  * then discarding most rows).
2408  *
2409  * The disadvantage is that we still have to read all rows and evaluate the
2410  * random(), while TABLESAMPLE (at least with the "system" method) may skip.
2411  * It's not that different from the "bernoulli" method, though.
2412  *
2413  * We could also do "ORDER BY random() LIMIT x", which would always pick
2414  * the expected number of rows, but it requires sorting so it may be much
2415  * more expensive (particularly on large tables, which is what the
2416  * remote sampling is meant to improve).
2417  */
2418 void
2419 deparseAnalyzeSql(StringInfo buf, Relation rel,
2420  PgFdwSamplingMethod sample_method, double sample_frac,
2421  List **retrieved_attrs)
2422 {
2423  Oid relid = RelationGetRelid(rel);
2424  TupleDesc tupdesc = RelationGetDescr(rel);
2425  int i;
2426  char *colname;
2427  List *options;
2428  ListCell *lc;
2429  bool first = true;
2430 
2431  *retrieved_attrs = NIL;
2432 
2433  appendStringInfoString(buf, "SELECT ");
2434  for (i = 0; i < tupdesc->natts; i++)
2435  {
2436  /* Ignore dropped columns. */
2437  if (TupleDescAttr(tupdesc, i)->attisdropped)
2438  continue;
2439 
2440  if (!first)
2441  appendStringInfoString(buf, ", ");
2442  first = false;
2443 
2444  /* Use attribute name or column_name option. */
2445  colname = NameStr(TupleDescAttr(tupdesc, i)->attname);
2446  options = GetForeignColumnOptions(relid, i + 1);
2447 
2448  foreach(lc, options)
2449  {
2450  DefElem *def = (DefElem *) lfirst(lc);
2451 
2452  if (strcmp(def->defname, "column_name") == 0)
2453  {
2454  colname = defGetString(def);
2455  break;
2456  }
2457  }
2458 
2459  appendStringInfoString(buf, quote_identifier(colname));
2460 
2461  *retrieved_attrs = lappend_int(*retrieved_attrs, i + 1);
2462  }
2463 
2464  /* Don't generate bad syntax for zero-column relation. */
2465  if (first)
2466  appendStringInfoString(buf, "NULL");
2467 
2468  /*
2469  * Construct FROM clause, and perhaps WHERE clause too, depending on the
2470  * selected sampling method.
2471  */
2472  appendStringInfoString(buf, " FROM ");
2473  deparseRelation(buf, rel);
2474 
2475  switch (sample_method)
2476  {
2477  case ANALYZE_SAMPLE_OFF:
2478  /* nothing to do here */
2479  break;
2480 
2481  case ANALYZE_SAMPLE_RANDOM:
2482  appendStringInfo(buf, " WHERE pg_catalog.random() < %f", sample_frac);
2483  break;
2484 
2485  case ANALYZE_SAMPLE_SYSTEM:
2486  appendStringInfo(buf, " TABLESAMPLE SYSTEM(%f)", (100.0 * sample_frac));
2487  break;
2488 
2489  case ANALYZE_SAMPLE_BERNOULLI:
2490  appendStringInfo(buf, " TABLESAMPLE BERNOULLI(%f)", (100.0 * sample_frac));
2491  break;
2492 
2493  case ANALYZE_SAMPLE_AUTO:
2494  /* should have been resolved into actual method */
2495  elog(ERROR, "unexpected sampling method");
2496  break;
2497  }
2498 }
2499 
2500 /*
2501  * Construct a simple "TRUNCATE rel" statement
2502  */
2503 void
2504 deparseTruncateSql(StringInfo buf,
2505  List *rels,
2506  DropBehavior behavior,
2507  bool restart_seqs)
2508 {
2509  ListCell *cell;
2510 
2511  appendStringInfoString(buf, "TRUNCATE ");
2512 
2513  foreach(cell, rels)
2514  {
2515  Relation rel = lfirst(cell);
2516 
2517  if (cell != list_head(rels))
2518  appendStringInfoString(buf, ", ");
2519 
2520  deparseRelation(buf, rel);
2521  }
2522 
2523  appendStringInfo(buf, " %s IDENTITY",
2524  restart_seqs ? "RESTART" : "CONTINUE");
2525 
2526  if (behavior == DROP_RESTRICT)
2527  appendStringInfoString(buf, " RESTRICT");
2528  else if (behavior == DROP_CASCADE)
2529  appendStringInfoString(buf, " CASCADE");
2530 }
2531 
2532 /*
2533  * Construct name to use for given column, and emit it into buf.
2534  * If it has a column_name FDW option, use that instead of attribute name.
2535  *
2536  * If qualify_col is true, qualify column name with the alias of relation.
2537  */
2538 static void
2539 deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte,
2540  bool qualify_col)
2541 {
2542  /* We support fetching the remote side's CTID and OID. */
2543  if (varattno == SelfItemPointerAttributeNumber)
2544  {
2545  if (qualify_col)
2546  ADD_REL_QUALIFIER(buf, varno);
2547  appendStringInfoString(buf, "ctid");
2548  }
2549  else if (varattno < 0)
2550  {
2551  /*
2552  * All other system attributes are fetched as 0, except for table OID,
2553  * which is fetched as the local table OID. However, we must be
2554  * careful; the table could be beneath an outer join, in which case it
2555  * must go to NULL whenever the rest of the row does.
2556  */
2557  Oid fetchval = 0;
2558 
2559  if (varattno == TableOidAttributeNumber)
2560  fetchval = rte->relid;
2561 
2562  if (qualify_col)
2563  {
2564  appendStringInfoString(buf, "CASE WHEN (");
2565  ADD_REL_QUALIFIER(buf, varno);
2566  appendStringInfo(buf, "*)::text IS NOT NULL THEN %u END", fetchval);
2567  }
2568  else
2569  appendStringInfo(buf, "%u", fetchval);
2570  }
2571  else if (varattno == 0)
2572  {
2573  /* Whole row reference */
2574  Relation rel;
2575  Bitmapset *attrs_used;
2576 
2577  /* Required only to be passed down to deparseTargetList(). */
2578  List *retrieved_attrs;
2579 
2580  /*
2581  * The lock on the relation will be held by upper callers, so it's
2582  * fine to open it with no lock here.
2583  */
2584  rel = table_open(rte->relid, NoLock);
2585 
2586  /*
2587  * The local name of the foreign table can not be recognized by the
2588  * foreign server and the table it references on foreign server might
2589  * have different column ordering or different columns than those
2590  * declared locally. Hence we have to deparse whole-row reference as
2591  * ROW(columns referenced locally). Construct this by deparsing a
2592  * "whole row" attribute.
2593  */
2594  attrs_used = bms_add_member(NULL,
2595  0 - FirstLowInvalidHeapAttributeNumber);
2596 
2597  /*
2598  * In case the whole-row reference is under an outer join then it has
2599  * to go NULL whenever the rest of the row goes NULL. Deparsing a join
2600  * query would always involve multiple relations, thus qualify_col
2601  * would be true.
2602  */
2603  if (qualify_col)
2604  {
2605  appendStringInfoString(buf, "CASE WHEN (");
2606  ADD_REL_QUALIFIER(buf, varno);
2607  appendStringInfoString(buf, "*)::text IS NOT NULL THEN ");
2608  }
2609 
2610  appendStringInfoString(buf, "ROW(");
2611  deparseTargetList(buf, rte, varno, rel, false, attrs_used, qualify_col,
2612  &retrieved_attrs);
2613  appendStringInfoChar(buf, ')');
2614 
2615  /* Complete the CASE WHEN statement started above. */
2616  if (qualify_col)
2617  appendStringInfoString(buf, " END");
2618 
2619  table_close(rel, NoLock);
2620  bms_free(attrs_used);
2621  }
2622  else
2623  {
2624  char *colname = NULL;
2625  List *options;
2626  ListCell *lc;
2627 
2628  /* varno must not be any of OUTER_VAR, INNER_VAR and INDEX_VAR. */
2629  Assert(!IS_SPECIAL_VARNO(varno));
2630 
2631  /*
2632  * If it's a column of a foreign table, and it has the column_name FDW
2633  * option, use that value.
2634  */
2635  options = GetForeignColumnOptions(rte->relid, varattno);
2636  foreach(lc, options)
2637  {
2638  DefElem *def = (DefElem *) lfirst(lc);
2639 
2640  if (strcmp(def->defname, "column_name") == 0)
2641  {
2642  colname = defGetString(def);
2643  break;
2644  }
2645  }
2646 
2647  /*
2648  * If it's a column of a regular table or it doesn't have column_name
2649  * FDW option, use attribute name.
2650  */
2651  if (colname == NULL)
2652  colname = get_attname(rte->relid, varattno, false);
2653 
2654  if (qualify_col)
2655  ADD_REL_QUALIFIER(buf, varno);
2656 
2657  appendStringInfoString(buf, quote_identifier(colname));
2658  }
2659 }
2660 
2661 /*
2662  * Append remote name of specified foreign table to buf.
2663  * Use value of table_name FDW option (if any) instead of relation's name.
2664  * Similarly, schema_name FDW option overrides schema name.
2665  */
2666 static void
2667 deparseRelation(StringInfo buf, Relation rel)
2668 {
2669  ForeignTable *table;
2670  const char *nspname = NULL;
2671  const char *relname = NULL;
2672  ListCell *lc;
2673 
2674  /* obtain additional catalog information. */
2675  table = GetForeignTable(RelationGetRelid(rel));
2676 
2677  /*
2678  * Use value of FDW options if any, instead of the name of object itself.
2679  */
2680  foreach(lc, table->options)
2681  {
2682  DefElem *def = (DefElem *) lfirst(lc);
2683 
2684  if (strcmp(def->defname, "schema_name") == 0)
2685  nspname = defGetString(def);
2686  else if (strcmp(def->defname, "table_name") == 0)
2687  relname = defGetString(def);
2688  }
2689 
2690  /*
2691  * Note: we could skip printing the schema name if it's pg_catalog, but
2692  * that doesn't seem worth the trouble.
