/*------------------------------------------------------------------------- * * indxpath.c * Routines to determine which indexes are usable for scanning a * given relation, and create Paths accordingly. * * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.219 2007/04/06 22:33:42 tgl Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include "access/skey.h" #include "catalog/pg_am.h" #include "catalog/pg_operator.h" #include "catalog/pg_opfamily.h" #include "catalog/pg_type.h" #include "nodes/makefuncs.h" #include "optimizer/clauses.h" #include "optimizer/cost.h" #include "optimizer/pathnode.h" #include "optimizer/paths.h" #include "optimizer/predtest.h" #include "optimizer/restrictinfo.h" #include "optimizer/var.h" #include "utils/builtins.h" #include "utils/lsyscache.h" #include "utils/pg_locale.h" #include "utils/selfuncs.h" /* * DoneMatchingIndexKeys() - MACRO */ #define DoneMatchingIndexKeys(families) (families[0] == InvalidOid) #define IsBooleanOpfamily(opfamily) \ ((opfamily) == BOOL_BTREE_FAM_OID || (opfamily) == BOOL_HASH_FAM_OID) static List *find_usable_indexes(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *outer_clauses, bool istoplevel, RelOptInfo *outer_rel, SaOpControl saop_control); static List *find_saop_paths(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *outer_clauses, bool istoplevel, RelOptInfo *outer_rel); static Path *choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths, RelOptInfo *outer_rel); static int bitmap_path_comparator(const void *a, const void *b); static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths, RelOptInfo *outer_rel); static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds); static bool lists_intersect(List *list1, List *list2); static bool match_clause_to_indexcol(IndexOptInfo *index, int indexcol, Oid opfamily, RestrictInfo *rinfo, Relids outer_relids, SaOpControl saop_control); static bool is_indexable_operator(Oid expr_op, Oid opfamily, bool indexkey_on_left); static bool match_rowcompare_to_indexcol(IndexOptInfo *index, int indexcol, Oid opfamily, RowCompareExpr *clause, Relids outer_relids); static Relids indexable_outerrelids(PlannerInfo *root, RelOptInfo *rel); static bool matches_any_index(RestrictInfo *rinfo, RelOptInfo *rel, Relids outer_relids); static List *find_clauses_for_join(PlannerInfo *root, RelOptInfo *rel, Relids outer_relids, bool isouterjoin); static bool match_boolean_index_clause(Node *clause, int indexcol, IndexOptInfo *index); static bool match_special_index_operator(Expr *clause, Oid opfamily, bool indexkey_on_left); static Expr *expand_boolean_index_clause(Node *clause, int indexcol, IndexOptInfo *index); static List *expand_indexqual_opclause(RestrictInfo *rinfo, Oid opfamily); static RestrictInfo *expand_indexqual_rowcompare(RestrictInfo *rinfo, IndexOptInfo *index, int indexcol); static List *prefix_quals(Node *leftop, Oid opfamily, Const *prefix, Pattern_Prefix_Status pstatus); static List *network_prefix_quals(Node *leftop, Oid expr_op, Oid opfamily, Datum rightop); 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). * * 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, or have a predicate that * matches the query's qual 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 plain index * scan this routine deems potentially interesting for the current query. * * We also determine the set of other relids that participate in join * clauses that could be used with each index. The actually best innerjoin * path will be generated for each outer relation later on, but knowing the * set of potential otherrels allows us to identify equivalent outer relations * and avoid repeated computation. * * 'rel' is the relation for which we want to generate index paths * * Note: check_partial_indexes() must have been run previously for this rel. */ void create_index_paths(PlannerInfo *root, RelOptInfo *rel) { List *indexpaths; List *bitindexpaths; ListCell *l; /* Skip the whole mess if no indexes */ if (rel->indexlist == NIL) { rel->index_outer_relids = NULL; return; } /* * Examine join clauses to see which ones are potentially usable with * indexes of this rel, and generate the set of all other relids that * participate in such join clauses. We'll use this set later to * recognize outer rels that are equivalent for joining purposes. */ rel->index_outer_relids = indexable_outerrelids(root, rel); /* * Find all the index paths that are directly usable for this relation * (ie, are valid without considering OR or JOIN clauses). */ indexpaths = find_usable_indexes(root, rel, rel->baserestrictinfo, NIL, true, NULL, SAOP_FORBID); /* * We can submit them all to add_path. (This generates access paths for * plain IndexScan plans.) However, for the next step we will only want * the ones that have some selectivity; we must discard anything that was * generated solely for ordering purposes. */ bitindexpaths = NIL; foreach(l, indexpaths) { IndexPath *ipath = (IndexPath *) lfirst(l); add_path(rel, (Path *) ipath); if (ipath->indexselectivity < 1.0 && !ScanDirectionIsBackward(ipath->indexscandir)) bitindexpaths = lappend(bitindexpaths, ipath); } /* * Generate BitmapOrPaths for any suitable OR-clauses present in the * restriction list. Add these to bitindexpaths. */ indexpaths = generate_bitmap_or_paths(root, rel, rel->baserestrictinfo, NIL, NULL); bitindexpaths = list_concat(bitindexpaths, indexpaths); /* * Likewise, generate paths using ScalarArrayOpExpr clauses; these can't * be simple indexscans but they can be used in bitmap scans. */ indexpaths = find_saop_paths(root, rel, rel->baserestrictinfo, NIL, true, NULL); bitindexpaths = list_concat(bitindexpaths, indexpaths); /* * If we found anything usable, generate a BitmapHeapPath for the most * promising combination of bitmap index paths. */ if (bitindexpaths != NIL) { Path *bitmapqual; BitmapHeapPath *bpath; bitmapqual = choose_bitmap_and(root, rel, bitindexpaths, NULL); bpath = create_bitmap_heap_path(root, rel, bitmapqual, NULL); add_path(rel, (Path *) bpath); } } /*---------- * find_usable_indexes * Given a list of restriction clauses, find all the potentially usable * indexes for the given relation, and return a list of IndexPaths. * * The caller actually supplies two lists of restriction clauses: some * "current" ones and some "outer" ones. Both lists can be used freely * to match keys of the index, but an index must use at least one of the * "current" clauses to be considered usable. The motivation for this is * examples like * WHERE (x = 42) AND (... OR (y = 52 AND z = 77) OR ....) * While we are considering the y/z subclause of the OR, we can use "x = 42" * as one of the available index conditions; but we shouldn't match the * subclause to any index on x alone, because such a Path would already have * been generated at the upper level. So we could use an index on x,y,z * or an index on x,y for the OR subclause, but not an index on just x. * When dealing with a partial index, a match of the index predicate to * one of the "current" clauses also makes the index usable. * * If istoplevel is true (indicating we are considering the top level of a * rel's restriction clauses), we will include indexes in the result that * have an interesting sort order, even if they have no matching restriction * clauses. * * 'rel' is the relation for which we want to generate index paths * 'clauses' is the current list of clauses (RestrictInfo nodes) * 'outer_clauses' is the list of additional upper-level clauses * 'istoplevel' is true if clauses are the rel's top-level restriction list * (outer_clauses must be NIL when this is true) * 'outer_rel' is the outer side of the join if forming an inner indexscan * (so some of the given clauses are join clauses); NULL if not * 'saop_control' indicates whether ScalarArrayOpExpr clauses can be used * * Note: check_partial_indexes() must have been run previously. *---------- */ static List * find_usable_indexes(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *outer_clauses, bool istoplevel, RelOptInfo *outer_rel, SaOpControl saop_control) { Relids outer_relids = outer_rel ? outer_rel->relids : NULL; List *result = NIL; List *all_clauses = NIL; /* not computed till needed */ ListCell *ilist; foreach(ilist, rel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(ilist); IndexPath *ipath; List *restrictclauses; List *index_pathkeys; List *useful_pathkeys; bool useful_predicate; bool found_clause; bool index_is_ordered; /* * Ignore partial indexes that do not match the query. If a partial * index is marked predOK then we know it's OK; otherwise, if we are * at top level we know it's not OK (since predOK is exactly whether * its predicate could be proven from the toplevel clauses). * Otherwise, we have to test whether the added clauses are sufficient * to imply the predicate. If so, we could use the index in the * current context. * * We set useful_predicate to true iff the predicate was proven using * the current set of clauses. This is needed to prevent matching a * predOK index to an arm of an OR, which would be a legal but * pointlessly inefficient plan. (A better plan will be generated by * just scanning the predOK