indxpath.c 38.3 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446
/*-------------------------------------------------------------------------
 *
 * indxpath.c
 *	  Routines to determine which indices are usable for scanning a
 *	  given relation
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.57 1999/06/19 04:54:14 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <math.h>

#include "postgres.h"

#include "access/attnum.h"
#include "access/heapam.h"
#include "access/nbtree.h"
#include "catalog/catname.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_type.h"
#include "executor/executor.h"
#include "fmgr.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "nodes/pg_list.h"
#include "nodes/relation.h"
#include "optimizer/clauses.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/cost.h"
#include "optimizer/internal.h"
#include "optimizer/keys.h"
#include "optimizer/ordering.h"
#include "optimizer/paths.h"
#include "optimizer/plancat.h"
#include "optimizer/pathnode.h"
#include "optimizer/xfunc.h"
#include "parser/parsetree.h"	/* for getrelid() */
#include "parser/parse_expr.h"	/* for exprType() */
#include "parser/parse_oper.h"	/* for oprid() and oper() */
#include "parser/parse_coerce.h"/* for IS_BINARY_COMPATIBLE() */
#include "utils/lsyscache.h"


static void match_index_orclauses(RelOptInfo *rel, RelOptInfo *index, int indexkey,
					  int xclass, List *restrictinfo_list);
static bool match_index_to_operand(int indexkey, Expr *operand,
					   RelOptInfo *rel, RelOptInfo *index);
static List *match_index_orclause(RelOptInfo *rel, RelOptInfo *index, int indexkey,
			 int xclass, List *or_clauses, List *other_matching_indices);
static List *group_clauses_by_indexkey(RelOptInfo *rel, RelOptInfo *index,
				  int *indexkeys, Oid *classes, List *restrictinfo_list);
static List *group_clauses_by_ikey_for_joins(RelOptInfo *rel, RelOptInfo *index,
								int *indexkeys, Oid *classes, List *join_cinfo_list, List *restr_cinfo_list);
static RestrictInfo *match_clause_to_indexkey(RelOptInfo *rel, RelOptInfo *index, int indexkey,
					  int xclass, RestrictInfo *restrictInfo, bool join);
static bool pred_test(List *predicate_list, List *restrictinfo_list,
		  List *joininfo_list);
static bool one_pred_test(Expr *predicate, List *restrictinfo_list);
static bool one_pred_clause_expr_test(Expr *predicate, Node *clause);
static bool one_pred_clause_test(Expr *predicate, Node *clause);
static bool clause_pred_clause_test(Expr *predicate, Node *clause);
static List *indexable_joinclauses(RelOptInfo *rel, RelOptInfo *index,
					  List *joininfo_list, List *restrictinfo_list);
static List *index_innerjoin(Query *root, RelOptInfo *rel,
				List *clausegroup_list, RelOptInfo *index);
static List *create_index_path_group(Query *root, RelOptInfo *rel, RelOptInfo *index,
						List *clausegroup_list, bool join);
static List *add_index_paths(List *indexpaths, List *new_indexpaths);
static bool function_index_operand(Expr *funcOpnd, RelOptInfo *rel, RelOptInfo *index);


/* find_index_paths()
 *	  Finds all possible index paths by determining which indices in the
 *	  list 'indices' are usable.
 *
 *	  To be usable, an index must match against either a set of
 *	  restriction clauses or join clauses.
 *
 *	  Note that the current implementation requires that there exist
 *	  matching clauses for every key in the index (i.e., no partial
 *	  matches are allowed).
 *
 *	  If an index can't be used with restriction clauses, but its keys
 *	  match those of the result sort order (according to information stored
 *	  within 'sortkeys'), then the index is also considered.
 *
 * 'rel' is the relation entry to which these index paths correspond
 * 'indices' is a list of possible index paths
 * 'restrictinfo_list' is a list of restriction restrictinfo nodes for 'rel'
 * 'joininfo_list' is a list of joininfo nodes for 'rel'
 * 'sortkeys' is a node describing the result sort order (from
 *		(find_sortkeys))
 *
 * Returns a list of index nodes.
 *
 */
List *
create_index_paths(Query *root,
				   RelOptInfo *rel,
				   List *indices,
				   List *restrictinfo_list,
				   List *joininfo_list)
{
	List	   *scanclausegroups = NIL;
	List	   *scanpaths = NIL;
	RelOptInfo *index = (RelOptInfo *) NULL;
	List	   *joinclausegroups = NIL;
	List	   *joinpaths = NIL;
	List	   *retval = NIL;
	List	   *ilist;

	foreach(ilist, indices)
	{
		index = (RelOptInfo *) lfirst(ilist);

		/*
		 * If this is a partial index, return if it fails the predicate
		 * test
		 */
		if (index->indpred != NIL)
			if (!pred_test(index->indpred, restrictinfo_list, joininfo_list))
				continue;

		/*
		 * 1. Try matching the index against subclauses of an 'or' clause.
		 * The fields of the restrictinfo nodes are marked with lists of
		 * the matching indices.  No path are actually created.  We
		 * currently only look to match the first key.	We don't find
		 * multi-key index cases where an AND matches the first key, and
		 * the OR matches the second key.
		 */
		match_index_orclauses(rel,
							  index,
							  index->indexkeys[0],
							  index->classlist[0],
							  restrictinfo_list);

