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dblink.c
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1 /*
2  * dblink.c
3  *
4  * Functions returning results from a remote database
5  *
6  * Joe Conway <mail@joeconway.com>
7  * And contributors:
8  * Darko Prenosil <Darko.Prenosil@finteh.hr>
9  * Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
10  *
11  * contrib/dblink/dblink.c
12  * Copyright (c) 2001-2020, PostgreSQL Global Development Group
13  * ALL RIGHTS RESERVED;
14  *
15  * Permission to use, copy, modify, and distribute this software and its
16  * documentation for any purpose, without fee, and without a written agreement
17  * is hereby granted, provided that the above copyright notice and this
18  * paragraph and the following two paragraphs appear in all copies.
19  *
20  * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
21  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
22  * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
23  * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
24  * POSSIBILITY OF SUCH DAMAGE.
25  *
26  * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
27  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
28  * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
29  * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
30  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
31  *
32  */
33 #include "postgres.h"
34 
35 #include <limits.h>
36 
37 #include "access/htup_details.h"
38 #include "access/relation.h"
39 #include "access/reloptions.h"
40 #include "access/table.h"
41 #include "catalog/indexing.h"
42 #include "catalog/namespace.h"
45 #include "catalog/pg_type.h"
47 #include "executor/spi.h"
48 #include "foreign/foreign.h"
49 #include "funcapi.h"
50 #include "lib/stringinfo.h"
51 #include "libpq-fe.h"
52 #include "mb/pg_wchar.h"
53 #include "miscadmin.h"
54 #include "parser/scansup.h"
55 #include "utils/acl.h"
56 #include "utils/builtins.h"
57 #include "utils/fmgroids.h"
58 #include "utils/guc.h"
59 #include "utils/lsyscache.h"
60 #include "utils/memutils.h"
61 #include "utils/rel.h"
62 #include "utils/varlena.h"
63 
65 
66 typedef struct remoteConn
67 {
68  PGconn *conn; /* Hold the remote connection */
69  int openCursorCount; /* The number of open cursors */
70  bool newXactForCursor; /* Opened a transaction for a cursor */
71 } remoteConn;
72 
73 typedef struct storeInfo
74 {
79  char **cstrs;
80  /* temp storage for results to avoid leaks on exception */
83 } storeInfo;
84 
85 /*
86  * Internal declarations
87  */
88 static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async);
89 static void prepTuplestoreResult(FunctionCallInfo fcinfo);
90 static void materializeResult(FunctionCallInfo fcinfo, PGconn *conn,
91  PGresult *res);
92 static void materializeQueryResult(FunctionCallInfo fcinfo,
93  PGconn *conn,
94  const char *conname,
95  const char *sql,
96  bool fail);
97 static PGresult *storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql);
98 static void storeRow(volatile storeInfo *sinfo, PGresult *res, bool first);
99 static remoteConn *getConnectionByName(const char *name);
100 static HTAB *createConnHash(void);
101 static void createNewConnection(const char *name, remoteConn *rconn);
102 static void deleteConnection(const char *name);
103 static char **get_pkey_attnames(Relation rel, int16 *indnkeyatts);
104 static char **get_text_array_contents(ArrayType *array, int *numitems);
105 static char *get_sql_insert(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
106 static char *get_sql_delete(Relation rel, int *pkattnums, int pknumatts, char **tgt_pkattvals);
107 static char *get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals);
108 static char *quote_ident_cstr(char *rawstr);
109 static int get_attnum_pk_pos(int *pkattnums, int pknumatts, int key);
110 static HeapTuple get_tuple_of_interest(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals);
111 static Relation get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode);
112 static char *generate_relation_name(Relation rel);
113 static void dblink_connstr_check(const char *connstr);
114 static void dblink_security_check(PGconn *conn, remoteConn *rconn);
115 static void dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
116  bool fail, const char *fmt,...) pg_attribute_printf(5, 6);
117 static char *get_connect_string(const char *servername);
118 static char *escape_param_str(const char *from);
119 static void validate_pkattnums(Relation rel,
120  int2vector *pkattnums_arg, int32 pknumatts_arg,
121  int **pkattnums, int *pknumatts);
123  const char *option, Oid context);
124 static int applyRemoteGucs(PGconn *conn);
125 static void restoreLocalGucs(int nestlevel);
126 
127 /* Global */
128 static remoteConn *pconn = NULL;
129 static HTAB *remoteConnHash = NULL;
130 
131 /*
132  * Following is list that holds multiple remote connections.
133  * Calling convention of each dblink function changes to accept
134  * connection name as the first parameter. The connection list is
135  * much like ecpg e.g. a mapping between a name and a PGconn object.
136  */
137 
138 typedef struct remoteConnHashEnt
139 {
143 
144 /* initial number of connection hashes */
145 #define NUMCONN 16
146 
147 static char *
148 xpstrdup(const char *in)
149 {
150  if (in == NULL)
151  return NULL;
152  return pstrdup(in);
153 }
154 
155 static void
157 dblink_res_internalerror(PGconn *conn, PGresult *res, const char *p2)
158 {
159  char *msg = pchomp(PQerrorMessage(conn));
160 
161  if (res)
162  PQclear(res);
163  elog(ERROR, "%s: %s", p2, msg);
164 }
165 
166 static void
168 dblink_conn_not_avail(const char *conname)
169 {
170  if (conname)
171  ereport(ERROR,
172  (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
173  errmsg("connection \"%s\" not available", conname)));
174  else
175  ereport(ERROR,
176  (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
177  errmsg("connection not available")));
178 }
179 
180 static void
181 dblink_get_conn(char *conname_or_str,
182  PGconn *volatile *conn_p, char **conname_p, volatile bool *freeconn_p)
183 {
184  remoteConn *rconn = getConnectionByName(conname_or_str);
185  PGconn *conn;
186  char *conname;
187  bool freeconn;
188 
189  if (rconn)
190  {
191  conn = rconn->conn;
192  conname = conname_or_str;
193  freeconn = false;
194  }
195  else
196  {
197  const char *connstr;
198 
199  connstr = get_connect_string(conname_or_str);
200  if (connstr == NULL)
201  connstr = conname_or_str;
202  dblink_connstr_check(connstr);
203 
204  /*
205  * We must obey fd.c's limit on non-virtual file descriptors. Assume
206  * that a PGconn represents one long-lived FD. (Doing this here also
207  * ensures that VFDs are closed if needed to make room.)
208  */
209  if (!AcquireExternalFD())
210  {
211 #ifndef WIN32 /* can't write #if within ereport() macro */
212  ereport(ERROR,
213  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
214  errmsg("could not establish connection"),
215  errdetail("There are too many open files on the local server."),
216  errhint("Raise the server's max_files_per_process and/or \"ulimit -n\" limits.")));
217 #else
218  ereport(ERROR,
219  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
220  errmsg("could not establish connection"),
221  errdetail("There are too many open files on the local server."),
222  errhint("Raise the server's max_files_per_process setting.")));
223 #endif
224  }
225 
226  /* OK to make connection */
227  conn = PQconnectdb(connstr);
228 
229  if (PQstatus(conn) == CONNECTION_BAD)
230  {
231  char *msg = pchomp(PQerrorMessage(conn));
232 
233  PQfinish(conn);
235  ereport(ERROR,
236  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
237  errmsg("could not establish connection"),
238  errdetail_internal("%s", msg)));
239  }
240  dblink_security_check(conn, rconn);
241  if (PQclientEncoding(conn) != GetDatabaseEncoding())
243  freeconn = true;
244  conname = NULL;
245  }
246 
247  *conn_p = conn;
248  *conname_p = conname;
249  *freeconn_p = freeconn;
250 }
251 
252 static PGconn *
253 dblink_get_named_conn(const char *conname)
254 {
255  remoteConn *rconn = getConnectionByName(conname);
256 
257  if (rconn)
258  return rconn->conn;
259 
260  dblink_conn_not_avail(conname);
261  return NULL; /* keep compiler quiet */
262 }
263 
264 static void
266 {
267  if (!pconn)
268  {
270  pconn->conn = NULL;
271  pconn->openCursorCount = 0;
272  pconn->newXactForCursor = false;
273  }
274 }
275 
276 /*
277  * Create a persistent connection to another database
278  */
280 Datum
282 {
283  char *conname_or_str = NULL;
284  char *connstr = NULL;
285  char *connname = NULL;
286  char *msg;
287  PGconn *conn = NULL;
288  remoteConn *rconn = NULL;
289 
290  dblink_init();
291 
292  if (PG_NARGS() == 2)
293  {
294  conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(1));
295  connname = text_to_cstring(PG_GETARG_TEXT_PP(0));
296  }
297  else if (PG_NARGS() == 1)
298  conname_or_str = text_to_cstring(PG_GETARG_TEXT_PP(0));
299 
300  if (connname)
301  {
303  sizeof(remoteConn));
304  rconn->conn = NULL;
305  rconn->openCursorCount = 0;
306  rconn->newXactForCursor = false;
307  }
308 
309  /* first check for valid foreign data server */
310  connstr = get_connect_string(conname_or_str);
311  if (connstr == NULL)
312  connstr = conname_or_str;
313 
314  /* check password in connection string if not superuser */
315  dblink_connstr_check(connstr);
316 
317  /*
318  * We must obey fd.c's limit on non-virtual file descriptors. Assume that
319  * a PGconn represents one long-lived FD. (Doing this here also ensures
320  * that VFDs are closed if needed to make room.)
321  */
322  if (!AcquireExternalFD())
323  {
324 #ifndef WIN32 /* can't write #if within ereport() macro */
325  ereport(ERROR,
326  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
327  errmsg("could not establish connection"),
328  errdetail("There are too many open files on the local server."),
329  errhint("Raise the server's max_files_per_process and/or \"ulimit -n\" limits.")));
330 #else
331  ereport(ERROR,
332  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
333  errmsg("could not establish connection"),
334  errdetail("There are too many open files on the local server."),
335  errhint("Raise the server's max_files_per_process setting.")));
336 #endif
337  }
338 
339  /* OK to make connection */
340  conn = PQconnectdb(connstr);
341 
342  if (PQstatus(conn) == CONNECTION_BAD)
343  {
344  msg = pchomp(PQerrorMessage(conn));
345  PQfinish(conn);
347  if (rconn)
348  pfree(rconn);
349 
350  ereport(ERROR,
351  (errcode(ERRCODE_SQLCLIENT_UNABLE_TO_ESTABLISH_SQLCONNECTION),
352  errmsg("could not establish connection"),
353  errdetail_internal("%s", msg)));
354  }
355 
356  /* check password actually used if not superuser */
357  dblink_security_check(conn, rconn);
358 
359  /* attempt to set client encoding to match server encoding, if needed */
360  if (PQclientEncoding(conn) != GetDatabaseEncoding())
362 
363  if (connname)
364  {
365  rconn->conn = conn;
366  createNewConnection(connname, rconn);
367  }
368  else
369  {
370  if (pconn->conn)
371  {
372  PQfinish(pconn->conn);
374  }
375  pconn->conn = conn;
376  }
377 
379 }
380 
381 /*
382  * Clear a persistent connection to another database
383  */
385 Datum
387 {
388  char *conname = NULL;
389  remoteConn *rconn = NULL;
390  PGconn *conn = NULL;
391 
392  dblink_init();
393 
394  if (PG_NARGS() == 1)
395  {
396  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
397  rconn = getConnectionByName(conname);
398  if (rconn)
399  conn = rconn->conn;
400  }
401  else
402  conn = pconn->conn;
403 
404  if (!conn)
405  dblink_conn_not_avail(conname);
406 
407  PQfinish(conn);
409  if (rconn)
410  {
411  deleteConnection(conname);
412  pfree(rconn);
413  }
414  else
415  pconn->conn = NULL;
416 
418 }
419 
420 /*
421  * opens a cursor using a persistent connection
422  */
424 Datum
426 {
427  PGresult *res = NULL;
428  PGconn *conn;
429  char *curname = NULL;
430  char *sql = NULL;
431  char *conname = NULL;
433  remoteConn *rconn = NULL;
434  bool fail = true; /* default to backward compatible behavior */
435 
436  dblink_init();
437  initStringInfo(&buf);
438 
439  if (PG_NARGS() == 2)
440  {
441  /* text,text */
442  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
444  rconn = pconn;
445  }
446  else if (PG_NARGS() == 3)
447  {
448  /* might be text,text,text or text,text,bool */
449  if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
450  {
451  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
453  fail = PG_GETARG_BOOL(2);
454  rconn = pconn;
455  }
456  else
457  {
458  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
459  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
461  rconn = getConnectionByName(conname);
462  }
463  }
464  else if (PG_NARGS() == 4)
465  {
466  /* text,text,text,bool */
467  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
468  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
470  fail = PG_GETARG_BOOL(3);
471  rconn = getConnectionByName(conname);
472  }
473 
474  if (!rconn || !rconn->conn)
475  dblink_conn_not_avail(conname);
476 
477  conn = rconn->conn;
478 
479  /* If we are not in a transaction, start one */
480  if (PQtransactionStatus(conn) == PQTRANS_IDLE)
481  {
482  res = PQexec(conn, "BEGIN");
483  if (PQresultStatus(res) != PGRES_COMMAND_OK)
484  dblink_res_internalerror(conn, res, "begin error");
485  PQclear(res);
486  rconn->newXactForCursor = true;
487 
488  /*
489  * Since transaction state was IDLE, we force cursor count to
490  * initially be 0. This is needed as a previous ABORT might have wiped
491  * out our transaction without maintaining the cursor count for us.
