diff options
Diffstat (limited to 'src/backend/optimizer/path/indxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 1009 |
1 files changed, 589 insertions, 420 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index e387a7bd76..faf410c955 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -1,15 +1,15 @@ /*------------------------------------------------------------------------- * * indxpath.c - * Routines to determine which indices are usable for scanning a - * given relation, and create IndexPaths accordingly. + * Routines to determine which indexes are usable for scanning a + * given relation, and create Paths accordingly. * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.175 2005/04/21 02:28:01 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.176 2005/04/22 21:58:31 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -54,23 +54,30 @@ ((opclass) == BOOL_BTREE_OPS_OID || (opclass) == BOOL_HASH_OPS_OID) -static List *group_clauses_by_indexkey_for_join(Query *root, - IndexOptInfo *index, - Relids outer_relids, - JoinType jointype, bool isouterjoin); +static List *find_usable_indexes(Query *root, RelOptInfo *rel, + List *clauses, List *outer_clauses, + bool istoplevel, bool isjoininner, + Relids outer_relids); +static List *generate_bitmap_or_paths(Query *root, RelOptInfo *rel, + List *clauses, List *outer_clauses, + bool isjoininner, + Relids outer_relids); +static Path *choose_bitmap_and(Query *root, RelOptInfo *rel, List *paths); static bool match_clause_to_indexcol(IndexOptInfo *index, int indexcol, Oid opclass, - RestrictInfo *rinfo); -static bool match_join_clause_to_indexcol(IndexOptInfo *index, - int indexcol, Oid opclass, - RestrictInfo *rinfo); + RestrictInfo *rinfo, + Relids outer_relids); static Oid indexable_operator(Expr *clause, Oid opclass, bool indexkey_on_left); static bool pred_test_recurse(Node *clause, Node *predicate); static bool pred_test_simple_clause(Expr *predicate, Node *clause); -static Relids indexable_outerrelids(IndexOptInfo *index); -static Path *make_innerjoin_index_path(Query *root, IndexOptInfo *index, - List *clausegroups); +static Relids indexable_outerrelids(RelOptInfo *rel); +static bool list_matches_any_index(List *clauses, RelOptInfo *rel, + Relids outer_relids); +static bool matches_any_index(RestrictInfo *rinfo, RelOptInfo *rel, + Relids outer_relids); +static List *find_clauses_for_join(Query *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 opclass, @@ -120,34 +127,168 @@ static Const *string_to_const(const char *str, Oid datatype); void create_index_paths(Query *root, RelOptInfo *rel) { - Relids all_join_outerrelids = NULL; + 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(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, false, NULL); + + /* + * 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, + false, 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); + bpath = create_bitmap_heap_path(root, rel, bitmapqual, false); + 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. + * + * 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 + * 'isjoininner' is true if forming an inner indexscan (so some of the + * given clauses are join clauses) + * 'outer_relids' identifies the outer side of the join (pass NULL + * if not isjoininner) + * + * Note: check_partial_indexes() must have been run previously. + *---------- + */ +static List * +find_usable_indexes(Query *root, RelOptInfo *rel, + List *clauses, List *outer_clauses, + bool istoplevel, bool isjoininner, + Relids outer_relids) +{ + 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 index_is_ordered; - Relids join_outerrelids; - /* Ignore partial indexes that do not match the query */ + /* + * 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. + */ if (index->indpred != NIL && !index->predOK) - continue; + { + 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 (!pred_test(index->indpred, all_clauses) || + pred_test(index->indpred, outer_clauses)) + continue; + } /* - * 1. Match the index against non-OR restriction clauses. (OR - * clauses will be considered later by orindxpath.c.) + * 1. Match the index against the available restriction clauses. */ - restrictclauses = group_clauses_by_indexkey(index); + restrictclauses = group_clauses_by_indexkey(index, + clauses, + outer_clauses, + outer_relids); /* * 2. Compute pathkeys describing index's ordering, if any, then - * see how many of them are actually useful for this query. + * 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->ordering[0]); - if (index_is_ordered) + if (istoplevel && index_is_ordered && !isjoininner) { index_pathkeys = build_index_pathkeys(root, index, ForwardScanDirection); @@ -174,48 +315,174 @@ create_index_paths(Query *root, RelOptInfo *rel) if (restrictclauses != NIL || useful_pathkeys != NIL || (index->indpred != NIL && index_is_ordered)) - add_path(rel, (Path *) - create_index_path(root, index, - restrictclauses, - useful_pathkeys, - index_is_ordered ? - ForwardScanDirection : - NoMovementScanDirection)); + { + ipath = create_index_path(root, index, + restrictclauses, + useful_pathkeys, + index_is_ordered ? + ForwardScanDirection : + NoMovementScanDirection, + isjoininner); + result = lappend(result, ipath); + } /* * 4. 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) + if (istoplevel && index_is_ordered && !isjoininner) { index_pathkeys = build_index_pathkeys(root, index, BackwardScanDirection); useful_pathkeys = truncate_useless_pathkeys(root, rel, index_pathkeys); if (useful_pathkeys != NIL) - add_path(rel, (Path *) - create_index_path(root, index, - restrictclauses, - useful_pathkeys, - BackwardScanDirection)); + { + ipath = create_index_path(root, index, + restrictclauses, + useful_pathkeys, + BackwardScanDirection, + false); + result = lappend(result, ipath); + } } + } + + return result; +} + + +/* + * 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.) + */ +static List * +generate_bitmap_or_paths(Query *root, RelOptInfo *rel, + List *clauses, List *outer_clauses, + bool isjoininner, + Relids outer_relids) +{ + 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; /* - * 5. Examine join clauses to see which ones are potentially - * usable with this index, 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. We compute both per-index and - * overall-for-relation sets. + * We must be able to match at least one index to each of the arms + * of the OR, else we can't use it. */ - join_outerrelids = indexable_outerrelids(index); - index->outer_relids = join_outerrelids; - all_join_outerrelids = bms_add_members(all_join_outerrelids, - join_outerrelids); + 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, + isjoininner, + outer_relids); + /* Recurse in case there are sub-ORs */ + indlist = list_concat(indlist, + generate_bitmap_or_paths(root, rel, + andargs, + all_clauses, + isjoininner, + outer_relids)); + } + else + { + Assert(IsA(orarg, RestrictInfo)); + Assert(!restriction_is_or_clause((RestrictInfo *) orarg)); + indlist = find_usable_indexes(root, rel, + list_make1(orarg), + all_clauses, + false, + isjoininner, + outer_relids); + } + /* + * 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); + 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); + } } - rel->index_outer_relids = all_join_outerrelids; + 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(Query *root, RelOptInfo *rel, List *paths) +{ + Assert(paths != NIL); /* else caller error */ + if (list_length(paths) == 1) + return (Path *) linitial(paths); /* easy case */ + /* + * XXX temporary stopgap: always use all available paths + */ + return (Path *) create_bitmap_and_path(root, rel, paths); } @@ -228,6 +495,14 @@ create_index_paths(Query *root, RelOptInfo *rel) * group_clauses_by_indexkey * Find restriction clauses that can be used with an index. * + * As explained in the comments for find_usable_indexes(), we can use + * clauses from either of the given lists, but the result is required to + * use at least one clause from the "current clauses" list. We return + * NIL if we don't find any such clause. + * + * outer_relids determines what Vars will be allowed on the other side + * of a possible index qual; see match_clause_to_indexcol(). + * * 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 @@ -242,15 +517,17 @@ create_index_paths(Query *root, RelOptInfo *rel) * Therefore, there are no empty sublists in the result. */ List * -group_clauses_by_indexkey(IndexOptInfo *index) +group_clauses_by_indexkey(IndexOptInfo *index, + List *clauses, List *outer_clauses, + Relids outer_relids) { List *clausegroup_list = NIL; - List *restrictinfo_list = index->rel->baserestrictinfo; + bool found_clause = false; int indexcol = 0; Oid *classes = index->classlist; - if (restrictinfo_list == NIL) - return NIL; + if (clauses == NIL) + return NIL; /* cannot succeed */ do { @@ -258,135 +535,37 @@ group_clauses_by_indexkey(IndexOptInfo *index) List *clausegroup = NIL; ListCell *l; - foreach(l, restrictinfo_list) + /* check the current clauses */ + foreach(l, clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); + Assert(IsA(rinfo, RestrictInfo)); if (match_clause_to_indexcol(index, indexcol, curClass, - rinfo)) + rinfo, + outer_relids)) + { clausegroup = lappend(clausegroup, rinfo); + found_clause = true; + } } - /* - * 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 = lappend(clausegroup_list, clausegroup); - - indexcol++; - classes++; - - } while (!DoneMatchingIndexKeys(classes)); - - return clausegroup_list; -} - -/* - * group_clauses_by_indexkey_for_join - * Generate a list of sublists of 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. 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 this index isn't interesting as an inner indexscan. (A scan using - * only restriction clauses shouldn't be created here, because a regular Path - * will already have been generated for it.) - */ -static List * -group_clauses_by_indexkey_for_join(Query *root, IndexOptInfo *index, - Relids outer_relids, - JoinType jointype, bool isouterjoin) -{ - List *clausegroup_list = NIL; - bool jfound = false; - int indexcol = 0; - Oid *classes = index->classlist; - - do - { - Oid curClass = classes[0]; - List *clausegroup = NIL; - int numsources; - ListCell *l; - - /* - * We can always use plain restriction clauses for the rel. We - * scan these first because we want them first in the clausegroup - * list for the convenience of remove_redundant_join_clauses, - * which can never remove non-join clauses and hence won't be able - * to get rid of a non-join clause if it appears after a join - * clause it is redundant with. - */ - foreach(l, index->rel->baserestrictinfo) + /* check the outer clauses */ + foreach(l, outer_clauses) { RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); - /* Can't use pushed-down clauses in outer join */ - if (isouterjoin && rinfo->is_pushed_down) - continue; - + Assert(IsA(rinfo, RestrictInfo)); if (match_clause_to_indexcol(index, indexcol, curClass, - rinfo)) + rinfo, + outer_relids)) clausegroup = lappend(clausegroup, rinfo); } - /* found anything in base restrict list? */ - numsources = (clausegroup != NIL) ? 1 : 0; - - /* Look for joinclauses that are usable with given outer_relids */ - foreach(l, index->rel->joininfo) - { - JoinInfo *joininfo = (JoinInfo *) lfirst(l); - bool jfoundhere = false; - ListCell *j; - - if (!bms_is_subset(joininfo->unjoined_relids, outer_relids)) - continue; - - foreach(j, joininfo->jinfo_restrictinfo) - { - RestrictInfo *rinfo = (RestrictInfo *) lfirst(j); - - /* Can't use pushed-down clauses in outer join */ - if (isouterjoin && rinfo->is_pushed_down) - continue; - - if (match_join_clause_to_indexcol(index, - indexcol, - curClass, - rinfo)) - { - clausegroup = lappend(clausegroup, rinfo); - if (!jfoundhere) - { - jfoundhere = true; - jfound = true; - numsources++; - } - } - } - } - - /* - * If we found clauses in more than one list, we may now have - * clauses that are known redundant. Get rid of 'em. - */ - if (numsources > 1) - { - clausegroup = remove_redundant_join_clauses(root, - clausegroup, - jointype); - } - /* * If no clauses match this key, we're done; we don't want to look * at keys to its right. @@ -401,8 +580,7 @@ group_clauses_by_indexkey_for_join(Query *root, IndexOptInfo *index, } while (!DoneMatchingIndexKeys(classes)); - /* if no join clause was matched then forget it, per comments above */ - if (!jfound) + if (!found_clause) return NIL; return clausegroup_list; @@ -419,7 +597,7 @@ group_clauses_by_indexkey_for_join(Query *root, IndexOptInfo *index, * top-level restriction clauses of the relation. Furthermore, we demand * that at least one such use be made, otherwise we fail and