diff options
Diffstat (limited to 'src/backend/optimizer/plan/analyzejoins.c')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 160 |
1 files changed, 145 insertions, 15 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index be19167e4a2..4d55c2ea591 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -74,6 +74,8 @@ static bool is_innerrel_unique_for(PlannerInfo *root, List *restrictlist, List **extra_clauses); static int self_join_candidates_cmp(const void *a, const void *b); +static bool replace_relid_callback(Node *node, + ChangeVarNodes_context *context); /* @@ -397,7 +399,8 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel, { Assert(subst > 0); - ChangeVarNodes((Node *) sjinf->semi_rhs_exprs, relid, subst, 0); + ChangeVarNodesExtended((Node *) sjinf->semi_rhs_exprs, relid, subst, + 0, replace_relid_callback); } } @@ -469,7 +472,8 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel, sjinfo->ojrelid, subst); Assert(!bms_is_empty(phv->phrels)); - ChangeVarNodes((Node *) phv->phexpr, relid, subst, 0); + ChangeVarNodesExtended((Node *) phv->phexpr, relid, subst, 0, + replace_relid_callback); Assert(phv->phnullingrels == NULL); /* no need to adjust */ } @@ -523,7 +527,8 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel, } if (subst > 0) - ChangeVarNodes((Node *) otherrel->lateral_vars, relid, subst, 0); + ChangeVarNodesExtended((Node *) otherrel->lateral_vars, relid, + subst, 0, replace_relid_callback); } } @@ -757,7 +762,8 @@ remove_rel_from_eclass(EquivalenceClass *ec, SpecialJoinInfo *sjinfo, RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc); if (sjinfo == NULL) - ChangeVarNodes((Node *) rinfo, relid, subst, 0); + ChangeVarNodesExtended((Node *) rinfo, relid, subst, 0, + replace_relid_callback); else remove_rel_from_restrictinfo(rinfo, relid, sjinfo->ojrelid); } @@ -1548,7 +1554,8 @@ update_eclasses(EquivalenceClass *ec, int from, int to) em->em_jdomain->jd_relids = adjust_relid_set(em->em_jdomain->jd_relids, from, to); /* We only process inner joins */ - ChangeVarNodes((Node *) em->em_expr, from, to, 0); + ChangeVarNodesExtended((Node *) em->em_expr, from, to, 0, + replace_relid_callback); foreach_node(EquivalenceMember, other, new_members) { @@ -1582,7 +1589,8 @@ update_eclasses(EquivalenceClass *ec, int from, int to) continue; } - ChangeVarNodes((Node *) rinfo, from, to, 0); + ChangeVarNodesExtended((Node *) rinfo, from, to, 0, + replace_relid_callback); /* * After switching the clause to the remaining relation, check it for @@ -1678,6 +1686,118 @@ add_non_redundant_clauses(PlannerInfo *root, } /* + * A custom callback for ChangeVarNodesExtended() providing + * Self-join elimination (SJE) related functionality + * + * SJE needs to skip the RangeTblRef node + * type. During SJE's last step, remove_rel_from_joinlist() removes + * remaining RangeTblRefs with target relid. If ChangeVarNodes() replaces + * the target relid before, remove_rel_from_joinlist() fails to identify + * the nodes to delete. + * + * SJE also needs to change the relids within RestrictInfo's. + */ +static bool +replace_relid_callback(Node *node, ChangeVarNodes_context *context) +{ + if (IsA(node, RangeTblRef)) + { + return true; + } + else if (IsA(node, RestrictInfo)) + { + RestrictInfo *rinfo = (RestrictInfo *) node; + int relid = -1; + bool is_req_equal = + (rinfo->required_relids == rinfo->clause_relids); + bool clause_relids_is_multiple = + (bms_membership(rinfo->clause_relids) == BMS_MULTIPLE); + + /* + * Recurse down into clauses if the target relation is present in + * clause_relids or required_relids. We must check required_relids + * because the relation not present in clause_relids might still be + * present somewhere in orclause. + */ + if (bms_is_member(context->rt_index, rinfo->clause_relids) || + bms_is_member(context->rt_index, rinfo->required_relids)) + { + Relids new_clause_relids; + + ChangeVarNodesWalkExpression((Node *) rinfo->clause, context); + ChangeVarNodesWalkExpression((Node *) rinfo->orclause, context); + + new_clause_relids = adjust_relid_set(rinfo->clause_relids, + context->rt_index, + context->new_index); + + /* + * Incrementally adjust num_base_rels based on the change of + * clause_relids, which could contain both base relids and + * outer-join relids. This operation is legal until we remove + * only baserels. + */ + rinfo->num_base_rels -= bms_num_members(rinfo->clause_relids) - + bms_num_members(new_clause_relids); + + rinfo->clause_relids = new_clause_relids; + rinfo->left_relids = + adjust_relid_set(rinfo->left_relids, context->rt_index, context->new_index); + rinfo->right_relids = + adjust_relid_set(rinfo->right_relids, context->rt_index, context->new_index); + } + + if (is_req_equal) + rinfo->required_relids = rinfo->clause_relids; + else + rinfo->required_relids = + adjust_relid_set(rinfo->required_relids, context->rt_index, context->new_index); + + rinfo->outer_relids = + adjust_relid_set(rinfo->outer_relids, context->rt_index, context->new_index); + rinfo->incompatible_relids = + adjust_relid_set(rinfo->incompatible_relids, context->rt_index, context->new_index); + + if (rinfo->mergeopfamilies && + bms_get_singleton_member(rinfo->clause_relids, &relid) && + clause_relids_is_multiple && + relid == context->new_index && IsA(rinfo->clause, OpExpr)) + { + Expr *leftOp; + Expr *rightOp; + + leftOp = (Expr *) get_leftop(rinfo->clause); + rightOp = (Expr *) get_rightop(rinfo->clause); + + /* + * For self-join elimination, changing varnos could transform + * "t1.a = t2.a" into "t1.a = t1.a". That is always true as long + * as "t1.a" is not null. We use qual() to check for such a case, + * and then we replace the qual for a check for not null + * (NullTest). + */ + if (leftOp != NULL && equal(leftOp, rightOp)) + { + NullTest *ntest = makeNode(NullTest); + + ntest->arg = leftOp; + ntest->nulltesttype = IS_NOT_NULL; + ntest->argisrow = false; + ntest->location = -1; + rinfo->clause = (Expr *) ntest; + rinfo->mergeopfamilies = NIL; + rinfo->left_em = NULL; + rinfo->right_em = NULL; + } + Assert(rinfo->orclause == NULL); + } + return true; + } + + return false; +} + +/* * Remove a relation after we have proven that it participates only in an * unneeded unique self-join. * @@ -1725,7 +1845,8 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark, foreach_node(RestrictInfo, rinfo, joininfos) { remove_join_clause_from_rels(root, rinfo, rinfo->required_relids); - ChangeVarNodes((Node *) rinfo, toRemove->relid, toKeep->relid, 0); + ChangeVarNodesExtended((Node *) rinfo, toRemove->relid, toKeep->relid, + 0, replace_relid_callback); if (bms_membership(rinfo->required_relids) == BMS_MULTIPLE) jinfo_candidates = lappend(jinfo_candidates, rinfo); @@ -1743,7 +1864,8 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark, restrictlist); foreach_node(RestrictInfo, rinfo, toRemove->baserestrictinfo) { - ChangeVarNodes((Node *) rinfo, toRemove->relid, toKeep->relid, 0); + ChangeVarNodesExtended((Node *) rinfo, toRemove->relid, toKeep->relid, + 0, replace_relid_callback); if (bms_membership(rinfo->required_relids) == BMS_MULTIPLE) jinfo_candidates = lappend(jinfo_candidates, rinfo); @@ -1785,7 +1907,8 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark, { Node *node = lfirst(lc); - ChangeVarNodes(node, toRemove->relid, toKeep->relid, 0); + ChangeVarNodesExtended(node, toRemove->relid, toKeep->relid, 0, + replace_relid_callback); if (!list_member(toKeep->reltarget->exprs, node)) toKeep->reltarget->exprs = lappend(toKeep->reltarget->exprs, node); } @@ -1829,14 +1952,18 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark, * Replace varno in all the query structures, except nodes RangeTblRef * otherwise later remove_rel_from_joinlist will yield errors. */ - ChangeVarNodesExtended((Node *) root->parse, toRemove->relid, toKeep->relid, 0, false); + ChangeVarNodesExtended((Node *) root->parse, toRemove->relid, toKeep->relid, + 0, replace_relid_callback); /* Replace links in the planner info */ remove_rel_from_query(root, toRemove, toKeep->relid, NULL, NULL); /* At last, replace varno in root targetlist and HAVING clause */ - ChangeVarNodes((Node *) root->processed_tlist, toRemove->relid, toKeep->relid, 0); - ChangeVarNodes((Node *) root->processed_groupClause, toRemove->relid, toKeep->relid, 0); + ChangeVarNodesExtended((Node *) root->processed_tlist, toRemove->relid, + toKeep->relid, 0, replace_relid_callback); + ChangeVarNodesExtended((Node *) root->processed_groupClause, + toRemove->relid, toKeep->relid, 0, + replace_relid_callback); adjust_relid_set(root->all_result_relids, toRemove->relid, toKeep->relid); adjust_relid_set(root->leaf_result_relids, toRemove->relid, toKeep->relid); @@ -1919,8 +2046,10 @@ split_selfjoin_quals(PlannerInfo *root, List *joinquals, List **selfjoinquals, * when we have cast of the same var to different (but compatible) * types. */ - ChangeVarNodes(rightexpr, bms_singleton_member(rinfo->right_relids), - bms_singleton_member(rinfo->left_relids), 0); + ChangeVarNodesExtended(rightexpr, + bms_singleton_member(rinfo->right_relids), + bms_singleton_member(rinfo->left_relids), 0, + replace_relid_callback); if (equal(leftexpr, rightexpr)) sjoinquals = lappend(sjoinquals, rinfo); @@ -1956,7 +2085,8 @@ match_unique_clauses(PlannerInfo *root, RelOptInfo *outer, List *uclauses, bms_is_empty(rinfo->right_relids)); clause = (Expr *) copyObject(rinfo->clause); - ChangeVarNodes((Node *) clause, relid, outer->relid, 0); + ChangeVarNodesExtended((Node *) clause, relid, outer->relid, 0, + replace_relid_callback); iclause = bms_is_empty(rinfo->left_relids) ? get_rightop(clause) : get_leftop(clause); |