2693  */
2694  if (nspname == NULL)
2695  nspname = get_namespace_name(RelationGetNamespace(rel));
2696  if (relname == NULL)
2697  relname = RelationGetRelationName(rel);
2698 
2699  appendStringInfo(buf, "%s.%s",
2700  quote_identifier(nspname), quote_identifier(relname));
2701 }
2702 
2703 /*
2704  * Append a SQL string literal representing "val" to buf.
2705  */
2706 void
2707 deparseStringLiteral(StringInfo buf, const char *val)
2708 {
2709  const char *valptr;
2710 
2711  /*
2712  * Rather than making assumptions about the remote server's value of
2713  * standard_conforming_strings, always use E'foo' syntax if there are any
2714  * backslashes. This will fail on remote servers before 8.1, but those
2715  * are long out of support.
2716  */
2717  if (strchr(val, '\\') != NULL)
2718  appendStringInfoChar(buf, ESCAPE_STRING_SYNTAX);
2719  appendStringInfoChar(buf, '\'');
2720  for (valptr = val; *valptr; valptr++)
2721  {
2722  char ch = *valptr;
2723 
2724  if (SQL_STR_DOUBLE(ch, true))
2725  appendStringInfoChar(buf, ch);
2726  appendStringInfoChar(buf, ch);
2727  }
2728  appendStringInfoChar(buf, '\'');
2729 }
2730 
2731 /*
2732  * Deparse given expression into context->buf.
2733  *
2734  * This function must support all the same node types that foreign_expr_walker
2735  * accepts.
2736  *
2737  * Note: unlike ruleutils.c, we just use a simple hard-wired parenthesization
2738  * scheme: anything more complex than a Var, Const, function call or cast
2739  * should be self-parenthesized.
2740  */
2741 static void
2742 deparseExpr(Expr *node, deparse_expr_cxt *context)
2743 {
2744  if (node == NULL)
2745  return;
2746 
2747  switch (nodeTag(node))
2748  {
2749  case T_Var:
2750  deparseVar((Var *) node, context);
2751  break;
2752  case T_Const:
2753  deparseConst((Const *) node, context, 0);
2754  break;
2755  case T_Param:
2756  deparseParam((Param *) node, context);
2757  break;
2758  case T_SubscriptingRef:
2759  deparseSubscriptingRef((SubscriptingRef *) node, context);
2760  break;
2761  case T_FuncExpr:
2762  deparseFuncExpr((FuncExpr *) node, context);
2763  break;
2764  case T_OpExpr:
2765  deparseOpExpr((OpExpr *) node, context);
2766  break;
2767  case T_DistinctExpr:
2768  deparseDistinctExpr((DistinctExpr *) node, context);
2769  break;
2770  case T_ScalarArrayOpExpr:
2771  deparseScalarArrayOpExpr((ScalarArrayOpExpr *) node, context);
2772  break;
2773  case T_RelabelType:
2774  deparseRelabelType((RelabelType *) node, context);
2775  break;
2776  case T_BoolExpr:
2777  deparseBoolExpr((BoolExpr *) node, context);
2778  break;
2779  case T_NullTest:
2780  deparseNullTest((NullTest *) node, context);
2781  break;
2782  case T_CaseExpr:
2783  deparseCaseExpr((CaseExpr *) node, context);
2784  break;
2785  case T_ArrayExpr:
2786  deparseArrayExpr((ArrayExpr *) node, context);
2787  break;
2788  case T_Aggref:
2789  deparseAggref((Aggref *) node, context);
2790  break;
2791  default:
2792  elog(ERROR, "unsupported expression type for deparse: %d",
2793  (int) nodeTag(node));
2794  break;
2795  }
2796 }
2797 
2798 /*
2799  * Deparse given Var node into context->buf.
2800  *
2801  * If the Var belongs to the foreign relation, just print its remote name.
2802  * Otherwise, it's effectively a Param (and will in fact be a Param at
2803  * run time). Handle it the same way we handle plain Params --- see
2804  * deparseParam for comments.
2805  */
2806 static void
2807 deparseVar(Var *node, deparse_expr_cxt *context)
2808 {
2809  Relids relids = context->scanrel->relids;
2810  int relno;
2811  int colno;
2812 
2813  /* Qualify columns when multiple relations are involved. */
2814  bool qualify_col = (bms_membership(relids) == BMS_MULTIPLE);
2815 
2816  /*
2817  * If the Var belongs to the foreign relation that is deparsed as a
2818  * subquery, use the relation and column alias to the Var provided by the
2819  * subquery, instead of the remote name.
2820  */
2821  if (is_subquery_var(node, context->scanrel, &relno, &colno))
2822  {
2823  appendStringInfo(context->buf, "%s%d.%s%d",
2824  SUBQUERY_REL_ALIAS_PREFIX, relno,
2825  SUBQUERY_COL_ALIAS_PREFIX, colno);
2826  return;
2827  }
2828 
2829  if (bms_is_member(node->varno, relids) && node->varlevelsup == 0)
2830  deparseColumnRef(context->buf, node->varno, node->varattno,
2831  planner_rt_fetch(node->varno, context->root),
2832  qualify_col);
2833  else
2834  {
2835  /* Treat like a Param */
2836  if (context->params_list)
2837  {
2838  int pindex = 0;
2839  ListCell *lc;
2840 
2841  /* find its index in params_list */
2842  foreach(lc, *context->params_list)
2843  {
2844  pindex++;
2845  if (equal(node, (Node *) lfirst(lc)))
2846  break;
2847  }
2848  if (lc == NULL)
2849  {
2850  /* not in list, so add it */
2851  pindex++;
2852  *context->params_list = lappend(*context->params_list, node);
2853  }
2854 
2855  printRemoteParam(pindex, node->vartype, node->vartypmod, context);
2856  }
2857  else
2858  {
2859  printRemotePlaceholder(node->vartype, node->vartypmod, context);
2860  }
2861  }
2862 }
2863 
2864 /*
2865  * Deparse given constant value into context->buf.
2866  *
2867  * This function has to be kept in sync with ruleutils.c's get_const_expr.
2868  *
2869  * As in that function, showtype can be -1 to never show "::typename"
2870  * decoration, +1 to always show it, or 0 to show it only if the constant
2871  * wouldn't be assumed to be the right type by default.
2872  *
2873  * In addition, this code allows showtype to be -2 to indicate that we should
2874  * not show "::typename" decoration if the constant is printed as an untyped
2875  * literal or NULL (while in other cases, behaving as for showtype == 0).
2876  */
2877 static void
2878 deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
2879 {
2880  StringInfo buf = context->buf;
2881  Oid typoutput;
2882  bool typIsVarlena;
2883  char *extval;
2884  bool isfloat = false;
2885  bool isstring = false;
2886  bool needlabel;
2887 
2888  if (node->constisnull)
2889  {
2890  appendStringInfoString(buf, "NULL");
2891  if (showtype >= 0)
2892  appendStringInfo(buf, "::%s",
2893  deparse_type_name(node->consttype,
2894  node->consttypmod));
2895  return;
2896  }
2897 
2898  getTypeOutputInfo(node->consttype,
2899  &typoutput, &typIsVarlena);
2900  extval = OidOutputFunctionCall(typoutput, node->constvalue);
2901 
2902  switch (node->consttype)
2903  {
2904  case INT2OID:
2905  case INT4OID:
2906  case INT8OID:
2907  case OIDOID:
2908  case FLOAT4OID:
2909  case FLOAT8OID:
2910  case NUMERICOID:
2911  {
2912  /*
2913  * No need to quote unless it's a special value such as 'NaN'.
2914  * See comments in get_const_expr().
2915  */
2916  if (strspn(extval, "0123456789+-eE.") == strlen(extval))
2917  {
2918  if (extval[0] == '+' || extval[0] == '-')
2919  appendStringInfo(buf, "(%s)", extval);
2920  else
2921  appendStringInfoString(buf, extval);
2922  if (strcspn(extval, "eE.") != strlen(extval))
2923  isfloat = true; /* it looks like a float */
2924  }
2925  else
2926  appendStringInfo(buf, "'%s'", extval);
2927  }
2928  break;
2929  case BITOID:
2930  case VARBITOID:
2931  appendStringInfo(buf, "B'%s'", extval);
2932  break;
2933  case BOOLOID:
2934  if (strcmp(extval, "t") == 0)
2935  appendStringInfoString(buf, "true");
2936  else
2937  appendStringInfoString(buf, "false");
2938  break;
2939  default:
2940  deparseStringLiteral(buf, extval);
2941  isstring = true;
2942  break;
2943  }
2944 
2945  pfree(extval);
2946 
2947  if (showtype == -1)
2948  return; /* never print type label */
2949 
2950  /*
2951  * For showtype == 0, append ::typename unless the constant will be
2952  * implicitly typed as the right type when it is read in.
2953  *
2954  * XXX this code has to be kept in sync with the behavior of the parser,
2955  * especially make_const.
2956  */
2957  switch (node->consttype)
2958  {
2959  case BOOLOID:
2960  case INT4OID:
2961  case UNKNOWNOID:
2962  needlabel = false;
2963  break;
2964  case NUMERICOID:
2965  needlabel = !isfloat || (node->consttypmod >= 0);
2966  break;
2967  default:
2968  if (showtype == -2)
2969  {
2970  /* label unless we printed it as an untyped string */
2971  needlabel = !isstring;
2972  }
2973  else
2974  needlabel = true;
2975  break;
2976  }
2977  if (needlabel || showtype > 0)
2978  appendStringInfo(buf, "::%s",
2979  deparse_type_name(node->consttype,
2980  node->consttypmod));
2981 }
2982 
2983 /*
2984  * Deparse given Param node.
2985  *
2986  * If we're generating the query "for real", add the Param to
2987  * context->params_list if it's not already present, and then use its index
2988  * in that list as the remote parameter number. During EXPLAIN, there's
2989  * no need to identify a parameter number.