		/*
		 * 2. If the keys of this index match any of the available
		 * restriction clauses, then create pathnodes corresponding to
		 * each group of usable clauses.
		 */
		scanclausegroups = group_clauses_by_indexkey(rel,
													 index,
													 index->indexkeys,
													 index->classlist,
													 restrictinfo_list);

		scanpaths = NIL;
		if (scanclausegroups != NIL)
			scanpaths = create_index_path_group(root,
												rel,
												index,
												scanclausegroups,
												false);

		/*
		 * 3. If this index can be used with any join clause, then create
		 * pathnodes for each group of usable clauses.	An index can be
		 * used with a join clause if its ordering is useful for a
		 * mergejoin, or if the index can possibly be used for scanning
		 * the inner relation of a nestloop join.
		 */
		joinclausegroups = indexable_joinclauses(rel, index, joininfo_list, restrictinfo_list);
		joinpaths = NIL;

		if (joinclausegroups != NIL)
		{
			joinpaths = create_index_path_group(root, rel,
												index,
												joinclausegroups,
												true);
			rel->innerjoin = nconc(rel->innerjoin,
								   index_innerjoin(root, rel,
											   joinclausegroups, index));
		}

		/*
		 * Some sanity checks to make sure that the indexpath is valid.
		 */
		if (joinpaths != NULL)
			retval = add_index_paths(joinpaths, retval);
		if (scanpaths != NULL)
			retval = add_index_paths(scanpaths, retval);
	}

	return retval;

}


/****************************************************************************
 *		----  ROUTINES TO MATCH 'OR' CLAUSES  ----
 ****************************************************************************/


/*
 * match_index_orclauses
 *	  Attempt to match an index against subclauses within 'or' clauses.
 *	  If the index does match, then the clause is marked with information
 *	  about the index.
 *
 *	  Essentially, this adds 'index' to the list of indices in the
 *	  RestrictInfo field of each of the clauses which it matches.
 *
 * 'rel' is the node of the relation on which the index is defined.
 * 'index' is the index node.
 * 'indexkey' is the (single) key of the index
 * 'class' is the class of the operator corresponding to 'indexkey'.
 * 'restrictinfo_list' is the list of available restriction clauses.
 *
 * Returns nothing.
 *
 */
static void
match_index_orclauses(RelOptInfo *rel,
					  RelOptInfo *index,
					  int indexkey,
					  int xclass,
					  List *restrictinfo_list)
{
	RestrictInfo *restrictinfo = (RestrictInfo *) NULL;
	List	   *i = NIL;

	foreach(i, restrictinfo_list)
	{
		restrictinfo = (RestrictInfo *) lfirst(i);
		if (valid_or_clause(restrictinfo))
		{

			/*
			 * Mark the 'or' clause with a list of indices which match
			 * each of its subclauses.	The list is generated by adding
			 * 'index' to the existing list where appropriate.
			 */
			restrictinfo->indexids = match_index_orclause(rel, index, indexkey,
														  xclass,
											  restrictinfo->clause->args,
												 restrictinfo->indexids);
		}
	}
}

/* match_index_to_operand()
 *	  Generalize test for a match between an existing index's key
 *	  and the operand on the rhs of a restriction clause.  Now check
 *	  for functional indices as well.
 */
static bool
match_index_to_operand(int indexkey,
					   Expr *operand,
					   RelOptInfo *rel,
					   RelOptInfo *index)
{
	bool		result;

	/*
	 * Normal index.
	 */
	if (index->indproc == InvalidOid)
	{
		result = match_indexkey_operand(indexkey, (Var *) operand, rel);
		return result;
	}

	/*
	 * functional index check
	 */
	result = function_index_operand(operand, rel, index);
	return result;
}

/*
 * match_index_orclause
 *	  Attempts to match an index against the subclauses of an 'or' clause.
 *
 *	  A match means that:
 *	  (1) the operator within the subclause can be used with one
 *				of the index's operator classes, and
 *	  (2) there is a usable key that matches the variable within a
 *				searchable clause.
 *
 * 'or_clauses' are the remaining subclauses within the 'or' clause
 * 'other_matching_indices' is the list of information on other indices
 *		that have already been matched to subclauses within this
 *		particular 'or' clause (i.e., a list previously generated by
 *		this routine)
 *
 * Returns a list of the form ((a b c) (d e f) nil (g h) ...) where
 * a,b,c are nodes of indices that match the first subclause in
 * 'or-clauses', d,e,f match the second subclause, no indices
 * match the third, g,h match the fourth, etc.
 */
static List *
match_index_orclause(RelOptInfo *rel,
					 RelOptInfo *index,
					 int indexkey,
					 int xclass,
					 List *or_clauses,
					 List *other_matching_indices)
{
	Node	   *clause = NULL;
	List	   *matching_indices = other_matching_indices;
	List	   *index_list = NIL;
	List	   *clist;

	/* first time through, we create index list */
	if (!other_matching_indices)
	{
		foreach(clist, or_clauses)
			matching_indices = lcons(NIL, matching_indices);
	}
	else
		matching_indices = other_matching_indices;

	index_list = matching_indices;

	foreach(clist, or_clauses)
	{
		clause = lfirst(clist);

		if (is_opclause(clause))
		{
			Expr	   *left = (Expr *) get_leftop((Expr *) clause);
			Expr	   *right = (Expr *) get_rightop((Expr *) clause);

			if (left && right &&
				op_class(((Oper *) ((Expr *) clause)->oper)->opno,
						 xclass, index->relam) &&
				((IsA(right, Const) &&
				  match_index_to_operand(indexkey, left, rel, index)) ||
				 (IsA(left, Const) &&
				  match_index_to_operand(indexkey, right, rel, index))))
				lfirst(matching_indices) = lcons(index,
											   lfirst(matching_indices));
		}

		matching_indices = lnext(matching_indices);
	}

	return index_list;
}

/****************************************************************************
 *				----  ROUTINES TO CHECK RESTRICTIONS  ----
 ****************************************************************************/