index alone, no OR.) */ useful_predicate = false; if (index->indpred != NIL) { if (index->predOK) { if (istoplevel) { /* we know predicate was proven from these clauses */ useful_predicate = true; } } else { if (istoplevel) continue; /* no point in trying to prove it */ /* Form all_clauses if not done already */ if (all_clauses == NIL) all_clauses = list_concat(list_copy(clauses), outer_clauses); if (!predicate_implied_by(index->indpred, all_clauses)) continue; /* can't use it at all */ if (!predicate_implied_by(index->indpred, outer_clauses)) useful_predicate = true; } } /* * 1. Match the index against the available restriction clauses. * found_clause is set true only if at least one of the current * clauses was used (and, if saop_control is SAOP_REQUIRE, it has to * have been a ScalarArrayOpExpr clause). */ restrictclauses = group_clauses_by_indexkey(index, clauses, outer_clauses, outer_relids, saop_control, &found_clause); /* * Not all index AMs support scans with no restriction clauses. We * can't generate a scan over an index with amoptionalkey = false * unless there's at least one restriction clause. */ if (restrictclauses == NIL && !index->amoptionalkey) continue; /* * 2. Compute pathkeys describing index's ordering, if any, then see * how many of them are actually useful for this query. This is not * relevant unless we are at top level. */ index_is_ordered = OidIsValid(index->fwdsortop[0]); if (index_is_ordered && istoplevel && outer_rel == NULL) { index_pathkeys = build_index_pathkeys(root, index, ForwardScanDirection); useful_pathkeys = truncate_useless_pathkeys(root, rel, index_pathkeys); } else useful_pathkeys = NIL; /* * 3. Generate an indexscan path if there are relevant restriction * clauses in the current clauses, OR the index ordering is * potentially useful for later merging or final output ordering, OR * the index has a predicate that was proven by the current clauses. */ if (found_clause || useful_pathkeys != NIL || useful_predicate) { ipath = create_index_path(root, index, restrictclauses, useful_pathkeys, index_is_ordered ? ForwardScanDirection : NoMovementScanDirection, outer_rel); result = lappend(result, ipath); } /* * 4. If the index is ordered, a backwards scan might be * interesting. Again, this is only interesting at top level. */ if (index_is_ordered && istoplevel && outer_rel == NULL) { index_pathkeys = build_index_pathkeys(root, index, BackwardScanDirection); useful_pathkeys = truncate_useless_pathkeys(root, rel, index_pathkeys); if (useful_pathkeys != NIL) { ipath = create_index_path(root, index, restrictclauses, useful_pathkeys, BackwardScanDirection, outer_rel); result = lappend(result, ipath); } } } return result; } /* * find_saop_paths * Find all the potential indexpaths that make use of ScalarArrayOpExpr * clauses. The executor only supports these in bitmap scans, not * plain indexscans, so we need to segregate them from the normal case. * Otherwise, same API as find_usable_indexes(). * Returns a list of IndexPaths. */ static List * find_saop_paths(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *outer_clauses, bool istoplevel, RelOptInfo *outer_rel) { bool have_saop = false; ListCell *l; /* * Since find_usable_indexes is relatively expensive, don't bother to run * it unless there are some top-level ScalarArrayOpExpr clauses. */ foreach(l, clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); Assert(IsA(rinfo, RestrictInfo)); if (IsA(rinfo->clause, ScalarArrayOpExpr)) { have_saop = true; break; } } if (!have_saop) return NIL; return find_usable_indexes(root, rel, clauses, outer_clauses, istoplevel, outer_rel, SAOP_REQUIRE); } /* * generate_bitmap_or_paths * Look through the list of clauses to find OR clauses, and generate * a BitmapOrPath for each one we can handle that way. Return a list * of the generated BitmapOrPaths. * * outer_clauses is a list of additional clauses that can be assumed true * for the purpose of generating indexquals, but are not to be searched for * ORs. (See find_usable_indexes() for motivation.) outer_rel is the outer * side when we are considering a nestloop inner indexpath. */ List * generate_bitmap_or_paths(PlannerInfo *root, RelOptInfo *rel, List *clauses, List *outer_clauses, RelOptInfo *outer_rel) { List *result = NIL; List *all_clauses; ListCell *l; /* * We can use both the current and outer clauses as context for * find_usable_indexes */ all_clauses = list_concat(list_copy(clauses), outer_clauses); foreach(l, clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); List *pathlist; Path *bitmapqual; ListCell *j; Assert(IsA(rinfo, RestrictInfo)); /* Ignore RestrictInfos that aren't ORs */ if (!restriction_is_or_clause(rinfo)) continue; /* * We must be able to match at least one index to each of the arms of * the OR, else we can't use it. */ pathlist = NIL; foreach(j, ((BoolExpr *) rinfo->orclause)->args) { Node *orarg = (Node *) lfirst(j); List *indlist; /* OR arguments should be ANDs or sub-RestrictInfos */ if (and_clause(orarg)) { List *andargs = ((BoolExpr *) orarg)->args; indlist = find_usable_indexes(root, rel, andargs, all_clauses, false, outer_rel, SAOP_ALLOW); /* Recurse in case there are sub-ORs */ indlist = list_concat(indlist, generate_bitmap_or_paths(root, rel, andargs, all_clauses, outer_rel)); } else { Assert(IsA(orarg, RestrictInfo)); Assert(!restriction_is_or_clause((RestrictInfo *) orarg)); indlist = find_usable_indexes(root, rel, list_make1(orarg), all_clauses, false, outer_rel, SAOP_ALLOW); } /* * If nothing matched this arm, we can't do anything with this OR * clause. */ if (indlist == NIL) { pathlist = NIL; break; } /* * OK, pick the most promising AND combination, and add it to * pathlist. */ bitmapqual = choose_bitmap_and(root, rel, indlist, outer_rel); pathlist = lappend(pathlist, bitmapqual); } /* * If we have a match for every arm, then turn them into a * BitmapOrPath, and add to result list. */ if (pathlist != NIL) { bitmapqual = (Path *) create_bitmap_or_path(root, rel, pathlist); result = lappend(result, bitmapqual); } } return result; } /* * choose_bitmap_and * Given a nonempty list of bitmap paths, AND them into one path. * * This is a nontrivial decision since we can legally use any subset of the * given path set. We want to choose a good tradeoff between selectivity * and cost of computing the bitmap. * * The result is either a single one of the inputs, or a BitmapAndPath * combining multiple inputs. */ static Path * choose_bitmap_and(PlannerInfo *root, RelOptInfo *rel, List *paths, RelOptInfo *outer_rel) { int npaths = list_length(paths); Path **patharray; Cost costsofar; List *qualsofar; List *firstpred; ListCell *lastcell; int i; ListCell *l; Assert(npaths > 0); /* else caller error */ if (npaths == 1) return (Path *) linitial(paths); /* easy case */ /* * In theory we should consider every nonempty subset of the given paths. * In practice that seems like overkill, given the crude nature of the * estimates, not to mention the possible effects of higher-level AND and * OR clauses. As a compromise, we sort the paths by selectivity. We * always take the first, and sequentially add on paths that result in a * lower estimated cost. * * We also make some effort to detect directly redundant input paths, as * can happen if there are multiple possibly usable indexes. (Another way * it can happen is that best_inner_indexscan will find the same OR join * clauses that create_or_index_quals has pulled OR restriction clauses * out of, and then both versions show up as duplicate paths.) We * consider an index redundant if any of its index conditions were already * used by earlier indexes. (We could use predicate_implied_by to have a * more intelligent, but much more expensive, check --- but in most cases * simple equality should suffice.) * * You might think the condition for redundancy should be "all index * conditions already used", not "any", but this turns out to be wrong. * For example, if we use an index on A, and then come to an index with * conditions on A and B, the only way that the second index can be later * in the selectivity-order sort is if the condition on B is completely * non-selective. In any case, we'd surely be drastically misestimating * the selectivity if we count the same condition twice. * * We must also consider index predicate conditions in checking for * redundancy, because the estimated selectivity of a partial index * includes its predicate even if the explicit index conditions don't. * Here we have to work harder than just checking expression equality: * we check to see if any of the predicate clauses are implied by * index conditions or predicate clauses of previous paths. This covers * cases such as a condition "x = 42" used with a plain index, followed * by a clauseless scan of a partial index "WHERE x >= 40 AND x < 50". * Also, we reject indexes that have a qual condition matching any * previously-used index's predicate (by including predicate conditions * into qualsofar). It should be sufficient to check equality in this * case, not implication, since we've sorted the paths by selectivity * and so tighter conditions are seen first --- only for exactly