492  */
493  rconn->openCursorCount = 0;
494  }
495 
496  /* if we started a transaction, increment cursor count */
497  if (rconn->newXactForCursor)
498  (rconn->openCursorCount)++;
499 
500  appendStringInfo(&buf, "DECLARE %s CURSOR FOR %s", curname, sql);
501  res = PQexec(conn, buf.data);
502  if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
503  {
504  dblink_res_error(conn, conname, res, fail,
505  "while opening cursor \"%s\"", curname);
507  }
508 
509  PQclear(res);
511 }
512 
513 /*
514  * closes a cursor
515  */
517 Datum
519 {
520  PGconn *conn;
521  PGresult *res = NULL;
522  char *curname = NULL;
523  char *conname = NULL;
525  remoteConn *rconn = NULL;
526  bool fail = true; /* default to backward compatible behavior */
527 
528  dblink_init();
529  initStringInfo(&buf);
530 
531  if (PG_NARGS() == 1)
532  {
533  /* text */
534  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
535  rconn = pconn;
536  }
537  else if (PG_NARGS() == 2)
538  {
539  /* might be text,text or text,bool */
540  if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
541  {
542  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
543  fail = PG_GETARG_BOOL(1);
544  rconn = pconn;
545  }
546  else
547  {
548  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
549  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
550  rconn = getConnectionByName(conname);
551  }
552  }
553  if (PG_NARGS() == 3)
554  {
555  /* text,text,bool */
556  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
557  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
558  fail = PG_GETARG_BOOL(2);
559  rconn = getConnectionByName(conname);
560  }
561 
562  if (!rconn || !rconn->conn)
563  dblink_conn_not_avail(conname);
564 
565  conn = rconn->conn;
566 
567  appendStringInfo(&buf, "CLOSE %s", curname);
568 
569  /* close the cursor */
570  res = PQexec(conn, buf.data);
571  if (!res || PQresultStatus(res) != PGRES_COMMAND_OK)
572  {
573  dblink_res_error(conn, conname, res, fail,
574  "while closing cursor \"%s\"", curname);
576  }
577 
578  PQclear(res);
579 
580  /* if we started a transaction, decrement cursor count */
581  if (rconn->newXactForCursor)
582  {
583  (rconn->openCursorCount)--;
584 
585  /* if count is zero, commit the transaction */
586  if (rconn->openCursorCount == 0)
587  {
588  rconn->newXactForCursor = false;
589 
590  res = PQexec(conn, "COMMIT");
591  if (PQresultStatus(res) != PGRES_COMMAND_OK)
592  dblink_res_internalerror(conn, res, "commit error");
593  PQclear(res);
594  }
595  }
596 
598 }
599 
600 /*
601  * Fetch results from an open cursor
602  */
604 Datum
606 {
607  PGresult *res = NULL;
608  char *conname = NULL;
609  remoteConn *rconn = NULL;
610  PGconn *conn = NULL;
612  char *curname = NULL;
613  int howmany = 0;
614  bool fail = true; /* default to backward compatible */
615 
616  prepTuplestoreResult(fcinfo);
617 
618  dblink_init();
619 
620  if (PG_NARGS() == 4)
621  {
622  /* text,text,int,bool */
623  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
624  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
625  howmany = PG_GETARG_INT32(2);
626  fail = PG_GETARG_BOOL(3);
627 
628  rconn = getConnectionByName(conname);
629  if (rconn)
630  conn = rconn->conn;
631  }
632  else if (PG_NARGS() == 3)
633  {
634  /* text,text,int or text,int,bool */
635  if (get_fn_expr_argtype(fcinfo->flinfo, 2) == BOOLOID)
636  {
637  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
638  howmany = PG_GETARG_INT32(1);
639  fail = PG_GETARG_BOOL(2);
640  conn = pconn->conn;
641  }
642  else
643  {
644  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
645  curname = text_to_cstring(PG_GETARG_TEXT_PP(1));
646  howmany = PG_GETARG_INT32(2);
647 
648  rconn = getConnectionByName(conname);
649  if (rconn)
650  conn = rconn->conn;
651  }
652  }
653  else if (PG_NARGS() == 2)
654  {
655  /* text,int */
656  curname = text_to_cstring(PG_GETARG_TEXT_PP(0));
657  howmany = PG_GETARG_INT32(1);
658  conn = pconn->conn;
659  }
660 
661  if (!conn)
662  dblink_conn_not_avail(conname);
663 
664  initStringInfo(&buf);
665  appendStringInfo(&buf, "FETCH %d FROM %s", howmany, curname);
666 
667  /*
668  * Try to execute the query. Note that since libpq uses malloc, the
669  * PGresult will be long-lived even though we are still in a short-lived
670  * memory context.
671  */
672  res = PQexec(conn, buf.data);
673  if (!res ||
674  (PQresultStatus(res) != PGRES_COMMAND_OK &&
676  {
677  dblink_res_error(conn, conname, res, fail,
678  "while fetching from cursor \"%s\"", curname);
679  return (Datum) 0;
680  }
681  else if (PQresultStatus(res) == PGRES_COMMAND_OK)
682  {
683  /* cursor does not exist - closed already or bad name */
684  PQclear(res);
685  ereport(ERROR,
686  (errcode(ERRCODE_INVALID_CURSOR_NAME),
687  errmsg("cursor \"%s\" does not exist", curname)));
688  }
689 
690  materializeResult(fcinfo, conn, res);
691  return (Datum) 0;
692 }
693 
694 /*
695  * Note: this is the new preferred version of dblink
696  */
698 Datum
700 {
701  return dblink_record_internal(fcinfo, false);
702 }
703 
705 Datum
707 {
708  PGconn *conn;
709  char *sql;
710  int retval;
711 
712  if (PG_NARGS() == 2)
713  {
716  }
717  else
718  /* shouldn't happen */
719  elog(ERROR, "wrong number of arguments");
720 
721  /* async query send */
722  retval = PQsendQuery(conn, sql);
723  if (retval != 1)
724  elog(NOTICE, "could not send query: %s", pchomp(PQerrorMessage(conn)));
725 
726  PG_RETURN_INT32(retval);
727 }
728 
730 Datum
732 {
733  return dblink_record_internal(fcinfo, true);
734 }
735 
736 static Datum
738 {
739  PGconn *volatile conn = NULL;
740  volatile bool freeconn = false;
741 
742  prepTuplestoreResult(fcinfo);
743 
744  dblink_init();
745 
746  PG_TRY();
747  {
748  char *sql = NULL;
749  char *conname = NULL;
750  bool fail = true; /* default to backward compatible */
751 
752  if (!is_async)
753  {
754  if (PG_NARGS() == 3)
755  {
756  /* text,text,bool */
757  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
759  fail = PG_GETARG_BOOL(2);
760  dblink_get_conn(conname, &conn, &conname, &freeconn);
761  }
762  else if (PG_NARGS() == 2)
763  {
764  /* text,text or text,bool */
765  if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
766  {
768  fail = PG_GETARG_BOOL(1);
769  conn = pconn->conn;
770  }
771  else
772  {
773  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
775  dblink_get_conn(conname, &conn, &conname, &freeconn);
776  }
777  }
778  else if (PG_NARGS() == 1)
779  {
780  /* text */
781  conn = pconn->conn;
783  }
784  else
785  /* shouldn't happen */
786  elog(ERROR, "wrong number of arguments");
787  }
788  else /* is_async */
789  {
790  /* get async result */
791  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
792 
793  if (PG_NARGS() == 2)
794  {
795  /* text,bool */
796  fail = PG_GETARG_BOOL(1);
797  conn = dblink_get_named_conn(conname);
798  }
799  else if (PG_NARGS() == 1)
800  {
801  /* text */
802  conn = dblink_get_named_conn(conname);
803  }
804  else
805  /* shouldn't happen */
806  elog(ERROR, "wrong number of arguments");
807  }
808 
809  if (!conn)
810  dblink_conn_not_avail(conname);
811 
812  if (!is_async)
813  {
814  /* synchronous query, use efficient tuple collection method */
815  materializeQueryResult(fcinfo, conn, conname, sql, fail);
816  }
817  else
818  {
819  /* async result retrieval, do it the old way */
820  PGresult *res = PQgetResult(conn);
821 
822  /* NULL means we're all done with the async results */
823  if (res)
824  {
825  if (PQresultStatus(res) != PGRES_COMMAND_OK &&
827  {
828  dblink_res_error(conn, conname, res, fail,
829  "while executing query");
830  /* if fail isn't set, we'll return an empty query result */
831  }
832  else
833  {
834  materializeResult(fcinfo, conn, res);
835  }
836  }
837  }
838  }
839  PG_FINALLY();
840  {
841  /* if needed, close the connection to the database */
842  if (freeconn)
843  {
844  PQfinish(conn);
846  }
847  }
848  PG_END_TRY();
849 
850  return (Datum) 0;
851 }
852 
853 /*
854  * Verify function caller can handle a tuplestore result, and set up for that.
855  *
856  * Note: if the caller returns without actually creating a tuplestore, the
857  * executor will treat the function result as an empty set.
858  */
859 static void
861 {
862  ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
863 
864  /* check to see if query supports us returning a tuplestore */
865  if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
866  ereport(ERROR,
867  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
868  errmsg("set-valued function called in context that cannot accept a set")));
869  if (!(rsinfo->allowedModes & SFRM_Materialize))
870  ereport(ERROR,
871  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
872  errmsg("materialize mode required, but it is not allowed in this context")));
873 
874  /* let the executor know we're sending back a tuplestore */
875  rsinfo->returnMode = SFRM_Materialize;
876 
877  /* caller must fill these to return a non-empty result */
878  rsinfo->setResult = NULL;
879  rsinfo->setDesc = NULL;
880 }
881 
882 /*
883  * Copy the contents of the PGresult into a tuplestore to be returned
884  * as the result of the current function.
885  * The PGresult will be released in this function.