/*
 * DoneMatchingIndexKeys() - MACRO
 *
 * Determine whether we should continue matching index keys in a clause.
 * Depends on if there are more to match or if this is a functional index.
 * In the latter case we stop after the first match since the there can
 * be only key (i.e. the function's return value) and the attributes in
 * keys list represent the arguments to the function.  -mer 3 Oct. 1991
 */
#define DoneMatchingIndexKeys(indexkeys, index) \
		(indexkeys[0] == 0 || \
		 (index->indproc != InvalidOid))

/*
 * group_clauses_by_indexkey
 *	  Determines whether there are clauses which will match each and every
 *	  one of the remaining keys of an index.
 *
 * 'rel' is the node of the relation corresponding to the index.
 * 'indexkeys' are the remaining index keys to be matched.
 * 'classes' are the classes of the index operators on those keys.
 * 'clauses' is either:
 *		(1) the list of available restriction clauses on a single
 *				relation, or
 *		(2) a list of join clauses between 'rel' and a fixed set of
 *				relations,
 *		depending on the value of 'join'.
 *
 *		NOTE: it works now for restriction clauses only. - vadim 03/18/97
 *
 * Returns all possible groups of clauses that will match (given that
 * one or more clauses can match any of the remaining keys).
 * E.g., if you have clauses A, B, and C, ((A B) (A C)) might be
 * returned for an index with 2 keys.
 *
 */
static List *
group_clauses_by_indexkey(RelOptInfo *rel,
						  RelOptInfo *index,
						  int *indexkeys,
						  Oid *classes,
						  List *restrictinfo_list)
{
	List	   *curCinfo = NIL;
	RestrictInfo *matched_clause = (RestrictInfo *) NULL;
	List	   *clausegroup = NIL;
	int			curIndxKey;
	Oid			curClass;

	if (restrictinfo_list == NIL || indexkeys[0] == 0)
		return NIL;

	do
	{
		List	   *tempgroup = NIL;

		curIndxKey = indexkeys[0];
		curClass = classes[0];

		foreach(curCinfo, restrictinfo_list)
		{
			RestrictInfo *temp = (RestrictInfo *) lfirst(curCinfo);

			matched_clause = match_clause_to_indexkey(rel,
													  index,
													  curIndxKey,
													  curClass,
													  temp,
													  false);
			if (!matched_clause)
				continue;

			tempgroup = lappend(tempgroup, matched_clause);
		}
		if (tempgroup == NIL)
			break;

		clausegroup = nconc(clausegroup, tempgroup);

		indexkeys++;
		classes++;

	} while (!DoneMatchingIndexKeys(indexkeys, index));

	/* clausegroup holds all matched clauses ordered by indexkeys */

	if (clausegroup != NIL)
		return lcons(clausegroup, NIL);
	return NIL;
}

/*
 * group_clauses_by_ikey_for_joins
 *	  special edition of group_clauses_by_indexkey - will
 *	  match join & restriction clauses. See comment in indexable_joinclauses.
 *		- vadim 03/18/97
 *
 */
static List *
group_clauses_by_ikey_for_joins(RelOptInfo *rel,
								RelOptInfo *index,
								int *indexkeys,
								Oid *classes,
								List *join_cinfo_list,
								List *restr_cinfo_list)
{
	List	   *curCinfo = NIL;
	RestrictInfo *matched_clause = (RestrictInfo *) NULL;
	List	   *clausegroup = NIL;
	int			curIndxKey;
	Oid			curClass;
	bool		jfound = false;

	if (join_cinfo_list == NIL || indexkeys[0] == 0)
		return NIL;

	do
	{
		List	   *tempgroup = NIL;

		curIndxKey = indexkeys[0];
		curClass = classes[0];

		foreach(curCinfo, join_cinfo_list)
		{
			RestrictInfo *temp = (RestrictInfo *) lfirst(curCinfo);

			matched_clause = match_clause_to_indexkey(rel,
													  index,
													  curIndxKey,
													  curClass,
													  temp,
													  true);
			if (!matched_clause)
				continue;

			tempgroup = lappend(tempgroup, matched_clause);
			jfound = true;
		}
		foreach(curCinfo, restr_cinfo_list)
		{
			RestrictInfo *temp = (RestrictInfo *) lfirst(curCinfo);

			matched_clause = match_clause_to_indexkey(rel,
													  index,
													  curIndxKey,
													  curClass,
													  temp,
													  false);
			if (!matched_clause)
				continue;

			tempgroup = lappend(tempgroup, matched_clause);
		}
		if (tempgroup == NIL)
			break;

		clausegroup = nconc(clausegroup, tempgroup);

		indexkeys++;
		classes++;

	} while (!DoneMatchingIndexKeys(indexkeys, index));

