/*------------------------------------------------------------------------- * * make_join_rel.c * Routines copied from PostgreSQL core distribution with some * modifications. * * src/backend/optimizer/path/joinrels.c * * This file contains the following functions from corresponding files. * * static functions: * make_join_rel() * populate_joinrel_with_paths() * * Portions Copyright (c) 2013-2023, NIPPON TELEGRAPH AND TELEPHONE CORPORATION * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * *------------------------------------------------------------------------- */ /* * adjust_rows: tweak estimated row numbers according to the hint. */ static double adjust_rows(double rows, RowsHint *hint) { double result = 0.0; /* keep compiler quiet */ if (hint->value_type == RVT_ABSOLUTE) result = hint->rows; else if (hint->value_type == RVT_ADD) result = rows + hint->rows; else if (hint->value_type == RVT_SUB) result = rows - hint->rows; else if (hint->value_type == RVT_MULTI) result = rows * hint->rows; else Assert(false); /* unrecognized rows value type */ hint->base.state = HINT_STATE_USED; if (result < 1.0) ereport(WARNING, (errmsg("Force estimate to be at least one row, to avoid possible divide-by-zero when interpolating costs : %s", hint->base.hint_str))); result = clamp_row_est(result); elog(DEBUG1, "adjusted rows %d to %d", (int) rows, (int) result); return result; } /* * make_join_rel * Find or create a join RelOptInfo that represents the join of * the two given rels, and add to it path information for paths * created with the two rels as outer and inner rel. * (The join rel may already contain paths generated from other * pairs of rels that add up to the same set of base rels.) * * NB: will return NULL if attempted join is not valid. This can happen * when working with outer joins, or with IN or EXISTS clauses that have been * turned into joins. */ RelOptInfo * make_join_rel(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2) { Relids joinrelids; SpecialJoinInfo *sjinfo; bool reversed; SpecialJoinInfo sjinfo_data; RelOptInfo *joinrel; List *restrictlist; /* We should never try to join two overlapping sets of rels. */ Assert(!bms_overlap(rel1->relids, rel2->relids)); /* Construct Relids set that identifies the joinrel. */ joinrelids = bms_union(rel1->relids, rel2->relids); /* Check validity and determine join type. */ if (!join_is_legal(root, rel1, rel2, joinrelids, &sjinfo, &reversed)) { /* invalid join path */ bms_free(joinrelids); return NULL; } /* Swap rels if needed to match the join info. */ if (reversed) { RelOptInfo *trel = rel1; rel1 = rel2; rel2 = trel; } /* * If it's a plain inner join, then we won't have found anything in * join_info_list. Make up a SpecialJoinInfo so that selectivity * estimation functions will know what's being joined. */ if (sjinfo == NULL) { sjinfo = &sjinfo_data; sjinfo->type = T_SpecialJoinInfo; sjinfo->min_lefthand = rel1->relids; sjinfo->min_righthand = rel2->relids; sjinfo->syn_lefthand = rel1->relids; sjinfo->syn_righthand = rel2->relids; sjinfo->jointype = JOIN_INNER; /* we don't bother trying to make the remaining fields valid */ sjinfo->lhs_strict = false; sjinfo->delay_upper_joins = false; sjinfo->semi_can_btree = false; sjinfo->semi_can_hash = false; sjinfo->semi_operators = NIL; sjinfo->semi_rhs_exprs = NIL; } /* * Find or build the join RelOptInfo, and compute the restrictlist that * goes with this particular joining. */ joinrel = build_join_rel(root, joinrelids, rel1, rel2, sjinfo, &restrictlist); /* !!! START: HERE IS THE PART WHICH IS ADDED FOR PG_HINT_PLAN !!! */ { RowsHint *rows_hint = NULL; int i; RowsHint *justforme = NULL; RowsHint *domultiply = NULL; /* Search for applicable rows hint for this join node */ for (i = 0; i < current_hint_state->num_hints[HINT_TYPE_ROWS]; i++) { rows_hint = current_hint_state->rows_hints[i]; /* * Skip this rows_hint if it is invalid from the first or it * doesn't target any join rels. */ if (!rows_hint->joinrelids || rows_hint->base.state == HINT_STATE_ERROR) continue; if (bms_equal(joinrelids, rows_hint->joinrelids)) { /* * This joinrel is just the target of this rows_hint, so tweak * rows estimation according to the hint. */ justforme = rows_hint; } else if (!(bms_is_subset(rows_hint->joinrelids, rel1->relids) || bms_is_subset(rows_hint->joinrelids, rel2->relids)) && bms_is_subset(rows_hint->joinrelids, joinrelids) && rows_hint->value_type == RVT_MULTI) { /* * If the rows_hint's target relids is not a subset of both of * component rels and is a subset of this joinrel, ths hint's * targets spread over both component rels. This menas that * this hint has been never applied so far and this joinrel is * the first (and only) chance to fire in current join tree. * Only the multiplication hint has the cumulative nature so we * apply only RVT_MULTI in this way. */ domultiply = rows_hint; } } if (justforme) { /* * If a hint just for me is found, no other adjust method is * useles, but this cannot be more than twice becuase this joinrel * is already adjusted by this hint. */ if (justforme->base.state == HINT_STATE_NOTUSED) joinrel->rows = adjust_rows(joinrel->rows, justforme); } else { if (domultiply) { /* * If we have multiple routes up to this joinrel which are not * applicable this hint, this multiply hint will applied more * than twice. But there's no means to know of that, * re-estimate the row number of this joinrel always just * before applying the hint. This is a bit different from * normal planner behavior but it doesn't harm so much. */ set_joinrel_size_estimates(root, joinrel, rel1, rel2, sjinfo, restrictlist); joinrel->rows = adjust_rows(joinrel->rows, domultiply); } } } /* !!! END: HERE IS THE PART WHICH IS ADDED FOR PG_HINT_PLAN !!! */ /* * If we've already proven this join is empty, we needn't consider any * more paths for it. */ if (is_dummy_rel(joinrel)) { bms_free(joinrelids); return joinrel; } /* Add paths to the join relation. */ populate_joinrel_with_paths(root, rel1, rel2, joinrel, sjinfo, restrictlist); bms_free(joinrelids); return joinrel; } /* * populate_joinrel_with_paths * Add paths to the given joinrel for given pair of joining relations. The * SpecialJoinInfo provides details about the join and the restrictlist * contains the join clauses and the other clauses applicable for given pair * of the joining relations. */ static void populate_joinrel_with_paths(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2, RelOptInfo *joinrel, SpecialJoinInfo *sjinfo, List *restrictlist) { /* * Consider paths using each rel as both outer and inner. Depending on * the join type, a provably empty outer or inner rel might mean the join * is provably empty too; in which case throw away any previously computed * paths and mark the join as dummy. (We do it this way since it's * conceivable that dummy-ness of a multi-element join might only be * noticeable for certain construction paths.) * * Also, a provably constant-false join restriction typically means that * we can skip evaluating one or both sides of the join. We do this by * marking the appropriate rel as dummy. For outer joins, a * constant-false restriction that is pushed down still means the whole * join is dummy, while a non-pushed-down one means that no inner rows * will join so we can treat the inner rel as dummy. * * We need only consider the jointypes that appear in join_info_list, plus * JOIN_INNER. */ switch (sjinfo->jointype) { case JOIN_INNER: if (is_dummy_rel(rel1) || is_dummy_rel(rel2) || restriction_is_constant_false(restrictlist, joinrel, false)) { mark_dummy_rel(joinrel); break; } add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_INNER, sjinfo, restrictlist); add_paths_to_joinrel(root, joinrel, rel2, rel1, JOIN_INNER, sjinfo, restrictlist); break; case JOIN_LEFT: if (is_dummy_rel(rel1) || restriction_is_constant_false(restrictlist, joinrel, true)) { mark_dummy_rel(joinrel); break; } if (restriction_is_constant_false(restrictlist, joinrel, false) && bms_is_subset(rel2->relids, sjinfo->syn_righthand)) mark_dummy_rel(rel2); add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_LEFT, sjinfo, restrictlist); add_paths_to_joinrel(root, joinrel, rel2, rel1, JOIN_RIGHT, sjinfo, restrictlist); break; case JOIN_FULL: if ((is_dummy_rel(rel1) && is_dummy_rel(rel2)) || restriction_is_constant_false(restrictlist, joinrel, true)) { mark_dummy_rel(joinrel); break; } add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_FULL, sjinfo, restrictlist); add_paths_to_joinrel(root, joinrel, rel2, rel1, JOIN_FULL, sjinfo, restrictlist); /* * If there are join quals that aren't mergeable or hashable, we * may not be able to build any valid plan. Complain here so that * we can give a somewhat-useful error message. (Since we have no * flexibility of planning for a full join, there's no chance of * succeeding later with another pair of input rels.) */ if (joinrel->pathlist == NIL) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("FULL JOIN is only supported with merge-joinable or hash-joinable join conditions"))); break; case JOIN_SEMI: /* * We might have a normal semijoin, or a case where we don't have * enough rels to do the semijoin but can unique-ify the RHS and * then do an innerjoin (see comments in join_is_legal). In the * latter case we can't apply JOIN_SEMI joining. */ if (bms_is_subset(sjinfo->min_lefthand, rel1->relids) && bms_is_subset(sjinfo->min_righthand, rel2->relids)) { if (is_dummy_rel(rel1) || is_dummy_rel(rel2) || restriction_is_constant_false(restrictlist, joinrel, false)) { mark_dummy_rel(joinrel); break; } add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_SEMI, sjinfo, restrictlist); } /* * If we know how to unique-ify the RHS and one input rel is * exactly the RHS (not a superset) we can consider unique-ifying * it and then doing a regular join. (The create_unique_path * check here is probably redundant with what join_is_legal did, * but if so the check is cheap because it's cached. So test * anyway to be sure.) */ if (bms_equal(sjinfo->syn_righthand, rel2->relids) && create_unique_path(root, rel2, rel2->cheapest_total_path, sjinfo) != NULL) { if (is_dummy_rel(rel1) || is_dummy_rel(rel2) || restriction_is_constant_false(restrictlist, joinrel, false)) { mark_dummy_rel(joinrel); break; } add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_UNIQUE_INNER, sjinfo, restrictlist); add_paths_to_joinrel(root, joinrel, rel2, rel1, JOIN_UNIQUE_OUTER, sjinfo, restrictlist); } break; case JOIN_ANTI: if (is_dummy_rel(rel1) || restriction_is_constant_false(restrictlist, joinrel, true)) { mark_dummy_rel(joinrel); break; } if (restriction_is_constant_false(restrictlist, joinrel, false) && bms_is_subset(rel2->relids, sjinfo->syn_righthand)) mark_dummy_rel(rel2); add_paths_to_joinrel(root, joinrel, rel1, rel2, JOIN_ANTI, sjinfo, restrictlist); break; default: /* other values not expected here */ elog(ERROR, "unrecognized join type: %d", (int) sjinfo->jointype); break; } /* Apply partitionwise join technique, if possible. */ try_partitionwise_join(root, rel1, rel2, joinrel, sjinfo, restrictlist); }