886  */
887 static void
889 {
890  ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
891 
892  /* prepTuplestoreResult must have been called previously */
893  Assert(rsinfo->returnMode == SFRM_Materialize);
894 
895  PG_TRY();
896  {
897  TupleDesc tupdesc;
898  bool is_sql_cmd;
899  int ntuples;
900  int nfields;
901 
902  if (PQresultStatus(res) == PGRES_COMMAND_OK)
903  {
904  is_sql_cmd = true;
905 
906  /*
907  * need a tuple descriptor representing one TEXT column to return
908  * the command status string as our result tuple
909  */
910  tupdesc = CreateTemplateTupleDesc(1);
911  TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
912  TEXTOID, -1, 0);
913  ntuples = 1;
914  nfields = 1;
915  }
916  else
917  {
919 
920  is_sql_cmd = false;
921 
922  /* get a tuple descriptor for our result type */
923  switch (get_call_result_type(fcinfo, NULL, &tupdesc))
924  {
925  case TYPEFUNC_COMPOSITE:
926  /* success */
927  break;
928  case TYPEFUNC_RECORD:
929  /* failed to determine actual type of RECORD */
930  ereport(ERROR,
931  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
932  errmsg("function returning record called in context "
933  "that cannot accept type record")));
934  break;
935  default:
936  /* result type isn't composite */
937  elog(ERROR, "return type must be a row type");
938  break;
939  }
940 
941  /* make sure we have a persistent copy of the tupdesc */
942  tupdesc = CreateTupleDescCopy(tupdesc);
943  ntuples = PQntuples(res);
944  nfields = PQnfields(res);
945  }
946 
947  /*
948  * check result and tuple descriptor have the same number of columns
949  */
950  if (nfields != tupdesc->natts)
951  ereport(ERROR,
952  (errcode(ERRCODE_DATATYPE_MISMATCH),
953  errmsg("remote query result rowtype does not match "
954  "the specified FROM clause rowtype")));
955 
956  if (ntuples > 0)
957  {
958  AttInMetadata *attinmeta;
959  int nestlevel = -1;
960  Tuplestorestate *tupstore;
961  MemoryContext oldcontext;
962  int row;
963  char **values;
964 
965  attinmeta = TupleDescGetAttInMetadata(tupdesc);
966 
967  /* Set GUCs to ensure we read GUC-sensitive data types correctly */
968  if (!is_sql_cmd)
969  nestlevel = applyRemoteGucs(conn);
970 
972  tupstore = tuplestore_begin_heap(true, false, work_mem);
973  rsinfo->setResult = tupstore;
974  rsinfo->setDesc = tupdesc;
975  MemoryContextSwitchTo(oldcontext);
976 
977  values = (char **) palloc(nfields * sizeof(char *));
978 
979  /* put all tuples into the tuplestore */
980  for (row = 0; row < ntuples; row++)
981  {
982  HeapTuple tuple;
983 
984  if (!is_sql_cmd)
985  {
986  int i;
987 
988  for (i = 0; i < nfields; i++)
989  {
990  if (PQgetisnull(res, row, i))
991  values[i] = NULL;
992  else
993  values[i] = PQgetvalue(res, row, i);
994  }
995  }
996  else
997  {
998  values[0] = PQcmdStatus(res);
999  }
1000 
1001  /* build the tuple and put it into the tuplestore. */
1002  tuple = BuildTupleFromCStrings(attinmeta, values);
1003  tuplestore_puttuple(tupstore, tuple);
1004  }
1005 
1006  /* clean up GUC settings, if we changed any */
1007  restoreLocalGucs(nestlevel);
1008 
1009  /* clean up and return the tuplestore */
1010  tuplestore_donestoring(tupstore);
1011  }
1012  }
1013  PG_FINALLY();
1014  {
1015  /* be sure to release the libpq result */
1016  PQclear(res);
1017  }
1018  PG_END_TRY();
1019 }
1020 
1021 /*
1022  * Execute the given SQL command and store its results into a tuplestore
1023  * to be returned as the result of the current function.
1024  *
1025  * This is equivalent to PQexec followed by materializeResult, but we make
1026  * use of libpq's single-row mode to avoid accumulating the whole result
1027  * inside libpq before it gets transferred to the tuplestore.
1028  */
1029 static void
1031  PGconn *conn,
1032  const char *conname,
1033  const char *sql,
1034  bool fail)
1035 {
1036  ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
1037  PGresult *volatile res = NULL;
1038  volatile storeInfo sinfo = {0};
1039 
1040  /* prepTuplestoreResult must have been called previously */
1041  Assert(rsinfo->returnMode == SFRM_Materialize);
1042 
1043  sinfo.fcinfo = fcinfo;
1044 
1045  PG_TRY();
1046  {
1047  /* Create short-lived memory context for data conversions */
1048  sinfo.tmpcontext = AllocSetContextCreate(CurrentMemoryContext,
1049  "dblink temporary context",
1051 
1052  /* execute query, collecting any tuples into the tuplestore */
1053  res = storeQueryResult(&sinfo, conn, sql);
1054 
1055  if (!res ||
1056  (PQresultStatus(res) != PGRES_COMMAND_OK &&
1058  {
1059  /*
1060  * dblink_res_error will clear the passed PGresult, so we need
1061  * this ugly dance to avoid doing so twice during error exit
1062  */
1063  PGresult *res1 = res;
1064 
1065  res = NULL;
1066  dblink_res_error(conn, conname, res1, fail,
1067  "while executing query");
1068  /* if fail isn't set, we'll return an empty query result */
1069  }
1070  else if (PQresultStatus(res) == PGRES_COMMAND_OK)
1071  {
1072  /*
1073  * storeRow didn't get called, so we need to convert the command
1074  * status string to a tuple manually
1075  */
1076  TupleDesc tupdesc;
1077  AttInMetadata *attinmeta;
1078  Tuplestorestate *tupstore;
1079  HeapTuple tuple;
1080  char *values[1];
1081  MemoryContext oldcontext;
1082 
1083  /*
1084  * need a tuple descriptor representing one TEXT column to return
1085  * the command status string as our result tuple
1086  */
1087  tupdesc = CreateTemplateTupleDesc(1);
1088  TupleDescInitEntry(tupdesc, (AttrNumber) 1, "status",
1089  TEXTOID, -1, 0);
1090  attinmeta = TupleDescGetAttInMetadata(tupdesc);
1091 
1092  oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1093  tupstore = tuplestore_begin_heap(true, false, work_mem);
1094  rsinfo->setResult = tupstore;
1095  rsinfo->setDesc = tupdesc;
1096  MemoryContextSwitchTo(oldcontext);
1097 
1098  values[0] = PQcmdStatus(res);
1099 
1100  /* build the tuple and put it into the tuplestore. */
1101  tuple = BuildTupleFromCStrings(attinmeta, values);
1102  tuplestore_puttuple(tupstore, tuple);
1103 
1104  PQclear(res);
1105  res = NULL;
1106  }
1107  else
1108  {
1110  /* storeRow should have created a tuplestore */
1111  Assert(rsinfo->setResult != NULL);
1112 
1113  PQclear(res);
1114  res = NULL;
1115  }
1116 
1117  /* clean up data conversion short-lived memory context */
1118  if (sinfo.tmpcontext != NULL)
1119  MemoryContextDelete(sinfo.tmpcontext);
1120  sinfo.tmpcontext = NULL;
1121 
1122  PQclear(sinfo.last_res);
1123  sinfo.last_res = NULL;
1124  PQclear(sinfo.cur_res);
1125  sinfo.cur_res = NULL;
1126  }
1127  PG_CATCH();
1128  {
1129  /* be sure to release any libpq result we collected */
1130  PQclear(res);
1131  PQclear(sinfo.last_res);
1132  PQclear(sinfo.cur_res);
1133  /* and clear out any pending data in libpq */
1134  while ((res = PQgetResult(conn)) != NULL)
1135  PQclear(res);
1136  PG_RE_THROW();
1137  }
1138  PG_END_TRY();
1139 }
1140 
1141 /*
1142  * Execute query, and send any result rows to sinfo->tuplestore.
1143  */
1144 static PGresult *
1145 storeQueryResult(volatile storeInfo *sinfo, PGconn *conn, const char *sql)
1146 {
1147  bool first = true;
1148  int nestlevel = -1;
1149  PGresult *res;
1150 
1151  if (!PQsendQuery(conn, sql))
1152  elog(ERROR, "could not send query: %s", pchomp(PQerrorMessage(conn)));
1153 
1154  if (!PQsetSingleRowMode(conn)) /* shouldn't fail */
1155  elog(ERROR, "failed to set single-row mode for dblink query");
1156 
1157  for (;;)
1158  {
1160 
1161  sinfo->cur_res = PQgetResult(conn);
1162  if (!sinfo->cur_res)
1163  break;
1164 
1165  if (PQresultStatus(sinfo->cur_res) == PGRES_SINGLE_TUPLE)
1166  {
1167  /* got one row from possibly-bigger resultset */
1168 
1169  /*
1170  * Set GUCs to ensure we read GUC-sensitive data types correctly.
1171  * We shouldn't do this until we have a row in hand, to ensure
1172  * libpq has seen any earlier ParameterStatus protocol messages.
1173  */
1174  if (first && nestlevel < 0)
1175  nestlevel = applyRemoteGucs(conn);
1176 
1177  storeRow(sinfo, sinfo->cur_res, first);
1178 
1179  PQclear(sinfo->cur_res);
1180  sinfo->cur_res = NULL;
1181  first = false;
1182  }
1183  else
1184  {
1185  /* if empty resultset, fill tuplestore header */
1186  if (first && PQresultStatus(sinfo->cur_res) == PGRES_TUPLES_OK)
1187  storeRow(sinfo, sinfo->cur_res, first);
1188 
1189  /* store completed result at last_res */
1190  PQclear(sinfo->last_res);
1191  sinfo->last_res = sinfo->cur_res;
1192  sinfo->cur_res = NULL;
1193  first = true;
1194  }
1195  }
1196 
1197  /* clean up GUC settings, if we changed any */
1198  restoreLocalGucs(nestlevel);
1199 
1200  /* return last_res */
1201  res = sinfo->last_res;
1202  sinfo->last_res = NULL;
1203  return res;
1204 }
1205 
1206 /*
1207  * Send single row to sinfo->tuplestore.
1208  *
1209  * If "first" is true, create the tuplestore using PGresult's metadata
1210  * (in this case the PGresult might contain either zero or one row).
1211  */
1212 static void
1213 storeRow(volatile storeInfo *sinfo, PGresult *res, bool first)
1214 {
1215  int nfields = PQnfields(res);
1216  HeapTuple tuple;
1217  int i;
1218  MemoryContext oldcontext;
1219 
1220  if (first)
1221  {
1222  /* Prepare for new result set */
1223  ReturnSetInfo *rsinfo = (ReturnSetInfo *) sinfo->fcinfo->resultinfo;
1224  TupleDesc tupdesc;
1225 
1226  /*
1227  * It's possible to get more than one result set if the query string
1228  * contained multiple SQL commands. In that case, we follow PQexec's
1229  * traditional behavior of throwing away all but the last result.
1230  */
1231  if (sinfo->tuplestore)
1232  tuplestore_end(sinfo->tuplestore);
1233  sinfo->tuplestore = NULL;
1234 
1235  /* get a tuple descriptor for our result type */
1236  switch (get_call_result_type(sinfo->fcinfo, NULL, &tupdesc))
1237  {
1238  case TYPEFUNC_COMPOSITE:
1239  /* success */
1240  break;
1241  case TYPEFUNC_RECORD:
1242  /* failed to determine actual type of RECORD */
1243  ereport(ERROR,
1244  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1245  errmsg("function returning record called in context "
1246  "that cannot accept type record")));
1247  break;
1248  default:
1249  /* result type isn't composite */
1250  elog(ERROR, "return type must be a row type");
1251  break;
1252  }
1253 
1254  /* make sure we have a persistent copy of the tupdesc */
1255  tupdesc = CreateTupleDescCopy(tupdesc);
1256 
1257  /* check result and tuple descriptor have the same number of columns */
1258  if (nfields != tupdesc->natts)
1259  ereport(ERROR,
1260  (errcode(ERRCODE_DATATYPE_MISMATCH),
1261  errmsg("remote query result rowtype does not match "
1262  "the specified FROM clause rowtype")));
1263 
1264  /* Prepare attinmeta for later data conversions */
1265  sinfo->attinmeta = TupleDescGetAttInMetadata(tupdesc);
1266 
1267  /* Create a new, empty tuplestore */
1268  oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
1269  sinfo->tuplestore = tuplestore_begin_heap(true, false, work_mem);
1270  rsinfo->setResult = sinfo->tuplestore;
1271  rsinfo->setDesc = tupdesc;
1272  MemoryContextSwitchTo(oldcontext);
1273 
1274  /* Done if empty resultset */
1275  if (PQntuples(res) == 0)
1276  return;
1277 
1278  /*
1279  * Set up sufficiently-wide string pointers array; this won't change
1280  * in size so it's easy to preallocate.
