diff options
| -rw-r--r-- | src/backend/optimizer/plan/createplan.c | 71 |
1 files changed, 65 insertions, 6 deletions
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 98bb4a622d..6c42be9366 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -91,7 +91,7 @@ static WorkTableScan *create_worktablescan_plan(PlannerInfo *root, Path *best_pa #ifdef PGXC static RowMarkClause *mk_row_mark_clause(PlanRowMark *prm); static bool compare_alias(Alias *a1, Alias *a2); -static RemoteQuery *create_remotequery_plan(PlannerInfo *root, Path *best_path, +static Plan *create_remotequery_plan(PlannerInfo *root, Path *best_path, List *tlist, List *scan_clauses); static Plan *create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Plan *outer_plan, Plan *inner_plan); @@ -799,7 +799,7 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla * intermediate, the children vars may or may not be referenced * multiple times in it. */ - parent_vars = pull_var_clause((Node *)parent->targetlist, PVC_REJECT_PLACEHOLDERS); + parent_vars = pull_var_clause((Node *)parent->targetlist, PVC_RECURSE_PLACEHOLDERS); findReferencedVars(parent_vars, outer_plan, &out_tlist, &out_relids); findReferencedVars(parent_vars, inner_plan, &in_tlist, &in_relids); @@ -2540,14 +2540,40 @@ compare_alias(Alias *a1, Alias *a2) } /* + * contains_only_vars(tlist) + * Return true only if each element of tlist is a target entry having Var node + * as its containing expression. + */ +static bool +contains_only_vars(List *tlist) +{ + ListCell *l; + + foreach(l, (List *) tlist) + { + Node *tle = lfirst(l); + if (nodeTag(tle) != T_TargetEntry) + return false; + else + { + Expr *expr = ((TargetEntry *) tle)->expr; + if (nodeTag(expr) != T_Var) + return false; + } + } + return true; +} + +/* * create_remotequery_plan * Returns a remotequery plan for the base relation scanned by 'best_path' * with restriction clauses 'scan_clauses' and targetlist 'tlist'. */ -static RemoteQuery * +static Plan * create_remotequery_plan(PlannerInfo *root, Path *best_path, List *tlist, List *scan_clauses) { + Plan *result_node ; RemoteQuery *scan_plan; Index scan_relid = best_path->parent->relid; RangeTblEntry *rte; @@ -2565,6 +2591,8 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path, Oid distcol_type; Node *tmp_node; List *rmlist; + List *tvarlist; + bool tlist_is_simple = contains_only_vars(tlist); Assert(scan_relid > 0); Assert(best_path->parent->rtekind == RTE_RELATION); @@ -2612,7 +2640,22 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path, query->jointree->fromlist = list_make1(rtr); query->jointree->quals = (Node *)make_ands_explicit(copyObject(remote_scan_clauses)); - query->targetList = copyObject(tlist); + + /* + * RemoteQuery node cannot handle arbitrary expressions in the target list. + * So if the target list has any elements that are not plain Vars, we need + * to create a Result node above RemoteQuery, and assign a plain var tlist + * in RemoteQuery node, and Result node will handle the expressions. So if + * the passed-in tlist is not a simple vars tlist, derive one out of the + * tlist. + */ + if (tlist_is_simple) + query->targetList = copyObject(tlist); + else + { + tvarlist = copyObject(pull_var_clause((Node *)tlist, PVC_RECURSE_PLACEHOLDERS)); + query->targetList = add_to_flat_tlist(NIL, copyObject(tvarlist)); + } /* * Change the varno in Var nodes in the targetlist of the query to be shipped to the @@ -2708,7 +2751,23 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path, rel_loc_info = GetRelationLocInfo(rte->relid); if (!rel_loc_info) elog(ERROR, "No distribution information found for relid %d", rte->relid); - scan_plan = make_remotequery(tlist, local_scan_clauses, scan_relid); + + if (tlist_is_simple) + { + scan_plan = make_remotequery(tlist, local_scan_clauses, scan_relid); + result_node = (Plan *) scan_plan; + } + else + { + /* + * Use simple tlist for RemoteQuery, and let Result plan handle + * non-simple target list. + */ + scan_plan = make_remotequery(add_to_flat_tlist(NIL, copyObject(tvarlist)), + local_scan_clauses, scan_relid); + result_node = (Plan *) make_result(root, tlist, NULL, (Plan*) scan_plan); + } + /* Track if the remote query involves a temporary object */ scan_plan->is_temp = IsTempTable(rte->relid); @@ -2776,7 +2835,7 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path, /* PGXCTODO - get better estimates */ scan_plan->scan.plan.plan_rows = 1000; - return scan_plan; + return result_node; } #endif |