diff options
Diffstat (limited to 'src/backend/optimizer/plan/setrefs.c')
| -rw-r--r-- | src/backend/optimizer/plan/setrefs.c | 73 |
1 files changed, 61 insertions, 12 deletions
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c index 5240a7283b..5c11d788e0 100644 --- a/src/backend/optimizer/plan/setrefs.c +++ b/src/backend/optimizer/plan/setrefs.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.132 2007/02/22 23:44:25 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.133 2007/02/23 21:59:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -73,6 +73,7 @@ static void set_join_references(Join *join, int rtoffset); static void set_inner_join_references(Plan *inner_plan, indexed_tlist *outer_itlist); static void set_upper_references(Plan *plan, int rtoffset); +static void set_dummy_tlist_references(Plan *plan, int rtoffset); static indexed_tlist *build_tlist_index(List *tlist); static Var *search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist, @@ -315,8 +316,7 @@ set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset) * executor, we fix it up for possible use by EXPLAIN (not to * mention ease of debugging --- wrong varnos are very confusing). */ - plan->targetlist = - fix_scan_list(plan->targetlist, rtoffset); + set_dummy_tlist_references(plan, rtoffset); /* * Since these plan types don't check quals either, we should not * find any qual expression attached to them. @@ -330,11 +330,12 @@ set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset) /* * Like the plan types above, Limit doesn't evaluate its tlist * or quals. It does have live expressions for limit/offset, - * however. + * however; and those cannot contain subplan variable refs, + * so fix_scan_expr works for them. */ - splan->plan.targetlist = - fix_scan_list(splan->plan.targetlist, rtoffset); + set_dummy_tlist_references(plan, rtoffset); Assert(splan->plan.qual == NIL); + splan->limitOffset = fix_scan_expr(splan->limitOffset, rtoffset); splan->limitCount = @@ -375,8 +376,7 @@ set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset) * Append, like Sort et al, doesn't actually evaluate its * targetlist or check quals. */ - splan->plan.targetlist = - fix_scan_list(splan->plan.targetlist, rtoffset); + set_dummy_tlist_references(plan, rtoffset); Assert(splan->plan.qual == NIL); foreach(l, splan->appendplans) { @@ -892,10 +892,7 @@ set_upper_references(Plan *plan, int rtoffset) List *output_targetlist; ListCell *l; - if (subplan != NULL) - subplan_itlist = build_tlist_index(subplan->targetlist); - else - subplan_itlist = build_tlist_index(NIL); + subplan_itlist = build_tlist_index(subplan->targetlist); output_targetlist = NIL; foreach(l, plan->targetlist) @@ -921,6 +918,58 @@ set_upper_references(Plan *plan, int rtoffset) } /* + * set_dummy_tlist_references + * Replace the targetlist of an upper-level plan node with a simple + * list of OUTER references to its child. + * + * This is used for plan types like Sort and Append that don't evaluate + * their targetlists. Although the executor doesn't care at all what's in + * the tlist, EXPLAIN needs it to be realistic. + * + * Note: we could almost use set_upper_references() here, but it fails for + * Append for lack of a lefttree subplan. Single-purpose code is faster + * anyway. + */ +static void +set_dummy_tlist_references(Plan *plan, int rtoffset) +{ + List *output_targetlist; + ListCell *l; + + output_targetlist = NIL; + foreach(l, plan->targetlist) + { + TargetEntry *tle = (TargetEntry *) lfirst(l); + Var *oldvar = (Var *) tle->expr; + Var *newvar; + + newvar = makeVar(OUTER, + tle->resno, + exprType((Node *) oldvar), + exprTypmod((Node *) oldvar), + 0); + if (IsA(oldvar, Var)) + { + newvar->varnoold = oldvar->varno + rtoffset; + newvar->varoattno = oldvar->varattno; + } + else + { + newvar->varnoold = 0; /* wasn't ever a plain Var */ + newvar->varoattno = 0; + } + + tle = flatCopyTargetEntry(tle); + tle->expr = (Expr *) newvar; + output_targetlist = lappend(output_targetlist, tle); + } + plan->targetlist = output_targetlist; + + /* We don't touch plan->qual here */ +} + + +/* * build_tlist_index --- build an index data structure for a child tlist * * In most cases, subplan tlists will be "flat" tlists with only Vars, |