2990  */
2991 static void
2992 deparseParam(Param *node, deparse_expr_cxt *context)
2993 {
2994  if (context->params_list)
2995  {
2996  int pindex = 0;
2997  ListCell *lc;
2998 
2999  /* find its index in params_list */
3000  foreach(lc, *context->params_list)
3001  {
3002  pindex++;
3003  if (equal(node, (Node *) lfirst(lc)))
3004  break;
3005  }
3006  if (lc == NULL)
3007  {
3008  /* not in list, so add it */
3009  pindex++;
3010  *context->params_list = lappend(*context->params_list, node);
3011  }
3012 
3013  printRemoteParam(pindex, node->paramtype, node->paramtypmod, context);
3014  }
3015  else
3016  {
3017  printRemotePlaceholder(node->paramtype, node->paramtypmod, context);
3018  }
3019 }
3020 
3021 /*
3022  * Deparse a container subscript expression.
3023  */
3024 static void
3025 deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context)
3026 {
3027  StringInfo buf = context->buf;
3028  ListCell *lowlist_item;
3029  ListCell *uplist_item;
3030 
3031  /* Always parenthesize the expression. */
3032  appendStringInfoChar(buf, '(');
3033 
3034  /*
3035  * Deparse referenced array expression first. If that expression includes
3036  * a cast, we have to parenthesize to prevent the array subscript from
3037  * being taken as typename decoration. We can avoid that in the typical
3038  * case of subscripting a Var, but otherwise do it.
3039  */
3040  if (IsA(node->refexpr, Var))
3041  deparseExpr(node->refexpr, context);
3042  else
3043  {
3044  appendStringInfoChar(buf, '(');
3045  deparseExpr(node->refexpr, context);
3046  appendStringInfoChar(buf, ')');
3047  }
3048 
3049  /* Deparse subscript expressions. */
3050  lowlist_item = list_head(node->reflowerindexpr); /* could be NULL */
3051  foreach(uplist_item, node->refupperindexpr)
3052  {
3053  appendStringInfoChar(buf, '[');
3054  if (lowlist_item)
3055  {
3056  deparseExpr(lfirst(lowlist_item), context);
3057  appendStringInfoChar(buf, ':');
3058  lowlist_item = lnext(node->reflowerindexpr, lowlist_item);
3059  }
3060  deparseExpr(lfirst(uplist_item), context);
3061  appendStringInfoChar(buf, ']');
3062  }
3063 
3064  appendStringInfoChar(buf, ')');
3065 }
3066 
3067 /*
3068  * Deparse a function call.
3069  */
3070 static void
3071 deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
3072 {
3073  StringInfo buf = context->buf;
3074  bool use_variadic;
3075  bool first;
3076  ListCell *arg;
3077 
3078  /*
3079  * If the function call came from an implicit coercion, then just show the
3080  * first argument.
3081  */
3082  if (node->funcformat == COERCE_IMPLICIT_CAST)
3083  {
3084  deparseExpr((Expr *) linitial(node->args), context);
3085  return;
3086  }
3087 
3088  /*
3089  * If the function call came from a cast, then show the first argument
3090  * plus an explicit cast operation.
3091  */
3092  if (node->funcformat == COERCE_EXPLICIT_CAST)
3093  {
3094  Oid rettype = node->funcresulttype;
3095  int32 coercedTypmod;
3096 
3097  /* Get the typmod if this is a length-coercion function */
3098  (void) exprIsLengthCoercion((Node *) node, &coercedTypmod);
3099 
3100  deparseExpr((Expr *) linitial(node->args), context);
3101  appendStringInfo(buf, "::%s",
3102  deparse_type_name(rettype, coercedTypmod));
3103  return;
3104  }
3105 
3106  /* Check if need to print VARIADIC (cf. ruleutils.c) */
3107  use_variadic = node->funcvariadic;
3108 
3109  /*
3110  * Normal function: display as proname(args).
3111  */
3112  appendFunctionName(node->funcid, context);
3113  appendStringInfoChar(buf, '(');
3114 
3115  /* ... and all the arguments */
3116  first = true;
3117  foreach(arg, node->args)
3118  {
3119  if (!first)
3120  appendStringInfoString(buf, ", ");
3121  if (use_variadic && lnext(node->args, arg) == NULL)
3122  appendStringInfoString(buf, "VARIADIC ");
3123  deparseExpr((Expr *) lfirst(arg), context);
3124  first = false;
3125  }
3126  appendStringInfoChar(buf, ')');
3127 }
3128 
3129 /*
3130  * Deparse given operator expression. To avoid problems around
3131  * priority of operations, we always parenthesize the arguments.
3132  */
3133 static void
3134 deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
3135 {
3136  StringInfo buf = context->buf;
3137  HeapTuple tuple;
3138  Form_pg_operator form;
3139  Expr *right;
3140  bool canSuppressRightConstCast = false;
3141  char oprkind;
3142 
3143  /* Retrieve information about the operator from system catalog. */
3144  tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
3145  if (!HeapTupleIsValid(tuple))
3146  elog(ERROR, "cache lookup failed for operator %u", node->opno);
3147  form = (Form_pg_operator) GETSTRUCT(tuple);
3148  oprkind = form->oprkind;
3149 
3150  /* Sanity check. */
3151  Assert((oprkind == 'l' && list_length(node->args) == 1) ||
3152  (oprkind == 'b' && list_length(node->args) == 2));
3153 
3154  right = llast(node->args);
3155 
3156  /* Always parenthesize the expression. */
3157  appendStringInfoChar(buf, '(');
3158 
3159  /* Deparse left operand, if any. */
3160  if (oprkind == 'b')
3161  {
3162  Expr *left = linitial(node->args);
3163  Oid leftType = exprType((Node *) left);
3164  Oid rightType = exprType((Node *) right);
3165  bool canSuppressLeftConstCast = false;
3166 
3167  /*
3168  * When considering a binary operator, if one operand is a Const that
3169  * can be printed as a bare string literal or NULL (i.e., it will look
3170  * like type UNKNOWN to the remote parser), the Const normally
3171  * receives an explicit cast to the operator's input type. However,
3172  * in Const-to-Var comparisons where both operands are of the same
3173  * type, we prefer to suppress the explicit cast, leaving the Const's
3174  * type resolution up to the remote parser. The remote's resolution
3175  * heuristic will assume that an unknown input type being compared to
3176  * a known input type is of that known type as well.
3177  *
3178  * This hack allows some cases to succeed where a remote column is
3179  * declared with a different type in the local (foreign) table. By
3180  * emitting "foreigncol = 'foo'" not "foreigncol = 'foo'::text" or the
3181  * like, we allow the remote parser to pick an "=" operator that's
3182  * compatible with whatever type the remote column really is, such as
3183  * an enum.
3184  *
3185  * We allow cast suppression to happen only when the other operand is
3186  * a plain foreign Var. Although the remote's unknown-type heuristic
3187  * would apply to other cases just as well, we would be taking a
3188  * bigger risk that the inferred type is something unexpected. With
3189  * this restriction, if anything goes wrong it's the user's fault for
3190  * not declaring the local column with the same type as the remote
3191  * column.
3192  */
3193  if (leftType == rightType)
3194  {
3195  if (IsA(left, Const))
3196  canSuppressLeftConstCast = isPlainForeignVar(right, context);
3197  else if (IsA(right, Const))
3198  canSuppressRightConstCast = isPlainForeignVar(left, context);
3199  }
3200 
3201  if (canSuppressLeftConstCast)
3202  deparseConst((Const *) left, context, -2);
3203  else
3204  deparseExpr(left, context);
3205 
3206  appendStringInfoChar(buf, ' ');
3207  }
3208 
3209  /* Deparse operator name. */
3210  deparseOperatorName(buf, form);
3211 
3212  /* Deparse right operand. */
3213  appendStringInfoChar(buf, ' ');
3214 
3215  if (canSuppressRightConstCast)
3216  deparseConst((Const *) right, context, -2);
3217  else
3218  deparseExpr(right, context);
3219 
3220  appendStringInfoChar(buf, ')');
3221 
3222  ReleaseSysCache(tuple);
3223 }
3224 
3225 /*
3226  * Will "node" deparse as a plain foreign Var?
3227  */
3228 static bool
3229 isPlainForeignVar(Expr *node, deparse_expr_cxt *context)
3230 {
3231  /*
3232  * We allow the foreign Var to have an implicit RelabelType, mainly so
3233  * that this'll work with varchar columns. Note that deparseRelabelType
3234  * will not print such a cast, so we're not breaking the restriction that
3235  * the expression print as a plain Var. We won't risk it for an implicit
3236  * cast that requires a function, nor for non-implicit RelabelType; such
3237  * cases seem too likely to involve semantics changes compared to what
3238  * would happen on the remote side.
3239  */
3240  if (IsA(node, RelabelType) &&
3241  ((RelabelType *) node)->relabelformat == COERCE_IMPLICIT_CAST)
3242  node = ((RelabelType *) node)->arg;
3243 
3244  if (IsA(node, Var))
3245  {
3246  /*
3247  * The Var must be one that'll deparse as a foreign column reference
3248  * (cf. deparseVar).
3249  */
3250  Var *var = (Var *) node;
3251  Relids relids = context->scanrel->relids;
3252 
3253  if (bms_is_member(var->varno, relids) && var->varlevelsup == 0)
3254  return true;
3255  }
3256 
3257  return false;
3258 }
3259 
3260 /*
3261  * Print the name of an operator.
3262  */
3263 static void
3264 deparseOperatorName(StringInfo buf, Form_pg_operator opform)
3265 {
3266  char *opname;
3267 
3268  /* opname is not a SQL identifier, so we should not quote it. */
3269  opname = NameStr(opform->oprname);
3270 
3271  /* Print schema name only if it's not pg_catalog */
3272  if (opform->oprnamespace != PG_CATALOG_NAMESPACE)
3273  {
3274  const char *opnspname;
3275 
3276  opnspname = get_namespace_name(opform->oprnamespace);
3277  /* Print fully qualified operator name. */
3278  appendStringInfo(buf, "OPERATOR(%s.%s)",
3279  quote_identifier(opnspname), opname);
3280  }
3281  else
3282  {
3283  /* Just print operator name. */
3284  appendStringInfoString(buf, opname);
3285  }
3286 }
3287 
3288 /*
3289  * Deparse IS DISTINCT FROM.