equal * cases might the partial index come first. * * XXX the reason we need all these redundancy checks is that costsize.c * and clausesel.c aren't very smart about redundant clauses: they will * usually double-count the redundant clauses, producing a too-small * selectivity that makes a redundant AND look like it reduces the total * cost. Perhaps someday that code will be smarter and we can remove * these heuristics. * * Note: outputting the selected sub-paths in selectivity order is a good * thing even if we weren't using that as part of the selection method, * because it makes the short-circuit case in MultiExecBitmapAnd() more * likely to apply. */ /* Convert list to array so we can apply qsort */ patharray = (Path **) palloc(npaths * sizeof(Path *)); i = 0; foreach(l, paths) { patharray[i++] = (Path *) lfirst(l); } qsort(patharray, npaths, sizeof(Path *), bitmap_path_comparator); paths = list_make1(patharray[0]); costsofar = bitmap_and_cost_est(root, rel, paths, outer_rel); find_indexpath_quals(patharray[0], &qualsofar, &firstpred); qualsofar = list_concat(qualsofar, firstpred); lastcell = list_head(paths); /* for quick deletions */ for (i = 1; i < npaths; i++) { Path *newpath = patharray[i]; List *newqual; List *newpred; Cost newcost; find_indexpath_quals(newpath, &newqual, &newpred); if (lists_intersect(newqual, qualsofar)) continue; /* consider it redundant */ if (newpred) { bool redundant = false; /* we check each predicate clause separately */ foreach(l, newpred) { Node *np = (Node *) lfirst(l); if (predicate_implied_by(list_make1(np), qualsofar)) { redundant = true; break; /* out of inner loop */ } } if (redundant) continue; } /* tentatively add newpath to paths, so we can estimate cost */ paths = lappend(paths, newpath); newcost = bitmap_and_cost_est(root, rel, paths, outer_rel); if (newcost < costsofar) { /* keep newpath in paths, update subsidiary variables */ costsofar = newcost; qualsofar = list_concat(list_concat(qualsofar, newqual), newpred); lastcell = lnext(lastcell); } else { /* reject newpath, remove it from paths list */ paths = list_delete_cell(paths, lnext(lastcell), lastcell); } Assert(lnext(lastcell) == NULL); } if (list_length(paths) == 1) return (Path *) linitial(paths); /* no need for AND */ return (Path *) create_bitmap_and_path(root, rel, paths); } /* qsort comparator to sort in increasing selectivity order */ static int bitmap_path_comparator(const void *a, const void *b) { Path *pa = *(Path *const *) a; Path *pb = *(Path *const *) b; Cost acost; Cost bcost; Selectivity aselec; Selectivity bselec; cost_bitmap_tree_node(pa, &acost, &aselec); cost_bitmap_tree_node(pb, &bcost, &bselec); /* * If selectivities are the same, sort by cost. (Note: there used to be * logic here to do "fuzzy comparison", but that's a bad idea because it * fails to be transitive, which will confuse qsort terribly.) */ if (aselec < bselec) return -1; if (aselec > bselec) return 1; if (acost < bcost) return -1; if (acost > bcost) return 1; return 0; } /* * Estimate the cost of actually executing a BitmapAnd with the given * inputs. */ static Cost bitmap_and_cost_est(PlannerInfo *root, RelOptInfo *rel, List *paths, RelOptInfo *outer_rel) { BitmapAndPath apath; Path bpath; /* Set up a dummy BitmapAndPath */ apath.path.type = T_BitmapAndPath; apath.path.parent = rel; apath.bitmapquals = paths; cost_bitmap_and_node(&apath, root); /* Now we can do cost_bitmap_heap_scan */ cost_bitmap_heap_scan(&bpath, root, rel, (Path *) &apath, outer_rel); return bpath.total_cost; } /* * find_indexpath_quals * * Given the Path structure for a plain or bitmap indexscan, extract lists * of all the indexquals and index predicate conditions used in the Path. * * This is sort of a simplified version of make_restrictinfo_from_bitmapqual; * here, we are not trying to produce an accurate representation of the AND/OR * semantics of the Path, but just find out all the base conditions used. * * The result lists contain pointers to the expressions used in the Path, * but all the list cells are freshly built, so it's safe to destructively * modify the lists (eg, by concat'ing with other lists). */ static void find_indexpath_quals(Path *bitmapqual, List **quals, List **preds) { ListCell *l; *quals = NIL; *preds = NIL; if (IsA(bitmapqual, BitmapAndPath)) { BitmapAndPath *apath = (BitmapAndPath *) bitmapqual; foreach(l, apath->bitmapquals) { List *subquals; List *subpreds; find_indexpath_quals((Path *) lfirst(l), &subquals, &subpreds); *quals = list_concat(*quals, subquals); *preds = list_concat(*preds, subpreds); } } else if (IsA(bitmapqual, BitmapOrPath)) { BitmapOrPath *opath = (BitmapOrPath *) bitmapqual; foreach(l, opath->bitmapquals) { List *subquals; List *subpreds; find_indexpath_quals((Path *) lfirst(l), &subquals, &subpreds); *quals = list_concat(*quals, subquals); *preds = list_concat(*preds, subpreds); } } else if (IsA(bitmapqual, IndexPath)) { IndexPath *ipath = (IndexPath *) bitmapqual; *quals = get_actual_clauses(ipath->indexclauses); *preds = list_copy(ipath->indexinfo->indpred); } else elog(ERROR, "unrecognized node type: %d", nodeTag(bitmapqual)); } /* * lists_intersect * Detect whether two lists have a nonempty intersection, * using equal() to compare members. * * This possibly should go into list.c, but it doesn't yet have any use * except in choose_bitmap_and. */ static bool lists_intersect(List *list1, List *list2) { ListCell *cell1; foreach(cell1, list1) { void *datum1 = lfirst(cell1); ListCell *cell2; foreach(cell2, list2) { if (equal(lfirst(cell2), datum1)) return true; } } return false; } /**************************************************************************** * ---- ROUTINES TO CHECK RESTRICTIONS ---- ****************************************************************************/ /* * group_clauses_by_indexkey * Find restriction clauses that can be used with an index. * * Returns a list of sublists of RestrictInfo nodes for clauses that can be * used with this index. Each sublist contains clauses that can be used * with one index key (in no particular order); the top list is ordered by * index key. (This is depended on by expand_indexqual_conditions().) * * We can use clauses from either the current clauses or outer_clauses lists, * but *found_clause is set TRUE only if we used at least one clause from * the "current clauses" list. See find_usable_indexes() for motivation. * * outer_relids determines what Vars will be allowed on the other side * of a possible index qual; see match_clause_to_indexcol(). * * 'saop_control' indicates whether ScalarArrayOpExpr clauses can be used. * When it's SAOP_REQUIRE, *found_clause is set TRUE only if we used at least * one ScalarArrayOpExpr from the current clauses list. * * If the index has amoptionalkey = false, we give up and return NIL when * there are no restriction clauses matching the first index key. Otherwise, * we return NIL if there are no restriction clauses matching any index key. * A non-NIL result will have one (possibly empty) sublist for each index key. * * Example: given an index on (A,B,C), we would return ((C1 C2) () (C3 C4)) * if we find that clauses C1 and C2 use column A, clauses C3 and C4 use * column C, and no clauses use column B. * * Note: in some circumstances we may find the same RestrictInfos coming * from multiple places. Defend against redundant outputs by using * list_append_unique_ptr (pointer equality should be good enough). */ List * group_clauses_by_indexkey(IndexOptInfo *index, List *clauses, List *outer_clauses, Relids outer_relids, SaOpControl saop_control, bool *found_clause) { List *clausegroup_list = NIL; bool found_outer_clause = false; int indexcol = 0; Oid *families = index->opfamily; *found_clause = false; /* default result */ if (clauses == NIL && outer_clauses == NIL) return NIL; /* cannot succeed */ do { Oid curFamily = families[0]; List *clausegroup = NIL; ListCell *l; /* check the current clauses */ foreach(l, clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); Assert(IsA(rinfo, RestrictInfo)); if (match_clause_to_indexcol(index, indexcol, curFamily, rinfo, outer_relids, saop_control)) { clausegroup = list_append_unique_ptr(clausegroup, rinfo); if (saop_control != SAOP_REQUIRE || IsA(rinfo->clause, ScalarArrayOpExpr)) *found_clause = true; } } /* check the outer clauses */ foreach(l, outer_clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); Assert(IsA(rinfo, RestrictInfo)); if (match_clause_to_indexcol(index, indexcol, curFamily, rinfo, outer_relids, saop_control)) { clausegroup = list_append_unique_ptr(clausegroup, rinfo); found_outer_clause = true; } } /* * If no clauses match this key, check for amoptionalkey restriction. */ if (clausegroup == NIL && !index->amoptionalkey && indexcol == 0) return NIL; clausegroup_list = lappend(clausegroup_list, clausegroup); indexcol++; families++; } while (!DoneMatchingIndexKeys(families)); if (!