1281  */
1282  if (sinfo->cstrs)
1283  pfree(sinfo->cstrs);
1284  sinfo->cstrs = (char **) palloc(nfields * sizeof(char *));
1285  }
1286 
1287  /* Should have a single-row result if we get here */
1288  Assert(PQntuples(res) == 1);
1289 
1290  /*
1291  * Do the following work in a temp context that we reset after each tuple.
1292  * This cleans up not only the data we have direct access to, but any
1293  * cruft the I/O functions might leak.
1294  */
1295  oldcontext = MemoryContextSwitchTo(sinfo->tmpcontext);
1296 
1297  /*
1298  * Fill cstrs with null-terminated strings of column values.
1299  */
1300  for (i = 0; i < nfields; i++)
1301  {
1302  if (PQgetisnull(res, 0, i))
1303  sinfo->cstrs[i] = NULL;
1304  else
1305  sinfo->cstrs[i] = PQgetvalue(res, 0, i);
1306  }
1307 
1308  /* Convert row to a tuple, and add it to the tuplestore */
1309  tuple = BuildTupleFromCStrings(sinfo->attinmeta, sinfo->cstrs);
1310 
1311  tuplestore_puttuple(sinfo->tuplestore, tuple);
1312 
1313  /* Clean up */
1314  MemoryContextSwitchTo(oldcontext);
1316 }
1317 
1318 /*
1319  * List all open dblink connections by name.
1320  * Returns an array of all connection names.
1321  * Takes no params
1322  */
1324 Datum
1326 {
1328  remoteConnHashEnt *hentry;
1329  ArrayBuildState *astate = NULL;
1330 
1331  if (remoteConnHash)
1332  {
1333  hash_seq_init(&status, remoteConnHash);
1334  while ((hentry = (remoteConnHashEnt *) hash_seq_search(&status)) != NULL)
1335  {
1336  /* stash away current value */
1337  astate = accumArrayResult(astate,
1338  CStringGetTextDatum(hentry->name),
1339  false, TEXTOID, CurrentMemoryContext);
1340  }
1341  }
1342 
1343  if (astate)
1346  else
1347  PG_RETURN_NULL();
1348 }
1349 
1350 /*
1351  * Checks if a given remote connection is busy
1352  *
1353  * Returns 1 if the connection is busy, 0 otherwise
1354  * Params:
1355  * text connection_name - name of the connection to check
1356  *
1357  */
1359 Datum
1361 {
1362  PGconn *conn;
1363 
1364  dblink_init();
1366 
1367  PQconsumeInput(conn);
1368  PG_RETURN_INT32(PQisBusy(conn));
1369 }
1370 
1371 /*
1372  * Cancels a running request on a connection
1373  *
1374  * Returns text:
1375  * "OK" if the cancel request has been sent correctly,
1376  * an error message otherwise
1377  *
1378  * Params:
1379  * text connection_name - name of the connection to check
1380  *
1381  */
1383 Datum
1385 {
1386  int res;
1387  PGconn *conn;
1388  PGcancel *cancel;
1389  char errbuf[256];
1390 
1391  dblink_init();
1393  cancel = PQgetCancel(conn);
1394 
1395  res = PQcancel(cancel, errbuf, 256);
1396  PQfreeCancel(cancel);
1397 
1398  if (res == 1)
1400  else
1402 }
1403 
1404 
1405 /*
1406  * Get error message from a connection
1407  *
1408  * Returns text:
1409  * "OK" if no error, an error message otherwise
1410  *
1411  * Params:
1412  * text connection_name - name of the connection to check
1413  *
1414  */
1416 Datum
1418 {
1419  char *msg;
1420  PGconn *conn;
1421 
1422  dblink_init();
1424 
1425  msg = PQerrorMessage(conn);
1426  if (msg == NULL || msg[0] == '\0')
1428  else
1430 }
1431 
1432 /*
1433  * Execute an SQL non-SELECT command
1434  */
1436 Datum
1438 {
1439  text *volatile sql_cmd_status = NULL;
1440  PGconn *volatile conn = NULL;
1441  volatile bool freeconn = false;
1442 
1443  dblink_init();
1444 
1445  PG_TRY();
1446  {
1447  PGresult *res = NULL;
1448  char *sql = NULL;
1449  char *conname = NULL;
1450  bool fail = true; /* default to backward compatible behavior */
1451 
1452  if (PG_NARGS() == 3)
1453  {
1454  /* must be text,text,bool */
1455  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1457  fail = PG_GETARG_BOOL(2);
1458  dblink_get_conn(conname, &conn, &conname, &freeconn);
1459  }
1460  else if (PG_NARGS() == 2)
1461  {
1462  /* might be text,text or text,bool */
1463  if (get_fn_expr_argtype(fcinfo->flinfo, 1) == BOOLOID)
1464  {
1466  fail = PG_GETARG_BOOL(1);
1467  conn = pconn->conn;
1468  }
1469  else
1470  {
1471  conname = text_to_cstring(PG_GETARG_TEXT_PP(0));
1473  dblink_get_conn(conname, &conn, &conname, &freeconn);
1474  }
1475  }
1476  else if (PG_NARGS() == 1)
1477  {
1478  /* must be single text argument */
1479  conn = pconn->conn;
1481  }
1482  else
1483  /* shouldn't happen */
1484  elog(ERROR, "wrong number of arguments");
1485 
1486  if (!conn)
1487  dblink_conn_not_avail(conname);
1488 
1489  res = PQexec(conn, sql);
1490  if (!res ||
1491  (PQresultStatus(res) != PGRES_COMMAND_OK &&
1493  {
1494  dblink_res_error(conn, conname, res, fail,
1495  "while executing command");
1496 
1497  /*
1498  * and save a copy of the command status string to return as our
1499  * result tuple
1500  */
1501  sql_cmd_status = cstring_to_text("ERROR");
1502  }
1503  else if (PQresultStatus(res) == PGRES_COMMAND_OK)
1504  {
1505  /*
1506  * and save a copy of the command status string to return as our
1507  * result tuple
1508  */
1509  sql_cmd_status = cstring_to_text(PQcmdStatus(res));
1510  PQclear(res);
1511  }
1512  else
1513  {
1514  PQclear(res);
1515  ereport(ERROR,
1516  (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
1517  errmsg("statement returning results not allowed")));
1518  }
1519  }
1520  PG_FINALLY();
1521  {
1522  /* if needed, close the connection to the database */
1523  if (freeconn)
1524  {
1525  PQfinish(conn);
1527  }
1528  }
1529  PG_END_TRY();
1530 
1531  PG_RETURN_TEXT_P(sql_cmd_status);
1532 }
1533 
1534 
1535 /*
1536  * dblink_get_pkey
1537  *
1538  * Return list of primary key fields for the supplied relation,
1539  * or NULL if none exists.
1540  */
1542 Datum
1544 {
1545  int16 indnkeyatts;
1546  char **results;
1547  FuncCallContext *funcctx;
1548  int32 call_cntr;
1549  int32 max_calls;
1550  AttInMetadata *attinmeta;
1551  MemoryContext oldcontext;
1552 
1553  /* stuff done only on the first call of the function */
1554  if (SRF_IS_FIRSTCALL())
1555  {
1556  Relation rel;
1557  TupleDesc tupdesc;
1558 
1559  /* create a function context for cross-call persistence */
1560  funcctx = SRF_FIRSTCALL_INIT();
1561 
1562  /*
1563  * switch to memory context appropriate for multiple function calls
1564  */
1565  oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
1566 
1567  /* open target relation */
1569 
1570  /* get the array of attnums */
1571  results = get_pkey_attnames(rel, &indnkeyatts);
1572 
1574 
1575  /*
1576  * need a tuple descriptor representing one INT and one TEXT column
1577  */
1578  tupdesc = CreateTemplateTupleDesc(2);
1579  TupleDescInitEntry(tupdesc, (AttrNumber) 1, "position",
1580  INT4OID, -1, 0);
1581  TupleDescInitEntry(tupdesc, (AttrNumber) 2, "colname",
1582  TEXTOID, -1, 0);
1583 
1584  /*
1585  * Generate attribute metadata needed later to produce tuples from raw
1586  * C strings
1587  */
1588  attinmeta = TupleDescGetAttInMetadata(tupdesc);
1589  funcctx->attinmeta = attinmeta;
1590 
1591  if ((results != NULL) && (indnkeyatts > 0))
1592  {
1593  funcctx->max_calls = indnkeyatts;
1594 
1595  /* got results, keep track of them */
1596  funcctx->user_fctx = results;
1597  }
1598  else
1599  {
1600  /* fast track when no results */
1601  MemoryContextSwitchTo(oldcontext);
1602  SRF_RETURN_DONE(funcctx);
1603  }
1604 
1605  MemoryContextSwitchTo(oldcontext);
1606  }
1607 
1608  /* stuff done on every call of the function */
1609  funcctx = SRF_PERCALL_SETUP();
1610 
1611  /*
1612  * initialize per-call variables
1613  */
1614  call_cntr = funcctx->call_cntr;
1615  max_calls = funcctx->max_calls;
1616 
1617  results = (char **) funcctx->user_fctx;
1618  attinmeta = funcctx->attinmeta;
1619 
1620  if (call_cntr < max_calls) /* do when there is more left to send */
1621  {
1622  char **values;
1623  HeapTuple tuple;
1624  Datum result;
1625 
1626  values = (char **) palloc(2 * sizeof(char *));
1627  values[0] = psprintf("%d", call_cntr + 1);
1628  values[1] = results[call_cntr];
1629 
1630  /* build the tuple */
1631  tuple = BuildTupleFromCStrings(attinmeta, values);
1632 
1633  /* make the tuple into a datum */
1634  result = HeapTupleGetDatum(tuple);
1635 
1636  SRF_RETURN_NEXT(funcctx, result);
1637  }
1638  else
1639  {
1640  /* do when there is no more left */
1641  SRF_RETURN_DONE(funcctx);
1642  }
1643 }
1644 
1645 
1646 /*
1647  * dblink_build_sql_insert
1648  *
1649  * Used to generate an SQL insert statement
1650  * based on an existing tuple in a local relation.
1651  * This is useful for selectively replicating data
1652  * to another server via dblink.
1653  *
1654  * API:
1655  * <relname> - name of local table of interest
1656  * <pkattnums> - an int2vector of attnums which will be used
1657  * to identify the local tuple of interest
1658  * <pknumatts> - number of attnums in pkattnums
1659  * <src_pkattvals_arry> - text array of key values which will be used
1660  * to identify the local tuple of interest
1661  * <tgt_pkattvals_arry> - text array of key values which will be used
1662  * to build the string for execution remotely. These are substituted
1663  * for their counterparts in src_pkattvals_arry
1664  */
1666 Datum
1668 {
1669  text *relname_text = PG_GETARG_TEXT_PP(0);
1670  int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1671  int32 pknumatts_arg = PG_GETARG_INT32(2);
1672  ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1673  ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
1674  Relation rel;
1675  int *pkattnums;
1676  int pknumatts;
1677  char **src_pkattvals;
1678  char **tgt_pkattvals;
1679  int src_nitems;
1680  int tgt_nitems;
1681  char *sql;
1682 
1683  /*
1684  * Open target relation.
