Add support for INSERT SELECT.

Also, initial changes for setting execution nodes in general planner.

We execute a query normally, directed by the Coordinator,
and then use COPY running down on the data nodes to insert
the data there.

We also check for a special case of INSERT SELECT where the source
and destination columns are both the distribution columns of
tables, and where the query is a single step query. In such a
case, we just execute the query locally on the data nodes without
the use of COPY directed by the Coordinator.

In testing we uncovered an issue for INSERT SELECT when the
query is from a replicated table; it was selecting from all
tables because exec_nodes was not set for the RemoteQuery.
As a result, this commit also sets the exec_nodes for base
RemoteQuery structs as well as join reduced ones.

It does not yet, however, take into account WHERE clause
equality conditions against the distribution column, as
is done in a regular SELECT.  This is left as a future
optimization, best done as a step for further merging
the Postgres-XC planner and the standard planner.

1 files changed, 21 insertions, 8 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 30084633e4..bebb81a276 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -630,6 +630,7 @@ static Plan *
 create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Plan *outer_plan, Plan *inner_plan)
 {
 	NestLoop   *nest_parent;
+	JoinReduceInfo  join_info;
 
 	if (!enable_remotejoin)
 		return parent;
@@ -638,10 +639,6 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla
 	if (root->hasPseudoConstantQuals)
 		return parent;
 
-	/* Works only for SELECT commands right now */
-	if (root->parse->commandType != CMD_SELECT)
-		return parent;
-
 	/* do not optimize CURSOR based select statements */
 	if (root->parse->rowMarks != NIL)
 		return parent;
@@ -664,7 +661,6 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla
 	{
 		int i;
 		List *rtable_list = NIL;
-		bool partitioned_replicated_join = false;
 
 		Material *outer_mat = (Material *)outer_plan;
 		Material *inner_mat = (Material *)inner_plan;
@@ -692,7 +688,7 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla
 		}
 
 		/* XXX Check if the join optimization is possible */
-		if (IsJoinReducible(inner, outer, rtable_list, best_path, &partitioned_replicated_join))
+		if (IsJoinReducible(inner, outer, rtable_list, best_path, &join_info))
 		{
 			RemoteQuery	   *result;
 			Plan		   *result_plan;
@@ -829,6 +825,7 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla
 			result->outer_reduce_level = outer->reduce_level;
 			result->inner_relids       = in_relids;
 			result->outer_relids       = out_relids;
+			result->exec_nodes         = copyObject(join_info.exec_nodes);
 
 			appendStringInfo(&fromlist, " %s (%s) %s",
 							 pname, inner->sql_statement, quote_identifier(in_alias));
@@ -917,8 +914,7 @@ create_remotejoin_plan(PlannerInfo *root, JoinPath *best_path, Plan *parent, Pla
 			/* set_plan_refs needs this later */
 			result->base_tlist		= base_tlist;
 			result->relname			= "__FOREIGN_QUERY__";
-
-			result->partitioned_replicated = partitioned_replicated_join;
+			result->partitioned_replicated = join_info.partitioned_replicated;
 
 			/*
 			 * if there were any local scan clauses stick them up here. They
@@ -2233,6 +2229,8 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path,
 	TupleDesc		tupdesc;
 	bool			first;
 	StringInfoData	sql;
+	RelationLocInfo *rel_loc_info;
+
 
 	Assert(scan_relid > 0);
 	rte = planner_rt_fetch(scan_relid, root);
@@ -2393,6 +2391,21 @@ create_remotequery_plan(PlannerInfo *root, Path *best_path,
 
 	scan_plan->sql_statement = sql.data;
 
+	/*
+	 * Populate what nodes we execute on.
+	 * This is still basic, and was done to make sure we do not select
+	 * a replicated table from all nodes.
+	 * It does not take into account conditions on partitioned relations
+	 * that could reduce to one node. To do that, we need to move general
+	 * planning earlier.
+	 */
+	rel_loc_info = GetRelationLocInfo(rte->relid);
+	scan_plan->exec_nodes = makeNode(ExecNodes);
+	scan_plan->exec_nodes->tableusagetype = TABLE_USAGE_TYPE_USER;
+	scan_plan->exec_nodes->baselocatortype = rel_loc_info->locatorType;
+	scan_plan->exec_nodes = GetRelationNodes(rel_loc_info,
+														   NULL,
+														   RELATION_ACCESS_READ);
 	copy_path_costsize(&scan_plan->scan.plan, best_path);
 
 	/* PGXCTODO - get better estimates */