/*------------------------------------------------------------------------- * * 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: /usr/local/cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.11 1997/09/08 21:44:55 momjian Exp $ * *------------------------------------------------------------------------- */ #include #include "postgres.h" #include "access/attnum.h" #include "access/heapam.h" #include "access/nbtree.h" #include "nodes/pg_list.h" #include "nodes/relation.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "utils/lsyscache.h" #include "utils/elog.h" #include "optimizer/internal.h" #include "optimizer/paths.h" #include "optimizer/clauses.h" #include "optimizer/clauseinfo.h" #include "optimizer/plancat.h" #include "optimizer/keys.h" #include "optimizer/cost.h" #include "optimizer/pathnode.h" #include "optimizer/xfunc.h" #include "optimizer/ordering.h" #include "catalog/catname.h" #include "catalog/pg_amop.h" #include "catalog/pg_proc.h" #include "executor/executor.h" #include "parser/parsetree.h" /* for getrelid() */ static void match_index_orclauses(Rel *rel, Rel *index, int indexkey, int xclass, List *clauseinfo_list); static bool match_index_to_operand(int indexkey, Expr *operand, Rel *rel, Rel *index); static List * match_index_orclause(Rel *rel, Rel *index, int indexkey, int xclass, List *or_clauses, List *other_matching_indices); static List * group_clauses_by_indexkey(Rel *rel, Rel *index, int *indexkeys, Oid *classes, List *clauseinfo_list); static List * group_clauses_by_ikey_for_joins(Rel *rel, Rel *index, int *indexkeys, Oid *classes, List *join_cinfo_list, List *restr_cinfo_list); static CInfo * match_clause_to_indexkey(Rel *rel, Rel *index, int indexkey, int xclass, CInfo *clauseInfo, bool join); static bool pred_test(List *predicate_list, List *clauseinfo_list, List *joininfo_list); static bool one_pred_test(Expr *predicate, List *clauseinfo_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(Rel *rel, Rel *index, List *joininfo_list, List *clauseinfo_list); static List * index_innerjoin(Query *root, Rel *rel, List *clausegroup_list, Rel *index); static List * create_index_paths(Query *root, Rel *rel, Rel *index, List *clausegroup_list, bool join); static List *add_index_paths(List *indexpaths, List *new_indexpaths); static bool function_index_operand(Expr *funcOpnd, Rel *rel, Rel *index); static bool SingleAttributeIndex(Rel *index); /* If Spyros can use a constant PRS2_BOOL_TYPEID, I can use this */ #define BOOL_TYPEID ((Oid) 16) /* * 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 * 'clauseinfo-list' is a list of restriction clauseinfo 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 * find_index_paths(Query *root, Rel *rel, List *indices, List *clauseinfo_list, List *joininfo_list) { List *scanclausegroups = NIL; List *scanpaths = NIL; Rel *index = (Rel *) NULL; List *joinclausegroups = NIL; List *joinpaths = NIL; List *retval = NIL; if (indices == NIL) return (NULL); index = (Rel *) lfirst(indices); retval = find_index_paths(root, rel, lnext(indices), clauseinfo_list, joininfo_list); /* If this is a partial index, return if it fails the predicate test */ if (index->indpred != NIL) if (!pred_test(index->indpred, clauseinfo_list, joininfo_list)) return retval; /* * 1. If this index has only one key, try matching it against * subclauses of an 'or' clause. The fields of the clauseinfo nodes * are marked with lists of the matching indices no path are actually * created. * * XXX NOTE: Currently btrees dos not support indices with > 1 key, so * the following test will always be true for now but we have decided * not to support index-scans on disjunction . -- lp */ if (SingleAttributeIndex(index)) { match_index_orclauses(rel, index, index->indexkeys[0], index->classlist[0], clauseinfo_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, clauseinfo_list); scanpaths = NIL; if (scanclausegroups != NIL) scanpaths = create_index_paths(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, clauseinfo_list); joinpaths = NIL; if (joinclausegroups != NIL) { List *new_join_paths = create_index_paths(root, rel, index, joinclausegroups, true); List *innerjoin_paths = index_innerjoin(root, rel, joinclausegroups, index); rel->innerjoin = nconc(rel->innerjoin, innerjoin_paths); joinpaths = new_join_paths; } /* * 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 * ClauseInfo 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'. * 'clauseinfo-list' is the list of available restriction clauses. * * Returns nothing. * */ static void match_index_orclauses(Rel *rel, Rel *index, int indexkey, int xclass, List *clauseinfo_list) { CInfo *clauseinfo = (CInfo *) NULL; List *i = NIL; foreach(i, clauseinfo_list) { clauseinfo = (CInfo *) lfirst(i); if (valid_or_clause(clauseinfo)) { /* * 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. */ clauseinfo->indexids = match_index_orclause(rel, index, indexkey, xclass, clauseinfo->clause->args, clauseinfo->indexids); } } } /* * match_index_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, Rel *rel, Rel *index) { /* * Normal index. */ if (index->indproc == InvalidOid) return match_indexkey_operand(indexkey, (Var *) operand, rel); /* * functional index check */ return (function_index_operand(operand, rel, index)); } /* * 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 * sargable 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(Rel *rel, Rel *index, int indexkey, int xclass, List *or_clauses, List *other_matching_indices) { Node *clause = NULL; List *matched_indices = other_matching_indices; List *index_list = NIL; List *clist; List *ind; if (!matched_indices) matched_indices = lcons(NIL, NIL); for (clist = or_clauses, ind = matched_indices; clist; clist = lnext(clist), ind = lnext(ind)) { clause = lfirst(clist); if (is_opclause(clause) && op_class(((Oper *) ((Expr *) clause)->oper)->opno, xclass, index->relam) && match_index_to_operand(indexkey, (Expr *) get_leftop((Expr *) clause), rel, index) && IsA(get_rightop((Expr *) clause), Const)) { matched_indices = lcons(index, matched_indices); index_list = lappend(index_list, matched_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(Rel *rel, Rel *index, int *indexkeys, Oid *classes, List *clauseinfo_list) { List *curCinfo = NIL; CInfo *matched_clause = (CInfo *) NULL; List *clausegroup = NIL; int curIndxKey; Oid curClass; if (clauseinfo_list == NIL) return NIL; while (!DoneMatchingIndexKeys(indexkeys, index)) { List *tempgroup = NIL; curIndxKey = indexkeys[0]; curClass = classes[0]; foreach(curCinfo, clauseinfo_list) { CInfo *temp = (CInfo *) 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++; } /* 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(Rel *rel, Rel *index, int *indexkeys, Oid *classes, List *join_cinfo_list, List *restr_cinfo_list) { List *curCinfo = NIL; CInfo *matched_clause = (CInfo *) NULL; List *clausegroup = NIL; int curIndxKey; Oid curClass; bool jfound = false; if (join_cinfo_list == NIL) return NIL; while (!DoneMatchingIndexKeys(indexkeys, index)) { List *tempgroup = NIL; curIndxKey = indexkeys[0]; curClass = classes[0]; foreach(curCinfo, join_cinfo_list) { CInfo *temp = (CInfo *) 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) { CInfo *temp = (CInfo *) 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++; } /* 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 clauseinfo node corresponding to the matching * clause. * * NOTE: returns nil if clause is an or_clause. * */ static CInfo * match_clause_to_indexkey(Rel *rel, Rel *index, int indexkey, int xclass, CInfo *clauseInfo, bool join) { Expr *clause = clauseInfo->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 ((CInfo *) 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 */ #ifdef INDEXSCAN_PATCH /* Handle also function parameters. DZ - 27-8-1996 */ if ((rightop && IsA(rightop, Const)) || (rightop && IsA(rightop, Param))) #else if (rightop && IsA(rightop, Const)) #endif { restrict_op = ((Oper *) ((Expr *) clause)->oper)->opno; isIndexable = (op_class(restrict_op, xclass, index->relam) && IndexScanableOperand(leftop, indexkey, rel, index)); } /* * Must try to commute the clause to standard s-arg format. */ #ifdef INDEXSCAN_PATCH /* ...And here... - vadim 01/22/97 */ else if ((leftop && IsA(leftop, Const)) || (leftop && IsA(leftop, Param))) #else else if (leftop && IsA(leftop, Const)) #endif { restrict_op = get_commutator(((Oper *) ((Expr *) clause)->oper)->opno); if ((restrict_op != InvalidOid) && op_class(restrict_op, xclass, index->relam) && IndexScanableOperand(rightop, indexkey, rel, index)) { isIndexable = true; /* * 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) && join_clause_p((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 (clauseInfo); 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 clauseinfo_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 *clauseinfo_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 clauseinfo_list). --Nels, Dec '92 */ if (predicate_list == NULL) return true; /* no predicate: the index is usable */ if (clauseinfo_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), clauseinfo_list)) return false; } } else if (!one_pred_test(lfirst(pred), clauseinfo_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 *clauseinfo_list) { CInfo *clauseinfo; List *item; Assert(predicate != NULL); foreach(item, clauseinfo_list) { clauseinfo = (CInfo *) lfirst(item); /* if any clause implies the predicate, return true */ if (one_pred_clause_expr_test(predicate, (Node *) clauseinfo->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 form; 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) || !