	/* clausegroup holds all matched clauses ordered by indexkeys */

	if (clausegroup != NIL)
	{

		/*
		 * if no one join clause was matched then there ain't clauses for
		 * joins at all.
		 */
		if (!jfound)
		{
			freeList(clausegroup);
			return NIL;
		}
		return lcons(clausegroup, NIL);
	}
	return NIL;
}

/*
 * IndexScanableClause ()  MACRO
 *
 * Generalize condition on which we match a clause with an index.
 * Now we can match with functional indices.
 */
#define IndexScanableOperand(opnd, indkeys, rel, index) \
	((index->indproc == InvalidOid) ? \
		match_indexkey_operand(indkeys, opnd, rel) : \
		function_index_operand((Expr*)opnd,rel,index))

/*
 * There was
 *		equal_indexkey_var(indkeys,opnd) : \
 * above, and now
 *		match_indexkey_operand(indkeys, opnd, rel) : \
 * - vadim 01/22/97
 */

/* match_clause_to_indexkey()
 *	  Finds the first of a relation's available restriction clauses that
 *	  matches a key of an index.
 *
 *	  To match, the clause must:
 *	  (1) be in the form (op var const) if the clause is a single-
 *				relation clause, and
 *	  (2) contain an operator which is in the same class as the index
 *				operator for this key.
 *
 *	  If the clause being matched is a join clause, then 'join' is t.
 *
 * Returns a single restrictinfo node corresponding to the matching
 * clause.
 *
 * NOTE:  returns nil if clause is an or_clause.
 *
 */
static RestrictInfo *
match_clause_to_indexkey(RelOptInfo *rel,
						 RelOptInfo *index,
						 int indexkey,
						 int xclass,
						 RestrictInfo *restrictInfo,
						 bool join)
{
	Expr	   *clause = restrictInfo->clause;
	Var		   *leftop,
			   *rightop;
	Oid			join_op = InvalidOid;
	Oid			restrict_op = InvalidOid;
	bool		isIndexable = false;

	if (or_clause((Node *) clause) ||
		not_clause((Node *) clause) || single_node((Node *) clause))
		return (RestrictInfo *) NULL;

	leftop = get_leftop(clause);
	rightop = get_rightop(clause);

	/*
	 * If this is not a join clause, check for clauses of the form:
	 * (operator var/func constant) and (operator constant var/func)
	 */
	if (!join)
	{

		/*
		 * Check for standard s-argable clause
		 */
		if ((rightop && IsA(rightop, Const)) ||
			(rightop && IsA(rightop, Param)))
		{
			restrict_op = ((Oper *) ((Expr *) clause)->oper)->opno;

			isIndexable = (op_class(restrict_op, xclass, index->relam) &&
						   IndexScanableOperand(leftop,
												indexkey,
												rel,
												index));

#ifndef IGNORE_BINARY_COMPATIBLE_INDICES

			/*
			 * Didn't find an index? Then maybe we can find another
			 * binary-compatible index instead... thomas 1998-08-14
			 */
			if (!isIndexable)
			{
				Oid			ltype;
				Oid			rtype;

				ltype = exprType((Node *) leftop);
				rtype = exprType((Node *) rightop);

				/*
				 * make sure we have two different binary-compatible
				 * types...
				 */
				if ((ltype != rtype)
					&& IS_BINARY_COMPATIBLE(ltype, rtype))
				{
					char	   *opname;
					Operator	newop;

					opname = get_opname(restrict_op);
					if (opname != NULL)
						newop = oper(opname, ltype, ltype, TRUE);
					else
						newop = NULL;

					/* actually have a different operator to try? */
					if (HeapTupleIsValid(newop) && (oprid(newop) != restrict_op))
					{
						restrict_op = oprid(newop);

						isIndexable = (op_class(restrict_op, xclass, index->relam) &&
									   IndexScanableOperand(leftop,
															indexkey,
															rel,
															index));

						if (isIndexable)
							((Oper *) ((Expr *) clause)->oper)->opno = restrict_op;
					}
				}
			}
#endif
		}

		/*
		 * Must try to commute the clause to standard s-arg format.
		 */
		else if ((leftop && IsA(leftop, Const)) ||
				 (leftop && IsA(leftop, Param)))
		{
			restrict_op = get_commutator(((Oper *) ((Expr *) clause)->oper)->opno);

			isIndexable = ((restrict_op != InvalidOid) &&
						   op_class(restrict_op, xclass, index->relam) &&
						   IndexScanableOperand(rightop,
												indexkey, rel, index));

#ifndef IGNORE_BINARY_COMPATIBLE_INDICES
			if (!isIndexable)
			{
				Oid			ltype;
				Oid			rtype;

				ltype = exprType((Node *) leftop);
				rtype = exprType((Node *) rightop);

				if ((ltype != rtype)
					&& IS_BINARY_COMPATIBLE(ltype, rtype))
				{
					char	   *opname;
					Operator	newop;

					restrict_op = ((Oper *) ((Expr *) clause)->oper)->opno;

					opname = get_opname(restrict_op);
					if (opname != NULL)
						newop = oper(opname, rtype, rtype, TRUE);
					else
						newop = NULL;

					if (HeapTupleIsValid(newop) && (oprid(newop) != restrict_op))
					{
						restrict_op = get_commutator(oprid(newop));

						isIndexable = ((restrict_op != InvalidOid) &&
						   op_class(restrict_op, xclass, index->relam) &&
									   IndexScanableOperand(rightop,
															indexkey,
															rel,
															index));

						if (isIndexable)
							((Oper *) ((Expr *) clause)->oper)->opno = oprid(newop);
					}
				}
			}
#endif

			if (isIndexable)
			{

				/*
				 * In place list modification. (op const var/func) -> (op
				 * var/func const)
				 */
				CommuteClause((Node *) clause);
			}
		}
	}