3290  */
3291 static void
3292 deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
3293 {
3294  StringInfo buf = context->buf;
3295 
3296  Assert(list_length(node->args) == 2);
3297 
3298  appendStringInfoChar(buf, '(');
3299  deparseExpr(linitial(node->args), context);
3300  appendStringInfoString(buf, " IS DISTINCT FROM ");
3301  deparseExpr(lsecond(node->args), context);
3302  appendStringInfoChar(buf, ')');
3303 }
3304 
3305 /*
3306  * Deparse given ScalarArrayOpExpr expression. To avoid problems
3307  * around priority of operations, we always parenthesize the arguments.
3308  */
3309 static void
3310 deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
3311 {
3312  StringInfo buf = context->buf;
3313  HeapTuple tuple;
3314  Form_pg_operator form;
3315  Expr *arg1;
3316  Expr *arg2;
3317 
3318  /* Retrieve information about the operator from system catalog. */
3319  tuple = SearchSysCache1(OPEROID, ObjectIdGetDatum(node->opno));
3320  if (!HeapTupleIsValid(tuple))
3321  elog(ERROR, "cache lookup failed for operator %u", node->opno);
3322  form = (Form_pg_operator) GETSTRUCT(tuple);
3323 
3324  /* Sanity check. */
3325  Assert(list_length(node->args) == 2);
3326 
3327  /* Always parenthesize the expression. */
3328  appendStringInfoChar(buf, '(');
3329 
3330  /* Deparse left operand. */
3331  arg1 = linitial(node->args);
3332  deparseExpr(arg1, context);
3333  appendStringInfoChar(buf, ' ');
3334 
3335  /* Deparse operator name plus decoration. */
3336  deparseOperatorName(buf, form);
3337  appendStringInfo(buf, " %s (", node->useOr ? "ANY" : "ALL");
3338 
3339  /* Deparse right operand. */
3340  arg2 = lsecond(node->args);
3341  deparseExpr(arg2, context);
3342 
3343  appendStringInfoChar(buf, ')');
3344 
3345  /* Always parenthesize the expression. */
3346  appendStringInfoChar(buf, ')');
3347 
3348  ReleaseSysCache(tuple);
3349 }
3350 
3351 /*
3352  * Deparse a RelabelType (binary-compatible cast) node.
3353  */
3354 static void
3355 deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
3356 {
3357  deparseExpr(node->arg, context);
3358  if (node->relabelformat != COERCE_IMPLICIT_CAST)
3359  appendStringInfo(context->buf, "::%s",
3360  deparse_type_name(node->resulttype,
3361  node->resulttypmod));
3362 }
3363 
3364 /*
3365  * Deparse a BoolExpr node.
3366  */
3367 static void
3368 deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
3369 {
3370  StringInfo buf = context->buf;
3371  const char *op = NULL; /* keep compiler quiet */
3372  bool first;
3373  ListCell *lc;
3374 
3375  switch (node->boolop)
3376  {
3377  case AND_EXPR:
3378  op = "AND";
3379  break;
3380  case OR_EXPR:
3381  op = "OR";
3382  break;
3383  case NOT_EXPR:
3384  appendStringInfoString(buf, "(NOT ");
3385  deparseExpr(linitial(node->args), context);
3386  appendStringInfoChar(buf, ')');
3387  return;
3388  }
3389 
3390  appendStringInfoChar(buf, '(');
3391  first = true;
3392  foreach(lc, node->args)
3393  {
3394  if (!first)
3395  appendStringInfo(buf, " %s ", op);
3396  deparseExpr((Expr *) lfirst(lc), context);
3397  first = false;
3398  }
3399  appendStringInfoChar(buf, ')');
3400 }
3401 
3402 /*
3403  * Deparse IS [NOT] NULL expression.
3404  */
3405 static void
3406 deparseNullTest(NullTest *node, deparse_expr_cxt *context)
3407 {
3408  StringInfo buf = context->buf;
3409 
3410  appendStringInfoChar(buf, '(');
3411  deparseExpr(node->arg, context);
3412 
3413  /*
3414  * For scalar inputs, we prefer to print as IS [NOT] NULL, which is
3415  * shorter and traditional. If it's a rowtype input but we're applying a
3416  * scalar test, must print IS [NOT] DISTINCT FROM NULL to be semantically
3417  * correct.
3418  */
3419  if (node->argisrow || !type_is_rowtype(exprType((Node *) node->arg)))
3420  {
3421  if (node->nulltesttype == IS_NULL)
3422  appendStringInfoString(buf, " IS NULL)");
3423  else
3424  appendStringInfoString(buf, " IS NOT NULL)");
3425  }
3426  else
3427  {
3428  if (node->nulltesttype == IS_NULL)
3429  appendStringInfoString(buf, " IS NOT DISTINCT FROM NULL)");
3430  else
3431  appendStringInfoString(buf, " IS DISTINCT FROM NULL)");
3432  }
3433 }
3434 
3435 /*
3436  * Deparse CASE expression
3437  */
3438 static void
3439 deparseCaseExpr(CaseExpr *node, deparse_expr_cxt *context)
3440 {
3441  StringInfo buf = context->buf;
3442  ListCell *lc;
3443 
3444  appendStringInfoString(buf, "(CASE");
3445 
3446  /* If this is a CASE arg WHEN then emit the arg expression */
3447  if (node->arg != NULL)
3448  {
3449  appendStringInfoChar(buf, ' ');
3450  deparseExpr(node->arg, context);
3451  }
3452 
3453  /* Add each condition/result of the CASE clause */
3454  foreach(lc, node->args)
3455  {
3456  CaseWhen *whenclause = (CaseWhen *) lfirst(lc);
3457 
3458  /* WHEN */
3459  appendStringInfoString(buf, " WHEN ");
3460  if (node->arg == NULL) /* CASE WHEN */
3461  deparseExpr(whenclause->expr, context);
3462  else /* CASE arg WHEN */
3463  {
3464  /* Ignore the CaseTestExpr and equality operator. */
3465  deparseExpr(lsecond(castNode(OpExpr, whenclause->expr)->args),
3466  context);
3467  }
3468 
3469  /* THEN */
3470  appendStringInfoString(buf, " THEN ");
3471  deparseExpr(whenclause->result, context);
3472  }
3473 
3474  /* add ELSE if present */
3475  if (node->defresult != NULL)
3476  {
3477  appendStringInfoString(buf, " ELSE ");
3478  deparseExpr(node->defresult, context);
3479  }
3480 
3481  /* append END */
3482  appendStringInfoString(buf, " END)");
3483 }
3484 
3485 /*
3486  * Deparse ARRAY[...] construct.
3487  */
3488 static void
3489 deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
3490 {
3491  StringInfo buf = context->buf;
3492  bool first = true;
3493  ListCell *lc;
3494 
3495  appendStringInfoString(buf, "ARRAY[");
3496  foreach(lc, node->elements)
3497  {
3498  if (!first)
3499  appendStringInfoString(buf, ", ");
3500  deparseExpr(lfirst(lc), context);
3501  first = false;
3502  }
3503  appendStringInfoChar(buf, ']');
3504 
3505  /* If the array is empty, we need an explicit cast to the array type. */
3506  if (node->elements == NIL)
3507  appendStringInfo(buf, "::%s",
3508  deparse_type_name(node->array_typeid, -1));
3509 }
3510 
3511 /*
3512  * Deparse an Aggref node.
3513  */
3514 static void
3515 deparseAggref(Aggref *node, deparse_expr_cxt *context)
3516 {
3517  StringInfo buf = context->buf;
3518  bool use_variadic;
3519 
3520  /* Only basic, non-split aggregation accepted. */
3521  Assert(node->aggsplit == AGGSPLIT_SIMPLE);
3522 
3523  /* Check if need to print VARIADIC (cf. ruleutils.c) */
3524  use_variadic = node->aggvariadic;
3525 
3526  /* Find aggregate name from aggfnoid which is a pg_proc entry */
3527  appendFunctionName(node->aggfnoid, context);
3528  appendStringInfoChar(buf, '(');
3529 
3530  /* Add DISTINCT */
3531  appendStringInfoString(buf, (node->aggdistinct != NIL) ? "DISTINCT " : "");
3532 
3533  if (AGGKIND_IS_ORDERED_SET(node->aggkind))
3534  {
3535  /* Add WITHIN GROUP (ORDER BY ..) */
3536  ListCell *arg;
3537  bool first = true;
3538 
3539  Assert(!node->aggvariadic);
3540  Assert(node->aggorder != NIL);
3541 
3542  foreach(arg, node->aggdirectargs)
3543  {
3544  if (!first)
3545  appendStringInfoString(buf, ", ");
3546  first = false;
3547 
3548  deparseExpr((Expr *) lfirst(arg), context);
3549  }
3550 
3551  appendStringInfoString(buf, ") WITHIN GROUP (ORDER BY ");
3552  appendAggOrderBy(node->aggorder, node->args, context);
3553  }
3554  else
3555  {
3556  /* aggstar can be set only in zero-argument aggregates */
3557  if (node->aggstar)
3558  appendStringInfoChar(buf, '*');
3559  else
3560  {
3561  ListCell *arg;
3562  bool first = true;
3563 
3564  /* Add all the arguments */
3565  foreach(arg, node->args)
3566  {
3567  TargetEntry *tle = (TargetEntry *) lfirst(arg);
3568  Node *n = (Node *) tle->expr;
3569 
3570  if (tle->resjunk)
3571  continue;
3572 
3573  if (!first)
3574  appendStringInfoString(buf, ", ");
3575  first = false;
3576 
3577  /* Add VARIADIC */
3578  if (use_variadic && lnext(node->args, arg) == NULL)
3579  appendStringInfoString(buf, "VARIADIC ");
3580 
3581  deparseExpr((Expr *) n, context);
3582  }
3583  }
3584 
3585  /* Add ORDER BY */
3586  if (node->aggorder != NIL)
3587  {
3588  appendStringInfoString(buf, " ORDER BY ");
3589  appendAggOrderBy(node->aggorder, node->args, context);
3590  }
3591  }
3592 
3593  /* Add FILTER (WHERE ..) */
3594  if (node->aggfilter != NULL)
3595  {
3596  appendStringInfoString(buf, ") FILTER (WHERE ");
3597  deparseExpr((Expr *) node->aggfilter, context);
3598  }
3599 
3600  appendStringInfoChar(buf, ')');
3601 }
3602 
3603 /*
3604  * Append ORDER BY within aggregate function.
