/*------------------------------------------------------------------------- * * indxpath.c * Routines to determine which indices are usable for scanning a * given relation, and create IndexPaths accordingly. * * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.112 2001/10/25 05:49:32 momjian Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include "access/heapam.h" #include "access/nbtree.h" #include "catalog/catname.h" #include "catalog/pg_amop.h" #include "catalog/pg_operator.h" #include "executor/executor.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "optimizer/clauses.h" #include "optimizer/cost.h" #include "optimizer/pathnode.h" #include "optimizer/paths.h" #include "optimizer/restrictinfo.h" #include "optimizer/var.h" #include "parser/parse_coerce.h" #include "parser/parse_expr.h" #include "parser/parse_oper.h" #include "utils/builtins.h" #include "utils/fmgroids.h" #include "utils/lsyscache.h" #include "utils/selfuncs.h" #include "utils/syscache.h" /* * 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 there can * be only 1 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)) #define is_indexable_operator(clause,opclass,indexkey_on_left) \ (indexable_operator(clause,opclass,indexkey_on_left) != InvalidOid) static void match_index_orclauses(RelOptInfo *rel, IndexOptInfo *index, List *restrictinfo_list); static List *match_index_orclause(RelOptInfo *rel, IndexOptInfo *index, List *or_clauses, List *other_matching_indices); static bool match_or_subclause_to_indexkey(RelOptInfo *rel, IndexOptInfo *index, Expr *clause); static List *group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index, int *indexkeys, Oid *classes, List *restrictinfo_list); static List *group_clauses_by_ikey_for_joins(RelOptInfo *rel, IndexOptInfo *index, int *indexkeys, Oid *classes, List *join_cinfo_list, List *restr_cinfo_list); static bool match_clause_to_indexkey(RelOptInfo *rel, IndexOptInfo *index, int indexkey, Oid opclass, Expr *clause, bool join); static bool pred_test(List *predicate_list, List *restrictinfo_list, List *joininfo_list); static bool pred_test_restrict_list(Expr *predicate, List *restrictinfo_list); static bool pred_test_recurse_clause(Expr *predicate, Node *clause); static bool pred_test_recurse_pred(Expr *predicate, Node *clause); static bool pred_test_simple_clause(Expr *predicate, Node *clause); static void indexable_joinclauses(RelOptInfo *rel, IndexOptInfo *index, List *joininfo_list, List *restrictinfo_list, List **clausegroups, List **outerrelids); static List *index_innerjoin(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *clausegroup_list, List *outerrelids_list); static bool match_index_to_operand(int indexkey, Var *operand, RelOptInfo *rel, IndexOptInfo *index); static bool function_index_operand(Expr *funcOpnd, RelOptInfo *rel, IndexOptInfo *index); static bool match_special_index_operator(Expr *clause, Oid opclass, bool indexkey_on_left); static List *prefix_quals(Var *leftop, Oid expr_op, char *prefix, Pattern_Prefix_Status pstatus); static List *network_prefix_quals(Var *leftop, Oid expr_op, Datum rightop); static Oid find_operator(const char *opname, Oid datatype); static Datum string_to_datum(const char *str, Oid datatype); static Const *string_to_const(const char *str, Oid datatype); /* * create_index_paths() * Generate all interesting index paths for the given relation. * Candidate paths are added to the rel's pathlist (using add_path). * Additional IndexPath nodes may also be added to rel's innerjoin list. * * To be considered for an index scan, an index must match one or more * restriction clauses or join clauses from the query's qual condition, * or match the query's ORDER BY condition. * * There are two basic kinds of index scans. A "plain" index scan uses * only restriction clauses (possibly none at all) in its indexqual, * so it can be applied in any context. An "innerjoin" index scan uses * join clauses (plus restriction clauses, if available) in its indexqual. * Therefore it can only be used as the inner relation of a nestloop * join against an outer rel that includes all the other rels mentioned * in its join clauses. In that context, values for the other rels' * attributes are available and fixed during any one scan of the indexpath. * * An IndexPath is generated and submitted to add_path() for each index * this routine deems potentially interesting for the current query. * An innerjoin path is also generated for each interesting combination of * outer join relations. The innerjoin paths are *not* passed to add_path(), * but are appended to the "innerjoin" list of the relation for later * consideration in nested-loop joins. * * 'rel' is the relation for which we want to generate index paths */ void create_index_paths(Query *root, RelOptInfo *rel) { List *restrictinfo_list = rel->baserestrictinfo; List *joininfo_list = rel->joininfo; List *ilist; foreach(ilist, rel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(ilist); List *restrictclauses; List *index_pathkeys; List *useful_pathkeys; bool index_is_ordered; List *joinclausegroups; List *joinouterrelids; /* * If this is a partial index, we can only use it if it passes 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 restriction * 'or' clauses (ie, 'or' clauses that reference only this * relation). The restrictinfo nodes for the 'or' clauses are * marked with lists of the matching indices. No paths are * actually created now; that will be done in orindxpath.c after * all indexes for the rel have been examined. (We need to do it * that way because we can potentially use a different index for * each subclause of an 'or', so we can't build a path for an 'or' * clause until all indexes have been matched against it.) * * We don't even think about special handling of 'or' clauses that * involve more than one relation (ie, are join clauses). Can we * do anything useful with those? */ match_index_orclauses(rel, index, restrictinfo_list); /* * 2. Match the index against non-'or' restriction clauses. */ restrictclauses = group_clauses_by_indexkey(rel, index, index->indexkeys, index->classlist, restrictinfo_list); /* * 3. Compute pathkeys describing index's ordering, if any, then * see how many of them are actually useful for this query. */ index_pathkeys = build_index_pathkeys(root, rel, index, ForwardScanDirection); index_is_ordered = (index_pathkeys != NIL); useful_pathkeys = truncate_useless_pathkeys(root, rel, index_pathkeys); /* * 4. Generate an indexscan path if there are relevant restriction * clauses OR the index ordering is potentially useful for later * merging or final output ordering. * * If there is a predicate, consider it anyway since the index * predicate has already been found to match the query. The * selectivity of the predicate might alone make the index useful. */ if (restrictclauses != NIL || useful_pathkeys != NIL || index->indpred != NIL) add_path(rel, (Path *) create_index_path(root, rel, index, restrictclauses, useful_pathkeys, index_is_ordered ? ForwardScanDirection : NoMovementScanDirection)); /* * 5. If the index is ordered, a backwards scan might be * interesting. Currently this is only possible for a DESC query * result ordering. */ if (index_is_ordered) { index_pathkeys = build_index_pathkeys(root, rel, index, BackwardScanDirection); useful_pathkeys = truncate_useless_pathkeys(root, rel, index_pathkeys); if (useful_pathkeys != NIL) add_path(rel, (Path *) create_index_path(root, rel, index, restrictclauses, useful_pathkeys, BackwardScanDirection)); } /* * 6. Create an innerjoin index path for each combination of other * rels used in available join clauses. These paths will be * considered as the inner side of nestloop joins against those * sets of other rels. indexable_joinclauses() finds sets of * clauses that can be used with each combination of outer rels, * and index_innerjoin builds the paths themselves. We add the * paths to the rel's innerjoin list, NOT to the result list. */ indexable_joinclauses(rel, index, joininfo_list, restrictinfo_list, &joinclausegroups, &joinouterrelids); if (joinclausegroups != NIL) { rel->innerjoin = nconc(rel->innerjoin, index_innerjoin(root, rel, index, joinclausegroups, joinouterrelids)); } } } /**************************************************************************** * ---- ROUTINES TO PROCESS 'OR' CLAUSES ---- ****************************************************************************/ /* * match_index_orclauses * Attempt to match an index against subclauses within 'or' clauses. * Each subclause that does match is marked with the index's node. * * Essentially, this adds 'index' to the list of subclause indices in * the RestrictInfo field of each of the 'or' clauses where it matches. * NOTE: we can use storage in the RestrictInfo for this purpose because * this processing is only done on single-relation restriction clauses. * Therefore, we will never have indexes for more than one relation * mentioned in the same RestrictInfo node's list. * * 'rel' is the node of the relation on which the index is defined. * 'index' is the index node. * 'restrictinfo_list' is the list of available restriction clauses. */ static void match_index_orclauses(RelOptInfo *rel, IndexOptInfo *index, List *restrictinfo_list) { List *i; foreach(i, restrictinfo_list) { RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(i); if (restriction_is_or_clause(restrictinfo)) { /* * Add this index to the subclause index list for each * subclause that it matches. */ restrictinfo->subclauseindices = match_index_orclause(rel, index, restrictinfo->clause->args, restrictinfo->subclauseindices); } } } /* * 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 the * index's specified operator class, and * (2) one operand of the subclause matches the index key. * * If a subclause is an 'and' clause, then it matches if any of its * subclauses is an opclause that matches. * * 'or_clauses' is the list of 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), or NIL if this routine has not previously been * run for this 'or' clause. * * 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, IndexOptInfo *index, List *or_clauses, List *other_matching_indices) { List *matching_indices; List *index_list; List *clist; /* * first time through, we create list of same length as OR clause, * containing an empty sublist for each subclause. */ if (!other_matching_indices) { matching_indices = NIL; foreach(clist, or_clauses) matching_indices = lcons(NIL, matching_indices); } else matching_indices = other_matching_indices; index_list = matching_indices; foreach(clist, or_clauses) { Expr *clause = lfirst(clist); if (match_or_subclause_to_indexkey(rel, index, clause)) { /* OK to add this index to sublist for this subclause */ lfirst(matching_indices) = lcons(index, lfirst(matching_indices)); } matching_indices = lnext(matching_indices); } return index_list; } /* * See if a subclause of an OR clause matches an index. * * We accept the subclause if it is an operator clause that matches the * index, or if it is an AND clause any of whose members is an opclause * that matches the index. * * For multi-key indexes, we only look for matches to the first key; * without such a match the index is useless. If the clause is an AND * then we may be able to extract additional subclauses to use with the * later indexkeys, but we need not worry about that until * extract_or_indexqual_conditions() is called (if it ever is). */ static bool match_or_subclause_to_indexkey(RelOptInfo *rel, IndexOptInfo *index, Expr *clause) { int indexkey = index->indexkeys[0]; Oid opclass = index->classlist[0]; if (and_clause((Node *) clause)) { List *item; foreach(item, clause->args) { if (match_clause_to_indexkey(rel, index, indexkey, opclass, lfirst(item), false)) return true; } return false; } else return match_clause_to_indexkey(rel, index, indexkey, opclass, clause, false); } /*---------- * Given an OR subclause that has previously been determined to match * the specified index, extract a list of specific opclauses that can be * used as indexquals. * * In the simplest case this just means making a one-element list of the * given opclause. However, if the OR subclause is an AND, we have to * scan it to find the opclause(s) that match the index. (There should * be at least one, if match_or_subclause_to_indexkey succeeded, but there * could be more.) * * Also, we can look at other restriction clauses of the rel to discover * additional candidate indexquals: for example, consider * ... where (a = 11 or a = 12) and b = 42; * If we are dealing with an index on (a,b) then we can include the clause * b = 42 in the indexqual list generated for each of the OR subclauses. * Essentially, we are making an index-specific transformation from CNF to * DNF. (NOTE: when we do this, we end up with a slightly inefficient plan * because create_indexscan_plan is not very bright about figuring out which * restriction clauses are implied by the generated indexqual condition. * Currently we'll end up rechecking both the OR clause and the transferred * restriction clause as qpquals. FIXME someday.) * * Also, we apply expand_indexqual_conditions() to convert any special * matching opclauses to indexable operators. * * The passed-in clause is not changed. *---------- */ List * extract_or_indexqual_conditions(RelOptInfo *rel, IndexOptInfo *index, Expr *orsubclause) { List *quals = NIL; int *indexkeys = index->indexkeys; Oid *classes = index->classlist; /* * Extract relevant indexclauses in indexkey order. This is * essentially just like group_clauses_by_indexkey() except that the * input and output are lists of bare clauses, not of RestrictInfo * nodes. */ do { int curIndxKey = indexkeys[0]; Oid curClass = classes[0]; List *clausegroup = NIL; List *item; if (and_clause((Node *) orsubclause)) { foreach(item, orsubclause->args) { Expr *subsubclause = (Expr *) lfirst(item); if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, subsubclause, false)) clausegroup = lappend(clausegroup, subsubclause); } } else if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, orsubclause, false)) clausegroup = makeList1(orsubclause); /* * If we found no clauses for this indexkey in the OR subclause * itself, try looking in the rel's top-level restriction list. */ if (clausegroup == NIL) { foreach(item, rel->baserestrictinfo) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(item); if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, rinfo->clause, false)) clausegroup = lappend(clausegroup, rinfo->clause); } } /* * If still no clauses match this key, we're done; we don't want * to look at keys to its right. */ if (clausegroup == NIL) break; quals = nconc(quals, clausegroup); indexkeys++; classes++; } while (!DoneMatchingIndexKeys(indexkeys, index)); if (quals == NIL) elog(ERROR, "extract_or_indexqual_conditions: no matching clause"); return expand_indexqual_conditions(quals); } /**************************************************************************** * ---- ROUTINES TO CHECK RESTRICTIONS ---- ****************************************************************************/ /* * group_clauses_by_indexkey * Generates a list of restriction clauses that can be used with an index. * * 'rel' is the node of the relation itself. * 'index' is a index on 'rel'. * 'indexkeys' are the index keys to be matched. * 'classes' are the classes of the index operators on those keys. * 'restrictinfo_list' is the list of available restriction clauses for 'rel'. * * Returns a list of all the RestrictInfo nodes for clauses that can be * used with this index. * * The list is ordered by index key. (This is not depended on by any part * of the planner, as far as I can tell; but some parts of the executor * do assume that the indxqual list ultimately delivered to the executor * is so ordered. One such place is _bt_orderkeys() in the btree support. * Perhaps that ought to be fixed someday --- tgl 7/00) * * Note that in a multi-key index, we stop if we find a key that cannot be * used with any clause. For example, given an index on (A,B,C), we might * return (C1 C2 C3 C4) if we find that clauses C1 and C2 use column A, * clauses C3 and C4 use column B, and no clauses use column C. But if * no clauses match B we will return (C1 C2), whether or not there are * clauses matching column C, because the executor couldn't use them anyway. */ static List * group_clauses_by_indexkey(RelOptInfo *rel, IndexOptInfo *index, int *indexkeys, Oid *classes, List *restrictinfo_list) { List *clausegroup_list = NIL; if (restrictinfo_list == NIL || indexkeys[0] == 0) return NIL; do { int curIndxKey = indexkeys[0]; Oid curClass = classes[0]; List *clausegroup = NIL; List *curCinfo; foreach(curCinfo, restrictinfo_list) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(curCinfo); if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, rinfo->clause, false)) clausegroup = lappend(clausegroup, rinfo); } /* * If no clauses match this key, we're done; we don't want to look * at keys to its right. */ if (clausegroup == NIL) break; clausegroup_list = nconc(clausegroup_list, clausegroup); indexkeys++; classes++; } while (!DoneMatchingIndexKeys(indexkeys, index)); /* clausegroup_list holds all matched clauses ordered by indexkeys */ return clausegroup_list; } /* * group_clauses_by_ikey_for_joins * Generates a list of join clauses that can be used with an index * to scan the inner side of a nestloop join. * * This is much like group_clauses_by_indexkey(), but we consider both * join and restriction clauses. For each indexkey in the index, we * accept both join and restriction clauses that match it, since both * will make useful indexquals if the index is being used to scan the * inner side of a nestloop join. But there must be at least one matching * join clause, or we return NIL indicating that this index isn't useful * for nestloop joining. */ static List * group_clauses_by_ikey_for_joins(RelOptInfo *rel, IndexOptInfo *index, int *indexkeys, Oid *classes, List *join_cinfo_list, List *restr_cinfo_list) { List *clausegroup_list = NIL; bool jfound = false; if (join_cinfo_list == NIL || indexkeys[0] == 0) return NIL; do { int curIndxKey = indexkeys[0]; Oid curClass = classes[0]; List *clausegroup = NIL; List *curCinfo; foreach(curCinfo, join_cinfo_list) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(curCinfo); if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, rinfo->clause, true)) { clausegroup = lappend(clausegroup, rinfo); jfound = true; } } foreach(curCinfo, restr_cinfo_list) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(curCinfo); if (match_clause_to_indexkey(rel, index, curIndxKey, curClass, rinfo->clause, false)) clausegroup = lappend(clausegroup, rinfo); } /* * If no clauses match this key, we're done; we don't want to look * at keys to its right. */ if (clausegroup == NIL) break; clausegroup_list = nconc(clausegroup_list, clausegroup); indexkeys++; classes++; } while (!DoneMatchingIndexKeys(indexkeys, index)); /* * if no join clause was matched then there ain't clauses for joins at * all. */ if (!jfound) { freeList(clausegroup_list); return NIL; } /* clausegroup_list holds all matched clauses ordered by indexkeys */ return clausegroup_list; } /* * match_clause_to_indexkey() * Determines whether a restriction or join clause matches * a key of an index. * * To match, the clause: * * (1a) for a restriction clause: must be in the form (indexkey op const) * or (const op indexkey), or * (1b) for a join clause: must be in the form (indexkey op others) * or (others op indexkey), where others is an expression involving * only vars of the other relation(s); and * (2) must contain an operator which is in the same class as the index * operator for this key, or is a "special" operator as recognized * by match_special_index_operator(). * * Presently, the executor can only deal with indexquals that have the * indexkey on the left, so we can only use clauses that have the indexkey * on the right if we can commute the clause to put the key on the left. * We do not actually do the commuting here, but we check whether a * suitable commutator operator is available. * * Note that in the join case, we already know that the clause as a * whole uses vars from the interesting set of relations. But we need * to defend against expressions like (a.f1 OP (b.f2 OP a.f3)); that's * not processable by an indexscan nestloop join, whereas * (a.f1 OP (b.f2 OP c.f3)) is. * * 'rel' is the relation of interest. * 'index' is an index on 'rel'. * 'indexkey' is a key of 'index'. * 'opclass' is the corresponding operator class. * 'clause' is the clause to be tested. * 'join' is true if we are considering this clause for