	/*
	 * Check for an indexable scan on one of the join relations. clause is
	 * of the form (operator var/func var/func)
	 */
	else
	{
		if (rightop
		&& match_index_to_operand(indexkey, (Expr *) rightop, rel, index))
		{
			join_op = get_commutator(((Oper *) ((Expr *) clause)->oper)->opno);

		}
		else if (leftop
				 && match_index_to_operand(indexkey,
										   (Expr *) leftop, rel, index))
			join_op = ((Oper *) ((Expr *) clause)->oper)->opno;

		if (join_op && op_class(join_op, xclass, index->relam) &&
			is_joinable((Node *) clause))
		{
			isIndexable = true;

			/*
			 * If we're using the operand's commutator we must commute the
			 * clause.
			 */
			if (join_op != ((Oper *) ((Expr *) clause)->oper)->opno)
				CommuteClause((Node *) clause);
		}
	}

	if (isIndexable)
		return restrictInfo;

	return NULL;
}

/****************************************************************************
 *				----  ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS	----
 ****************************************************************************/

/*
 * pred_test
 *	  Does the "predicate inclusion test" for partial indexes.
 *
 *	  Recursively checks whether the clauses in restrictinfo_list imply
 *	  that the given predicate is true.
 *
 *	  This routine (together with the routines it calls) iterates over
 *	  ANDs in the predicate first, then reduces the qualification
 *	  clauses down to their constituent terms, and iterates over ORs
 *	  in the predicate last.  This order is important to make the test
 *	  succeed whenever possible (assuming the predicate has been
 *	  successfully cnfify()-ed). --Nels, Jan '93
 */
static bool
pred_test(List *predicate_list, List *restrictinfo_list, List *joininfo_list)
{
	List	   *pred,
			   *items,
			   *item;

	/*
	 * Note: if Postgres tried to optimize queries by forming equivalence
	 * classes over equi-joined attributes (i.e., if it recognized that a
	 * qualification such as "where a.b=c.d and a.b=5" could make use of
	 * an index on c.d), then we could use that equivalence class info
	 * here with joininfo_list to do more complete tests for the usability
	 * of a partial index.	For now, the test only uses restriction
	 * clauses (those in restrictinfo_list). --Nels, Dec '92
	 */

	if (predicate_list == NULL)
		return true;			/* no predicate: the index is usable */
	if (restrictinfo_list == NULL)
		return false;			/* no restriction clauses: the test must
								 * fail */

	foreach(pred, predicate_list)
	{

		/*
		 * if any clause is not implied, the whole predicate is not
		 * implied
		 */
		if (and_clause(lfirst(pred)))
		{
			items = ((Expr *) lfirst(pred))->args;
			foreach(item, items)
			{
				if (!one_pred_test(lfirst(item), restrictinfo_list))
					return false;
			}
		}
		else if (!one_pred_test(lfirst(pred), restrictinfo_list))
			return false;
	}
	return true;
}


/*
 * one_pred_test
 *	  Does the "predicate inclusion test" for one conjunct of a predicate
 *	  expression.
 */
static bool
one_pred_test(Expr *predicate, List *restrictinfo_list)
{
	RestrictInfo *restrictinfo;
	List	   *item;

	Assert(predicate != NULL);
	foreach(item, restrictinfo_list)
	{
		restrictinfo = (RestrictInfo *) lfirst(item);
		/* if any clause implies the predicate, return true */
		if (one_pred_clause_expr_test(predicate, (Node *) restrictinfo->clause))
			return true;
	}
	return false;
}


/*
 * one_pred_clause_expr_test
 *	  Does the "predicate inclusion test" for a general restriction-clause
 *	  expression.
 */
static bool
one_pred_clause_expr_test(Expr *predicate, Node *clause)
{
	List	   *items,
			   *item;

	if (is_opclause(clause))
		return one_pred_clause_test(predicate, clause);
	else if (or_clause(clause))
	{
		items = ((Expr *) clause)->args;
		foreach(item, items)
		{
			/* if any OR item doesn't imply the predicate, clause doesn't */
			if (!one_pred_clause_expr_test(predicate, lfirst(item)))
				return false;
		}
		return true;
	}
	else if (and_clause(clause))
	{
		items = ((Expr *) clause)->args;
		foreach(item, items)
		{

			/*
			 * if any AND item implies the predicate, the whole clause
			 * does
			 */
			if (one_pred_clause_expr_test(predicate, lfirst(item)))
				return true;
		}
		return false;
	}
	else
	{
		/* unknown clause type never implies the predicate */
		return false;
	}
}


/*
 * one_pred_clause_test
 *	  Does the "predicate inclusion test" for one conjunct of a predicate
 *	  expression for a simple restriction clause.
 */
static bool
one_pred_clause_test(Expr *predicate, Node *clause)
{
	List	   *items,
			   *item;

	if (is_opclause((Node *) predicate))
		return clause_pred_clause_test(predicate, clause);
	else if (or_clause((Node *) predicate))
	{
		items = predicate->args;
		foreach(item, items)
		{
			/* if any item is implied, the whole predicate is implied */
			if (one_pred_clause_test(lfirst(item), clause))
				return true;
		}
		return false;
	}
	else if (and_clause((Node *) predicate))
	{
		items = predicate->args;
		foreach(item, items)
		{