return NIL. * (Any path we made without such a use would be redundant with non-OR - * indexscans. Compare also group_clauses_by_indexkey_for_join.) + * indexscans.) * * XXX When we generate an indexqual list that uses both the OR subclause * and top-level restriction clauses, we end up with a slightly inefficient @@ -446,7 +624,8 @@ group_clauses_by_indexkey_for_or(IndexOptInfo *index, Expr *orsubclause) if (IsA(orsubclause, RestrictInfo)) { if (match_clause_to_indexcol(index, indexcol, curClass, - (RestrictInfo *) orsubclause)) + (RestrictInfo *) orsubclause, + NULL)) { clausegroup = lappend(clausegroup, orsubclause); matched = true; @@ -460,7 +639,8 @@ group_clauses_by_indexkey_for_or(IndexOptInfo *index, Expr *orsubclause) if (IsA(subsubclause, RestrictInfo) && match_clause_to_indexcol(index, indexcol, curClass, - subsubclause)) + subsubclause, + NULL)) { clausegroup = lappend(clausegroup, subsubclause); matched = true; @@ -482,7 +662,8 @@ group_clauses_by_indexkey_for_or(IndexOptInfo *index, Expr *orsubclause) RestrictInfo *rinfo = (RestrictInfo *) lfirst(item); if (match_clause_to_indexcol(index, indexcol, curClass, - rinfo)) + rinfo, + NULL)) clausegroup = lappend(clausegroup, rinfo); } } @@ -520,6 +701,19 @@ group_clauses_by_indexkey_for_or(IndexOptInfo *index, Expr *orsubclause) * 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. @@ -543,7 +737,8 @@ static bool match_clause_to_indexcol(IndexOptInfo *index, int indexcol, Oid opclass, - RestrictInfo *rinfo) + RestrictInfo *rinfo, + Relids outer_relids) { Expr *clause = rinfo->clause; Node *leftop, @@ -566,11 +761,11 @@ match_clause_to_indexcol(IndexOptInfo *index, /* * Check for clauses of the form: (indexkey operator constant) or - * (constant operator indexkey). Anything that is a "pseudo constant" - * expression will do. + * (constant operator indexkey). See above notes about const-ness. */ if (match_index_to_operand(leftop, indexcol, index) && - is_pseudo_constant_clause_relids(rightop, rinfo->right_relids)) + bms_is_subset(rinfo->right_relids, outer_relids) && + !contain_volatile_functions(rightop)) { if (is_indexable_operator(clause, opclass, true)) return true; @@ -585,7 +780,8 @@ match_clause_to_indexcol(IndexOptInfo *index, } if (match_index_to_operand(rightop, indexcol, index) && - is_pseudo_constant_clause_relids(leftop, rinfo->left_relids)) + bms_is_subset(rinfo->left_relids, outer_relids) && + !contain_volatile_functions(leftop)) { if (is_indexable_operator(clause, opclass, false)) return true; @@ -603,90 +799,6 @@ match_clause_to_indexcol(IndexOptInfo *index, } /* - * match_join_clause_to_indexcol() - * Determines whether a join clause matches a column of an index. - * - * To match, the clause: - * - * (1) 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 column, or is a "special" operator as recognized - * by match_special_index_operator(). - * - * The boolean-index cases don't apply. - * - * As above, we must be able to commute the clause to put the indexkey - * on the left. - * - * Note that 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. - * - * 'index' is the index of interest. - * 'indexcol' is a column number of 'index' (counting from 0). - * 'opclass' is the corresponding operator class. - * 'rinfo' is the clause to be tested (as a RestrictInfo node). - * - * 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_join_clause_to_indexcol(IndexOptInfo *index, - int indexcol, - Oid opclass, - RestrictInfo *rinfo) -{ - Expr *clause = rinfo->clause; - Node *leftop, - *rightop; - - /* Clause must be a binary opclause. */ - if (!is_opclause(clause)) - return false; - leftop = get_leftop(clause); - rightop = get_rightop(clause); - if (!leftop || !rightop) - return false; - - /* - * 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 volatile - * functions. - */ - if (match_index_to_operand(leftop, indexcol, index)) - { - Relids othervarnos = rinfo->right_relids; - bool isIndexable; - - isIndexable = - !bms_overlap(index->rel->relids, othervarnos) && - !contain_volatile_functions(rightop) && - is_indexable_operator(clause, opclass, true); - return isIndexable; - } - - if (match_index_to_operand(rightop, indexcol, index)) - { - Relids othervarnos = rinfo->left_relids; - bool