joins. * * Returns true if the clause can be used with this index key. * * NOTE: returns false if clause is an OR or AND clause; it is the * responsibility of higher-level routines to cope with those. */ static bool match_clause_to_indexkey(RelOptInfo *rel, IndexOptInfo *index, int indexkey, Oid opclass, Expr *clause, bool join) { Var *leftop, *rightop; /* Clause must be a binary opclause. */ if (!is_opclause((Node *) clause)) return false; leftop = get_leftop(clause); rightop = get_rightop(clause); if (!leftop || !rightop) return false; if (!join) { /* * Not considering joins, so check for clauses of the form: * (indexkey operator constant) or (constant operator indexkey). * Anything that is a "pseudo constant" expression will do. */ if (match_index_to_operand(indexkey, leftop, rel, index) && is_pseudo_constant_clause((Node *) rightop)) { if (is_indexable_operator(clause, opclass, true)) return true; /* * If we didn't find a member of the index's opclass, see * whether it is a "special" indexable operator. */ if (match_special_index_operator(clause, opclass, true)) return true; return false; } if (match_index_to_operand(indexkey, rightop, rel, index) && is_pseudo_constant_clause((Node *) leftop)) { if (is_indexable_operator(clause, opclass, false)) return true; /* * If we didn't find a member of the index's opclass, see * whether it is a "special" indexable operator. */ if (match_special_index_operator(clause, opclass, false)) return true; return false; } } else { /* * Check for an indexqual that could be handled by a nestloop * join. We need the index key to be compared against an * expression that uses none of the indexed relation's vars and * contains no non-cachable functions. */ if (match_index_to_operand(indexkey, leftop, rel, index)) { List *othervarnos = pull_varnos((Node *) rightop); bool isIndexable; isIndexable = !intMember(lfirsti(rel->relids), othervarnos) && !contain_noncachable_functions((Node *) rightop) && is_indexable_operator(clause, opclass, true); freeList(othervarnos); return isIndexable; } else if (match_index_to_operand(indexkey, rightop, rel, index)) { List *othervarnos = pull_varnos((Node *) leftop); bool isIndexable; isIndexable = !intMember(lfirsti(rel->relids), othervarnos) && !contain_noncachable_functions((Node *) leftop) && is_indexable_operator(clause, opclass, false); freeList(othervarnos); return isIndexable; } } return false; } /* * indexable_operator * Does a binary opclause contain an operator matching the index opclass? * * If the indexkey is on the right, what we actually want to know * is whether the operator has a commutator operator that matches * the index's opclass. * * We try both the straightforward match and matches that rely on * recognizing binary-compatible datatypes. For example, if we have * an expression like "oid = 123", the operator will be oideqint4, * which we need to replace with oideq in order to recognize it as * matching an oid_ops index on the oid field. A variant case is where * the expression is like "oid::int4 = 123", where the given operator * will be int4eq and again we need to intuit that we want to use oideq. * * Returns the OID of the matching operator, or InvalidOid if no match. * Note that the returned OID will be different from the one in the given * expression if we used a binary-compatible substitution. Also note that * if indexkey_on_left is FALSE (meaning we need to commute), the returned * OID is *not* commuted; it can be plugged directly into the given clause. */ Oid indexable_operator(Expr *clause, Oid opclass, bool indexkey_on_left) { Oid expr_op = ((Oper *) clause->oper)->opno; Oid commuted_op, new_op; Operator oldoptup; Form_pg_operator oldopform; char *opname; Oid ltype, rtype, indexkeytype; /* Get the commuted operator if necessary */ if (indexkey_on_left) commuted_op = expr_op; else commuted_op = get_commutator(expr_op); if (commuted_op == InvalidOid) return InvalidOid; /* Done if the (commuted) operator is a member of the index's opclass */ if (op_in_opclass(commuted_op, opclass)) return expr_op; /* * Maybe the index uses a binary-compatible operator set. * * Get the nominal input types of the given operator and the actual type * (before binary-compatible relabeling) of the index key. */ oldoptup = SearchSysCache(OPEROID, ObjectIdGetDatum(expr_op), 0, 0, 0); if (!HeapTupleIsValid(oldoptup)) return InvalidOid; /* probably can't happen */ oldopform = (Form_pg_operator) GETSTRUCT(oldoptup); opname = pstrdup(NameStr(oldopform->oprname)); ltype = oldopform->oprleft; rtype = oldopform->oprright; ReleaseSysCache(oldoptup); if (indexkey_on_left) { Node *leftop = (Node *) get_leftop(clause); if (leftop && IsA(leftop, RelabelType)) leftop = ((RelabelType *) leftop)->arg; indexkeytype = exprType(leftop); } else { Node *rightop = (Node *) get_rightop(clause); if (rightop && IsA(rightop, RelabelType)) rightop = ((RelabelType *) rightop)->arg; indexkeytype = exprType(rightop); } /* * Make sure we have different but binary-compatible types. */ if (ltype == indexkeytype && rtype == indexkeytype) return InvalidOid; /* no chance for a different operator */ if (ltype != indexkeytype && !IS_BINARY_COMPATIBLE(ltype, indexkeytype)) return InvalidOid; if (rtype != indexkeytype && !IS_BINARY_COMPATIBLE(rtype, indexkeytype)) return InvalidOid; /* * OK, look for operator of the same name with the indexkey's data * type. (In theory this might find a non-semantically-comparable * operator, but in practice that seems pretty unlikely for * binary-compatible types.) */ new_op = compatible_oper_opid(opname, indexkeytype, indexkeytype, true); if (OidIsValid(new_op)) { if (new_op != expr_op) { /* * OK, we found a binary-compatible operator of the same name; * now does it match the index? */ if (indexkey_on_left) commuted_op = new_op; else commuted_op = get_commutator(new_op); if (commuted_op == InvalidOid) return InvalidOid; if (op_in_opclass(commuted_op, opclass)) return new_op; } } return InvalidOid; } /**************************************************************************** * ---- 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 converted * to CNF format). --Nels, Jan '93 */ static bool pred_test(List *predicate_list, List *restrictinfo_list, List *joininfo_list) { List *pred; /* * 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 * * XXX as of 7.1, equivalence class info *is* available. Consider * improving this code as foreseen by Nels. */ if (predicate_list == NIL) return true; /* no predicate: the index is usable */ if (restrictinfo_list == NIL) 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. Note we assume that any sub-ANDs have been flattened * when the predicate was fed through canonicalize_qual(). */ if (!pred_test_restrict_list(lfirst(pred), restrictinfo_list)) return false; } return true; } /* * pred_test_restrict_list * Does the "predicate inclusion test" for one conjunct of a predicate * expression. */ static bool pred_test_restrict_list(Expr *predicate, List *restrictinfo_list) { List *item; foreach(item, restrictinfo_list) { RestrictInfo *restrictinfo = (RestrictInfo *) lfirst(item); /* if any clause implies the predicate, return true */ if (pred_test_recurse_clause(predicate, (Node *) restrictinfo->clause)) return true; } return false; } /* * pred_test_recurse_clause * Does the "predicate inclusion test" for a general restriction-clause * expression. Here we recursively deal with the possibility that the * restriction clause is itself an AND or OR structure. */ static bool pred_test_recurse_clause(Expr *predicate, Node *clause) { List *items, *item; Assert(clause != NULL); if (or_clause(clause)) { items = ((Expr *) clause)->args; foreach(item, items) { /* if any OR item doesn't imply the predicate, clause doesn't */ if (!pred_test_recurse_clause(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 (pred_test_recurse_clause(predicate, lfirst(item))) return true; } return false; } else return pred_test_recurse_pred(predicate, clause); } /* * pred_test_recurse_pred * Does the "predicate inclusion test" for one conjunct of a predicate * expression for a simple restriction clause. Here we recursively deal * with the possibility that the predicate conjunct is itself an AND or * OR structure. */ static bool pred_test_recurse_pred(Expr *predicate, Node *clause) { List *items, *item; Assert(predicate != NULL); if (or_clause((Node *) predicate)) { items = predicate->args; foreach(item, items) { /* if any item is implied, the whole predicate is implied */ if (pred_test_recurse_pred(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 (!pred_test_recurse_pred(lfirst(item), clause)) return false; } return true; } else return pred_test_simple_clause(predicate, clause); } /* * 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. */ static const 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} }; /* * pred_test_simple_clause * Does the "predicate inclusion test" for a "simple clause" predicate * and a "simple clause" restriction. * * We have two strategies for determining whether one simple clause * implies another. A simple and general way is to see if they are * equal(); this works for any kind of expression. (Actually, there * is an implied assumption that the functions in the expression are * cachable, ie dependent only on their input arguments --- but this * was checked for the predicate by CheckPredicate().) * * Our other way works only for (binary boolean) operators that are * in some btree operator class. We use the above operator implication * table to be able to derive implications between nonidentical clauses. * * Eventually, rtree operators could also be handled by defining an * appropriate "RT_implic_table" array. */ static bool pred_test_simple_clause(Expr *predicate, Node *clause) { Var *pred_var, *clause_var; Const *pred_const, *clause_const; Oid pred_op, clause_op, test_op; Oid opclass_id = InvalidOid; StrategyNumber pred_strategy = 0, clause_strategy, test_strategy; Oper *test_oper; Expr *test_expr; Datum test_result; bool isNull; Relation relation; HeapScanDesc scan; HeapTuple tuple; ScanKeyData entry[1]; Form_pg_amop aform; ExprContext *econtext; /* First try the equal() test */ if (equal((Node *) predicate, clause)) return true; /* * Can't do anything more unless they are both binary opclauses with a * Var on the left and a Const on the right. */ if (!is_opclause((Node *) predicate)) return false; pred_var = (Var *) get_leftop(predicate); pred_const = (Const *) get_rightop(predicate); if (!is_opclause(clause)) return false; clause_var = (Var *) get_leftop((Expr *) clause); clause_const = (Const *) get_rightop((Expr *) clause); if (!IsA(clause_var, Var) || clause_const == NULL || !IsA(clause_const, Const) || !IsA(pred_var, Var) || pred_const == NULL || !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->varno != pred_var->varno || 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 * * 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 */ ScanKeyEntryInitialize(&entry[0], 0x0, Anum_pg_amop_amopopr, F_OIDEQ, ObjectIdGetDatum(pred_op)); relation = heap_openr(AccessMethodOperatorRelationName, AccessShareLock); scan = heap_beginscan(relation, false, SnapshotNow, 1, entry); while (HeapTupleIsValid(tuple = heap_getnext(scan, 0))) { aform = (Form_pg_amop) GETSTRUCT(tuple); if (opclass_is_btree(aform->amopclaid)) { /* Get the predicate operator's btree strategy number (1 to 5) */ pred_strategy = (StrategyNumber) aform->amopstrategy; Assert(pred_strategy >= 1 && pred_strategy <= 5); /* * Remember which operator class this strategy number came * from */ opclass_id = aform->amopclaid; break; } } heap_endscan(scan); heap_close(relation, AccessShareLock); if (!OidIsValid(opclass_id)) { /* predicate operator isn't btree-indexable */ return false; } /* * 2. From the same opclass, find a strategy num for the clause_op */ tuple = SearchSysCache(AMOPOPID, ObjectIdGetDatum(opclass_id), ObjectIdGetDatum(clause_op), 0, 0); if (!HeapTupleIsValid(tuple)) { /* clause operator isn't btree-indexable, or isn't in this opclass */ return false; } aform = (Form_pg_amop) GETSTRUCT(tuple); /* Get the restriction clause operator's strategy number (1 to 5) */ clause_strategy = (StrategyNumber) aform->amopstrategy; Assert(clause_strategy >= 1 && clause_strategy <= 5); ReleaseSysCache(tuple); /* * 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 */ tuple = SearchSysCache(AMOPSTRATEGY, ObjectIdGetDatum(opclass_id), Int16GetDatum(test_strategy), 0, 0); if (!HeapTupleIsValid(tuple)) { /* this probably shouldn't fail? */ elog(DEBUG, "pred_test_simple_clause: unknown test_op"); return false; } aform = (Form_pg_amop) GETSTRUCT(tuple); /* Get the test operator */ test_op = aform->amopopr; ReleaseSysCache(tuple); /* * 5. Evaluate the test */ test_oper = makeOper(test_op, /* opno */ InvalidOid, /* opid */ BOOLOID); /* opresulttype */ replace_opid(test_oper); test_expr = make_opclause(test_oper, (Var *) clause_const, (Var *) pred_const); econtext = MakeExprContext(NULL, TransactionCommandContext); test_result = ExecEvalExprSwitchContext((Node *) test_expr, econtext, &isNull, NULL); FreeExprContext(econtext); if (isNull) { elog(DEBUG, "pred_test_simple_clause: null test result"); return false; } return DatumGetBool(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' for the inner scan of a nestjoin. * * Each clause group comes from a single joininfo node plus the current * rel's restrictinfo list. Therefore, every clause in the group references * the current rel plus the same set of other rels (except for the restrict * clauses, which only reference the current rel). Therefore, this set * of clauses could be used as an indexqual if the relation is scanned * as the inner side of a nestloop join when the outer side contains * (at least) all those "other rels". * * XXX