diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/util/placeholder.c | 28 | ||||
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 23 | ||||
| -rw-r--r-- | src/test/regress/expected/join.out | 4 |
3 files changed, 36 insertions, 19 deletions
diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c index 8a114fe9465..c7bfa293c9f 100644 --- a/src/backend/optimizer/util/placeholder.c +++ b/src/backend/optimizer/util/placeholder.c @@ -427,14 +427,16 @@ add_placeholders_to_base_rels(PlannerInfo *root) /* * add_placeholders_to_joinrel - * Add any required PlaceHolderVars to a join rel's targetlist; - * and if they contain lateral references, add those references to the - * joinrel's direct_lateral_relids. + * Add any newly-computable PlaceHolderVars to a join rel's targetlist; + * and if computable PHVs contain lateral references, add those + * references to the joinrel's direct_lateral_relids. * * A join rel should emit a PlaceHolderVar if (a) the PHV can be computed * at or below this join level and (b) the PHV is needed above this level. - * However, condition (a) is sufficient to add to direct_lateral_relids, - * as explained below. + * Our caller build_join_rel() has already added any PHVs that were computed + * in either join input rel, so we need add only newly-computable ones to + * the targetlist. However, direct_lateral_relids must be updated for every + * PHV computable at or below this join, as explained below. */ void add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel, @@ -453,13 +455,10 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel, /* Is it still needed above this joinrel? */ if (bms_nonempty_difference(phinfo->ph_needed, relids)) { - /* Yup, add it to the output */ - joinrel->reltarget->exprs = lappend(joinrel->reltarget->exprs, - phinfo->ph_var); - joinrel->reltarget->width += phinfo->ph_width; - /* - * Charge the cost of evaluating the contained expression if + * Yes, but only add to tlist if it wasn't computed in either + * input; otherwise it should be there already. Also, we + * charge the cost of evaluating the contained expression if * the PHV can be computed here but not in either input. This * is a bit bogus because we make the decision based on the * first pair of possible input relations considered for the @@ -472,12 +471,15 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel, if (!bms_is_subset(phinfo->ph_eval_at, outer_rel->relids) && !bms_is_subset(phinfo->ph_eval_at, inner_rel->relids)) { + PlaceHolderVar *phv = phinfo->ph_var; QualCost cost; - cost_qual_eval_node(&cost, (Node *) phinfo->ph_var->phexpr, - root); + joinrel->reltarget->exprs = lappend(joinrel->reltarget->exprs, + phv); + cost_qual_eval_node(&cost, (Node *) phv->phexpr, root); joinrel->reltarget->cost.startup += cost.startup; joinrel->reltarget->cost.per_tuple += cost.per_tuple; + joinrel->reltarget->width += phinfo->ph_width; } } diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index 520409f4ba0..965eb5b3b45 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -679,8 +679,9 @@ build_join_rel(PlannerInfo *root, set_foreign_rel_properties(joinrel, outer_rel, inner_rel); /* - * Create a new tlist containing just the vars that need to be output from - * this join (ie, are needed for higher joinclauses or final output). + * Fill the joinrel's tlist with just the Vars and PHVs that need to be + * output from this join (ie, are needed for higher joinclauses or final + * output). * * NOTE: the tlist order for a join rel will depend on which pair of outer * and inner rels we first try to build it from. But the contents should @@ -966,6 +967,7 @@ min_join_parameterization(PlannerInfo *root, * The join's targetlist includes all Vars of its member relations that * will still be needed above the join. This subroutine adds all such * Vars from the specified input rel's tlist to the join rel's tlist. + * Likewise for any PlaceHolderVars emitted by the input rel. * * We also compute the expected width of the join's output, making use * of data that was cached at the baserel level by set_rel_width(). @@ -982,11 +984,24 @@ build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel, Var *var = (Var *) lfirst(vars); /* - * Ignore PlaceHolderVars in the input tlists; we'll make our own - * decisions about whether to copy them. + * For a PlaceHolderVar, we have to look up the PlaceHolderInfo. */ if (IsA(var, PlaceHolderVar)) + { + PlaceHolderVar *phv = (PlaceHolderVar *) var; + PlaceHolderInfo *phinfo = find_placeholder_info(root, phv); + + /* Is it still needed above this joinrel? */ + if (bms_nonempty_difference(phinfo->ph_needed, relids)) + { + /* Yup, add it to the output */ + joinrel->reltarget->exprs = lappend(joinrel->reltarget->exprs, + phv); + /* Bubbling up the precomputed result has cost zero */ + joinrel->reltarget->width += phinfo->ph_width; + } continue; + } /* * Otherwise, anything in a baserel or joinrel targetlist ought to be diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out index b9853af2dc8..2ed2e542a44 100644 --- a/src/test/regress/expected/join.out +++ b/src/test/regress/expected/join.out @@ -5793,10 +5793,10 @@ select * from Nested Loop Output: c.q1, c.q2, a.q1, a.q2, b.q1, (COALESCE(b.q2, '42'::bigint)), d.q1, (COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2)), ((COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2))) -> Hash Right Join - Output: c.q1, c.q2, a.q1, a.q2, b.q1, d.q1, (COALESCE(b.q2, '42'::bigint)), (COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2)) + Output: c.q1, c.q2, a.q1, a.q2, b.q1, (COALESCE(b.q2, '42'::bigint)), d.q1, (COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2)) Hash Cond: (d.q1 = c.q2) -> Nested Loop - Output: a.q1, a.q2, b.q1, d.q1, (COALESCE(b.q2, '42'::bigint)), (COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2)) + Output: a.q1, a.q2, b.q1, (COALESCE(b.q2, '42'::bigint)), d.q1, (COALESCE((COALESCE(b.q2, '42'::bigint)), d.q2)) -> Hash Left Join Output: a.q1, a.q2, b.q1, (COALESCE(b.q2, '42'::bigint)) Hash Cond: (a.q2 = b.q1) |