3605  */
3606 static void
3607 appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
3608 {
3609  StringInfo buf = context->buf;
3610  ListCell *lc;
3611  bool first = true;
3612 
3613  foreach(lc, orderList)
3614  {
3615  SortGroupClause *srt = (SortGroupClause *) lfirst(lc);
3616  Node *sortexpr;
3617 
3618  if (!first)
3619  appendStringInfoString(buf, ", ");
3620  first = false;
3621 
3622  /* Deparse the sort expression proper. */
3623  sortexpr = deparseSortGroupClause(srt->tleSortGroupRef, targetList,
3624  false, context);
3625  /* Add decoration as needed. */
3626  appendOrderBySuffix(srt->sortop, exprType(sortexpr), srt->nulls_first,
3627  context);
3628  }
3629 }
3630 
3631 /*
3632  * Append the ASC, DESC, USING <OPERATOR> and NULLS FIRST / NULLS LAST parts
3633  * of an ORDER BY clause.
3634  */
3635 static void
3636 appendOrderBySuffix(Oid sortop, Oid sortcoltype, bool nulls_first,
3637  deparse_expr_cxt *context)
3638 {
3639  StringInfo buf = context->buf;
3640  TypeCacheEntry *typentry;
3641 
3642  /* See whether operator is default < or > for sort expr's datatype. */
3643  typentry = lookup_type_cache(sortcoltype,
3644  TYPECACHE_LT_OPR | TYPECACHE_GT_OPR);
3645 
3646  if (sortop == typentry->lt_opr)
3647  appendStringInfoString(buf, " ASC");
3648  else if (sortop == typentry->gt_opr)
3649  appendStringInfoString(buf, " DESC");
3650  else
3651  {
3652  HeapTuple opertup;
3653  Form_pg_operator operform;
3654 
3655  appendStringInfoString(buf, " USING ");
3656 
3657  /* Append operator name. */
3658  opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(sortop));
3659  if (!HeapTupleIsValid(opertup))
3660  elog(ERROR, "cache lookup failed for operator %u", sortop);
3661  operform = (Form_pg_operator) GETSTRUCT(opertup);
3662  deparseOperatorName(buf, operform);
3663  ReleaseSysCache(opertup);
3664  }
3665 
3666  if (nulls_first)
3667  appendStringInfoString(buf, " NULLS FIRST");
3668  else
3669  appendStringInfoString(buf, " NULLS LAST");
3670 }
3671 
3672 /*
3673  * Print the representation of a parameter to be sent to the remote side.
3674  *
3675  * Note: we always label the Param's type explicitly rather than relying on
3676  * transmitting a numeric type OID in PQexecParams(). This allows us to
3677  * avoid assuming that types have the same OIDs on the remote side as they
3678  * do locally --- they need only have the same names.
3679  */
3680 static void
3681 printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod,
3682  deparse_expr_cxt *context)
3683 {
3684  StringInfo buf = context->buf;
3685  char *ptypename = deparse_type_name(paramtype, paramtypmod);
3686 
3687  appendStringInfo(buf, "$%d::%s", paramindex, ptypename);
3688 }
3689 
3690 /*
3691  * Print the representation of a placeholder for a parameter that will be
3692  * sent to the remote side at execution time.
3693  *
3694  * This is used when we're just trying to EXPLAIN the remote query.
3695  * We don't have the actual value of the runtime parameter yet, and we don't
3696  * want the remote planner to generate a plan that depends on such a value
3697  * anyway. Thus, we can't do something simple like "$1::paramtype".
3698  * Instead, we emit "((SELECT null::paramtype)::paramtype)".
3699  * In all extant versions of Postgres, the planner will see that as an unknown
3700  * constant value, which is what we want. This might need adjustment if we
3701  * ever make the planner flatten scalar subqueries. Note: the reason for the
3702  * apparently useless outer cast is to ensure that the representation as a
3703  * whole will be parsed as an a_expr and not a select_with_parens; the latter
3704  * would do the wrong thing in the context "x = ANY(...)".
3705  */
3706 static void
3707 printRemotePlaceholder(Oid paramtype, int32 paramtypmod,
3708  deparse_expr_cxt *context)
3709 {
3710  StringInfo buf = context->buf;
3711  char *ptypename = deparse_type_name(paramtype, paramtypmod);
3712 
3713  appendStringInfo(buf, "((SELECT null::%s)::%s)", ptypename, ptypename);
3714 }
3715 
3716 /*
3717  * Deparse GROUP BY clause.
3718  */
3719 static void
3720 appendGroupByClause(List *tlist, deparse_expr_cxt *context)
3721 {
3722  StringInfo buf = context->buf;
3723  Query *query = context->root->parse;
3724  ListCell *lc;
3725  bool first = true;
3726 
3727  /* Nothing to be done, if there's no GROUP BY clause in the query. */
3728  if (!query->groupClause)
3729  return;
3730 
3731  appendStringInfoString(buf, " GROUP BY ");
3732 
3733  /*
3734  * Queries with grouping sets are not pushed down, so we don't expect
3735  * grouping sets here.
3736  */
3737  Assert(!query->groupingSets);
3738 
3739  /*
3740  * We intentionally print query->groupClause not processed_groupClause,
3741  * leaving it to the remote planner to get rid of any redundant GROUP BY
3742  * items again. This is necessary in case processed_groupClause reduced
3743  * to empty, and in any case the redundancy situation on the remote might
3744  * be different than what we think here.
3745  */
3746  foreach(lc, query->groupClause)
3747  {
3748  SortGroupClause *grp = (SortGroupClause *) lfirst(lc);
3749 
3750  if (!first)
3751  appendStringInfoString(buf, ", ");
3752  first = false;
3753 
3754  deparseSortGroupClause(grp->tleSortGroupRef, tlist, true, context);
3755  }
3756 }
3757 
3758 /*
3759  * Deparse ORDER BY clause defined by the given pathkeys.
3760  *
3761  * The clause should use Vars from context->scanrel if !has_final_sort,
3762  * or from context->foreignrel's targetlist if has_final_sort.
3763  *
3764  * We find a suitable pathkey expression (some earlier step
3765  * should have verified that there is one) and deparse it.
3766  */
3767 static void
3768 appendOrderByClause(List *pathkeys, bool has_final_sort,
3769  deparse_expr_cxt *context)
3770 {
3771  ListCell *lcell;
3772  int nestlevel;
3773  const char *delim = " ";
3774  StringInfo buf = context->buf;
3775 
3776  /* Make sure any constants in the exprs are printed portably */
3777  nestlevel = set_transmission_modes();
3778 
3779  appendStringInfoString(buf, " ORDER BY");
3780  foreach(lcell, pathkeys)
3781  {
3782  PathKey *pathkey = lfirst(lcell);
3783  EquivalenceMember *em;
3784  Expr *em_expr;
3785  Oid oprid;
3786 
3787  if (has_final_sort)
3788  {
3789  /*
3790  * By construction, context->foreignrel is the input relation to
3791  * the final sort.
3792  */
3793  em = find_em_for_rel_target(context->root,
3794  pathkey->pk_eclass,
3795  context->foreignrel);
3796  }
3797  else
3798  em = find_em_for_rel(context->root,
3799  pathkey->pk_eclass,
3800  context->scanrel);
3801 
3802  /*
3803  * We don't expect any error here; it would mean that shippability
3804  * wasn't verified earlier. For the same reason, we don't recheck
3805  * shippability of the sort operator.
3806  */
3807  if (em == NULL)
3808  elog(ERROR, "could not find pathkey item to sort");
3809 
3810  em_expr = em->em_expr;
3811 
3812  /*
3813  * Lookup the operator corresponding to the strategy in the opclass.
3814  * The datatype used by the opfamily is not necessarily the same as
3815  * the expression type (for array types for example).
3816  */
3817  oprid = get_opfamily_member(pathkey->pk_opfamily,
3818  em->em_datatype,
3819  em->em_datatype,
3820  pathkey->pk_strategy);
3821  if (!OidIsValid(oprid))
3822  elog(ERROR, "missing operator %d(%u,%u) in opfamily %u",
3823  pathkey->pk_strategy, em->em_datatype, em->em_datatype,
3824  pathkey->pk_opfamily);
3825 
3826  appendStringInfoString(buf, delim);
3827  deparseExpr(em_expr, context);
3828 
3829  /*
3830  * Here we need to use the expression's actual type to discover
3831  * whether the desired operator will be the default or not.
3832  */
3833  appendOrderBySuffix(oprid, exprType((Node *) em_expr),
3834  pathkey->pk_nulls_first, context);
3835 
3836  delim = ", ";
3837  }
3838  reset_transmission_modes(nestlevel);
3839 }
3840 
3841 /*
3842  * Deparse LIMIT/OFFSET clause.
3843  */
3844 static void
3845 appendLimitClause(deparse_expr_cxt *context)
3846 {
3847  PlannerInfo *root = context->root;
3848  StringInfo buf = context->buf;
3849  int nestlevel;
3850 
3851  /* Make sure any constants in the exprs are printed portably */
3852  nestlevel = set_transmission_modes();
3853 
3854  if (root->parse->limitCount)
3855  {
3856  appendStringInfoString(buf, " LIMIT ");
3857  deparseExpr((Expr *) root->parse->limitCount, context);
3858  }
3859  if (root->parse->limitOffset)
3860  {
3861  appendStringInfoString(buf, " OFFSET ");
3862  deparseExpr((Expr *) root->parse->limitOffset, context);
3863  }
3864 
3865  reset_transmission_modes(nestlevel);
3866 }
3867 
3868 /*
3869  * appendFunctionName
3870  * Deparses function name from given function oid.