1685  */
1686  rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1687 
1688  /*
1689  * Process pkattnums argument.
1690  */
1691  validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1692  &pkattnums, &pknumatts);
1693 
1694  /*
1695  * Source array is made up of key values that will be used to locate the
1696  * tuple of interest from the local system.
1697  */
1698  src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
1699 
1700  /*
1701  * There should be one source array key value for each key attnum
1702  */
1703  if (src_nitems != pknumatts)
1704  ereport(ERROR,
1705  (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1706  errmsg("source key array length must match number of key attributes")));
1707 
1708  /*
1709  * Target array is made up of key values that will be used to build the
1710  * SQL string for use on the remote system.
1711  */
1712  tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1713 
1714  /*
1715  * There should be one target array key value for each key attnum
1716  */
1717  if (tgt_nitems != pknumatts)
1718  ereport(ERROR,
1719  (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1720  errmsg("target key array length must match number of key attributes")));
1721 
1722  /*
1723  * Prep work is finally done. Go get the SQL string.
1724  */
1725  sql = get_sql_insert(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1726 
1727  /*
1728  * Now we can close the relation.
1729  */
1731 
1732  /*
1733  * And send it
1734  */
1736 }
1737 
1738 
1739 /*
1740  * dblink_build_sql_delete
1741  *
1742  * Used to generate an SQL delete statement.
1743  * This is useful for selectively replicating a
1744  * delete to another server via dblink.
1745  *
1746  * API:
1747  * <relname> - name of remote table of interest
1748  * <pkattnums> - an int2vector of attnums which will be used
1749  * to identify the remote tuple of interest
1750  * <pknumatts> - number of attnums in pkattnums
1751  * <tgt_pkattvals_arry> - text array of key values which will be used
1752  * to build the string for execution remotely.
1753  */
1755 Datum
1757 {
1758  text *relname_text = PG_GETARG_TEXT_PP(0);
1759  int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1760  int32 pknumatts_arg = PG_GETARG_INT32(2);
1761  ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1762  Relation rel;
1763  int *pkattnums;
1764  int pknumatts;
1765  char **tgt_pkattvals;
1766  int tgt_nitems;
1767  char *sql;
1768 
1769  /*
1770  * Open target relation.
1771  */
1772  rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1773 
1774  /*
1775  * Process pkattnums argument.
1776  */
1777  validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1778  &pkattnums, &pknumatts);
1779 
1780  /*
1781  * Target array is made up of key values that will be used to build the
1782  * SQL string for use on the remote system.
1783  */
1784  tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1785 
1786  /*
1787  * There should be one target array key value for each key attnum
1788  */
1789  if (tgt_nitems != pknumatts)
1790  ereport(ERROR,
1791  (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1792  errmsg("target key array length must match number of key attributes")));
1793 
1794  /*
1795  * Prep work is finally done. Go get the SQL string.
1796  */
1797  sql = get_sql_delete(rel, pkattnums, pknumatts, tgt_pkattvals);
1798 
1799  /*
1800  * Now we can close the relation.
1801  */
1803 
1804  /*
1805  * And send it
1806  */
1808 }
1809 
1810 
1811 /*
1812  * dblink_build_sql_update
1813  *
1814  * Used to generate an SQL update statement
1815  * based on an existing tuple in a local relation.
1816  * This is useful for selectively replicating data
1817  * to another server via dblink.
1818  *
1819  * API:
1820  * <relname> - name of local table of interest
1821  * <pkattnums> - an int2vector of attnums which will be used
1822  * to identify the local tuple of interest
1823  * <pknumatts> - number of attnums in pkattnums
1824  * <src_pkattvals_arry> - text array of key values which will be used
1825  * to identify the local tuple of interest
1826  * <tgt_pkattvals_arry> - text array of key values which will be used
1827  * to build the string for execution remotely. These are substituted
1828  * for their counterparts in src_pkattvals_arry
1829  */
1831 Datum
1833 {
1834  text *relname_text = PG_GETARG_TEXT_PP(0);
1835  int2vector *pkattnums_arg = (int2vector *) PG_GETARG_POINTER(1);
1836  int32 pknumatts_arg = PG_GETARG_INT32(2);
1837  ArrayType *src_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(3);
1838  ArrayType *tgt_pkattvals_arry = PG_GETARG_ARRAYTYPE_P(4);
1839  Relation rel;
1840  int *pkattnums;
1841  int pknumatts;
1842  char **src_pkattvals;
1843  char **tgt_pkattvals;
1844  int src_nitems;
1845  int tgt_nitems;
1846  char *sql;
1847 
1848  /*
1849  * Open target relation.
1850  */
1851  rel = get_rel_from_relname(relname_text, AccessShareLock, ACL_SELECT);
1852 
1853  /*
1854  * Process pkattnums argument.
1855  */
1856  validate_pkattnums(rel, pkattnums_arg, pknumatts_arg,
1857  &pkattnums, &pknumatts);
1858 
1859  /*
1860  * Source array is made up of key values that will be used to locate the
1861  * tuple of interest from the local system.
1862  */
1863  src_pkattvals = get_text_array_contents(src_pkattvals_arry, &src_nitems);
1864 
1865  /*
1866  * There should be one source array key value for each key attnum
1867  */
1868  if (src_nitems != pknumatts)
1869  ereport(ERROR,
1870  (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1871  errmsg("source key array length must match number of key attributes")));
1872 
1873  /*
1874  * Target array is made up of key values that will be used to build the
1875  * SQL string for use on the remote system.
1876  */
1877  tgt_pkattvals = get_text_array_contents(tgt_pkattvals_arry, &tgt_nitems);
1878 
1879  /*
1880  * There should be one target array key value for each key attnum
1881  */
1882  if (tgt_nitems != pknumatts)
1883  ereport(ERROR,
1884  (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
1885  errmsg("target key array length must match number of key attributes")));
1886 
1887  /*
1888  * Prep work is finally done. Go get the SQL string.
1889  */
1890  sql = get_sql_update(rel, pkattnums, pknumatts, src_pkattvals, tgt_pkattvals);
1891 
1892  /*
1893  * Now we can close the relation.
1894  */
1896 
1897  /*
1898  * And send it
1899  */
1901 }
1902 
1903 /*
1904  * dblink_current_query
1905  * return the current query string
1906  * to allow its use in (among other things)
1907  * rewrite rules
1908  */
1910 Datum
1912 {
1913  /* This is now just an alias for the built-in function current_query() */
1914  PG_RETURN_DATUM(current_query(fcinfo));
1915 }
1916 
1917 /*
1918  * Retrieve async notifications for a connection.
1919  *
1920  * Returns a setof record of notifications, or an empty set if none received.
1921  * Can optionally take a named connection as parameter, but uses the unnamed
1922  * connection per default.
1923  *
1924  */
1925 #define DBLINK_NOTIFY_COLS 3
1926 
1928 Datum
1930 {
1931  PGconn *conn;
1932  PGnotify *notify;
1933  ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
1934  TupleDesc tupdesc;
1935  Tuplestorestate *tupstore;
1936  MemoryContext per_query_ctx;
1937  MemoryContext oldcontext;
1938 
1939  prepTuplestoreResult(fcinfo);
1940 
1941  dblink_init();
1942  if (PG_NARGS() == 1)
1944  else
1945  conn = pconn->conn;
1946 
1947  /* create the tuplestore in per-query memory */
1948  per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
1949  oldcontext = MemoryContextSwitchTo(per_query_ctx);
1950 
1952  TupleDescInitEntry(tupdesc, (AttrNumber) 1, "notify_name",
1953  TEXTOID, -1, 0);
1954  TupleDescInitEntry(tupdesc, (AttrNumber) 2, "be_pid",
1955  INT4OID, -1, 0);
1956  TupleDescInitEntry(tupdesc, (AttrNumber) 3, "extra",
1957  TEXTOID, -1, 0);
1958 
1959  tupstore = tuplestore_begin_heap(true, false, work_mem);
1960  rsinfo->setResult = tupstore;
1961  rsinfo->setDesc = tupdesc;
1962 
1963  MemoryContextSwitchTo(oldcontext);
1964 
1965  PQconsumeInput(conn);
1966  while ((notify = PQnotifies(conn)) != NULL)
1967  {
1968  Datum values[DBLINK_NOTIFY_COLS];
1969  bool nulls[DBLINK_NOTIFY_COLS];
1970 
1971  memset(values, 0, sizeof(values));
1972  memset(nulls, 0, sizeof(nulls));
1973 
1974  if (notify->relname != NULL)
1975  values[0] = CStringGetTextDatum(notify->relname);
1976  else
1977  nulls[0] = true;
1978 
1979  values[1] = Int32GetDatum(notify->be_pid);
1980 
1981  if (notify->extra != NULL)
1982  values[2] = CStringGetTextDatum(notify->extra);
1983  else
1984  nulls[2] = true;
1985 
1986  tuplestore_putvalues(tupstore, tupdesc, values, nulls);
1987 
1988  PQfreemem(notify);
1989  PQconsumeInput(conn);
1990  }
1991 
1992  /* clean up and return the tuplestore */
1993  tuplestore_donestoring(tupstore);
1994 
1995  return (Datum) 0;
1996 }
1997 
1998 /*
1999  * Validate the options given to a dblink foreign server or user mapping.
2000  * Raise an error if any option is invalid.
2001  *
2002  * We just check the names of options here, so semantic errors in options,
2003  * such as invalid numeric format, will be detected at the attempt to connect.
2004  */
2006 Datum
2008 {
2009  List *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
2010  Oid context = PG_GETARG_OID(1);
2011  ListCell *cell;
2012 
2013  static const PQconninfoOption *options = NULL;
2014 
2015  /*
2016  * Get list of valid libpq options.
2017  *
2018  * To avoid unnecessary work, we get the list once and use it throughout
2019  * the lifetime of this backend process. We don't need to care about
2020  * memory context issues, because PQconndefaults allocates with malloc.
2021  */
2022  if (!options)
2023  {
2024  options = PQconndefaults();
2025  if (!options) /* assume reason for failure is OOM */
2026  ereport(ERROR,
2027  (errcode(ERRCODE_FDW_OUT_OF_MEMORY),
2028  errmsg("out of memory"),
2029  errdetail("Could not get libpq's default connection options.")));
2030  }
2031 
2032  /* Validate each supplied option. */
2033  foreach(cell, options_list)
2034  {
2035  DefElem *def = (DefElem *) lfirst(cell);
2036 
2037  if (!is_valid_dblink_option(options, def->defname, context))
2038  {
2039  /*
2040  * Unknown option, or invalid option for the context specified, so
2041  * complain about it. Provide a hint with list of valid options
2042  * for the context.
2043  */
2045  const PQconninfoOption *opt;
2046 
2047  initStringInfo(&buf);
2048  for (opt = options; opt->keyword; opt++)
2049  {
2050  if (is_valid_dblink_option(options, opt->keyword, context))
2051  appendStringInfo(&buf, "%s%s",
2052  (buf.len > 0) ? ", " : "",
2053  opt->keyword);
2054  }
2055  ereport(ERROR,
2056  (errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
2057  errmsg("invalid option \"%s\"", def->defname),
2058  errhint("Valid options in this context are: %s",
2059  buf.data)));
2060  }
2061  }
2062 
2063  PG_RETURN_VOID();
2064 }
2065 
2066 
2067 /*************************************************************
2068  * internal functions
2069  */
2070 
2071 
2072 /*
2073  * get_pkey_attnames
2074  *
2075  * Get the primary key attnames for the given relation.