isIndexable; - - isIndexable = - !bms_overlap(index->rel->relids, othervarnos) && - !contain_volatile_functions(leftop) && - is_indexable_operator(clause, opclass, false); - return isIndexable; - } - - return false; -} - -/* * indexable_operator * Does a binary opclause contain an operator matching the index opclass? * @@ -1407,63 +1519,123 @@ pred_test_simple_clause(Expr *predicate, Node *clause) /* * indexable_outerrelids * Finds all other relids that participate in any indexable join clause - * for the specified index. Returns a set of relids. + * for the specified table. Returns a set of relids. */ static Relids -indexable_outerrelids(IndexOptInfo *index) +indexable_outerrelids(RelOptInfo *rel) { Relids outer_relids = NULL; ListCell *l; - foreach(l, index->rel->joininfo) + foreach(l, rel->joininfo) { JoinInfo *joininfo = (JoinInfo *) lfirst(l); - bool match_found = false; - ListCell *j; /* * Examine each joinclause in the JoinInfo node's list to see if - * it matches any key of the index. If so, add the JoinInfo's + * it matches any key of any index. If so, add the JoinInfo's * otherrels to the result. We can skip examining other - * joinclauses in the same list as soon as we find a match (since - * by definition they all have the same otherrels). + * joinclauses in the same list as soon as we find a match, since + * by definition they all have the same otherrels. */ - foreach(j, joininfo->jinfo_restrictinfo) - { - RestrictInfo *rinfo = (RestrictInfo *) lfirst(j); - int indexcol = 0; - Oid *classes = index->classlist; + if (list_matches_any_index(joininfo->jinfo_restrictinfo, + rel, + joininfo->unjoined_relids)) + outer_relids = bms_add_members(outer_relids, + joininfo->unjoined_relids); + } - do - { - Oid curClass = classes[0]; + return outer_relids; +} - if (match_join_clause_to_indexcol(index, - indexcol, - curClass, - rinfo)) - { - match_found = true; - break; - } +/* + * list_matches_any_index + * Workhorse for indexable_outerrelids: given a list of RestrictInfos, + * see if any of them match any index of the given rel. + * + * We define it like this so that we can recurse into OR subclauses. + */ +static bool +list_matches_any_index(List *clauses, RelOptInfo *rel, Relids outer_relids) +{ + ListCell *l; - indexcol++; - classes++; + foreach(l, clauses) + { + RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); + ListCell *j; - } while (!DoneMatchingIndexKeys(classes)); + Assert(IsA(rinfo, RestrictInfo)); - if (match_found) - break; + /* RestrictInfos that aren't ORs are easy */ + if (!restriction_is_or_clause(rinfo)) + { + if (matches_any_index(rinfo, rel, outer_relids)) + return true; + continue; } - if (match_found) + foreach(j, ((BoolExpr *) rinfo->orclause)->args) { - outer_relids = bms_add_members(outer_relids, - joininfo->unjoined_relids); + Node *orarg = (Node *) lfirst(j); + + /* OR arguments should be ANDs or sub-RestrictInfos */ + if (and_clause(orarg)) + { + List *andargs = ((BoolExpr *) orarg)->args; + + /* Recurse to examine AND items and sub-ORs */ + if (list_matches_any_index(andargs, rel, outer_relids)) + return true; + } + else + { + Assert(IsA(orarg, RestrictInfo)); + Assert(!restriction_is_or_clause((RestrictInfo *) orarg)); + if (matches_any_index((RestrictInfo *) orarg, rel, + outer_relids)) + return true; + } } } - return outer_relids; + return false; +} + +/* + * matches_any_index + * Workhorse for indexable_outerrelids: see if a simple 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; + + /* Normal case for a simple restriction clause */ + foreach(l, rel->indexlist) + { + IndexOptInfo *index = (IndexOptInfo *) lfirst(l); + int indexcol = 0; + Oid *classes = index->classlist; + + do + { + Oid curClass = classes[0]; + + if (match_clause_to_indexcol(index, + indexcol, + curClass, + rinfo, + outer_relids)) + return true; + + indexcol++; + classes++; + } while (!DoneMatchingIndexKeys(classes)); + } + + return false; } /* @@ -1483,10 +1655,12 @@ Path * best_inner_indexscan(Query *root, RelOptInfo *rel, Relids outer_relids, JoinType jointype) { - Path *cheapest = NULL; + Path *cheapest; bool isouterjoin; - ListCell *ilist; - ListCell *jlist; + List *clause_list; + List *indexpaths; + List *bitindexpaths; + ListCell *l; InnerIndexscanInfo *info; MemoryContext oldcontext; @@ -1523,7 +1697,7 @@ best_inner_indexscan(Query *root, RelOptInfo *rel, /* * Intersect the given outer_relids with index_outer_relids to find - * the set of outer relids actually relevant for this index. If there + * 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_relids); @@ -1541,9 +1715,9 @@ best_inner_indexscan(Query *root, RelOptInfo *rel, * necessary because it should always be the same for a given * innerrel.) */ - foreach(jlist, rel->index_inner_paths) + foreach(l, rel->index_inner_paths) { - info = (InnerIndexscanInfo *) lfirst(jlist); + info = (InnerIndexscanInfo *) lfirst(l); if (bms_equal(info->other_relids, outer_relids) && info->isouterjoin == isouterjoin) { @@ -1554,69 +1728,57 @@ best_inner_indexscan(Query *root, RelOptInfo *rel, } /* - * For each index of the rel, find the best path; then choose the best - * overall. We cache the per-index results as well as the overall - * result. (This is useful because different indexes may have - * different relevant outerrel sets, so different overall outerrel - * sets might still map to the same computation for a given index.) + * Find all the relevant restriction and join clauses. */ - foreach(ilist, rel->indexlist) - { - IndexOptInfo *index = (IndexOptInfo *) lfirst(ilist); - Relids index_outer_relids; - Path *path = NULL; + clause_list = find_clauses_for_join(root, rel, outer_relids, isouterjoin); - /* identify set of relevant outer relids for this index */ - index_outer_relids = bms_intersect(index->outer_relids, outer_relids); - /* skip if none */ - if (bms_is_empty(index_outer_relids)) - { - bms_free(index_outer_relids); - continue; - } + /* + * Find all the index paths that are usable for this join, except for + * stuff involving OR clauses. + */ + indexpaths = find_usable_indexes(root, rel, + clause_list, NIL, + false, true, + outer_relids); - /* - * Look to see if we already computed the result for this index. - */ - foreach(jlist, index->inner_paths) - { - info = (InnerIndexscanInfo *) lfirst(jlist); - if (bms_equal(info->other_relids, index_outer_relids) && - info->isouterjoin == isouterjoin) - { - path = info->best_innerpath; - bms_free(index_outer_relids); /* not needed anymore */ - break; - } - } + /* + * Generate BitmapOrPaths for any suitable OR-clauses present in the + * clause list. + */ + bitindexpaths = generate_bitmap_or_paths(root, rel, + clause_list, NIL, + true, + outer_relids); - if (jlist == NULL) /* failed to find a match? */ - { - List *clausegroups; - - /* find useful clauses for this index and outerjoin set */ - clausegroups = group_clauses_by_indexkey_for_join(root, - index, - index_outer_relids, - jointype, - isouterjoin); - if (clausegroups) - { - /* make the path */ - path = make_innerjoin_index_path(root, index, clausegroups); - } + /* + * Include the regular index paths in bitindexpaths. + */ + bitindexpaths = list_concat(bitindexpaths, list_copy(indexpaths)); - /* Cache the result --- whether positive or negative */ - info = makeNode(InnerIndexscanInfo); - info->other_relids = index_outer_relids; - info->isouterjoin = isouterjoin; - info->best_innerpath = path; - index->inner_paths = lcons(info, index->inner_paths); - } + /* + * 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); + bpath = create_bitmap_heap_path(root, rel, bitmapqual, true); + indexpaths = lappend(indexpaths, bpath); + } - if (path != NULL && - (cheapest == NULL || - compare_path_costs(path, cheapest, TOTAL_COST) < 0)) + /* + * 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; } @@ -1632,89 +1794,96 @@ best_inner_indexscan(Query *root, RelOptInfo *rel, return cheapest; } -/**************************************************************************** - * ---- PATH CREATION UTILITIES ---- - ****************************************************************************/ - /* - * make_innerjoin_index_path - * Create an index path node for a path to be used as an inner - * relation in a nestloop join. - * - * 'index' is the index of interest - * 'clausegroups' is a list of lists of RestrictInfos that can use 'index' + * 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 Path * -make_innerjoin_index_path(Query *root, - IndexOptInfo *index, - List *clausegroups) +static List * +find_clauses_for_join(Query *root, RelOptInfo *rel, + Relids outer_relids, bool isouterjoin) { - IndexPath *pathnode = makeNode(IndexPath); - RelOptInfo *rel = index->rel; - List *indexquals, - *allclauses; - - /* XXX perhaps this code should be merged with create_index_path? */ - - pathnode->path.pathtype = T_IndexScan; - pathnode->path.parent = rel; + List *clause_list = NIL; + bool jfound = false; + int numsources; + ListCell *l; /* - * 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. + * We can always use plain restriction clauses for the rel. We + * scan these first because we want them first in the clause + * list for the convenience of remove_redundant_join_clauses, + * which can never remove non-join clauses and hence won't be able + * to get rid of a non-join clause if it appears after a join + * clause it is redundant with. */ - pathnode->path.pathkeys = NIL; + foreach(l, rel->baserestrictinfo) + { + RestrictInfo *rinfo = (RestrictInfo *) lfirst(l); - /* Convert clauses to indexquals the executor can handle */ - indexquals = expand_indexqual_conditions(index, clausegroups); + /* Can't use pushed-down clauses in outer join */ + if (isouterjoin && rinfo->is_pushed_down) + continue; + clause_list = lappend(clause_list, rinfo); + } - /* Flatten the clausegroups list to produce indexclauses list */ - allclauses = flatten_clausegroups_list(clausegroups); + /* found anything in base restrict list? */ + numsources = (clause_list != NIL) ? 1 : 0; - /* - * Note that we are making a pathnode for a single-scan indexscan; - * therefore, indexinfo etc should be single-element lists. - */ - pathnode->indexinfo = list_make1(index); - pathnode->indexclauses = list_make1(allclauses); - pathnode->indexquals = list_make1(indexquals); + /* Look for joinclauses that are usable with given outer_relids */ + foreach(l, rel->joininfo) + { + JoinInfo *joininfo = (JoinInfo *) lfirst(l); + bool jfoundhere = false; + ListCell *j; - pathnode->isjoininner = true; + if (!bms_is_subset(joininfo->unjoined_relids, outer_relids)) + continue; - /* We don't actually care what order the index scans in ... */ - pathnode->indexscandir = NoMovementScanDirection; + foreach(j, joininfo->jinfo_restrictinfo) + { + RestrictInfo *rinfo = (RestrictInfo *) lfirst(j); + + /* Can't use pushed-down clauses in outer join */ + if (isouterjoin && rinfo->is_pushed_down) + continue; + + clause_list = lappend(clause_list, rinfo); + if (!jfoundhere) + { + jfoundhere = true; + jfound = true; + numsources++; + } + } + } + + /* if no join clause was matched then forget it, per comments above */ + if (!jfound) + return NIL; /* - * 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 clausegroups 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. (Without the union operation, we might have - * some restriction clauses appearing twice, which'd mislead - * clauselist_selectivity into double-counting their selectivity. - * However, since RestrictInfo nodes aren't copied when linking them - * into different lists, it should be sufficient to use pointer - * comparison to remove duplicates.) - * - * Always assume the join type is JOIN_INNER; even if some of the join - * clauses come from other contexts, that's not our problem. + * If we found clauses in more than one list, we may now have + * clauses that are known redundant. Get rid of 'em. */ - allclauses = list_union_ptr(rel->baserestrictinfo, allclauses); - pathnode->rows = rel->tuples * - clauselist_selectivity(root, - allclauses, - rel->relid, /* do not use 0! */ - JOIN_INNER); - /* Like costsize.c, force estimate to be at least one row */ - pathnode->rows = clamp_row_est(pathnode->rows); - - cost_index(pathnode, root, index, indexquals, true); - - return (Path *) pathnode; + if (numsources > 1) + { + clause_list = remove_redundant_join_clauses(root, + clause_list, + isouterjoin); + } + + return clause_list; } +/**************************************************************************** + * ---- PATH CREATION UTILITIES ---- + ****************************************************************************/ + /* * flatten_clausegroups_list * Given a list of lists of RestrictInfos, flatten it to a list |