3871  */
3872 static void
3873 appendFunctionName(Oid funcid, deparse_expr_cxt *context)
3874 {
3875  StringInfo buf = context->buf;
3876  HeapTuple proctup;
3877  Form_pg_proc procform;
3878  const char *proname;
3879 
3880  proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
3881  if (!HeapTupleIsValid(proctup))
3882  elog(ERROR, "cache lookup failed for function %u", funcid);
3883  procform = (Form_pg_proc) GETSTRUCT(proctup);
3884 
3885  /* Print schema name only if it's not pg_catalog */
3886  if (procform->pronamespace != PG_CATALOG_NAMESPACE)
3887  {
3888  const char *schemaname;
3889 
3890  schemaname = get_namespace_name(procform->pronamespace);
3891  appendStringInfo(buf, "%s.", quote_identifier(schemaname));
3892  }
3893 
3894  /* Always print the function name */
3895  proname = NameStr(procform->proname);
3896  appendStringInfoString(buf, quote_identifier(proname));
3897 
3898  ReleaseSysCache(proctup);
3899 }
3900 
3901 /*
3902  * Appends a sort or group clause.
3903  *
3904  * Like get_rule_sortgroupclause(), returns the expression tree, so caller
3905  * need not find it again.
3906  */
3907 static Node *
3908 deparseSortGroupClause(Index ref, List *tlist, bool force_colno,
3909  deparse_expr_cxt *context)
3910 {
3911  StringInfo buf = context->buf;
3912  TargetEntry *tle;
3913  Expr *expr;
3914 
3915  tle = get_sortgroupref_tle(ref, tlist);
3916  expr = tle->expr;
3917 
3918  if (force_colno)
3919  {
3920  /* Use column-number form when requested by caller. */
3921  Assert(!tle->resjunk);
3922  appendStringInfo(buf, "%d", tle->resno);
3923  }
3924  else if (expr && IsA(expr, Const))
3925  {
3926  /*
3927  * Force a typecast here so that we don't emit something like "GROUP
3928  * BY 2", which will be misconstrued as a column position rather than
3929  * a constant.
3930  */
3931  deparseConst((Const *) expr, context, 1);
3932  }
3933  else if (!expr || IsA(expr, Var))
3934  deparseExpr(expr, context);
3935  else
3936  {
3937  /* Always parenthesize the expression. */
3938  appendStringInfoChar(buf, '(');
3939  deparseExpr(expr, context);
3940  appendStringInfoChar(buf, ')');
3941  }
3942 
3943  return (Node *) expr;
3944 }
3945 
3946 
3947 /*
3948  * Returns true if given Var is deparsed as a subquery output column, in
3949  * which case, *relno and *colno are set to the IDs for the relation and
3950  * column alias to the Var provided by the subquery.
3951  */
3952 static bool
3953 is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
3954 {
3955  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
3956  RelOptInfo *outerrel = fpinfo->outerrel;
3957  RelOptInfo *innerrel = fpinfo->innerrel;
3958 
3959  /* Should only be called in these cases. */
3960  Assert(IS_SIMPLE_REL(foreignrel) || IS_JOIN_REL(foreignrel));
3961 
3962  /*
3963  * If the given relation isn't a join relation, it doesn't have any lower
3964  * subqueries, so the Var isn't a subquery output column.
3965  */
3966  if (!IS_JOIN_REL(foreignrel))
3967  return false;
3968 
3969  /*
3970  * If the Var doesn't belong to any lower subqueries, it isn't a subquery
3971  * output column.
3972  */
3973  if (!bms_is_member(node->varno, fpinfo->lower_subquery_rels))
3974  return false;
3975 
3976  if (bms_is_member(node->varno, outerrel->relids))
3977  {
3978  /*
3979  * If outer relation is deparsed as a subquery, the Var is an output
3980  * column of the subquery; get the IDs for the relation/column alias.
3981  */
3982  if (fpinfo->make_outerrel_subquery)
3983  {
3984  get_relation_column_alias_ids(node, outerrel, relno, colno);
3985  return true;
3986  }
3987 
3988  /* Otherwise, recurse into the outer relation. */
3989  return is_subquery_var(node, outerrel, relno, colno);
3990  }
3991  else
3992  {
3993  Assert(bms_is_member(node->varno, innerrel->relids));
3994 
3995  /*
3996  * If inner relation is deparsed as a subquery, the Var is an output
3997  * column of the subquery; get the IDs for the relation/column alias.
3998  */
3999  if (fpinfo->make_innerrel_subquery)
4000  {
4001  get_relation_column_alias_ids(node, innerrel, relno, colno);
4002  return true;
4003  }
4004 
4005  /* Otherwise, recurse into the inner relation. */
4006  return is_subquery_var(node, innerrel, relno, colno);
4007  }
4008 }
4009 
4010 /*
4011  * Get the IDs for the relation and column alias to given Var belonging to
4012  * given relation, which are returned into *relno and *colno.
4013  */
4014 static void
4015 get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel,
4016  int *relno, int *colno)
4017 {
4018  PgFdwRelationInfo *fpinfo = (PgFdwRelationInfo *) foreignrel->fdw_private;
4019  int i;
4020  ListCell *lc;
4021 
4022  /* Get the relation alias ID */
4023  *relno = fpinfo->relation_index;
4024 
4025  /* Get the column alias ID */
4026  i = 1;
4027  foreach(lc, foreignrel->reltarget->exprs)
4028  {
4029  Var *tlvar = (Var *) lfirst(lc);
4030 
4031  /*
4032  * Match reltarget entries only on varno/varattno. Ideally there
4033  * would be some cross-check on varnullingrels, but it's unclear what
4034  * to do exactly; we don't have enough context to know what that value
4035  * should be.
4036  */
4037  if (IsA(tlvar, Var) &&
4038  tlvar->varno == node->varno &&
4039  tlvar->varattno == node->varattno)
4040  {
4041  *colno = i;
4042  return;
4043  }
4044  i++;
4045  }
4046 
4047  /* Shouldn't get here */
4048  elog(ERROR, "unexpected expression in subquery output");
4049 }
AttrNumber
int16 AttrNumber
Definition: attnum.h:21
bms_next_member
int bms_next_member(const Bitmapset *a, int prevbit)
Definition: bitmapset.c:1039
bms_free
void bms_free(Bitmapset *a)
Definition: bitmapset.c:209
bms_is_member
bool bms_is_member(int x, const Bitmapset *a)
Definition: bitmapset.c:444
bms_make_singleton
Bitmapset * bms_make_singleton(int x)
Definition: bitmapset.c:186
bms_add_member
Bitmapset * bms_add_member(Bitmapset *a, int x)
Definition: bitmapset.c:755
bms_membership
BMS_Membership bms_membership(const Bitmapset *a)
Definition: bitmapset.c:691
BMS_MULTIPLE
@ BMS_MULTIPLE
Definition: bitmapset.h:73
FORMAT_TYPE_TYPEMOD_GIVEN
#define FORMAT_TYPE_TYPEMOD_GIVEN
Definition: builtins.h:121
FORMAT_TYPE_FORCE_QUALIFY
#define FORMAT_TYPE_FORCE_QUALIFY
Definition: builtins.h:123
NameStr
#define NameStr(name)
Definition: c.h:730
bits16
uint16 bits16
Definition: c.h:498
int32
signed int int32
Definition: c.h:478
ESCAPE_STRING_SYNTAX
#define ESCAPE_STRING_SYNTAX
Definition: c.h:1156
SQL_STR_DOUBLE
#define SQL_STR_DOUBLE(ch, escape_backslash)
Definition: c.h:1153
Index
unsigned int Index
Definition: c.h:598
OidIsValid
#define OidIsValid(objectId)
Definition: c.h:759
contain_mutable_functions
bool contain_mutable_functions(Node *clause)
Definition: clauses.c:367
defGetString
char * defGetString(DefElem *def)
Definition: define.c:49
deparseCaseExpr
static void deparseCaseExpr(CaseExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3439
deparseAnalyzeSizeSql
void deparseAnalyzeSizeSql(StringInfo buf, Relation rel)
Definition: deparse.c:2357
deparseBoolExpr
static void deparseBoolExpr(BoolExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3368
appendGroupByClause
static void appendGroupByClause(List *tlist, deparse_expr_cxt *context)
Definition: deparse.c:3720
deparseTargetList
static void deparseTargetList(StringInfo buf, RangeTblEntry *rte, Index rtindex, Relation rel, bool is_returning, Bitmapset *attrs_used, bool qualify_col, List **retrieved_attrs)
Definition: deparse.c:1403
deparseRangeTblRef
static void deparseRangeTblRef(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel, bool make_subquery, Index ignore_rel, List **ignore_conds, List **params_list)
Definition: deparse.c:1868
SUBQUERY_REL_ALIAS_PREFIX
#define SUBQUERY_REL_ALIAS_PREFIX
Definition: deparse.c:114
deparseFromExpr
static void deparseFromExpr(List *quals, deparse_expr_cxt *context)
Definition: deparse.c:1369
deparseSortGroupClause
static Node * deparseSortGroupClause(Index ref, List *tlist, bool force_colno, deparse_expr_cxt *context)
Definition: deparse.c:3908
deparseLockingClause
static void deparseLockingClause(deparse_expr_cxt *context)
Definition: deparse.c:1479
get_jointype_name
const char * get_jointype_name(JoinType jointype)
Definition: deparse.c:1603
deparseAnalyzeInfoSql
void deparseAnalyzeInfoSql(StringInfo buf, Relation rel)
Definition: deparse.c:2379
deparseAggref