2076  * Return NULL, and set indnkeyatts = 0, if no primary key exists.
2077  */
2078 static char **
2080 {
2081  Relation indexRelation;
2082  ScanKeyData skey;
2083  SysScanDesc scan;
2084  HeapTuple indexTuple;
2085  int i;
2086  char **result = NULL;
2087  TupleDesc tupdesc;
2088 
2089  /* initialize indnkeyatts to 0 in case no primary key exists */
2090  *indnkeyatts = 0;
2091 
2092  tupdesc = rel->rd_att;
2093 
2094  /* Prepare to scan pg_index for entries having indrelid = this rel. */
2095  indexRelation = table_open(IndexRelationId, AccessShareLock);
2096  ScanKeyInit(&skey,
2097  Anum_pg_index_indrelid,
2098  BTEqualStrategyNumber, F_OIDEQ,
2100 
2101  scan = systable_beginscan(indexRelation, IndexIndrelidIndexId, true,
2102  NULL, 1, &skey);
2103 
2104  while (HeapTupleIsValid(indexTuple = systable_getnext(scan)))
2105  {
2106  Form_pg_index index = (Form_pg_index) GETSTRUCT(indexTuple);
2107 
2108  /* we're only interested if it is the primary key */
2109  if (index->indisprimary)
2110  {
2111  *indnkeyatts = index->indnkeyatts;
2112  if (*indnkeyatts > 0)
2113  {
2114  result = (char **) palloc(*indnkeyatts * sizeof(char *));
2115 
2116  for (i = 0; i < *indnkeyatts; i++)
2117  result[i] = SPI_fname(tupdesc, index->indkey.values[i]);
2118  }
2119  break;
2120  }
2121  }
2122 
2123  systable_endscan(scan);
2124  table_close(indexRelation, AccessShareLock);
2125 
2126  return result;
2127 }
2128 
2129 /*
2130  * Deconstruct a text[] into C-strings (note any NULL elements will be
2131  * returned as NULL pointers)
2132  */
2133 static char **
2134 get_text_array_contents(ArrayType *array, int *numitems)
2135 {
2136  int ndim = ARR_NDIM(array);
2137  int *dims = ARR_DIMS(array);
2138  int nitems;
2139  int16 typlen;
2140  bool typbyval;
2141  char typalign;
2142  char **values;
2143  char *ptr;
2144  bits8 *bitmap;
2145  int bitmask;
2146  int i;
2147 
2148  Assert(ARR_ELEMTYPE(array) == TEXTOID);
2149 
2150  *numitems = nitems = ArrayGetNItems(ndim, dims);
2151 
2153  &typlen, &typbyval, &typalign);
2154 
2155  values = (char **) palloc(nitems * sizeof(char *));
2156 
2157  ptr = ARR_DATA_PTR(array);
2158  bitmap = ARR_NULLBITMAP(array);
2159  bitmask = 1;
2160 
2161  for (i = 0; i < nitems; i++)
2162  {
2163  if (bitmap && (*bitmap & bitmask) == 0)
2164  {
2165  values[i] = NULL;
2166  }
2167  else
2168  {
2169  values[i] = TextDatumGetCString(PointerGetDatum(ptr));
2170  ptr = att_addlength_pointer(ptr, typlen, ptr);
2171  ptr = (char *) att_align_nominal(ptr, typalign);
2172  }
2173 
2174  /* advance bitmap pointer if any */
2175  if (bitmap)
2176  {
2177  bitmask <<= 1;
2178  if (bitmask == 0x100)
2179  {
2180  bitmap++;
2181  bitmask = 1;
2182  }
2183  }
2184  }
2185 
2186  return values;
2187 }
2188 
2189 static char *
2190 get_sql_insert(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals)
2191 {
2192  char *relname;
2193  HeapTuple tuple;
2194  TupleDesc tupdesc;
2195  int natts;
2197  char *val;
2198  int key;
2199  int i;
2200  bool needComma;
2201 
2202  initStringInfo(&buf);
2203 
2204  /* get relation name including any needed schema prefix and quoting */
2205  relname = generate_relation_name(rel);
2206 
2207  tupdesc = rel->rd_att;
2208  natts = tupdesc->natts;
2209 
2210  tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2211  if (!tuple)
2212  ereport(ERROR,
2213  (errcode(ERRCODE_CARDINALITY_VIOLATION),
2214  errmsg("source row not found")));
2215 
2216  appendStringInfo(&buf, "INSERT INTO %s(", relname);
2217 
2218  needComma = false;
2219  for (i = 0; i < natts; i++)
2220  {
2221  Form_pg_attribute att = TupleDescAttr(tupdesc, i);
2222 
2223  if (att->attisdropped)
2224  continue;
2225 
2226  if (needComma)
2227  appendStringInfoChar(&buf, ',');
2228 
2230  quote_ident_cstr(NameStr(att->attname)));
2231  needComma = true;
2232  }
2233 
2234  appendStringInfoString(&buf, ") VALUES(");
2235 
2236  /*
2237  * Note: i is physical column number (counting from 0).
2238  */
2239  needComma = false;
2240  for (i = 0; i < natts; i++)
2241  {
2242  if (TupleDescAttr(tupdesc, i)->attisdropped)
2243  continue;
2244 
2245  if (needComma)
2246  appendStringInfoChar(&buf, ',');
2247 
2248  key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2249 
2250  if (key >= 0)
2251  val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2252  else
2253  val = SPI_getvalue(tuple, tupdesc, i + 1);
2254 
2255  if (val != NULL)
2256  {
2258  pfree(val);
2259  }
2260  else
2261  appendStringInfoString(&buf, "NULL");
2262  needComma = true;
2263  }
2264  appendStringInfoChar(&buf, ')');
2265 
2266  return buf.data;
2267 }
2268 
2269 static char *
2270 get_sql_delete(Relation rel, int *pkattnums, int pknumatts, char **tgt_pkattvals)
2271 {
2272  char *relname;
2273  TupleDesc tupdesc;
2275  int i;
2276 
2277  initStringInfo(&buf);
2278 
2279  /* get relation name including any needed schema prefix and quoting */
2280  relname = generate_relation_name(rel);
2281 
2282  tupdesc = rel->rd_att;
2283 
2284  appendStringInfo(&buf, "DELETE FROM %s WHERE ", relname);
2285  for (i = 0; i < pknumatts; i++)
2286  {
2287  int pkattnum = pkattnums[i];
2288  Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2289 
2290  if (i > 0)
2291  appendStringInfoString(&buf, " AND ");
2292 
2294  quote_ident_cstr(NameStr(attr->attname)));
2295 
2296  if (tgt_pkattvals[i] != NULL)
2297  appendStringInfo(&buf, " = %s",
2298  quote_literal_cstr(tgt_pkattvals[i]));
2299  else
2300  appendStringInfoString(&buf, " IS NULL");
2301  }
2302 
2303  return buf.data;
2304 }
2305 
2306 static char *
2307 get_sql_update(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals, char **tgt_pkattvals)
2308 {
2309  char *relname;
2310  HeapTuple tuple;
2311  TupleDesc tupdesc;
2312  int natts;
2314  char *val;
2315  int key;
2316  int i;
2317  bool needComma;
2318 
2319  initStringInfo(&buf);
2320 
2321  /* get relation name including any needed schema prefix and quoting */
2322  relname = generate_relation_name(rel);
2323 
2324  tupdesc = rel->rd_att;
2325  natts = tupdesc->natts;
2326 
2327  tuple = get_tuple_of_interest(rel, pkattnums, pknumatts, src_pkattvals);
2328  if (!tuple)
2329  ereport(ERROR,
2330  (errcode(ERRCODE_CARDINALITY_VIOLATION),
2331  errmsg("source row not found")));
2332 
2333  appendStringInfo(&buf, "UPDATE %s SET ", relname);
2334 
2335  /*
2336  * Note: i is physical column number (counting from 0).
2337  */
2338  needComma = false;
2339  for (i = 0; i < natts; i++)
2340  {
2341  Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2342 
2343  if (attr->attisdropped)
2344  continue;
2345 
2346  if (needComma)
2347  appendStringInfoString(&buf, ", ");
2348 
2349  appendStringInfo(&buf, "%s = ",
2350  quote_ident_cstr(NameStr(attr->attname)));
2351 
2352  key = get_attnum_pk_pos(pkattnums, pknumatts, i);
2353 
2354  if (key >= 0)
2355  val = tgt_pkattvals[key] ? pstrdup(tgt_pkattvals[key]) : NULL;
2356  else
2357  val = SPI_getvalue(tuple, tupdesc, i + 1);
2358 
2359  if (val != NULL)
2360  {
2362  pfree(val);
2363  }
2364  else
2365  appendStringInfoString(&buf, "NULL");
2366  needComma = true;
2367  }
2368 
2369  appendStringInfoString(&buf, " WHERE ");
2370 
2371  for (i = 0; i < pknumatts; i++)
2372  {
2373  int pkattnum = pkattnums[i];
2374  Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2375 
2376  if (i > 0)
2377  appendStringInfoString(&buf, " AND ");
2378 
2380  quote_ident_cstr(NameStr(attr->attname)));
2381 
2382  val = tgt_pkattvals[i];
2383 
2384  if (val != NULL)
2385  appendStringInfo(&buf, " = %s", quote_literal_cstr(val));
2386  else
2387  appendStringInfoString(&buf, " IS NULL");
2388  }
2389 
2390  return buf.data;
2391 }
2392 
2393 /*
2394  * Return a properly quoted identifier.
2395  * Uses quote_ident in quote.c
2396  */
2397 static char *
2398 quote_ident_cstr(char *rawstr)
2399 {
2400  text *rawstr_text;
2401  text *result_text;
2402  char *result;
2403 
2404  rawstr_text = cstring_to_text(rawstr);
2406  PointerGetDatum(rawstr_text)));
2407  result = text_to_cstring(result_text);
2408 
2409  return result;
2410 }
2411 
2412 static int
2413 get_attnum_pk_pos(int *pkattnums, int pknumatts, int key)
2414 {
2415  int i;
2416 
2417  /*
2418  * Not likely a long list anyway, so just scan for the value
2419  */
2420  for (i = 0; i < pknumatts; i++)
2421  if (key == pkattnums[i])
2422  return i;
2423 
2424  return -1;
2425 }
2426 
2427 static HeapTuple
2428 get_tuple_of_interest(Relation rel, int *pkattnums, int pknumatts, char **src_pkattvals)
2429 {
2430  char *relname;
2431  TupleDesc tupdesc;
2432  int natts;
2434  int ret;
2435  HeapTuple tuple;
2436  int i;
2437 
2438  /*
2439  * Connect to SPI manager
2440  */
2441  if ((ret = SPI_connect()) < 0)
2442  /* internal error */
2443  elog(ERROR, "SPI connect failure - returned %d", ret);
2444 
2445  initStringInfo(&buf);
2446 
2447  /* get relation name including any needed schema prefix and quoting */
2448  relname = generate_relation_name(rel);
2449 
2450  tupdesc = rel->rd_att;
2451  natts = tupdesc->natts;
2452 
2453  /*
2454  * Build sql statement to look up tuple of interest, ie, the one matching
2455  * src_pkattvals. We used to use "SELECT *" here, but it's simpler to
2456  * generate a result tuple that matches the table's physical structure,
2457  * with NULLs for any dropped columns. Otherwise we have to deal with two
2458  * different tupdescs and everything's very confusing.