			/*
			 * if any item is not implied, the whole predicate is not
			 * implied
			 */
			if (!one_pred_clause_test(lfirst(item), clause))
				return false;
		}
		return true;
	}
	else
	{
		elog(DEBUG, "Unsupported predicate type, index will not be used");
		return false;
	}
}


/*
 * Define an "operator implication table" for btree operators ("strategies").
 * The "strategy numbers" are:	(1) <	(2) <=	 (3) =	 (4) >=   (5) >
 *
 * The interpretation of:
 *
 *		test_op = BT_implic_table[given_op-1][target_op-1]
 *
 * where test_op, given_op and target_op are strategy numbers (from 1 to 5)
 * of btree operators, is as follows:
 *
 *	 If you know, for some ATTR, that "ATTR given_op CONST1" is true, and you
 *	 want to determine whether "ATTR target_op CONST2" must also be true, then
 *	 you can use "CONST1 test_op CONST2" as a test.  If this test returns true,
 *	 then the target expression must be true; if the test returns false, then
 *	 the target expression may be false.
 *
 * An entry where test_op==0 means the implication cannot be determined, i.e.,
 * this test should always be considered false.
 */

StrategyNumber BT_implic_table[BTMaxStrategyNumber][BTMaxStrategyNumber] = {
	{2, 2, 0, 0, 0},
	{1, 2, 0, 0, 0},
	{1, 2, 3, 4, 5},
	{0, 0, 0, 4, 5},
	{0, 0, 0, 4, 4}
};


/*
 * clause_pred_clause_test
 *	  Use operator class info to check whether clause implies predicate.
 *
 *	  Does the "predicate inclusion test" for a "simple clause" predicate
 *	  for a single "simple clause" restriction.  Currently, this only handles
 *	  (binary boolean) operators that are in some btree operator class.
 *	  Eventually, rtree operators could also be handled by defining an
 *	  appropriate "RT_implic_table" array.
 */
static bool
clause_pred_clause_test(Expr *predicate, Node *clause)
{
	Var		   *pred_var,
			   *clause_var;
	Const	   *pred_const,
			   *clause_const;
	Oid			pred_op,
				clause_op,
				test_op;
	Oid			opclass_id;
	StrategyNumber pred_strategy,
				clause_strategy,
				test_strategy;
	Oper	   *test_oper;
	Expr	   *test_expr;
	bool		test_result,
				isNull;
	Relation	relation;
	HeapScanDesc scan;
	HeapTuple	tuple;
	ScanKeyData entry[3];
	Form_pg_amop aform;

	pred_var = (Var *) get_leftop(predicate);
	pred_const = (Const *) get_rightop(predicate);
	clause_var = (Var *) get_leftop((Expr *) clause);
	clause_const = (Const *) get_rightop((Expr *) clause);

	/* Check the basic form; for now, only allow the simplest case */
	if (!is_opclause(clause) ||
		!IsA(clause_var, Var) ||
		clause_const == NULL ||
		!IsA(clause_const, Const) ||
		!IsA(predicate->oper, Oper) ||
		!IsA(pred_var, Var) ||
		!IsA(pred_const, Const))
		return false;

	/*
	 * The implication can't be determined unless the predicate and the
	 * clause refer to the same attribute.
	 */
	if (clause_var->varattno != pred_var->varattno)
		return false;

	/* Get the operators for the two clauses we're comparing */
	pred_op = ((Oper *) ((Expr *) predicate)->oper)->opno;
	clause_op = ((Oper *) ((Expr *) clause)->oper)->opno;


	/*
	 * 1. Find a "btree" strategy number for the pred_op
	 */
	ScanKeyEntryInitialize(&entry[0], 0,
						   Anum_pg_amop_amopid,
						   F_OIDEQ,
						   ObjectIdGetDatum(BTREE_AM_OID));

	ScanKeyEntryInitialize(&entry[1], 0,
						   Anum_pg_amop_amopopr,
						   F_OIDEQ,
						   ObjectIdGetDatum(pred_op));

	relation = heap_openr(AccessMethodOperatorRelationName);

	/*
	 * The following assumes that any given operator will only be in a
	 * single btree operator class.  This is true at least for all the
	 * pre-defined operator classes.  If it isn't true, then whichever
	 * operator class happens to be returned first for the given operator
	 * will be used to find the associated strategy numbers for the test.
	 * --Nels, Jan '93
	 */
	scan = heap_beginscan(relation, false, SnapshotNow, 2, entry);
	tuple = heap_getnext(scan, 0);
	if (!HeapTupleIsValid(tuple))
	{
		elog(DEBUG, "clause_pred_clause_test: unknown pred_op");
		return false;
	}
	aform = (Form_pg_amop) GETSTRUCT(tuple);

	/* Get the predicate operator's strategy number (1 to 5) */
	pred_strategy = (StrategyNumber) aform->amopstrategy;

	/* Remember which operator class this strategy number came from */
	opclass_id = aform->amopclaid;

	heap_endscan(scan);


	/*
	 * 2. From the same opclass, find a strategy num for the clause_op
	 */
	ScanKeyEntryInitialize(&entry[1], 0,
						   Anum_pg_amop_amopclaid,
						   F_OIDEQ,
						   ObjectIdGetDatum(opclass_id));