Actually, given that we are considering a join that requires an * outer rel set (A,B,C), we should use all qual clauses that reference * any subset of these rels, not just the full set or none. This is * doable with a doubly nested loop over joininfo_list; is it worth it? * * Returns two parallel lists of the same length: the clause groups, * and the required outer rel set for each one. * * 'rel' is the relation for which 'index' is defined * 'joininfo_list' is the list of JoinInfo nodes for 'rel' * 'restrictinfo_list' is the list of restriction clauses for 'rel' * '*clausegroups' receives a list of clause sublists * '*outerrelids' receives a list of relid lists */ static void indexable_joinclauses(RelOptInfo *rel, IndexOptInfo *index, List *joininfo_list, List *restrictinfo_list, List **clausegroups, List **outerrelids) { List *cg_list = NIL; List *relid_list = NIL; List *i; foreach(i, joininfo_list) { JoinInfo *joininfo = (JoinInfo *) lfirst(i); List *clausegroup; clausegroup = group_clauses_by_ikey_for_joins(rel, index, index->indexkeys, index->classlist, joininfo->jinfo_restrictinfo, restrictinfo_list); if (clausegroup != NIL) { cg_list = lappend(cg_list, clausegroup); relid_list = lappend(relid_list, joininfo->unjoined_relids); } } *clausegroups = cg_list; *outerrelids = relid_list; } /**************************************************************************** * ---- PATH CREATION UTILITIES ---- ****************************************************************************/ /* * index_innerjoin * Creates index path nodes corresponding to paths to be used as inner * relations in nestloop joins. * * 'rel' is the relation for which 'index' is defined * 'clausegroup_list' is a list of lists of restrictinfo nodes which can use * 'index'. Each sublist refers to the same set of outer rels. * 'outerrelids_list' is a list of the required outer rels for each sublist * of join clauses. * * Returns a list of index pathnodes. */ static List * index_innerjoin(Query *root, RelOptInfo *rel, IndexOptInfo *index, List *clausegroup_list, List *outerrelids_list) { List *path_list = NIL; List *i; foreach(i, clausegroup_list) { List *clausegroup = lfirst(i); IndexPath *pathnode = makeNode(IndexPath); List *indexquals = NIL; bool alljoinquals = true; List *temp; /* XXX this code ought to be merged with create_index_path? */ pathnode->path.pathtype = T_IndexScan; pathnode->path.parent = rel; /* * There's no point in marking the path with any pathkeys, since * it will only ever be used as the inner path of a nestloop, and * so its ordering does not matter. */ pathnode->path.pathkeys = NIL; /* extract bare indexqual clauses, check whether all from JOIN/ON */ foreach(temp, clausegroup) { RestrictInfo *clause = (RestrictInfo *) lfirst(temp); indexquals = lappend(indexquals, clause->clause); if (clause->ispusheddown) alljoinquals = false; } /* expand special operators to indexquals the executor can handle */ indexquals = expand_indexqual_conditions(indexquals); /* * Note that we are making a pathnode for a single-scan indexscan; * therefore, both indexinfo and indexqual should be * single-element lists. */ pathnode->indexinfo = makeList1(index); pathnode->indexqual = makeList1(indexquals); /* We don't actually care what order the index scans in ... */ pathnode->indexscandir = NoMovementScanDirection; /* joinrelids saves the rels needed on the outer side of the join */ pathnode->joinrelids = lfirst(outerrelids_list); pathnode->alljoinquals = alljoinquals; /* * We must compute the estimated number of output rows for the * indexscan. This is less than rel->rows because of the * additional selectivity of the join clauses. Since clausegroup * may contain both restriction and join clauses, we have to do a * set union to get the full set of clauses that must be * considered to compute the correct selectivity. (We can't just * nconc the two lists; then we might have some restriction * clauses appearing twice, which'd mislead * restrictlist_selectivity into double-counting their * selectivity.) */ pathnode->rows = rel->tuples * restrictlist_selectivity(root, set_union(rel->baserestrictinfo, clausegroup), lfirsti(rel->relids)); /* Like costsize.c, force estimate to be at least one row */ if (pathnode->rows < 1.0) pathnode->rows = 1.0; cost_index(&pathnode->path, root, rel, index, indexquals, true); path_list = lappend(path_list, pathnode); outerrelids_list = lnext(outerrelids_list); } return path_list; } /**************************************************************************** * ---- ROUTINES TO CHECK OPERANDS ---- ****************************************************************************/ /* * match_index_to_operand() * Generalized test for a match between an index's key * and the operand on one side of a restriction or join clause. * Now check for functional indices as well. */ static bool match_index_to_operand(int indexkey, Var *operand, RelOptInfo *rel, IndexOptInfo *index) { /* * Ignore any RelabelType node above the indexkey. This is needed to * be able to apply indexscanning in binary-compatible-operator cases. * Note: we can assume there is at most one RelabelType node; * eval_const_expressions() will have simplified if more than one. */ if (operand && IsA(operand, RelabelType)) operand = (Var *) ((RelabelType *) operand)->arg; if (index->indproc == InvalidOid) { /* * Simple index. */ if (operand && IsA(operand, Var) && lfirsti(rel->relids) == operand->varno && indexkey == operand->varattno) return true; else return false; } /* * Functional index. */ return function_index_operand((Expr *) operand, rel, index); } static bool function_index_operand(Expr *funcOpnd, RelOptInfo *rel, IndexOptInfo *index) { int relvarno = 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 || !IsA(funcOpnd, 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. they refer to the right relation. * 2. the args have the right attr. numbers in the right order. * We must ignore RelabelType nodes above the argument Vars in order * to recognize binary-compatible-function cases correctly. *---------- */ i = 0; foreach(arg, funcargs) { Var *var = (Var *) lfirst(arg); if (var && IsA(var, RelabelType)) var = (Var *) ((RelabelType *) var)->arg; if (var == NULL || !IsA(var, Var)) return false; if (indexKeys[i] == 0) return false; if (var->varno != relvarno || var->varattno != indexKeys[i]) return false; i++; } if (indexKeys[i] != 0) return false; /* not enough arguments */ return true; } /**************************************************************************** * ---- ROUTINES FOR "SPECIAL" INDEXABLE OPERATORS ---- ****************************************************************************/ /*---------- * These routines handle special optimization of operators that can be * used with index scans even though they are not known to the executor's * indexscan machinery. The key idea is that these operators allow us * to derive