*found_clause && !found_outer_clause) return NIL; /* no indexable clauses anywhere */ return clausegroup_list; } /* * match_clause_to_indexcol() * Determines whether a restriction clause matches a column of an index. * * To match a normal index, the clause: * * (1) must be in the form (indexkey op const) or (const op indexkey); * and * (2) must contain an operator which is in the same family as the index * operator for this column, or is a "special" operator as recognized * by match_special_index_operator(). * * Our definition of "const" is pretty liberal: we allow Vars belonging * to the caller-specified outer_relids relations (which had better not * include the relation whose index is being tested). outer_relids should * be NULL when checking simple restriction clauses, and the outer side * of the join when building a join inner scan. Other than that, the * only thing we don't like is volatile functions. * * Note: in most cases we already know that the clause as a whole uses * vars from the interesting set of relations. The reason for the * outer_relids test is to reject clauses like (a.f1 OP (b.f2 OP a.f3)); * that's not processable by an indexscan nestloop join on A, whereas * (a.f1 OP (b.f2 OP c.f3)) is. * * 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. * * It is also possible to match RowCompareExpr clauses to indexes (but * currently, only btree indexes handle this). In this routine we will * report a match if the first column of the row comparison matches the * target index column. This is sufficient to guarantee that some index * condition can be constructed from the RowCompareExpr --- whether the * remaining columns match the index too is considered in * expand_indexqual_rowcompare(). * * It is also possible to match ScalarArrayOpExpr clauses to indexes, when * the clause is of the form "indexkey op ANY (arrayconst)". Since the * executor can only handle these in the context of bitmap index scans, * our caller specifies whether to allow these or not. * * For boolean indexes, it is also possible to match the clause directly * to the indexkey; or perhaps the clause is (NOT indexkey). * * 'index' is the index of interest. * 'indexcol' is a column number of 'index' (counting from 0). * 'opfamily' is the corresponding operator family. * 'rinfo' is the clause to be tested (as a RestrictInfo node). * 'saop_control' indicates whether ScalarArrayOpExpr clauses can be used. * * 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_indexcol(IndexOptInfo *index, int indexcol, Oid opfamily, RestrictInfo *rinfo, Relids outer_relids, SaOpControl saop_control) { Expr *clause = rinfo->clause; Node *leftop, *rightop; Relids left_relids; Relids right_relids; Oid expr_op; bool plain_op; /* * Never match pseudoconstants to indexes. (Normally this could not * happen anyway, since a pseudoconstant clause couldn't contain a Var, * but what if someone builds an expression index on a constant? It's not * totally unreasonable to do so with a partial index, either.) */ if (rinfo->pseudoconstant) return false; /* First check for boolean-index cases. */ if (IsBooleanOpfamily(opfamily)) { if (match_boolean_index_clause((Node *) clause, indexcol, index)) return true; } /* * Clause must be a binary opclause, or possibly a ScalarArrayOpExpr * (which is always binary, by definition). Or it could be a * RowCompareExpr, which we pass off to match_rowcompare_to_indexcol(). * Or, if the index supports it, we can handle IS NULL clauses. */ if (is_opclause(clause)) { leftop = get_leftop(clause); rightop = get_rightop(clause); if (!leftop || !rightop) return false; left_relids = rinfo->left_relids; right_relids = rinfo->right_relids; expr_op = ((OpExpr *) clause)->opno; plain_op = true; } else if (saop_control != SAOP_FORBID && clause && IsA(clause, ScalarArrayOpExpr)) { ScalarArrayOpExpr *saop = (ScalarArrayOpExpr *) clause; /* We only accept ANY clauses, not ALL */ if (!saop->useOr) return false; leftop = (Node *) linitial(saop->args); rightop = (Node *) lsecond(saop->args); left_relids = NULL; /* not actually needed */ right_relids = pull_varnos(rightop); expr_op = saop->opno; plain_op = false; } else if (clause && IsA(clause, RowCompareExpr)) { return match_rowcompare_to_indexcol(index, indexcol, opfamily, (RowCompareExpr *) clause, outer_relids); } else if (index->amsearchnulls && IsA(clause, NullTest)) { NullTest *nt = (NullTest *) clause; if (nt->nulltesttype == IS_NULL && match_index_to_operand((Node *) nt->arg, indexcol, index)) return true; return false; } else return false; /* * Check for clauses of the form: (indexkey operator constant) or * (constant operator indexkey). See above notes about const-ness. */ if (match_index_to_operand(leftop, indexcol, index) && bms_is_subset(right_relids, outer_relids) && !contain_volatile_functions(rightop)) { if (is_indexable_operator(expr_op, opfamily, true)) return true; /* * If we didn't find a member of the index's opfamily, see whether it * is a "special" indexable operator. */ if (plain_op && match_special_index_operator(clause, opfamily, true)) return true; return false; } if (plain_op && match_index_to_operand(rightop, indexcol, index) && bms_is_subset(left_relids, outer_relids) && !contain_volatile_functions(leftop)) { if (is_indexable_operator(expr_op, opfamily, false)) return true; /* * If we didn't find a member of the index's opfamily, see whether it * is a "special" indexable operator. */ if (match_special_index_operator(clause, opfamily, false)) return true; return false; } return false; } /* * is_indexable_operator * Does the operator match the specified index opfamily? * * If the indexkey is on the right, what we actually want to know * is whether the operator has a commutator operator that matches * the opfamily. */ static bool is_indexable_operator(Oid expr_op, Oid opfamily, bool indexkey_on_left) { /* Get the commuted operator if necessary */ if (!indexkey_on_left) { expr_op = get_commutator(expr_op); if (expr_op == InvalidOid) return false; } /* OK if the (commuted) operator is a member of the index's opfamily */ return op_in_opfamily(expr_op, opfamily); } /* * match_rowcompare_to_indexcol() * Handles the RowCompareExpr case for match_clause_to_indexcol(), * which see for comments. */ static bool match_rowcompare_to_indexcol(IndexOptInfo *index, int indexcol, Oid opfamily, RowCompareExpr *clause, Relids outer_relids) { Node *leftop, *rightop; Oid expr_op; /* Forget it if we're not dealing with a btree index */ if (index->relam != BTREE_AM_OID) return false; /* * We could do the matching on the basis of insisting that the opfamily * shown in the RowCompareExpr be the same as the index column's opfamily, * but that could fail in the presence of reverse-sort opfamilies: it'd * be a matter of chance whether RowCompareExpr had picked the forward * or reverse-sort family. So look only at the operator, and match * if it is a member of the index's opfamily (after commutation, if the * indexkey is on the right). We'll worry later about whether any * additional operators are matchable to the index. */ leftop = (Node *) linitial(clause->largs); rightop = (Node *) linitial(clause->rargs); expr_op = linitial_oid(clause->opnos); /* * These syntactic tests are the same as in match_clause_to_indexcol() */ if (match_index_to_operand(leftop, indexcol, index) && bms_is_subset(pull_varnos(rightop), outer_relids) && !contain_volatile_functions(rightop)) { /* OK, indexkey is on left */ } else if (match_index_to_operand(rightop, indexcol, index) && bms_is_subset(pull_varnos(leftop), outer_relids) && !contain_volatile_functions(leftop)) { /* indexkey is on right, so commute the operator */ expr_op = get_commutator(expr_op); if (expr_op == InvalidOid) return false; } else return false; /* We're good if the operator is the right type of opfamily member */ switch (get_op_opfamily_strategy(expr_op, opfamily)) { case BTLessStrategyNumber: case BTLessEqualStrategyNumber: case BTGreaterEqualStrategyNumber: case BTGreaterStrategyNumber: return true; } return false; } /**************************************************************************** * ---- ROUTINES TO DO PARTIAL INDEX PREDICATE TESTS ---- ****************************************************************************/ /* * check_partial_indexes * Check each partial index of the relation, and mark it predOK or not * depending on whether the predicate is satisfied for this query. */ void check_partial_indexes(PlannerInfo *root, RelOptInfo *rel) { List *restrictinfo_list = rel->baserestrictinfo; ListCell *ilist; foreach(ilist, rel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(ilist); if (index->indpred == NIL) continue; /* ignore non-partial indexes */ index->predOK = predicate_implied_by(index->indpred, restrictinfo_list); } } /**************************************************************************** * ---- ROUTINES TO CHECK JOIN CLAUSES ---- ****************************************************************************/ /* * indexable_outerrelids * Finds all other relids that participate in any indexable join clause * for the specified table. Returns a set of relids. */ static Relids indexable_outerrelids(PlannerInfo *root, RelOptInfo *rel) { Relids outer_relids = NULL; bool is_child_rel = (rel->reloptkind == RELOPT_OTHER_MEMBER_REL); ListCell *lc1; /* * Examine each joinclause in the joininfo list to see if it matches any * key of any index. If so, add the