	ScanKeyEntryInitialize(&entry[2], 0,
						   Anum_pg_amop_amopopr,
						   F_OIDEQ,
						   ObjectIdGetDatum(clause_op));

	scan = heap_beginscan(relation, false, SnapshotNow, 3, entry);
	tuple = heap_getnext(scan, 0);
	if (!HeapTupleIsValid(tuple))
	{
		elog(DEBUG, "clause_pred_clause_test: unknown clause_op");
		return false;
	}
	aform = (Form_pg_amop) GETSTRUCT(tuple);

	/* Get the restriction clause operator's strategy number (1 to 5) */
	clause_strategy = (StrategyNumber) aform->amopstrategy;
	heap_endscan(scan);


	/*
	 * 3. Look up the "test" strategy number in the implication table
	 */

	test_strategy = BT_implic_table[clause_strategy - 1][pred_strategy - 1];
	if (test_strategy == 0)
		return false;			/* the implication cannot be determined */


	/*
	 * 4. From the same opclass, find the operator for the test strategy
	 */

	ScanKeyEntryInitialize(&entry[2], 0,
						   Anum_pg_amop_amopstrategy,
						   F_INT2EQ,
						   Int16GetDatum(test_strategy));

	scan = heap_beginscan(relation, false, SnapshotNow, 3, entry);
	tuple = heap_getnext(scan, 0);
	if (!HeapTupleIsValid(tuple))
	{
		elog(DEBUG, "clause_pred_clause_test: unknown test_op");
		return false;
	}
	aform = (Form_pg_amop) GETSTRUCT(tuple);

	/* Get the test operator */
	test_op = aform->amopopr;
	heap_endscan(scan);


	/*
	 * 5. Evaluate the test
	 */
	test_oper = makeOper(test_op,		/* opno */
						 InvalidOid,	/* opid */
						 BOOLOID,		/* opresulttype */
						 0,		/* opsize */
						 NULL); /* op_fcache */
	replace_opid(test_oper);

	test_expr = make_opclause(test_oper,
							  copyObject(clause_const),
							  copyObject(pred_const));

#ifndef OMIT_PARTIAL_INDEX
	test_result = ExecEvalExpr((Node *) test_expr, NULL, &isNull, NULL);
#endif	 /* OMIT_PARTIAL_INDEX */
	if (isNull)
	{
		elog(DEBUG, "clause_pred_clause_test: null test result");
		return false;
	}
	return test_result;
}


/****************************************************************************
 *				----  ROUTINES TO CHECK JOIN CLAUSES  ----
 ****************************************************************************/

/*
 * indexable_joinclauses
 *	  Finds all groups of join clauses from among 'joininfo_list' that can
 *	  be used in conjunction with 'index'.
 *
 *	  The first clause in the group is marked as having the other relation
 *	  in the join clause as its outer join relation.
 *
 * Returns a list of these clause groups.
 *
 *	  Added: restrictinfo_list - list of restriction RestrictInfos. It's to
 *		support multi-column indices in joins and for cases
 *		when a key is in both join & restriction clauses. - vadim 03/18/97
 *
 */
static List *
indexable_joinclauses(RelOptInfo *rel, RelOptInfo *index,
					  List *joininfo_list, List *restrictinfo_list)
{
	JoinInfo   *joininfo = (JoinInfo *) NULL;
	List	   *cg_list = NIL;
	List	   *i = NIL;
	List	   *clausegroups = NIL;

	foreach(i, joininfo_list)
	{
		joininfo = (JoinInfo *) lfirst(i);

		if (joininfo->jinfo_restrictinfo == NIL)
			continue;
		clausegroups = group_clauses_by_ikey_for_joins(rel,
													   index,
													   index->indexkeys,
													   index->classlist,
											joininfo->jinfo_restrictinfo,
													   restrictinfo_list);

		if (clausegroups != NIL)
		{
			List	   *clauses = lfirst(clausegroups);

			((RestrictInfo *) lfirst(clauses))->restrictinfojoinid = joininfo->unjoined_relids;
		}
		cg_list = nconc(cg_list, clausegroups);
	}
	return cg_list;
}

/****************************************************************************
 *				----  PATH CREATION UTILITIES  ----
 ****************************************************************************/

/*
 * extract_restrict_clauses -
 *	  the list of clause info contains join clauses and restriction clauses.
 *	  This routine returns the restriction clauses only.
 */
#ifdef NOT_USED
static List *
extract_restrict_clauses(List *clausegroup)
{
	List	   *restrict_cls = NIL;
	List	   *l;

	foreach(l, clausegroup)
	{
		RestrictInfo *cinfo = lfirst(l);

		if (!is_joinable((Node *) cinfo->clause))
			restrict_cls = lappend(restrict_cls, cinfo);
	}
	return restrict_cls;
}