approximate indexscan qual clauses, such that any tuples * that pass the operator clause itself must also satisfy the simpler * indexscan condition(s). Then we can use the indexscan machinery * to avoid scanning as much of the table as we'd otherwise have to, * while applying the original operator as a qpqual condition to ensure * we deliver only the tuples we want. (In essence, we're using a regular * index as if it were a lossy index.) * * An example of what we're doing is * textfield LIKE 'abc%' * from which we can generate the indexscanable conditions * textfield >= 'abc' AND textfield < 'abd' * which allow efficient scanning of an index on textfield. * (In reality, character set and collation issues make the transformation * from LIKE to indexscan limits rather harder than one might think ... * but that's the basic idea.) * * Two routines are provided here, match_special_index_operator() and * expand_indexqual_conditions(). match_special_index_operator() is * just an auxiliary function for match_clause_to_indexkey(); after * the latter fails to recognize a restriction opclause's operator * as a member of an index's opclass, it asks match_special_index_operator() * whether the clause should be considered an indexqual anyway. * expand_indexqual_conditions() converts a list of "raw" indexqual * conditions (with implicit AND semantics across list elements) into * a list that the executor can actually handle. For operators that * are members of the index's opclass this transformation is a no-op, * but operators recognized by match_special_index_operator() must be * converted into one or more "regular" indexqual conditions. *---------- */ /* * match_special_index_operator * Recognize restriction clauses that can be used to generate * additional indexscanable qualifications. * * The given clause is already known to be a binary opclause having * the form (indexkey OP pseudoconst) or (pseudoconst OP indexkey), * but the OP proved not to be one of the index's opclass operators. * Return 'true' if we can do something with it anyway. */ static bool match_special_index_operator(Expr *clause, Oid opclass, bool indexkey_on_left) { bool isIndexable = false; Var *leftop, *rightop; Oid expr_op; Datum constvalue; char *patt; char *prefix; char *rest; /* * Currently, all known special operators require the indexkey on the * left, but this test could be pushed into the switch statement if * some are added that do not... */ if (!indexkey_on_left) return false; /* we know these will succeed */ leftop = get_leftop(clause); rightop = get_rightop(clause); expr_op = ((Oper *) clause->oper)->opno; /* again, required for all current special ops: */ if (!IsA(rightop, Const) || ((Const *) rightop)->constisnull) return false; constvalue = ((Const *) rightop)->constvalue; switch (expr_op) { case OID_TEXT_LIKE_OP: case OID_BPCHAR_LIKE_OP: case OID_VARCHAR_LIKE_OP: case OID_NAME_LIKE_OP: if (locale_is_like_safe()) { /* the right-hand const is type text for all of these */ patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like, &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); } break; case OID_TEXT_ICLIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_VARCHAR_ICLIKE_OP: case OID_NAME_ICLIKE_OP: if (locale_is_like_safe()) { /* the right-hand const is type text for all of these */ patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like_IC, &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); } break; case OID_TEXT_REGEXEQ_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_VARCHAR_REGEXEQ_OP: case OID_NAME_REGEXEQ_OP: if (locale_is_like_safe()) { /* the right-hand const is type text for all of these */ patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex, &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); } break; case OID_TEXT_ICREGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: case OID_VARCHAR_ICREGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: if (locale_is_like_safe()) { /* the right-hand const is type text for all of these */ patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); } break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: case OID_CIDR_SUB_OP: case OID_CIDR_SUBEQ_OP: isIndexable = true; break; } /* done if the expression doesn't look indexable */ if (!isIndexable) return false; /* * Must also check that index's opclass supports the operators we will * want to apply. (A hash index, for example, will not support ">=".) * We cheat a little by not checking for availability of "=" ... any * index type should support "=", methinks. */ switch (expr_op) { case OID_TEXT_LIKE_OP: case OID_TEXT_ICLIKE_OP: case OID_TEXT_REGEXEQ_OP: case OID_TEXT_ICREGEXEQ_OP: if (!op_in_opclass(find_operator(">=", TEXTOID), opclass) || !op_in_opclass(find_operator("<", TEXTOID), opclass)) isIndexable = false; break; case OID_BPCHAR_LIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: if (!op_in_opclass(find_operator(">=", BPCHAROID), opclass) || !op_in_opclass(find_operator("<", BPCHAROID), opclass)) isIndexable = false; break; case OID_VARCHAR_LIKE_OP: case OID_VARCHAR_ICLIKE_OP: case OID_VARCHAR_REGEXEQ_OP: case OID_VARCHAR_ICREGEXEQ_OP: if (!op_in_opclass(find_operator(">=", VARCHAROID), opclass) || !op_in_opclass(find_operator("<", VARCHAROID), opclass)) isIndexable = false; break; case OID_NAME_LIKE_OP: case OID_NAME_ICLIKE_OP: case OID_NAME_REGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: if (!op_in_opclass(find_operator(">=", NAMEOID), opclass) || !op_in_opclass(find_operator("<", NAMEOID), opclass)) isIndexable = false; break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: /* for SUB we actually need ">" not ">=", but this should do */ if (!op_in_opclass(find_operator(">=", INETOID), opclass) || !op_in_opclass(find_operator("<=", INETOID), opclass)) isIndexable = false; break; case OID_CIDR_SUB_OP: case OID_CIDR_SUBEQ_OP: /* for SUB we actually need ">" not ">=", but this should do */ if (!op_in_opclass(find_operator(">=", CIDROID), opclass) || !op_in_opclass(find_operator("<=", CIDROID), opclass)) isIndexable = false; break; } return isIndexable; } /* * expand_indexqual_conditions * Given a list of (implicitly ANDed) indexqual clauses, * expand any "special" index operators into clauses that the indexscan * machinery will know what to do with. Clauses that were not * recognized by match_special_index_operator() must be passed through * unchanged. */ List * expand_indexqual_conditions(List *indexquals) { List *resultquals = NIL; List *q; foreach(q, indexquals) { Expr *clause = (Expr *) lfirst(q); /* we know these will succeed */ Var *leftop = get_leftop(clause); Var *rightop = get_rightop(clause); Oid expr_op = ((Oper *) clause->oper)->opno; Datum constvalue; char *patt; char *prefix; char *rest; Pattern_Prefix_Status pstatus; switch (expr_op) { /* * LIKE and regex operators are not members of any index * opclass, so if we find