diff options
Diffstat (limited to 'src/backend/optimizer/util/placeholder.c')
| -rw-r--r-- | src/backend/optimizer/util/placeholder.c | 40 |
1 files changed, 32 insertions, 8 deletions
diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c index d95426555b6..4af06ab73e5 100644 --- a/src/backend/optimizer/util/placeholder.c +++ b/src/backend/optimizer/util/placeholder.c @@ -16,6 +16,7 @@ #include "postgres.h" #include "nodes/nodeFuncs.h" +#include "optimizer/cost.h" #include "optimizer/pathnode.h" #include "optimizer/placeholder.h" #include "optimizer/planmain.h" @@ -388,8 +389,9 @@ add_placeholders_to_base_rels(PlannerInfo *root) { RelOptInfo *rel = find_base_rel(root, varno); - rel->reltargetlist = lappend(rel->reltargetlist, - copyObject(phinfo->ph_var)); + rel->reltarget.exprs = lappend(rel->reltarget.exprs, + copyObject(phinfo->ph_var)); + /* reltarget's cost and width fields will be updated later */ } } } @@ -402,11 +404,10 @@ add_placeholders_to_base_rels(PlannerInfo *root) * * A join rel should emit a PlaceHolderVar if (a) the PHV is needed above * this join level and (b) the PHV can be computed at or below this level. - * At this time we do not need to distinguish whether the PHV will be - * computed here or copied up from below. */ void -add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel) +add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel, + RelOptInfo *outer_rel, RelOptInfo *inner_rel) { Relids relids = joinrel->relids; ListCell *lc; @@ -422,9 +423,32 @@ add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel) if (bms_is_subset(phinfo->ph_eval_at, relids)) { /* Yup, add it to the output */ - joinrel->reltargetlist = lappend(joinrel->reltargetlist, - phinfo->ph_var); - joinrel->width += phinfo->ph_width; + 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 + * 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 + * joinrel. With other pairs, it might be possible to compute + * the PHV in one input or the other, and then we'd be double + * charging the PHV's cost for some join paths. For now, live + * with that; but we might want to improve it later by + * refiguring the reltarget costs for each pair of inputs. + */ + if (!bms_is_subset(phinfo->ph_eval_at, outer_rel->relids) && + !bms_is_subset(phinfo->ph_eval_at, inner_rel->relids)) + { + QualCost cost; + + cost_qual_eval_node(&cost, (Node *) phinfo->ph_var->phexpr, + root); + joinrel->reltarget.cost.startup += cost.startup; + joinrel->reltarget.cost.per_tuple += cost.per_tuple; + } + /* Adjust joinrel's direct_lateral_relids as needed */ joinrel->direct_lateral_relids = bms_add_members(joinrel->direct_lateral_relids, |