static void deparseAggref(Aggref *node, deparse_expr_cxt *context)
Definition: deparse.c:3515
appendOrderBySuffix
static void appendOrderBySuffix(Oid sortop, Oid sortcoltype, bool nulls_first, deparse_expr_cxt *context)
Definition: deparse.c:3636
deparseDirectDeleteSql
void deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root, Index rtindex, Relation rel, RelOptInfo *foreignrel, List *remote_conds, List **params_list, List *returningList, List **retrieved_attrs)
Definition: deparse.c:2249
REL_ALIAS_PREFIX
#define REL_ALIAS_PREFIX
Definition: deparse.c:110
deparseDirectUpdateSql
void deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root, Index rtindex, Relation rel, RelOptInfo *foreignrel, List *targetlist, List *targetAttrs, List *remote_conds, List **params_list, List *returningList, List **retrieved_attrs)
Definition: deparse.c:2135
deparse_expr_cxt
struct deparse_expr_cxt deparse_expr_cxt
get_relation_column_alias_ids
static void get_relation_column_alias_ids(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
Definition: deparse.c:4015
FDWCollateState
FDWCollateState
Definition: deparse.c:81
FDW_COLLATE_SAFE
@ FDW_COLLATE_SAFE
Definition: deparse.c:85
FDW_COLLATE_UNSAFE
@ FDW_COLLATE_UNSAFE
Definition: deparse.c:86
FDW_COLLATE_NONE
@ FDW_COLLATE_NONE
Definition: deparse.c:82
printRemoteParam
static void printRemoteParam(int paramindex, Oid paramtype, int32 paramtypmod, deparse_expr_cxt *context)
Definition: deparse.c:3681
is_subquery_var
static bool is_subquery_var(Var *node, RelOptInfo *foreignrel, int *relno, int *colno)
Definition: deparse.c:3953
is_foreign_param
bool is_foreign_param(PlannerInfo *root, RelOptInfo *baserel, Expr *expr)
Definition: deparse.c:1078
printRemotePlaceholder
static void printRemotePlaceholder(Oid paramtype, int32 paramtypmod, deparse_expr_cxt *context)
Definition: deparse.c:3707
appendOrderByClause
static void appendOrderByClause(List *pathkeys, bool has_final_sort, deparse_expr_cxt *context)
Definition: deparse.c:3768
foreign_expr_walker
static bool foreign_expr_walker(Node *node, foreign_glob_cxt *glob_cxt, foreign_loc_cxt *outer_cxt, foreign_loc_cxt *case_arg_cxt)
Definition: deparse.c:308
deparseColumnRef
static void deparseColumnRef(StringInfo buf, int varno, int varattno, RangeTblEntry *rte, bool qualify_col)
Definition: deparse.c:2539
deparseRelabelType
static void deparseRelabelType(RelabelType *node, deparse_expr_cxt *context)
Definition: deparse.c:3355
deparseNullTest
static void deparseNullTest(NullTest *node, deparse_expr_cxt *context)
Definition: deparse.c:3406
deparseOperatorName
static void deparseOperatorName(StringInfo buf, Form_pg_operator opform)
Definition: deparse.c:3264
deparseOpExpr
static void deparseOpExpr(OpExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3134
deparseConst
static void deparseConst(Const *node, deparse_expr_cxt *context, int showtype)
Definition: deparse.c:2878
isPlainForeignVar
static bool isPlainForeignVar(Expr *node, deparse_expr_cxt *context)
Definition: deparse.c:3229
deparseDistinctExpr
static void deparseDistinctExpr(DistinctExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3292
deparseSelectStmtForRel
void deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *rel, List *tlist, List *remote_conds, List *pathkeys, bool has_final_sort, bool has_limit, bool is_subquery, List **retrieved_attrs, List **params_list)
Definition: deparse.c:1229
deparseFuncExpr
static void deparseFuncExpr(FuncExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3071
deparseStringLiteral
void deparseStringLiteral(StringInfo buf, const char *val)
Definition: deparse.c:2707
rebuildInsertSql
void rebuildInsertSql(StringInfo buf, Relation rel, char *orig_query, List *target_attrs, int values_end_len, int num_params, int num_rows)
Definition: deparse.c:2015
foreign_glob_cxt
struct foreign_glob_cxt foreign_glob_cxt
deparseArrayExpr
static void deparseArrayExpr(ArrayExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3489
deparseInsertSql
void deparseInsertSql(StringInfo buf, RangeTblEntry *rte, Index rtindex, Relation rel, List *targetAttrs, bool doNothing, List *withCheckOptionList, List *returningList, List **retrieved_attrs, int *values_end_len)
Definition: deparse.c:1942
deparseReturningList
static void deparseReturningList(StringInfo buf, RangeTblEntry *rte, Index rtindex, Relation rel, bool trig_after_row, List *withCheckOptionList, List *returningList, List **retrieved_attrs)
Definition: deparse.c:2300
deparseUpdateSql
void deparseUpdateSql(StringInfo buf, RangeTblEntry *rte, Index rtindex, Relation rel, List *targetAttrs, List *withCheckOptionList, List *returningList, List **retrieved_attrs)
Definition: deparse.c:2075
deparseVar
static void deparseVar(Var *node, deparse_expr_cxt *context)
Definition: deparse.c:2807
appendFunctionName
static void appendFunctionName(Oid funcid, deparse_expr_cxt *context)
Definition: deparse.c:3873
appendConditions
static void appendConditions(List *exprs, deparse_expr_cxt *context)
Definition: deparse.c:1569
foreign_loc_cxt
struct foreign_loc_cxt foreign_loc_cxt
deparseDeleteSql
void deparseDeleteSql(StringInfo buf, RangeTblEntry *rte, Index rtindex, Relation rel, List *returningList, List **retrieved_attrs)
Definition: deparse.c:2220
deparseAnalyzeSql
void deparseAnalyzeSql(StringInfo buf, Relation rel, PgFdwSamplingMethod sample_method, double sample_frac, List **retrieved_attrs)
Definition: deparse.c:2419
deparseSubscriptingRef
static void deparseSubscriptingRef(SubscriptingRef *node, deparse_expr_cxt *context)
Definition: deparse.c:3025
deparseRelation
static void deparseRelation(StringInfo buf, Relation rel)
Definition: deparse.c:2667
deparseExplicitTargetList
static void deparseExplicitTargetList(List *tlist, bool is_returning, List **retrieved_attrs, deparse_expr_cxt *context)
Definition: deparse.c:1640
deparse_type_name
static char * deparse_type_name(Oid type_oid, int32 typemod)
Definition: deparse.c:1153
ADD_REL_QUALIFIER
#define ADD_REL_QUALIFIER(buf, varno)
Definition: deparse.c:112
appendLimitClause
static void appendLimitClause(deparse_expr_cxt *context)
Definition: deparse.c:3845
deparseExpr
static void deparseExpr(Expr *node, deparse_expr_cxt *context)
Definition: deparse.c:2742
is_foreign_expr
bool is_foreign_expr(PlannerInfo *root, RelOptInfo *baserel, Expr *expr)
Definition: deparse.c:240
build_tlist_to_deparse
List * build_tlist_to_deparse(RelOptInfo *foreignrel)
Definition: deparse.c:1172
SUBQUERY_COL_ALIAS_PREFIX
#define SUBQUERY_COL_ALIAS_PREFIX
Definition: deparse.c:115
classifyConditions
void classifyConditions(PlannerInfo *root, RelOptInfo *baserel, List *input_conds, List **remote_conds, List **local_conds)
Definition: deparse.c:214
deparseScalarArrayOpExpr
static void deparseScalarArrayOpExpr(ScalarArrayOpExpr *node, deparse_expr_cxt *context)
Definition: deparse.c:3310
deparseFromExprForRel
static void deparseFromExprForRel(StringInfo buf, PlannerInfo *root, RelOptInfo *foreignrel, bool use_alias, Index ignore_rel, List **ignore_conds, List **params_list)
Definition: deparse.c:1717
deparseTruncateSql
void deparseTruncateSql(StringInfo buf, List *rels, DropBehavior behavior, bool restart_seqs)
Definition: deparse.c:2504
deparseSubqueryTargetList
static void deparseSubqueryTargetList(deparse_expr_cxt *context)
Definition: deparse.c:1676
is_foreign_pathkey
bool is_foreign_pathkey(PlannerInfo *root, RelOptInfo *baserel, PathKey *pathkey)
Definition: deparse.c:1119
deparseSelectSql
static void deparseSelectSql(List *tlist, bool is_subquery, List **retrieved_attrs, deparse_expr_cxt *context)
Definition: deparse.c:1311
deparseParam
static void deparseParam(Param *node, deparse_expr_cxt *context)
Definition: deparse.c:2992
appendAggOrderBy
static void appendAggOrderBy(List *orderList, List *targetList, deparse_expr_cxt *context)
Definition: deparse.c:3607
ERROR
#define ERROR
Definition: elog.h:39
equal
bool equal(const void *a, const void *b)
Definition: equalfuncs.c:223
OidOutputFunctionCall
char * OidOutputFunctionCall(Oid functionId, Datum val)
Definition: fmgr.c:1735
GetForeignTable
ForeignTable * GetForeignTable(Oid relid)
Definition: foreign.c:250
GetForeignColumnOptions
List * GetForeignColumnOptions(Oid relid, AttrNumber attnum)
Definition: foreign.c:288
format_type_extended
char * format_type_extended(Oid type_oid, int32 typemod, bits16 flags)