2459  */
2460  appendStringInfoString(&buf, "SELECT ");
2461 
2462  for (i = 0; i < natts; i++)
2463  {
2464  Form_pg_attribute attr = TupleDescAttr(tupdesc, i);
2465 
2466  if (i > 0)
2467  appendStringInfoString(&buf, ", ");
2468 
2469  if (attr->attisdropped)
2470  appendStringInfoString(&buf, "NULL");
2471  else
2473  quote_ident_cstr(NameStr(attr->attname)));
2474  }
2475 
2476  appendStringInfo(&buf, " FROM %s WHERE ", relname);
2477 
2478  for (i = 0; i < pknumatts; i++)
2479  {
2480  int pkattnum = pkattnums[i];
2481  Form_pg_attribute attr = TupleDescAttr(tupdesc, pkattnum);
2482 
2483  if (i > 0)
2484  appendStringInfoString(&buf, " AND ");
2485 
2487  quote_ident_cstr(NameStr(attr->attname)));
2488 
2489  if (src_pkattvals[i] != NULL)
2490  appendStringInfo(&buf, " = %s",
2491  quote_literal_cstr(src_pkattvals[i]));
2492  else
2493  appendStringInfoString(&buf, " IS NULL");
2494  }
2495 
2496  /*
2497  * Retrieve the desired tuple
2498  */
2499  ret = SPI_exec(buf.data, 0);
2500  pfree(buf.data);
2501 
2502  /*
2503  * Only allow one qualifying tuple
2504  */
2505  if ((ret == SPI_OK_SELECT) && (SPI_processed > 1))
2506  ereport(ERROR,
2507  (errcode(ERRCODE_CARDINALITY_VIOLATION),
2508  errmsg("source criteria matched more than one record")));
2509 
2510  else if (ret == SPI_OK_SELECT && SPI_processed == 1)
2511  {
2512  SPITupleTable *tuptable = SPI_tuptable;
2513 
2514  tuple = SPI_copytuple(tuptable->vals[0]);
2515  SPI_finish();
2516 
2517  return tuple;
2518  }
2519  else
2520  {
2521  /*
2522  * no qualifying tuples
2523  */
2524  SPI_finish();
2525 
2526  return NULL;
2527  }
2528 
2529  /*
2530  * never reached, but keep compiler quiet
2531  */
2532  return NULL;
2533 }
2534 
2535 /*
2536  * Open the relation named by relname_text, acquire specified type of lock,
2537  * verify we have specified permissions.
2538  * Caller must close rel when done with it.
2539  */
2540 static Relation
2541 get_rel_from_relname(text *relname_text, LOCKMODE lockmode, AclMode aclmode)
2542 {
2543  RangeVar *relvar;
2544  Relation rel;
2545  AclResult aclresult;
2546 
2547  relvar = makeRangeVarFromNameList(textToQualifiedNameList(relname_text));
2548  rel = table_openrv(relvar, lockmode);
2549 
2550  aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
2551  aclmode);
2552  if (aclresult != ACLCHECK_OK)
2553  aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
2555 
2556  return rel;
2557 }
2558 
2559 /*
2560  * generate_relation_name - copied from ruleutils.c
2561  * Compute the name to display for a relation
2562  *
2563  * The result includes all necessary quoting and schema-prefixing.
2564  */
2565 static char *
2567 {
2568  char *nspname;
2569  char *result;
2570 
2571  /* Qualify the name if not visible in search path */
2573  nspname = NULL;
2574  else
2575  nspname = get_namespace_name(rel->rd_rel->relnamespace);
2576 
2577  result = quote_qualified_identifier(nspname, RelationGetRelationName(rel));
2578 
2579  return result;
2580 }
2581 
2582 
2583 static remoteConn *
2585 {
2586  remoteConnHashEnt *hentry;
2587  char *key;
2588 
2589  if (!remoteConnHash)
2591 
2592  key = pstrdup(name);
2593  truncate_identifier(key, strlen(key), false);
2595  key, HASH_FIND, NULL);
2596 
2597  if (hentry)
2598  return hentry->rconn;
2599 
2600  return NULL;
2601 }
2602 
2603 static HTAB *
2605 {
2606  HASHCTL ctl;
2607 
2608  ctl.keysize = NAMEDATALEN;
2609  ctl.entrysize = sizeof(remoteConnHashEnt);
2610 
2611  return hash_create("Remote Con hash", NUMCONN, &ctl, HASH_ELEM);
2612 }
2613 
2614 static void
2616 {
2617  remoteConnHashEnt *hentry;
2618  bool found;
2619  char *key;
2620 
2621  if (!remoteConnHash)
2623 
2624  key = pstrdup(name);
2625  truncate_identifier(key, strlen(key), true);
2626  hentry = (remoteConnHashEnt *) hash_search(remoteConnHash, key,
2627  HASH_ENTER, &found);
2628 
2629  if (found)
2630  {
2631  PQfinish(rconn->conn);
2633  pfree(rconn);
2634 
2635  ereport(ERROR,
2637  errmsg("duplicate connection name")));
2638  }
2639 
2640  hentry->rconn = rconn;
2641  strlcpy(hentry->name, name, sizeof(hentry->name));
2642 }
2643 
2644 static void
2646 {
2647  remoteConnHashEnt *hentry;
2648  bool found;
2649  char *key;
2650 
2651  if (!remoteConnHash)
2653 
2654  key = pstrdup(name);
2655  truncate_identifier(key, strlen(key), false);
2657  key, HASH_REMOVE, &found);
2658 
2659  if (!hentry)
2660  ereport(ERROR,
2661  (errcode(ERRCODE_UNDEFINED_OBJECT),
2662  errmsg("undefined connection name")));
2663 
2664 }
2665 
2666 static void
2668 {
2669  if (!superuser())
2670  {
2671  if (!PQconnectionUsedPassword(conn))
2672  {
2673  PQfinish(conn);
2675  if (rconn)
2676  pfree(rconn);
2677 
2678  ereport(ERROR,
2679  (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
2680  errmsg("password is required"),
2681  errdetail("Non-superuser cannot connect if the server does not request a password."),
2682  errhint("Target server's authentication method must be changed.")));
2683  }
2684  }
2685 }
2686 
2687 /*
2688  * For non-superusers, insist that the connstr specify a password. This
2689  * prevents a password from being picked up from .pgpass, a service file,
2690  * the environment, etc. We don't want the postgres user's passwords
2691  * to be accessible to non-superusers.
2692  */
2693 static void
2695 {
2696  if (!superuser())
2697  {
2700  bool connstr_gives_password = false;
2701 
2702  options = PQconninfoParse(connstr, NULL);
2703  if (options)
2704  {
2705  for (option = options; option->keyword != NULL; option++)
2706  {
2707  if (strcmp(option->keyword, "password") == 0)
2708  {
2709  if (option->val != NULL && option->val[0] != '\0')
2710  {
2711  connstr_gives_password = true;
2712  break;
2713  }
2714  }
2715  }
2716  PQconninfoFree(options);
2717  }
2718 
2719  if (!connstr_gives_password)
2720  ereport(ERROR,
2721  (errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
2722  errmsg("password is required"),
2723  errdetail("Non-superusers must provide a password in the connection string.")));
2724  }
2725 }
2726 
2727 /*
2728  * Report an error received from the remote server
2729  *
2730  * res: the received error result (will be freed)
2731  * fail: true for ERROR ereport, false for NOTICE
2732  * fmt and following args: sprintf-style format and values for errcontext;
2733  * the resulting string should be worded like "while <some action>"
2734  */
2735 static void
2736 dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
2737  bool fail, const char *fmt,...)
2738 {
2739  int level;
2740  char *pg_diag_sqlstate = PQresultErrorField(res, PG_DIAG_SQLSTATE);
2741  char *pg_diag_message_primary = PQresultErrorField(res, PG_DIAG_MESSAGE_PRIMARY);
2742  char *pg_diag_message_detail = PQresultErrorField(res, PG_DIAG_MESSAGE_DETAIL);
2743  char *pg_diag_message_hint = PQresultErrorField(res, PG_DIAG_MESSAGE_HINT);
2744  char *pg_diag_context = PQresultErrorField(res, PG_DIAG_CONTEXT);
2745  int sqlstate;
2746  char *message_primary;
2747  char *message_detail;
2748  char *message_hint;
2749  char *message_context;
2750  va_list ap;
2751  char dblink_context_msg[512];
2752 
2753  if (fail)
2754  level = ERROR;
2755  else
2756  level = NOTICE;
2757 
2758  if (pg_diag_sqlstate)
2759  sqlstate = MAKE_SQLSTATE(pg_diag_sqlstate[0],
2760  pg_diag_sqlstate[1],
2761  pg_diag_sqlstate[2],
2762  pg_diag_sqlstate[3],
2763  pg_diag_sqlstate[4]);
2764  else
2765  sqlstate = ERRCODE_CONNECTION_FAILURE;
2766 
2767  message_primary = xpstrdup(pg_diag_message_primary);
2768  message_detail = xpstrdup(pg_diag_message_detail);
2769  message_hint = xpstrdup(pg_diag_message_hint);
2770  message_context = xpstrdup(pg_diag_context);
2771 
2772  /*
2773  * If we don't get a message from the PGresult, try the PGconn. This is
2774  * needed because for connection-level failures, PQexec may just return
2775  * NULL, not a PGresult at all.
2776  */
2777  if (message_primary == NULL)
2778  message_primary = pchomp(PQerrorMessage(conn));
2779 
2780  /*
2781  * Now that we've copied all the data we need out of the PGresult, it's
2782  * safe to free it. We must do this to avoid PGresult leakage. We're
2783  * leaking all the strings too, but those are in palloc'd memory that will
2784  * get cleaned up eventually.
2785  */
2786  if (res)
2787  PQclear(res);
2788 
2789  /*
2790  * Format the basic errcontext string. Below, we'll add on something
2791  * about the connection name. That's a violation of the translatability
2792  * guidelines about constructing error messages out of parts, but since
2793  * there's no translation support for dblink, there's no need to worry
2794  * about that (yet).
2795  */
2796  va_start(ap, fmt);
2797  vsnprintf(dblink_context_msg, sizeof(dblink_context_msg), fmt, ap);
2798  va_end(ap);
2799 
2800  ereport(level,
2801  (errcode(sqlstate),
2802  message_primary ? errmsg_internal("%s", message_primary) :
2803  errmsg("could not obtain message string for remote error"),
2804  message_detail ? errdetail_internal("%s", message_detail) : 0,
2805  message_hint ? errhint("%s", message_hint) : 0,
2806  message_context ? (errcontext("%s", message_context)) : 0,
2807  conname ?
2808  (errcontext("%s on dblink connection named \"%s\"",
2809  dblink_context_msg, conname)) :
2810  (errcontext("%s on unnamed dblink connection",
2811  dblink_context_msg))));
2812 }
2813 
2814 /*
2815  * Obtain connection string for a foreign server
2816  */
2817 static char *
2818 get_connect_string(const char *servername)
2819 {
2820  ForeignServer *foreign_server = NULL;
2821  UserMapping *user_mapping;
2822  ListCell *cell;
2824  ForeignDataWrapper *fdw;
2825  AclResult aclresult;
2826  char *srvname;
2827 
2828  static const PQconninfoOption *options = NULL;
2829 
2830  initStringInfo(&buf);
2831 
2832  /*
2833  * Get list of valid libpq options.
2834  *
2835  * To avoid unnecessary work, we get the list once and use it throughout
2836  * the lifetime of this backend process. We don't need to care about
2837  * memory context issues, because PQconndefaults allocates with malloc.