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 */ /* XXX - hardcoded amopid value 403 to find "btree" operator classes */ ScanKeyEntryInitialize(&entry[0], 0, Anum_pg_amop_amopid, ObjectIdEqualRegProcedure, ObjectIdGetDatum(403)); ScanKeyEntryInitialize(&entry[1], 0, Anum_pg_amop_amopopr, ObjectIdEqualRegProcedure, 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, NowTimeQual, 2, entry); tuple = heap_getnext(scan, false, (Buffer *) NULL); if (!HeapTupleIsValid(tuple)) { elog(DEBUG, "clause_pred_clause_test: unknown pred_op"); return false; } form = (Form_pg_amop) GETSTRUCT(tuple); /* Get the predicate operator's strategy number (1 to 5) */ pred_strategy = (StrategyNumber) form->amopstrategy; /* Remember which operator class this strategy number came from */ opclass_id = form->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, ObjectIdEqualRegProcedure, ObjectIdGetDatum(opclass_id)); ScanKeyEntryInitialize(&entry[2], 0, Anum_pg_amop_amopopr, ObjectIdEqualRegProcedure, ObjectIdGetDatum(clause_op)); scan = heap_beginscan(relation, false, NowTimeQual, 3, entry); tuple = heap_getnext(scan, false, (Buffer *) NULL); if (!HeapTupleIsValid(tuple)) { elog(DEBUG, "clause_pred_clause_test: unknown clause_op"); return false; } form = (Form_pg_amop) GETSTRUCT(tuple); /* Get the restriction clause operator's strategy number (1 to 5) */ clause_strategy = (StrategyNumber) form->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, Integer16EqualRegProcedure, Int16GetDatum(test_strategy)); scan = heap_beginscan(relation, false, NowTimeQual, 3, entry); tuple = heap_getnext(scan, false, (Buffer *) NULL); if (!HeapTupleIsValid(tuple)) { elog(DEBUG, "clause_pred_clause_test: unknown test_op"); return false; } form = (Form_pg_amop) GETSTRUCT(tuple); /* Get the test operator */ test_op = form->amopopr; heap_endscan(scan); /* * 5. Evaluate the test */ test_oper = makeOper(test_op, /* opno */ InvalidOid, /* opid */ BOOL_TYPEID, /* 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: clauseinfo_list - list of restriction CInfos. 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(Rel *rel, Rel *index, List *joininfo_list, List *clauseinfo_list) { JInfo *joininfo = (JInfo *) NULL; List *cg_list = NIL; List *i = NIL; List *clausegroups = NIL; foreach(i, joininfo_list) { joininfo = (JInfo *) lfirst(i); if (joininfo->jinfoclauseinfo == NIL) continue; clausegroups = group_clauses_by_ikey_for_joins(rel, index, index->indexkeys, index->classlist, joininfo->jinfoclauseinfo, clauseinfo_list); if (clausegroups != NIL) { List *clauses = lfirst(clausegroups); ((CInfo *) lfirst(clauses))->cinfojoinid = joininfo->otherrels; } 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) { CInfo *cinfo = lfirst(l); if (!join_clause_p((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 clauseinfo nodes which can use * 'index' on their inner relation. * * Returns a list of index pathnodes. * */ static List * index_innerjoin(Query *root, Rel *rel, List *clausegroup_list, Rel *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->indexid = index->relids; pathnode->indexkeys = index->indexkeys; pathnode->indexqual = clausegroup; pathnode->path.joinid = ((CInfo *) lfirst(clausegroup))->cinfojoinid; 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 clauseinfo list into path for expensive function * processing -- JMH, 7/7/92 */ pathnode->path.locclauseinfo = set_difference(copyObject((Node *) rel->clauseinfo), clausegroup); #if 0 /* 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-paths-- * 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 clauseinfo * nodes) grouped by mergesortorder * '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_paths(Query *root, Rel *rel, Rel *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) { CInfo *clauseinfo; List *temp_node = NIL; bool temp = true; clausegroup = lfirst(i); foreach(j, clausegroup) { clauseinfo = (CInfo *) lfirst(j); if (!(join_clause_p((Node *) clauseinfo->clause) && equal_path_merge_ordering(index->ordering, clauseinfo->mergesortorder))) { temp = false; } } if (!join || temp) { /* restriction, ordering scan */ temp_path = create_index_path(root, rel, index, clausegroup, join); temp_node = lcons(temp_path, NIL); ip_list = nconc(ip_list, temp_node); } } return (ip_list); } static List * add_index_paths(List *indexpaths, List *new_indexpaths) { return append(indexpaths, new_indexpaths); } static bool function_index_operand(Expr *funcOpnd, Rel *rel, Rel *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; } static bool SingleAttributeIndex(Rel *index) { /* * return false for now as I don't know if we support index scans on * disjunction and the code doesn't work */ return (false); #if 0 /* * Non-functional indices. */ if (index->indproc == InvalidOid) return (index->indexkeys[0] != 0 && index->indexkeys[1] == 0); /* * We have a functional index which is a single attr index */ return true; #endif }