Definition: format_type.c:112
HeapTupleIsValid
#define HeapTupleIsValid(tuple)
Definition: htup.h:78
htup_details.h
GETSTRUCT
#define GETSTRUCT(TUP)
Definition: htup_details.h:653
val
long val
Definition: informix.c:664
b
int b
Definition: isn.c:70
a
int a
Definition: isn.c:69
i
int i
Definition: isn.c:73
if
if(TABLE==NULL||TABLE_index==NULL)
Definition: isn.c:77
Assert
Assert(fmt[strlen(fmt) - 1] !='\n')
lappend
List * lappend(List *list, void *datum)
Definition: list.c:338
lappend_int
List * lappend_int(List *list, int datum)
Definition: list.c:356
list_concat
List * list_concat(List *list1, const List *list2)
Definition: list.c:560
NoLock
#define NoLock
Definition: lockdefs.h:34
LCS_FORUPDATE
@ LCS_FORUPDATE
Definition: lockoptions.h:27
LCS_NONE
@ LCS_NONE
Definition: lockoptions.h:23
LCS_FORSHARE
@ LCS_FORSHARE
Definition: lockoptions.h:25
LCS_FORKEYSHARE
@ LCS_FORKEYSHARE
Definition: lockoptions.h:24
LCS_FORNOKEYUPDATE
@ LCS_FORNOKEYUPDATE
Definition: lockoptions.h:26
type_is_rowtype
bool type_is_rowtype(Oid typid)
Definition: lsyscache.c:2613
get_namespace_name
char * get_namespace_name(Oid nspid)
Definition: lsyscache.c:3324
getTypeOutputInfo
void getTypeOutputInfo(Oid type, Oid *typOutput, bool *typIsVarlena)
Definition: lsyscache.c:2865
get_opfamily_member
Oid get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype, int16 strategy)
Definition: lsyscache.c:165
get_attname
char * get_attname(Oid relid, AttrNumber attnum, bool missing_ok)
Definition: lsyscache.c:826
pfree
void pfree(void *pointer)
Definition: mcxt.c:1436
exprType
Oid exprType(const Node *expr)
Definition: nodeFuncs.c:43
exprIsLengthCoercion
bool exprIsLengthCoercion(const Node *expr, int32 *coercedTypmod)
Definition: nodeFuncs.c:516
strip_implicit_coercions
Node * strip_implicit_coercions(Node *node)
Definition: nodeFuncs.c:664
IsA
#define IsA(nodeptr, _type_)
Definition: nodes.h:179
nodeTag
#define nodeTag(nodeptr)
Definition: nodes.h:133
CMD_DELETE
@ CMD_DELETE
Definition: nodes.h:279
CMD_UPDATE
@ CMD_UPDATE
Definition: nodes.h:277
AGGSPLIT_SIMPLE
@ AGGSPLIT_SIMPLE
Definition: nodes.h:385
castNode
#define castNode(_type_, nodeptr)
Definition: nodes.h:197
JoinType
JoinType
Definition: nodes.h:299
JOIN_FULL
@ JOIN_FULL
Definition: nodes.h:306
JOIN_INNER
@ JOIN_INNER
Definition: nodes.h:304
JOIN_RIGHT
@ JOIN_RIGHT
Definition: nodes.h:307
JOIN_LEFT
@ JOIN_LEFT
Definition: nodes.h:305
PVC_RECURSE_PLACEHOLDERS
#define PVC_RECURSE_PLACEHOLDERS
Definition: optimizer.h:188
oprid
Oid oprid(Operator op)
Definition: parse_oper.c:250
DropBehavior
DropBehavior
Definition: parsenodes.h:2154
DROP_CASCADE
@ DROP_CASCADE
Definition: parsenodes.h:2156
DROP_RESTRICT
@ DROP_RESTRICT
Definition: parsenodes.h:2155
IS_SIMPLE_REL
#define IS_SIMPLE_REL(rel)
Definition: pathnodes.h:830
IS_JOIN_REL
#define IS_JOIN_REL(rel)
Definition: pathnodes.h:835
planner_rt_fetch
#define planner_rt_fetch(rti, root)
Definition: pathnodes.h:561
RELOPT_JOINREL
@ RELOPT_JOINREL
Definition: pathnodes.h:819
IS_UPPER_REL
#define IS_UPPER_REL(rel)
Definition: pathnodes.h:840
pg_aggregate.h
attname
NameData attname
Definition: pg_attribute.h:41
attnum
int16 attnum
Definition: pg_attribute.h:74
Form_pg_attribute
FormData_pg_attribute * Form_pg_attribute
Definition: pg_attribute.h:209
pg_authid.h
arg
void * arg
Definition: pg_backup_utils.c:27
relname
NameData relname
Definition: pg_class.h:38
pg_collation.h
while
while(p+4<=pend)
Definition: pg_crc32c_sse42.c:54
lfirst
#define lfirst(lc)
Definition: pg_list.h:172
llast
#define llast(l)
Definition: pg_list.h:198
lfirst_node
#define lfirst_node(type, lc)
Definition: pg_list.h:176
list_length
static int list_length(const List *l)
Definition: pg_list.h:152
NIL
#define NIL
Definition: pg_list.h:68
forboth
#define forboth(cell1, list1, cell2, list2)
Definition: pg_list.h:467
lfirst_int
#define lfirst_int(lc)
Definition: pg_list.h:173
list_head
static ListCell * list_head(const List *l)
Definition: pg_list.h:128
linitial
#define linitial(l)
Definition: pg_list.h:178
lsecond
#define lsecond(l)
Definition: pg_list.h:183
lnext
static ListCell * lnext(const List *l, const ListCell *c)
Definition: pg_list.h:343
pg_namespace.h
pg_operator.h
Form_pg_operator
FormData_pg_operator * Form_pg_operator
Definition: pg_operator.h:83
pg_opfamily.h
pg_proc.h
Form_pg_proc
FormData_pg_proc * Form_pg_proc
Definition: pg_proc.h:136
proname
NameData proname
Definition: pg_proc.h:35
options
static char ** options
Definition: pg_recvlogical.c:51
buf
static char * buf
Definition: pg_test_fsync.c:67
pg_ts_config.h
pg_ts_dict.h
pg_type.h
DatumGetObjectId
static Oid DatumGetObjectId(Datum X)
Definition: postgres.h:242
ObjectIdGetDatum
static Datum ObjectIdGetDatum(Oid X)
Definition: postgres.h:252
InvalidOid
#define InvalidOid
Definition: postgres_ext.h:36
Oid
unsigned int Oid
Definition: postgres_ext.h:31
reset_transmission_modes
void reset_transmission_modes(int nestlevel)
Definition: postgres_fdw.c:3921
set_transmission_modes
int set_transmission_modes(void)
Definition: postgres_fdw.c:3885
find_em_for_rel
EquivalenceMember * find_em_for_rel(PlannerInfo *root, EquivalenceClass *ec, RelOptInfo *rel)
Definition: postgres_fdw.c:7676
find_em_for_rel_target
EquivalenceMember * find_em_for_rel_target(PlannerInfo *root, EquivalenceClass *ec, RelOptInfo *rel)
Definition: postgres_fdw.c:7709
postgres_fdw.h
is_shippable
bool is_shippable(Oid objectId, Oid classId, PgFdwRelationInfo *fpinfo)
Definition: shippable.c:162
is_builtin
bool is_builtin(Oid objectId)
Definition: shippable.c:152
PgFdwSamplingMethod
PgFdwSamplingMethod
Definition: postgres_fdw.h:141
ANALYZE_SAMPLE_AUTO
@ ANALYZE_SAMPLE_AUTO
Definition: postgres_fdw.h:143
ANALYZE_SAMPLE_OFF
@ ANALYZE_SAMPLE_OFF
Definition: postgres_fdw.h:142
ANALYZE_SAMPLE_BERNOULLI
@ ANALYZE_SAMPLE_BERNOULLI
Definition: postgres_fdw.h:146
ANALYZE_SAMPLE_SYSTEM
@ ANALYZE_SAMPLE_SYSTEM
Definition: postgres_fdw.h:145
ANALYZE_SAMPLE_RANDOM
@ ANALYZE_SAMPLE_RANDOM
Definition: postgres_fdw.h:144
c
char * c
Definition: preproc-cursor.c:31
fe
static int fe(enum e x)
Definition: preproc-init.c:111
get_plan_rowmark
PlanRowMark * get_plan_rowmark(List *rowmarks, Index rtindex)
Definition: preptlist.c:485
AND_EXPR
@ AND_EXPR
Definition: primnodes.h:858
OR_EXPR
@ OR_EXPR
Definition: primnodes.h:858
NOT_EXPR
@ NOT_EXPR
Definition: primnodes.h:858
PARAM_MULTIEXPR
@ PARAM_MULTIEXPR
Definition: primnodes.h:348
IS_SPECIAL_VARNO
#define IS_SPECIAL_VARNO(varno)
Definition: primnodes.h:219
COERCE_IMPLICIT_CAST
@ COERCE_IMPLICIT_CAST
Definition: primnodes.h:663
COERCE_EXPLICIT_CAST
@ COERCE_EXPLICIT_CAST
Definition: primnodes.h:662
IS_NULL
@ IS_NULL
Definition: primnodes.h:1607
RelationGetRelid
#define RelationGetRelid(relation)
Definition: rel.h:503
RelationGetDescr
#define RelationGetDescr(relation)
Definition: rel.h:529
RelationGetRelationName
#define RelationGetRelationName(relation)
Definition: rel.h:537
RelationGetNamespace
#define RelationGetNamespace(relation)
Definition: rel.h:544
quote_identifier
const char * quote_identifier(const char *ident)
Definition: ruleutils.c:11751
appendStringInfo
void appendStringInfo(StringInfo str, const char *fmt,...)
Definition: stringinfo.c:91
appendBinaryStringInfo
void appendBinaryStringInfo(StringInfo str, const void *data, int datalen)
Definition: stringinfo.c:227
appendStringInfoString
void appendStringInfoString(StringInfo str, const char *s)
Definition: stringinfo.c:176
appendStringInfoChar
void appendStringInfoChar(StringInfo str, char ch)
Definition: stringinfo.c:188
initStringInfo
void initStringInfo(StringInfo str)
Definition: stringinfo.c:59
Aggref::aggfnoid
Oid aggfnoid
Definition: primnodes.h:422
Aggref::aggdistinct
List * aggdistinct
Definition: primnodes.h:452
Aggref::aggdirectargs
List * aggdirectargs
Definition: primnodes.h:443
Aggref::args
List * args
Definition: primnodes.h:446
Aggref::aggfilter
Expr * aggfilter
Definition: primnodes.h:455
Aggref::aggorder
List * aggorder
Definition: primnodes.h:449
ArrayExpr::elements
List * elements
Definition: primnodes.h:1305
BoolExpr::boolop
BoolExprType boolop
Definition: primnodes.h:866
BoolExpr::args
List * args
Definition: primnodes.h:867
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Expr * arg
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@ OPEROID
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Definition: var.c:291