2838  */
2839  if (!options)
2840  {
2841  options = PQconndefaults();
2842  if (!options) /* assume reason for failure is OOM */
2843  ereport(ERROR,
2844  (errcode(ERRCODE_FDW_OUT_OF_MEMORY),
2845  errmsg("out of memory"),
2846  errdetail("Could not get libpq's default connection options.")));
2847  }
2848 
2849  /* first gather the server connstr options */
2850  srvname = pstrdup(servername);
2851  truncate_identifier(srvname, strlen(srvname), false);
2852  foreign_server = GetForeignServerByName(srvname, true);
2853 
2854  if (foreign_server)
2855  {
2856  Oid serverid = foreign_server->serverid;
2857  Oid fdwid = foreign_server->fdwid;
2858  Oid userid = GetUserId();
2859 
2860  user_mapping = GetUserMapping(userid, serverid);
2861  fdw = GetForeignDataWrapper(fdwid);
2862 
2863  /* Check permissions, user must have usage on the server. */
2864  aclresult = pg_foreign_server_aclcheck(serverid, userid, ACL_USAGE);
2865  if (aclresult != ACLCHECK_OK)
2866  aclcheck_error(aclresult, OBJECT_FOREIGN_SERVER, foreign_server->servername);
2867 
2868  foreach(cell, fdw->options)
2869  {
2870  DefElem *def = lfirst(cell);
2871 
2872  if (is_valid_dblink_option(options, def->defname, ForeignDataWrapperRelationId))
2873  appendStringInfo(&buf, "%s='%s' ", def->defname,
2874  escape_param_str(strVal(def->arg)));
2875  }
2876 
2877  foreach(cell, foreign_server->options)
2878  {
2879  DefElem *def = lfirst(cell);
2880 
2881  if (is_valid_dblink_option(options, def->defname, ForeignServerRelationId))
2882  appendStringInfo(&buf, "%s='%s' ", def->defname,
2883  escape_param_str(strVal(def->arg)));
2884  }
2885 
2886  foreach(cell, user_mapping->options)
2887  {
2888 
2889  DefElem *def = lfirst(cell);
2890 
2891  if (is_valid_dblink_option(options, def->defname, UserMappingRelationId))
2892  appendStringInfo(&buf, "%s='%s' ", def->defname,
2893  escape_param_str(strVal(def->arg)));
2894  }
2895 
2896  return buf.data;
2897  }
2898  else
2899  return NULL;
2900 }
2901 
2902 /*
2903  * Escaping libpq connect parameter strings.
2904  *
2905  * Replaces "'" with "\'" and "\" with "\\".
2906  */
2907 static char *
2908 escape_param_str(const char *str)
2909 {
2910  const char *cp;
2912 
2913  initStringInfo(&buf);
2914 
2915  for (cp = str; *cp; cp++)
2916  {
2917  if (*cp == '\\' || *cp == '\'')
2918  appendStringInfoChar(&buf, '\\');
2919  appendStringInfoChar(&buf, *cp);
2920  }
2921 
2922  return buf.data;
2923 }
2924 
2925 /*
2926  * Validate the PK-attnums argument for dblink_build_sql_insert() and related
2927  * functions, and translate to the internal representation.
2928  *
2929  * The user supplies an int2vector of 1-based logical attnums, plus a count
2930  * argument (the need for the separate count argument is historical, but we
2931  * still check it). We check that each attnum corresponds to a valid,
2932  * non-dropped attribute of the rel. We do *not* prevent attnums from being
2933  * listed twice, though the actual use-case for such things is dubious.
2934  * Note that before Postgres 9.0, the user's attnums were interpreted as
2935  * physical not logical column numbers; this was changed for future-proofing.
2936  *
2937  * The internal representation is a palloc'd int array of 0-based physical
2938  * attnums.
2939  */
2940 static void
2942  int2vector *pkattnums_arg, int32 pknumatts_arg,
2943  int **pkattnums, int *pknumatts)
2944 {
2945  TupleDesc tupdesc = rel->rd_att;
2946  int natts = tupdesc->natts;
2947  int i;
2948 
2949  /* Don't take more array elements than there are */
2950  pknumatts_arg = Min(pknumatts_arg, pkattnums_arg->dim1);
2951 
2952  /* Must have at least one pk attnum selected */
2953  if (pknumatts_arg <= 0)
2954  ereport(ERROR,
2955  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2956  errmsg("number of key attributes must be > 0")));
2957 
2958  /* Allocate output array */
2959  *pkattnums = (int *) palloc(pknumatts_arg * sizeof(int));
2960  *pknumatts = pknumatts_arg;
2961 
2962  /* Validate attnums and convert to internal form */
2963  for (i = 0; i < pknumatts_arg; i++)
2964  {
2965  int pkattnum = pkattnums_arg->values[i];
2966  int lnum;
2967  int j;
2968 
2969  /* Can throw error immediately if out of range */
2970  if (pkattnum <= 0 || pkattnum > natts)
2971  ereport(ERROR,
2972  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2973  errmsg("invalid attribute number %d", pkattnum)));
2974 
2975  /* Identify which physical column has this logical number */
2976  lnum = 0;
2977  for (j = 0; j < natts; j++)
2978  {
2979  /* dropped columns don't count */
2980  if (TupleDescAttr(tupdesc, j)->attisdropped)
2981  continue;
2982 
2983  if (++lnum == pkattnum)
2984  break;
2985  }
2986 
2987  if (j < natts)
2988  (*pkattnums)[i] = j;
2989  else
2990  ereport(ERROR,
2991  (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
2992  errmsg("invalid attribute number %d", pkattnum)));
2993  }
2994 }
2995 
2996 /*
2997  * Check if the specified connection option is valid.
2998  *
2999  * We basically allow whatever libpq thinks is an option, with these
3000  * restrictions:
3001  * debug options: disallowed
3002  * "client_encoding": disallowed
3003  * "user": valid only in USER MAPPING options
3004  * secure options (eg password): valid only in USER MAPPING options
3005  * others: valid only in FOREIGN SERVER options
3006  *
3007  * We disallow client_encoding because it would be overridden anyway via
3008  * PQclientEncoding; allowing it to be specified would merely promote
3009  * confusion.
3010  */
3011 static bool
3013  Oid context)
3014 {
3015  const PQconninfoOption *opt;
3016 
3017  /* Look up the option in libpq result */
3018  for (opt = options; opt->keyword; opt++)
3019  {
3020  if (strcmp(opt->keyword, option) == 0)
3021  break;
3022  }
3023  if (opt->keyword == NULL)
3024  return false;
3025 
3026  /* Disallow debug options (particularly "replication") */
3027  if (strchr(opt->dispchar, 'D'))
3028  return false;
3029 
3030  /* Disallow "client_encoding" */
3031  if (strcmp(opt->keyword, "client_encoding") == 0)
3032  return false;
3033 
3034  /*
3035  * If the option is "user" or marked secure, it should be specified only
3036  * in USER MAPPING. Others should be specified only in SERVER.
3037  */
3038  if (strcmp(opt->keyword, "user") == 0 || strchr(opt->dispchar, '*'))
3039  {
3040  if (context != UserMappingRelationId)
3041  return false;
3042  }
3043  else
3044  {
3045  if (context != ForeignServerRelationId)
3046  return false;
3047  }
3048 
3049  return true;
3050 }
3051 
3052 /*
3053  * Copy the remote session's values of GUCs that affect datatype I/O
3054  * and apply them locally in a new GUC nesting level. Returns the new
3055  * nestlevel (which is needed by restoreLocalGucs to undo the settings),
3056  * or -1 if no new nestlevel was needed.
3057  *
3058  * We use the equivalent of a function SET option to allow the settings to
3059  * persist only until the caller calls restoreLocalGucs. If an error is
3060  * thrown in between, guc.c will take care of undoing the settings.
3061  */
3062 static int
3064 {
3065  static const char *const GUCsAffectingIO[] = {
3066  "DateStyle",
3067  "IntervalStyle"
3068  };
3069 
3070  int nestlevel = -1;
3071  int i;
3072 
3073  for (i = 0; i < lengthof(GUCsAffectingIO); i++)
3074  {
3075  const char *gucName = GUCsAffectingIO[i];
3076  const char *remoteVal = PQparameterStatus(conn, gucName);
3077  const char *localVal;
3078 
3079  /*
3080  * If the remote server is pre-8.4, it won't have IntervalStyle, but
3081  * that's okay because its output format won't be ambiguous. So just
3082  * skip the GUC if we don't get a value for it. (We might eventually
3083  * need more complicated logic with remote-version checks here.)
3084  */
3085  if (remoteVal == NULL)
3086  continue;
3087 
3088  /*
3089  * Avoid GUC-setting overhead if the remote and local GUCs already
3090  * have the same value.
3091  */
3092  localVal = GetConfigOption(gucName, false, false);
3093  Assert(localVal != NULL);
3094 
3095  if (strcmp(remoteVal, localVal) == 0)
3096  continue;
3097 
3098  /* Create new GUC nest level if we didn't already */
3099  if (nestlevel < 0)
3100  nestlevel = NewGUCNestLevel();
3101 
3102  /* Apply the option (this will throw error on failure) */
3103  (void) set_config_option(gucName, remoteVal,
3105  GUC_ACTION_SAVE, true, 0, false);
3106  }
3107 
3108  return nestlevel;
3109 }
3110 
3111 /*
3112  * Restore local GUCs after they have been overlaid with remote settings.
3113  */
3114 static void
3115 restoreLocalGucs(int nestlevel)
3116 {
3117  /* Do nothing if no new nestlevel was created */
3118  if (nestlevel > 0)
3119  AtEOXact_GUC(true, nestlevel);
3120 }
void tuplestore_putvalues(Tuplestorestate *state, TupleDesc tdesc, Datum *values, bool *isnull)
Definition: tuplestore.c:750
uint64 call_cntr
Definition: funcapi.h:65
signed short int16
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PGresult * cur_res
Definition: dblink.c:82
char * extra
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int PQnfields(const PGresult *res)
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TypeFuncClass get_call_result_type(FunctionCallInfo fcinfo, Oid *resultTypeId, TupleDesc *resultTupleDesc)
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char * quote_literal_cstr(const char *rawstr)
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Tuplestorestate * tuplestore
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#define HASH_ELEM
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char * PQgetvalue(const PGresult *res, int tup_num, int field_num)
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PGnotify * PQnotifies(PGconn *conn)
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Oid GetUserId(void)
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remoteConn * rconn
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Size entrysize
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SPITupleTable * SPI_tuptable
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Definition: superuser.c:46
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NameData relname
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Definition: postgres.h:479
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Definition: guc.c:5913
FunctionCallInfo fcinfo
Definition: dblink.c:75
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Definition: fd.c:1100
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Definition: funcapi.h:82
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Definition: execnodes.h:311
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Definition: mcxt.c:949
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Definition: mcxt.c:796
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Definition: foreign.h:39
#define elog(elevel,...)
Definition: elog.h:214
int i
ObjectType get_relkind_objtype(char relkind)
PGresult * last_res
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Definition: builtins.h:87
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Definition: fe-exec.c:1939
Definition: c.h:562
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Definition: fmgr.h:193
char * defname
Definition: parsenodes.h:732
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static void static void status(const char *fmt,...) pg_attribute_printf(1
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Definition: fe-connect.c:6619
#define PG_TRY()
Definition: elog.h:295
Relation table_open(Oid relationId, LOCKMODE lockmode)
Definition: table.c:39
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Definition: streamutil.c:31
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Definition: guc.c:6920
Definition: pg_list.h:50
List * options
Definition: foreign.h:42
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Definition: array.h:280
int16 AttrNumber
Definition: attnum.h:21
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Definition: fe-exec.c:3296
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Definition: rel.h:456
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Definition: array.h:288
long val
Definition: informix.c:664
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Definition: fe-exec.c:1778
Oid serverid
Definition: foreign.h:36
#define PG_RETURN_NULL()
Definition: fmgr.h:344
#define PG_END_TRY()
Definition: elog.h:320
#define BTEqualStrategyNumber
Definition: stratnum.h:31
#define IndexIndrelidIndexId
Definition: indexing.h:166
uint64 max_calls
Definition: funcapi.h:74
#define PG_DIAG_CONTEXT
Definition: postgres_ext.h:64
PGconn * PQconnectdb(const char *conninfo)
Definition: fe-connect.c:702
#define SRF_RETURN_DONE(_funcctx)
Definition: funcapi.h:317
static char * connstr
Definition: pg_dumpall.c:61
#define SRF_FIRSTCALL_INIT()
Definition: funcapi.h:295