clause's other rels to the result. */ foreach(lc1, rel->joininfo) { RestrictInfo *joininfo = (RestrictInfo *) lfirst(lc1); Relids other_rels; other_rels = bms_difference(joininfo->required_relids, rel->relids); if (matches_any_index(joininfo, rel, other_rels)) outer_relids = bms_join(outer_relids, other_rels); else bms_free(other_rels); } /* * We also have to look through the query's EquivalenceClasses to see * if any of them could generate indexable join conditions for this rel. */ if (rel->has_eclass_joins) { foreach(lc1, root->eq_classes) { EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1); Relids other_rels = NULL; bool found_index = false; ListCell *lc2; /* * Won't generate joinclauses if const or single-member (the latter * test covers the volatile case too) */ if (cur_ec->ec_has_const || list_length(cur_ec->ec_members) <= 1) continue; /* * Note we don't test ec_broken; if we did, we'd need a separate * code path to look through ec_sources. Checking the members * anyway is OK as a possibly-overoptimistic heuristic. */ /* * No point in searching if rel not mentioned in eclass (but we * can't tell that for a child rel). */ if (!is_child_rel && !bms_is_subset(rel->relids, cur_ec->ec_relids)) continue; /* * Scan members, looking for both an index match and join * candidates */ foreach(lc2, cur_ec->ec_members) { EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2); /* Join candidate? */ if (!cur_em->em_is_child && !bms_overlap(cur_em->em_relids, rel->relids)) { other_rels = bms_add_members(other_rels, cur_em->em_relids); continue; } /* Check for index match (only need one) */ if (!found_index && bms_equal(cur_em->em_relids, rel->relids) && eclass_matches_any_index(cur_ec, cur_em, rel)) found_index = true; } if (found_index) outer_relids = bms_join(outer_relids, other_rels); else bms_free(other_rels); } } return outer_relids; } /* * matches_any_index * Workhorse for indexable_outerrelids: see if a joinclause can be * matched to any index of the given rel. */ static bool matches_any_index(RestrictInfo *rinfo, RelOptInfo *rel, Relids outer_relids) { ListCell *l; Assert(IsA(rinfo, RestrictInfo)); if (restriction_is_or_clause(rinfo)) { foreach(l, ((BoolExpr *) rinfo->orclause)->args) { Node *orarg = (Node *) lfirst(l); /* OR arguments should be ANDs or sub-RestrictInfos */ if (and_clause(orarg)) { ListCell *j; /* Recurse to examine AND items and sub-ORs */ foreach(j, ((BoolExpr *) orarg)->args) { RestrictInfo *arinfo = (RestrictInfo *) lfirst(j); if (matches_any_index(arinfo, rel, outer_relids)) return true; } } else { /* Recurse to examine simple clause */ Assert(IsA(orarg, RestrictInfo)); Assert(!restriction_is_or_clause((RestrictInfo *) orarg)); if (matches_any_index((RestrictInfo *) orarg, rel, outer_relids)) return true; } } return false; } /* Normal case for a simple restriction clause */ foreach(l, rel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(l); int indexcol = 0; Oid *families = index->opfamily; do { Oid curFamily = families[0]; if (match_clause_to_indexcol(index, indexcol, curFamily, rinfo, outer_relids, SAOP_ALLOW)) return true; indexcol++; families++; } while (!DoneMatchingIndexKeys(families)); } return false; } /* * eclass_matches_any_index * Workhorse for indexable_outerrelids: see if an EquivalenceClass member * can be matched to any index column of the given rel. * * This is also exported for use by find_eclass_clauses_for_index_join. */ bool eclass_matches_any_index(EquivalenceClass *ec, EquivalenceMember *em, RelOptInfo *rel) { ListCell *l; foreach(l, rel->indexlist) { IndexOptInfo *index = (IndexOptInfo *) lfirst(l); int indexcol = 0; Oid *families = index->opfamily; do { Oid curFamily = families[0]; if (list_member_oid(ec->ec_opfamilies, curFamily) && match_index_to_operand((Node *) em->em_expr, indexcol, index)) return true; indexcol++; families++; } while (!DoneMatchingIndexKeys(families)); } return false; } /* * best_inner_indexscan * Finds the best available inner indexscan for a nestloop join * with the given rel on the inside and the given outer_rel outside. * May return NULL if there are no possible inner indexscans. * * We ignore ordering considerations (since a nestloop's inner scan's order * is uninteresting). Also, we consider only total cost when deciding which * of two possible paths is better --- this assumes that all indexpaths have * negligible startup cost. (True today, but someday we might have to think * harder.) Therefore, there is only one dimension of comparison and so it's * sufficient to return a single "best" path. * * Note: create_index_paths() must have been run previously for this rel, * else the result will always be NULL. */ Path * best_inner_indexscan(PlannerInfo *root, RelOptInfo *rel, RelOptInfo *outer_rel, JoinType jointype) { Relids outer_relids; Path *cheapest; bool isouterjoin; List *clause_list; List *indexpaths; List *bitindexpaths; ListCell *l; InnerIndexscanInfo *info; MemoryContext oldcontext; /* * Nestloop only supports inner, left, and IN joins. */ switch (jointype) { case JOIN_INNER: case JOIN_IN: case JOIN_UNIQUE_OUTER: isouterjoin = false; break; case JOIN_LEFT: isouterjoin = true; break; default: return NULL; } /* * If there are no indexable joinclauses for this rel, exit quickly. */ if (bms_is_empty(rel->index_outer_relids)) return NULL; /* * Otherwise, we have to do path selection in the main planning context, * so that any created path can be safely attached to the rel's cache of * best inner paths. (This is not currently an issue for normal planning, * but it is an issue for GEQO planning.) */ oldcontext = MemoryContextSwitchTo(root->planner_cxt); /* * Intersect the given outer relids with index_outer_relids to find the * set of outer relids actually relevant for this rel. If there are none, * again we can fail immediately. */ outer_relids = bms_intersect(rel->index_outer_relids, outer_rel->relids); if (bms_is_empty(outer_relids)) { bms_free(outer_relids); MemoryContextSwitchTo(oldcontext); return NULL; } /* * Look to see if we already computed the result for this set of relevant * outerrels. (We include the isouterjoin status in the cache lookup key * for safety. In practice I suspect this is not necessary because it * should always be the same for a given innerrel.) * * NOTE: because we cache on outer_relids rather than outer_rel->relids, * we will report the same path and hence path cost for joins with * different sets of irrelevant rels on the outside. Now that cost_index * is sensitive to outer_rel->rows, this is not really right. However the * error is probably not large. Is it worth establishing a separate cache * entry for each distinct outer_rel->relids set to get this right? */ foreach(l, rel->index_inner_paths) { info = (InnerIndexscanInfo *) lfirst(l); if (bms_equal(info->other_relids, outer_relids) && info->isouterjoin == isouterjoin) { bms_free(outer_relids); MemoryContextSwitchTo(oldcontext); return info->best_innerpath; } } /* * Find all the relevant restriction and join clauses. * * Note: because we include restriction clauses, we will find indexscans * that could be plain indexscans, ie, they don't require the join context * at all. This may seem redundant, but we need to include those scans in * the input given to choose_bitmap_and() to be sure we find optimal AND * combinations of join and non-join scans. Also, even if the "best inner * indexscan" is just a plain indexscan, it will have a different cost * estimate because of cache effects. */ clause_list = find_clauses_for_join(root, rel, outer_relids, isouterjoin); /* * Find all the index paths that are usable for this join, except for * stuff involving OR and ScalarArrayOpExpr clauses. */ indexpaths = find_usable_indexes(root, rel, clause_list, NIL, false, outer_rel, SAOP_FORBID); /* * Generate BitmapOrPaths for any suitable OR-clauses present in the * clause list. */ bitindexpaths = generate_bitmap_or_paths(root, rel, clause_list, NIL, outer_rel); /* * Likewise, generate paths using ScalarArrayOpExpr clauses; these can't * be simple indexscans but they can be used in bitmap scans. */ bitindexpaths = list_concat(bitindexpaths, find_saop_paths(root, rel, clause_list, NIL, false, outer_rel)); /* * Include the regular index paths in bitindexpaths. */ bitindexpaths = list_concat(bitindexpaths, list_copy(indexpaths)); /* * If we found anything usable, generate a BitmapHeapPath for the most * promising combination of bitmap index paths. */ if (bitindexpaths != NIL) { Path *bitmapqual; BitmapHeapPath *bpath; bitmapqual = choose_bitmap_and(root, rel, bitindexpaths, outer_rel); bpath = create_bitmap_heap_path(root, rel, bitmapqual, outer_rel); indexpaths = lappend(indexpaths, bpath); } /* * Now choose the cheapest member of indexpaths. */ cheapest = NULL; foreach(l, indexpaths) { Path *path = (Path *) lfirst(l); if (cheapest == NULL || compare_path_costs(path, cheapest, TOTAL_COST) < 0) cheapest = path; } /* Cache the result --- whether positive or negative */ info = makeNode(InnerIndexscanInfo); info->other_relids = outer_relids; info->isouterjoin = isouterjoin; info->best_innerpath = cheapest; rel->index_inner_paths = lcons(info, rel->index_inner_paths); MemoryContextSwitchTo(oldcontext); return cheapest; } /* * find_clauses_for_join * Generate a list of clauses that are potentially useful for * scanning rel as the inner side of a nestloop join. * * We consider both join and restriction clauses. Any joinclause that uses * only otherrels in the specified outer_relids is fair game. But there must * be at least one such joinclause in the final list, otherwise we return NIL * indicating that there isn't any potential win here. */ static List * find_clauses_for_join(PlannerInfo *root, RelOptInfo *rel, Relids outer_relids, bool isouterjoin) { List *clause_list = NIL; Relids join_relids; ListCell *l; /* * Look for joinclauses that are usable with given outer_relids. Note * we'll take anything that's applicable to the join whether it has * anything to do with an index or not; since we're only building a list, * it's not worth filtering more finely here. */ join_relids = bms_union(rel->relids, outer_relids); foreach(l, rel->joininfo) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); /* Can't use pushed-down join clauses in outer join */ if (isouterjoin && rinfo->is_pushed_down) continue; if (!bms_is_subset(rinfo->required_relids, join_relids)) continue; clause_list = lappend(clause_list, rinfo); } bms_free(join_relids); /* * Also check to see if any EquivalenceClasses can produce a relevant * joinclause. Since all such clauses are effectively pushed-down, * this doesn't apply to outer joins. */ if (!isouterjoin && rel->has_eclass_joins) clause_list = list_concat(clause_list, find_eclass_clauses_for_index_join(root, rel, outer_relids)); /* If no join clause was matched then forget it, per comments above */ if (clause_list == NIL) return NIL; /* We can also use any plain restriction clauses for the rel */ clause_list = list_concat(list_copy(rel->baserestrictinfo), clause_list); return clause_list; } /**************************************************************************** * ---- PATH CREATION UTILITIES ---- ****************************************************************************/ /* * flatten_clausegroups_list * Given a list of lists of RestrictInfos, flatten it to a list * of RestrictInfos. * * This is used to flatten out the result of group_clauses_by_indexkey() * to produce an indexclauses list. The original list structure mustn't * be altered, but it's OK to share copies of the underlying RestrictInfos. */ List * flatten_clausegroups_list(List *clausegroups) { List *allclauses = NIL; ListCell *l; foreach(l, clausegroups) allclauses = list_concat(allclauses, list_copy((List *) lfirst(l))); return allclauses; } /**************************************************************************** * ---- 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. * * operand: the nodetree to be compared to the index * indexcol: the column number of the index (counting from 0) * index: the index of interest */ bool match_index_to_operand(Node *operand, int indexcol, IndexOptInfo *index) { int indkey; /* * Ignore any RelabelType node above the operand. 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 = (Node *) ((RelabelType *) operand)->arg; indkey = index->indexkeys[indexcol]; if (indkey != 0) { /* * Simple index column; operand must be a matching Var. */ if (operand && IsA(operand, Var) && index->rel->relid == ((Var *) operand)->varno && indkey == ((Var *) operand)->varattno) return true; } else { /* * Index expression; find the correct expression. (This search could * be avoided, at the cost of complicating all the callers of this * routine; doesn't seem worth it.) */ ListCell *indexpr_item; int i; Node *indexkey; indexpr_item = list_head(index->indexprs); for (i = 0; i < indexcol; i++) { if (index->indexkeys[i] == 0) { if (indexpr_item == NULL) elog(ERROR, "wrong number of index expressions"); indexpr_item = lnext(indexpr_item); } } if (indexpr_item == NULL) elog(ERROR, "wrong number of index expressions"); indexkey = (Node *) lfirst(indexpr_item); /* * Does it match the operand? Again, strip any relabeling. */ if (indexkey && IsA(indexkey, RelabelType)) indexkey = (Node *) ((RelabelType *) indexkey)->arg; if (equal(indexkey, operand)) return true; } return false; } /**************************************************************************** * ---- 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.) * * Another thing that we do with this machinery is to provide special * smarts for "boolean" indexes (that is, indexes on boolean columns * that support boolean equality). We can transform a plain reference * to the indexkey into "indexkey = true", or "NOT indexkey" into * "indexkey = false", so as to make the expression indexable using the * regular index operators. (As of Postgres 8.1, we must do this here * because constant simplification does the reverse transformation; * without this code there'd be no way to use such an index at all.) * * Three routines are provided here: * * match_special_index_operator() is just an auxiliary function for * match_clause_to_indexcol(); after the latter fails to recognize a * restriction opclause's operator as a member of an index's opfamily, * it asks match_special_index_operator() whether the clause should be * considered an indexqual anyway. * * match_boolean_index_clause() similarly detects clauses that can be * converted into boolean equality operators. * * expand_indexqual_conditions() converts a list of lists of RestrictInfo * nodes (with implicit AND semantics across list elements) into * a list of clauses that the executor can actually handle. For operators * that are members of the index's opfamily this transformation is a no-op, * but clauses recognized by match_special_index_operator() or * match_boolean_index_clause() must be converted into one or more "regular" * indexqual conditions. *---------- */ /* * match_boolean_index_clause * Recognize restriction clauses that can be matched to a boolean index. * * This should be called only when IsBooleanOpfamily() recognizes the * index's operator family. We check to see if the clause matches the * index's key. */ static bool match_boolean_index_clause(Node *clause, int indexcol, IndexOptInfo *index) { /* Direct match? */ if (match_index_to_operand(clause, indexcol, index)) return true; /* NOT clause? */ if (not_clause(clause)) { if (match_index_to_operand((Node *) get_notclausearg((Expr *) clause), indexcol, index)) return true; } /* * Since we only consider clauses at top level of WHERE, we can convert * indexkey IS TRUE and indexkey IS FALSE to index searches as well. The * different meaning for NULL isn't important. */ else if (clause && IsA(clause, BooleanTest)) { BooleanTest *btest = (BooleanTest *) clause; if (btest->booltesttype == IS_TRUE || btest->booltesttype == IS_FALSE) if (match_index_to_operand((Node *) btest->arg, indexcol, index)) return true; } return false; } /* * 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 opfamily operators. * Return 'true' if we can do something with it anyway. */ static bool match_special_index_operator(Expr *clause, Oid opfamily, bool indexkey_on_left) { bool isIndexable = false; Node *rightop; Oid expr_op; Const *patt; Const *prefix = NULL; Const *rest = NULL; /* * 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 */ rightop = get_rightop(clause); expr_op = ((OpExpr *) clause)->opno; /* again, required for all current special ops: */ if (!IsA(rightop, Const) || ((Const *) rightop)->constisnull) return false; patt = (Const *) rightop; switch (expr_op) { case OID_TEXT_LIKE_OP: case OID_BPCHAR_LIKE_OP: case OID_NAME_LIKE_OP: /* the right-hand const is type text for all of these */ isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like, &prefix, &rest) != Pattern_Prefix_None; break; case OID_BYTEA_LIKE_OP: isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like, &prefix, &rest) != Pattern_Prefix_None; break; case OID_TEXT_ICLIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_NAME_ICLIKE_OP: /* the right-hand const is type text for all of these */ isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like_IC, &prefix, &rest) != Pattern_Prefix_None; break; case OID_TEXT_REGEXEQ_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_NAME_REGEXEQ_OP: /* the right-hand const is type text for all of these */ isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex, &prefix, &rest) != Pattern_Prefix_None; break; case OID_TEXT_ICREGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: /* the right-hand const is type text for all of these */ isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, &prefix, &rest) != Pattern_Prefix_None; break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: isIndexable = true; break; } if (prefix) { pfree(DatumGetPointer(prefix->constvalue)); pfree(prefix); } /* done if the expression doesn't look indexable */ if (!isIndexable) return false; /* * Must also check that index's opfamily supports the operators we will * want to apply. (A hash index, for example, will not support ">=".) * Currently, only btree supports the operators we need. * * We insist on the opfamily being the specific one we expect, else we'd do * the wrong