one in an indexqual list we can * assume that it was accepted by * match_special_index_operator(). */ case OID_TEXT_LIKE_OP: case OID_BPCHAR_LIKE_OP: case OID_VARCHAR_LIKE_OP: case OID_NAME_LIKE_OP: /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); pstatus = pattern_fixed_prefix(patt, Pattern_Type_Like, &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); if (prefix) pfree(prefix); pfree(patt); break; case OID_TEXT_ICLIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_VARCHAR_ICLIKE_OP: case OID_NAME_ICLIKE_OP: /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); pstatus = pattern_fixed_prefix(patt, Pattern_Type_Like_IC, &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); if (prefix) pfree(prefix); pfree(patt); break; case OID_TEXT_REGEXEQ_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_VARCHAR_REGEXEQ_OP: case OID_NAME_REGEXEQ_OP: /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex, &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); if (prefix) pfree(prefix); pfree(patt); break; case OID_TEXT_ICREGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: case OID_VARCHAR_ICREGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = DatumGetCString(DirectFunctionCall1(textout, constvalue)); pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); if (prefix) pfree(prefix); pfree(patt); break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: case OID_CIDR_SUB_OP: case OID_CIDR_SUBEQ_OP: constvalue = ((Const *) rightop)->constvalue; resultquals = nconc(resultquals, network_prefix_quals(leftop, expr_op, constvalue)); break; default: resultquals = lappend(resultquals, clause); break; } } return resultquals; } /* * Given a fixed prefix that all the "leftop" values must have, * generate suitable indexqual condition(s). expr_op is the original * LIKE or regex operator; we use it to deduce the appropriate comparison * operators. */ static List * prefix_quals(Var *leftop, Oid expr_op, char *prefix, Pattern_Prefix_Status pstatus) { List *result; Oid datatype; Oid oproid; Const *con; Oper *op; Expr *expr; char *greaterstr; Assert(pstatus != Pattern_Prefix_None); switch (expr_op) { case OID_TEXT_LIKE_OP: case OID_TEXT_ICLIKE_OP: case OID_TEXT_REGEXEQ_OP: case OID_TEXT_ICREGEXEQ_OP: datatype = TEXTOID; break; case OID_BPCHAR_LIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: datatype = BPCHAROID; break; case OID_VARCHAR_LIKE_OP: case OID_VARCHAR_ICLIKE_OP: case OID_VARCHAR_REGEXEQ_OP: case OID_VARCHAR_ICREGEXEQ_OP: datatype = VARCHAROID; break; case OID_NAME_LIKE_OP: case OID_NAME_ICLIKE_OP: case OID_NAME_REGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: datatype = NAMEOID; break; default: elog(ERROR, "prefix_quals: unexpected operator %u", expr_op); return NIL; } /* * If we found an exact-match pattern, generate an "=" indexqual. */ if (pstatus == Pattern_Prefix_Exact) { oproid = find_operator("=", datatype); if (oproid == InvalidOid) elog(ERROR, "prefix_quals: no = operator for type %u", datatype); con = string_to_const(prefix, datatype); op = makeOper(oproid, InvalidOid, BOOLOID); expr = make_opclause(op, leftop, (Var *) con); result = makeList1(expr); return result; } /* * Otherwise, we have a nonempty required prefix of the values. * * We can always say "x >= prefix". */ oproid = find_operator(">=", datatype); if (oproid == InvalidOid) elog(ERROR, "prefix_quals: no >= operator for type %u", datatype); con = string_to_const(prefix, datatype); op = makeOper(oproid, InvalidOid, BOOLOID); expr = make_opclause(op, leftop, (Var *) con); result = makeList1(expr); /*------- * If we can create a string larger than the prefix, we can say * "x < greaterstr". *------- */ greaterstr = make_greater_string(prefix, datatype); if (greaterstr) { oproid = find_operator("<", datatype); if (oproid == InvalidOid) elog(ERROR, "prefix_quals: no < operator for type %u", datatype); con = string_to_const(greaterstr, datatype); op = makeOper(oproid, InvalidOid, BOOLOID); expr = make_opclause(op, leftop, (Var *) con); result = lappend(result, expr); pfree(greaterstr); } return result; } /* * Given a leftop and a rightop, and a inet-class sup/sub operator, * generate suitable indexqual condition(s). expr_op is the original * operator. */ static List * network_prefix_quals(Var *leftop, Oid expr_op, Datum rightop) { bool is_eq; char *opr1name; Datum opr1right; Datum opr2right; Oid opr1oid; Oid opr2oid; List *result; Oid datatype; Oper *op; Expr *expr; switch (expr_op) { case OID_INET_SUB_OP: datatype = INETOID; is_eq = false; break; case OID_INET_SUBEQ_OP: datatype = INETOID; is_eq = true; break; case OID_CIDR_SUB_OP: datatype = CIDROID; is_eq = false; break; case OID_CIDR_SUBEQ_OP: datatype = CIDROID; is_eq = true; break; default: elog(ERROR, "network_prefix_quals: unexpected operator %u", expr_op); return NIL; } /* * create clause "key >= network_scan_first( rightop )", or ">" if the * operator disallows equality. */ opr1name = is_eq ? ">=" : ">"; opr1oid = find_operator(opr1name, datatype); if (opr1oid == InvalidOid) elog(ERROR, "network_prefix_quals: no %s operator for type %u", opr1name, datatype); opr1right = network_scan_first(rightop); op = makeOper(opr1oid, InvalidOid, BOOLOID); expr = make_opclause(op, leftop, (Var *) makeConst(datatype, -1, opr1right, false, false, false, false)); result = makeList1(expr); /* create clause "key <= network_scan_last( rightop )" */ opr2oid = find_operator("<=", datatype); if (opr2oid == InvalidOid) elog(ERROR, "network_prefix_quals: no <= operator for type %u", datatype); opr2right = network_scan_last(rightop); op = makeOper(opr2oid, InvalidOid, BOOLOID); expr = make_opclause(op, leftop, (Var *) makeConst(datatype, -1, opr2right, false, false, false, false)); result = lappend(result, expr); return result; } /* * Handy subroutines for match_special_index_operator() and friends. */ /* See if there is a binary op of the given name for the given datatype */ static Oid find_operator(const char *opname, Oid datatype) { return GetSysCacheOid(OPERNAME, PointerGetDatum(opname), ObjectIdGetDatum(datatype), ObjectIdGetDatum(datatype), CharGetDatum('b')); } /* * Generate a Datum of the appropriate type from a C string. * Note that all of the supported types are pass-by-ref, so the * returned value should be pfree'd if no longer needed. */ static Datum string_to_datum(const char *str, Oid datatype) { /* * We cheat a little by assuming that textin() will do for bpchar and * varchar constants too... */ if (datatype == NAMEOID) return DirectFunctionCall1(namein, CStringGetDatum(str)); else return DirectFunctionCall1(textin, CStringGetDatum(str)); } /* * Generate a Const node of the appropriate type from a C string. */ static Const * string_to_const(const char *str, Oid datatype) { Datum conval = string_to_datum(str, datatype); return makeConst(datatype, ((datatype == NAMEOID) ? NAMEDATALEN : -1), conval, false, false, false, false); }