#endif

/*
 * index_innerjoin
 *	  Creates index path nodes corresponding to paths to be used as inner
 *	  relations in nestloop joins.
 *
 * 'clausegroup-list' is a list of list of restrictinfo nodes which can use
 * 'index' on their inner relation.
 *
 * Returns a list of index pathnodes.
 *
 */
static List *
index_innerjoin(Query *root, RelOptInfo *rel, List *clausegroup_list,
				RelOptInfo *index)
{
	List	   *clausegroup = NIL;
	List	   *cg_list = NIL;
	List	   *i = NIL;
	IndexPath  *pathnode = (IndexPath *) NULL;
	Cost		temp_selec;
	float		temp_pages;

	foreach(i, clausegroup_list)
	{
		List	   *attnos,
				   *values,
				   *flags;

		clausegroup = lfirst(i);
		pathnode = makeNode(IndexPath);

		get_joinvars(lfirsti(rel->relids), clausegroup,
					 &attnos, &values, &flags);
		index_selectivity(lfirsti(index->relids),
						  index->classlist,
						  get_opnos(clausegroup),
						  getrelid(lfirsti(rel->relids),
								   root->rtable),
						  attnos,
						  values,
						  flags,
						  length(clausegroup),
						  &temp_pages,
						  &temp_selec);

		pathnode->path.pathtype = T_IndexScan;
		pathnode->path.parent = rel;
		pathnode->path.pathorder = makeNode(PathOrder);
		pathnode->path.pathorder->ordtype = SORTOP_ORDER;
		pathnode->path.pathorder->ord.sortop = index->ordering;
		pathnode->path.pathkeys = NIL;

		pathnode->indexid = index->relids;
		pathnode->indexkeys = index->indexkeys;
		pathnode->indexqual = clausegroup;

		pathnode->path.joinid = ((RestrictInfo *) lfirst(clausegroup))->restrictinfojoinid;

		pathnode->path.path_cost = cost_index((Oid) lfirsti(index->relids),
											  (int) temp_pages,
											  temp_selec,
											  rel->pages,
											  rel->tuples,
											  index->pages,
											  index->tuples,
											  true);

		/*
		 * copy restrictinfo list into path for expensive function
		 * processing -- JMH, 7/7/92
		 */
		pathnode->path.loc_restrictinfo = set_difference(copyObject((Node *) rel->restrictinfo),
														 clausegroup);

#ifdef NOT_USED					/* fix xfunc */
		/* add in cost for expensive functions!  -- JMH, 7/7/92 */
		if (XfuncMode != XFUNC_OFF)
			((Path *) pathnode)->path_cost += xfunc_get_path_cost((Path *) pathnode);
#endif
		cg_list = lappend(cg_list, pathnode);
	}
	return cg_list;
}

/*
 * create_index_path_group
 *	  Creates a list of index path nodes for each group of clauses
 *	  (restriction or join) that can be used in conjunction with an index.
 *
 * 'rel' is the relation for which 'index' is defined
 * 'clausegroup-list' is the list of clause groups (lists of restrictinfo
 *				nodes) grouped by mergejoinorder
 * 'join' is a flag indicating whether or not the clauses are join
 *				clauses
 *
 * Returns a list of new index path nodes.
 *
 */
static List *
create_index_path_group(Query *root,
						RelOptInfo *rel,
						RelOptInfo *index,
						List *clausegroup_list,
						bool join)
{
	List	   *clausegroup = NIL;
	List	   *ip_list = NIL;
	List	   *i = NIL;
	List	   *j = NIL;
	IndexPath  *temp_path;

	foreach(i, clausegroup_list)
	{
		RestrictInfo *restrictinfo;
		bool		temp = true;

		clausegroup = lfirst(i);

		foreach(j, clausegroup)
		{
			restrictinfo = (RestrictInfo *) lfirst(j);
			if (!(is_joinable((Node *) restrictinfo->clause) &&
				  equal_path_merge_ordering(index->ordering,
										  restrictinfo->mergejoinorder)))
				temp = false;
		}

		if (!join || temp)
		{						/* restriction, ordering scan */
			temp_path = create_index_path(root, rel, index, clausegroup, join);
			ip_list = lappend(ip_list, temp_path);
		}
	}
	return ip_list;
}

static List *
add_index_paths(List *indexpaths, List *new_indexpaths)
{
	return nconc(indexpaths, new_indexpaths);
}

static bool
function_index_operand(Expr *funcOpnd, RelOptInfo *rel, RelOptInfo *index)
{
	Oid			heapRelid = (Oid) lfirsti(rel->relids);
	Func	   *function;
	List	   *funcargs;
	int		   *indexKeys = index->indexkeys;
	List	   *arg;
	int			i;

	/*
	 * sanity check, make sure we know what we're dealing with here.
	 */
	if (funcOpnd == NULL ||
		nodeTag(funcOpnd) != T_Expr || funcOpnd->opType != FUNC_EXPR ||
		funcOpnd->oper == NULL || indexKeys == NULL)
		return false;

	function = (Func *) funcOpnd->oper;
	funcargs = funcOpnd->args;

	if (function->funcid != index->indproc)
		return false;

	/*
	 * Check that the arguments correspond to the same arguments used to
	 * create the functional index.  To do this we must check that 1.
	 * refer to the right relatiion. 2. the args have the right attr.
	 * numbers in the right order.
	 *
	 *
	 * Check all args refer to the correct relation (i.e. the one with the
	 * functional index defined on it (rel).  To do this we can simply
	 * compare range table entry numbers, they must be the same.
	 */
	foreach(arg, funcargs)
	{
		if (heapRelid != ((Var *) lfirst(arg))->varno)
			return false;
	}

	/*
	 * check attr numbers and order.
	 */
	i = 0;
	foreach(arg, funcargs)
	{

		if (indexKeys[i] == 0)
			return false;

		if (((Var *) lfirst(arg))->varattno != indexKeys[i])
			return false;

		i++;
	}

	return true;
}