thing if someone were to make a reverse-sort opfamily with the * same operators. */ switch (expr_op) { case OID_TEXT_LIKE_OP: case OID_TEXT_ICLIKE_OP: case OID_TEXT_REGEXEQ_OP: case OID_TEXT_ICREGEXEQ_OP: isIndexable = (opfamily == TEXT_PATTERN_BTREE_FAM_OID) || (opfamily == TEXT_BTREE_FAM_OID && lc_collate_is_c()); break; case OID_BPCHAR_LIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: isIndexable = (opfamily == BPCHAR_PATTERN_BTREE_FAM_OID) || (opfamily == BPCHAR_BTREE_FAM_OID && lc_collate_is_c()); break; case OID_NAME_LIKE_OP: case OID_NAME_ICLIKE_OP: case OID_NAME_REGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: isIndexable = (opfamily == NAME_PATTERN_BTREE_FAM_OID) || (opfamily == NAME_BTREE_FAM_OID && lc_collate_is_c()); break; case OID_BYTEA_LIKE_OP: isIndexable = (opfamily == BYTEA_BTREE_FAM_OID); break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: isIndexable = (opfamily == NETWORK_BTREE_FAM_OID); break; } return isIndexable; } /* * expand_indexqual_conditions * Given a list of sublists of RestrictInfo nodes, produce a flat list * of index qual clauses. Standard qual clauses (those in the index's * opfamily) are passed through unchanged. Boolean clauses and "special" * index operators are expanded into clauses that the indexscan machinery * will know what to do with. RowCompare clauses are simplified if * necessary to create a clause that is fully checkable by the index. * * The input list is ordered by index key, and so the output list is too. * (The latter is not depended on by any part of the core planner, I believe, * but parts of the executor require it, and so do the amcostestimate * functions.) */ List * expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups) { List *resultquals = NIL; ListCell *clausegroup_item; int indexcol = 0; Oid *families = index->opfamily; if (clausegroups == NIL) return NIL; clausegroup_item = list_head(clausegroups); do { Oid curFamily = families[0]; ListCell *l; foreach(l, (List *) lfirst(clausegroup_item)) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); Expr *clause = rinfo->clause; /* First check for boolean cases */ if (IsBooleanOpfamily(curFamily)) { Expr *boolqual; boolqual = expand_boolean_index_clause((Node *) clause, indexcol, index); if (boolqual) { resultquals = lappend(resultquals, make_restrictinfo(boolqual, true, false, false, NULL)); continue; } } /* * Else it must be an opclause (usual case), ScalarArrayOp, * RowCompare, or NullTest */ if (is_opclause(clause)) { resultquals = list_concat(resultquals, expand_indexqual_opclause(rinfo, curFamily)); } else if (IsA(clause, ScalarArrayOpExpr)) { /* no extra work at this time */ resultquals = lappend(resultquals, rinfo); } else if (IsA(clause, RowCompareExpr)) { resultquals = lappend(resultquals, expand_indexqual_rowcompare(rinfo, index, indexcol)); } else if (IsA(clause, NullTest)) { Assert(index->amsearchnulls); resultquals = lappend(resultquals, make_restrictinfo(clause, true, false, false, NULL)); } else elog(ERROR, "unsupported indexqual type: %d", (int) nodeTag(clause)); } clausegroup_item = lnext(clausegroup_item); indexcol++; families++; } while (clausegroup_item != NULL && !DoneMatchingIndexKeys(families)); Assert(clausegroup_item == NULL); /* else more groups than indexkeys */ return resultquals; } /* * expand_boolean_index_clause * Convert a clause recognized by match_boolean_index_clause into * a boolean equality operator clause. * * Returns NULL if the clause isn't a boolean index qual. */ static Expr * expand_boolean_index_clause(Node *clause, int indexcol, IndexOptInfo *index) { /* Direct match? */ if (match_index_to_operand(clause, indexcol, index)) { /* convert to indexkey = TRUE */ return make_opclause(BooleanEqualOperator, BOOLOID, false, (Expr *) clause, (Expr *) makeBoolConst(true, false)); } /* NOT clause? */ if (not_clause(clause)) { Node *arg = (Node *) get_notclausearg((Expr *) clause); /* It must have matched the indexkey */ Assert(match_index_to_operand(arg, indexcol, index)); /* convert to indexkey = FALSE */ return make_opclause(BooleanEqualOperator, BOOLOID, false, (Expr *) arg, (Expr *) makeBoolConst(false, false)); } if (clause && IsA(clause, BooleanTest)) { BooleanTest *btest = (BooleanTest *) clause; Node *arg = (Node *) btest->arg; /* It must have matched the indexkey */ Assert(match_index_to_operand(arg, indexcol, index)); if (btest->booltesttype == IS_TRUE) { /* convert to indexkey = TRUE */ return make_opclause(BooleanEqualOperator, BOOLOID, false, (Expr *) arg, (Expr *) makeBoolConst(true, false)); } if (btest->booltesttype == IS_FALSE) { /* convert to indexkey = FALSE */ return make_opclause(BooleanEqualOperator, BOOLOID, false, (Expr *) arg, (Expr *) makeBoolConst(false, false)); } /* Oops */ Assert(false); } return NULL; } /* * expand_indexqual_opclause --- expand a single indexqual condition * that is an operator clause * * The input is a single RestrictInfo, the output a list of RestrictInfos */ static List * expand_indexqual_opclause(RestrictInfo *rinfo, Oid opfamily) { Expr *clause = rinfo->clause; /* we know these will succeed */ Node *leftop = get_leftop(clause); Node *rightop = get_rightop(clause); Oid expr_op = ((OpExpr *) clause)->opno; Const *patt = (Const *) rightop; Const *prefix = NULL; Const *rest = NULL; Pattern_Prefix_Status pstatus; List *result; switch (expr_op) { /* * LIKE and regex operators are not members of any index opfamily, * 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_NAME_LIKE_OP: case OID_BYTEA_LIKE_OP: pstatus = pattern_fixed_prefix(patt, Pattern_Type_Like, &prefix, &rest); result = prefix_quals(leftop, opfamily, prefix, pstatus); break; case OID_TEXT_ICLIKE_OP: case OID_BPCHAR_ICLIKE_OP: case OID_NAME_ICLIKE_OP: /* the right-hand const is type text for all of these */ pstatus = pattern_fixed_prefix(patt, Pattern_Type_Like_IC, &prefix, &rest); result = prefix_quals(leftop, opfamily, prefix, pstatus); break; case OID_TEXT_REGEXEQ_OP: case OID_BPCHAR_REGEXEQ_OP: case OID_NAME_REGEXEQ_OP: /* the right-hand const is type text for all of these */ pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex, &prefix, &rest); result = prefix_quals(leftop, opfamily, prefix, pstatus); break; case OID_TEXT_ICREGEXEQ_OP: case OID_BPCHAR_ICREGEXEQ_OP: case OID_NAME_ICREGEXEQ_OP: /* the right-hand const is type text for all of these */ pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, &prefix, &rest); result = prefix_quals(leftop, opfamily, prefix, pstatus); break; case OID_INET_SUB_OP: case OID_INET_SUBEQ_OP: result = network_prefix_quals(leftop, expr_op, opfamily, patt->constvalue); break; default: result = list_make1(rinfo); break; } return result; } /* * expand_indexqual_rowcompare --- expand a single indexqual condition * that is a RowCompareExpr * * It's already known that the first column of the row comparison matches * the specified column of the index. We can use additional columns of the * row comparison as index qualifications, so long as they match the index * in the "same direction", ie, the indexkeys are all on the same side of the * clause and the operators are all the same-type members of the opfamilies. * If all the columns of the RowCompareExpr match in this way, we just use it * as-is. Otherwise, we build a shortened RowCompareExpr (if more than one * column matches) or a simple OpExpr (if the first-column match is all * there is). In these cases the modified clause is always "<=" or ">=" * even when the original was "<" or ">" --- this is necessary to match all * the rows that could match the original. (We are essentially building a * lossy version of the row comparison when we do this.) */ static RestrictInfo * expand_indexqual_rowcompare(RestrictInfo *rinfo, IndexOptInfo *index, int indexcol) { RowCompareExpr *clause = (RowCompareExpr *) rinfo->clause; bool var_on_left; int op_strategy; Oid op_lefttype; Oid op_righttype; bool op_recheck; int matching_cols; Oid expr_op; List *opfamilies; List *lefttypes; List *righttypes; List *new_ops; ListCell *largs_cell; ListCell *rargs_cell; ListCell *opnos_cell; /* We have to figure out (again) how the first col matches */ var_on_left = match_index_to_operand((Node *) linitial(clause->largs), indexcol, index); Assert(var_on_left || match_index_to_operand((Node *) linitial(clause->rargs), indexcol, index)); expr_op = linitial_oid(clause->opnos); if (!var_on_left) expr_op = get_commutator(expr_op); get_op_opfamily_properties(expr_op, index->opfamily[indexcol], &op_strategy, &op_lefttype, &op_righttype, &op_recheck); /* Build lists of the opfamilies and operator datatypes in case needed */ opfamilies = list_make1_oid(index->opfamily[indexcol]); lefttypes = list_make1_oid(op_lefttype); righttypes = list_make1_oid(op_righttype); /* * See how many of the remaining columns match some index column in the * same way. A note about rel membership tests: we assume that the clause * as a whole is already known to use only Vars from the indexed relation * and possibly some acceptable outer relations. So the "other" side of * any potential index condition is OK as long as it doesn't use Vars from * the indexed relation. */ matching_cols = 1; largs_cell = lnext(list_head(clause->largs)); rargs_cell = lnext(list_head(clause->rargs)); opnos_cell = lnext(list_head(clause->opnos)); while (largs_cell != NULL) { Node *varop; Node *constop; int i; expr_op = lfirst_oid(opnos_cell); if (var_on_left) { varop = (Node *) lfirst(largs_cell); constop = (Node *) lfirst(rargs_cell); } else { varop = (Node *) lfirst(rargs_cell); constop = (Node *) lfirst(largs_cell); /* indexkey is on right, so commute the operator */ expr_op = get_commutator(expr_op); if (expr_op == InvalidOid) break; /* operator is not usable */ } if (bms_is_member(index->rel->relid, pull_varnos(constop))) break; /* no good, Var on wrong side */ if (contain_volatile_functions(constop)) break; /* no good, volatile comparison value */ /* * The Var side can match any column of the index. If the user does * something weird like having multiple identical index columns, we * insist the match be on the first such column, to avoid confusing * the executor. */ for (i = 0; i < index->ncolumns; i++) { if (match_index_to_operand(varop, i, index)) break; } if (i >= index->ncolumns) break; /* no match found */ /* Now, do we have the right operator for this column? */ if (get_op_opfamily_strategy(expr_op, index->opfamily[i]) != op_strategy) break; /* Add opfamily and datatypes to lists */ get_op_opfamily_properties(expr_op, index->opfamily[i], &op_strategy, &op_lefttype, &op_righttype, &op_recheck); opfamilies = lappend_oid(opfamilies, index->opfamily[i]); lefttypes = lappend_oid(lefttypes, op_lefttype); righttypes = lappend_oid(righttypes, op_righttype); /* This column matches, keep scanning */ matching_cols++; largs_cell = lnext(largs_cell); rargs_cell = lnext(rargs_cell); opnos_cell = lnext(opnos_cell); } /* Return clause as-is if it's all usable as index quals */ if (matching_cols == list_length(clause->opnos)) return rinfo; /* * We have to generate a subset rowcompare (possibly just one OpExpr). The * painful part of this is changing < to <= or > to >=, so deal with that * first. */ if (op_strategy == BTLessEqualStrategyNumber || op_strategy == BTGreaterEqualStrategyNumber) { /* easy, just use the same operators */ new_ops = list_truncate(list_copy(clause->opnos), matching_cols); } else { ListCell *opfamilies_cell; ListCell *lefttypes_cell; ListCell *righttypes_cell; if (op_strategy == BTLessStrategyNumber) op_strategy = BTLessEqualStrategyNumber; else if (op_strategy == BTGreaterStrategyNumber) op_strategy = BTGreaterEqualStrategyNumber; else elog(ERROR, "unexpected strategy number %d", op_strategy); new_ops = NIL; lefttypes_cell = list_head(lefttypes); righttypes_cell = list_head(righttypes); foreach(opfamilies_cell, opfamilies) { Oid opfam = lfirst_oid(opfamilies_cell); Oid lefttype = lfirst_oid(lefttypes_cell); Oid righttype = lfirst_oid(righttypes_cell); expr_op = get_opfamily_member(opfam, lefttype, righttype, op_strategy); if (!OidIsValid(expr_op)) /* should not happen */ elog(ERROR, "could not find member %d(%u,%u) of opfamily %u", op_strategy, lefttype, righttype, opfam); if (!var_on_left) { expr_op = get_commutator(expr_op); if (!OidIsValid(expr_op)) /* should not happen */ elog(ERROR, "could not find commutator of member %d(%u,%u) of opfamily %u", op_strategy, lefttype, righttype, opfam); } new_ops = lappend_oid(new_ops, expr_op); } lefttypes_cell = lnext(lefttypes_cell); righttypes_cell = lnext(righttypes_cell); } /* If we have more than one matching col, create a subset rowcompare */ if (matching_cols > 1) { RowCompareExpr *rc = makeNode(RowCompareExpr); if (var_on_left) rc->rctype = (RowCompareType) op_strategy; else rc->rctype = (op_strategy == BTLessEqualStrategyNumber) ? ROWCOMPARE_GE : ROWCOMPARE_LE; rc->opnos = new_ops; rc->opfamilies = list_truncate(list_copy(clause->opfamilies), matching_cols); rc->largs = list_truncate((List *) copyObject(clause->largs), matching_cols); rc->rargs = list_truncate((List *) copyObject(clause->rargs), matching_cols); return make_restrictinfo((Expr *) rc, true, false, false, NULL); } else { Expr *opexpr; opexpr = make_opclause(linitial_oid(new_ops), BOOLOID, false, copyObject(linitial(clause->largs)), copyObject(linitial(clause->rargs))); return make_restrictinfo(opexpr, true, false, false, NULL); } } /* * Given a fixed prefix that all the "leftop" values must have, * generate suitable indexqual condition(s). opfamily is the index * operator family; we use it to deduce the appropriate comparison * operators and operand datatypes. */ static List * prefix_quals(Node *leftop, Oid opfamily, Const *prefix_const, Pattern_Prefix_Status pstatus) { List *result; Oid datatype; Oid oproid; Expr *expr; Const *greaterstr; Assert(pstatus != Pattern_Prefix_None); switch (opfamily) { case TEXT_BTREE_FAM_OID: case TEXT_PATTERN_BTREE_FAM_OID: datatype = TEXTOID; break; case BPCHAR_BTREE_FAM_OID: case BPCHAR_PATTERN_BTREE_FAM_OID: datatype = BPCHAROID; break; case NAME_BTREE_FAM_OID: case NAME_PATTERN_BTREE_FAM_OID: datatype = NAMEOID; break; case BYTEA_BTREE_FAM_OID: datatype = BYTEAOID; break; default: /* shouldn't get here */ elog(ERROR, "unexpected opfamily: %u", opfamily); return NIL; } /* * If necessary, coerce the prefix constant to the right type. The given * prefix constant is either text or bytea type. */ if (prefix_const->consttype != datatype) { char *prefix; switch (prefix_const->consttype) { case TEXTOID: prefix = DatumGetCString(DirectFunctionCall1(textout, prefix_const->constvalue)); break; case BYTEAOID: prefix = DatumGetCString(DirectFunctionCall1(byteaout, prefix_const->constvalue)); break; default: elog(ERROR, "unexpected const type: %u", prefix_const->consttype); return NIL; } prefix_const = string_to_const(prefix, datatype); pfree(prefix); } /* * If we found an exact-match pattern, generate an "=" indexqual. */ if (pstatus == Pattern_Prefix_Exact) { oproid = get_opfamily_member(opfamily, datatype, datatype, BTEqualStrategyNumber); if (oproid == InvalidOid) elog(ERROR, "no = operator for opfamily %u", opfamily); expr = make_opclause(oproid, BOOLOID, false, (Expr *) leftop, (Expr *) prefix_const); result = list_make1(make_restrictinfo(expr, true, false, false, NULL)); return result; } /* * Otherwise, we have a nonempty required prefix of the values. * * We can always say "x >= prefix". */ oproid = get_opfamily_member(opfamily, datatype, datatype, BTGreaterEqualStrategyNumber); if (oproid == InvalidOid) elog(ERROR, "no >= operator for opfamily %u", opfamily); expr = make_opclause(oproid, BOOLOID, false, (Expr *) leftop, (Expr *) prefix_const); result = list_make1(make_restrictinfo(expr, true, false, false, NULL)); /*------- * If we can create a string larger than the prefix, we can say * "x < greaterstr". *------- */ greaterstr = make_greater_string(prefix_const); if (greaterstr) { oproid = get_opfamily_member(opfamily, datatype, datatype, BTLessStrategyNumber); if (oproid == InvalidOid) elog(ERROR, "no < operator for opfamily %u", opfamily); expr = make_opclause(oproid, BOOLOID, false, (Expr *) leftop, (Expr *) greaterstr); result = lappend(result, make_restrictinfo(expr, true, false, false, NULL)); } return result; } /* * Given a leftop and a rightop, and a inet-family sup/sub operator, * generate suitable indexqual condition(s). expr_op is the original * operator, and opfamily is the index opfamily. */ static List * network_prefix_quals(Node *leftop, Oid expr_op, Oid opfamily, Datum rightop) { bool is_eq; Oid datatype; Oid opr1oid; Oid opr2oid; Datum opr1right; Datum opr2right; List *result; 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; default: elog(ERROR, "unexpected operator: %u", expr_op); return NIL; } /* * create clause "key >= network_scan_first( rightop )", or ">" if the * operator disallows equality. */ if (is_eq) { opr1oid = get_opfamily_member(opfamily, datatype, datatype, BTGreaterEqualStrategyNumber); if (opr1oid == InvalidOid) elog(ERROR, "no >= operator for opfamily %u", opfamily); } else { opr1oid = get_opfamily_member(opfamily, datatype, datatype, BTGreaterStrategyNumber); if (opr1oid == InvalidOid) elog(ERROR, "no > operator for opfamily %u", opfamily); } opr1right = network_scan_first(rightop); expr = make_opclause(opr1oid, BOOLOID, false, (Expr *) leftop, (Expr *) makeConst(datatype, -1, -1, opr1right, false, false)); result = list_make1(make_restrictinfo(expr, true, false, false, NULL)); /* create clause "key <= network_scan_last( rightop )" */ opr2oid = get_opfamily_member(opfamily, datatype, datatype, BTLessEqualStrategyNumber); if (opr2oid == InvalidOid) elog(ERROR, "no <= operator for opfamily %u", opfamily); opr2right = network_scan_last(rightop); expr = make_opclause(opr2oid, BOOLOID, false, (Expr *) leftop, (Expr *) makeConst(datatype, -1, -1, opr2right, false, false)); result = lappend(result, make_restrictinfo(expr, true, false, false, NULL)); return result; } /* * Handy subroutines for match_special_index_operator() and friends. */ /* * 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 if (datatype == BYTEAOID) return DirectFunctionCall1(byteain, 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, -1, ((datatype == NAMEOID) ? NAMEDATALEN : -1), conval, false, false); }