Re-allow INSERT .. ON CONFLICT DO NOTHING on partitioned tables.

Commit 8355a011a0124bdf7ccbada206a967d427039553 was reverted in
f05230752d53c4aa74cffa9b699983bbb6bcb118, but this attempt is
hopefully better-considered: we now pass the correct value to
ExecOpenIndices, which should avoid the crash that we hit before.

Amit Langote, reviewed by Simon Riggs and by me.  Some final
editing by me.

Discussion: http://postgr.es/m/7ff1e8ec-dc39-96b1-7f47-ff5965dceeac@lab.ntt.co.jp

4 files changed, 14 insertions, 15 deletions

diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 13eb9e34ba2..bace390470f 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -2478,7 +2478,8 @@ CopyFrom(CopyState cstate)
 		int			num_parted,
 					num_partitions;
 
-		ExecSetupPartitionTupleRouting(cstate->rel,
+		ExecSetupPartitionTupleRouting(NULL,
+									   cstate->rel,
 									   1,
 									   estate,
 									   &partition_dispatch_info,
diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 34875945e81..d545af2b677 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -63,7 +63,8 @@ static char *ExecBuildSlotPartitionKeyDescription(Relation rel,
  * RowExclusiveLock mode upon return from this function.
  */
 void
-ExecSetupPartitionTupleRouting(Relation rel,
+ExecSetupPartitionTupleRouting(ModifyTableState *mtstate,
+							   Relation rel,
 							   Index resultRTindex,
 							   EState *estate,
 							   PartitionDispatch **pd,
@@ -133,13 +134,17 @@ ExecSetupPartitionTupleRouting(Relation rel,
 		CheckValidResultRel(leaf_part_rri, CMD_INSERT);
 
 		/*
-		 * Open partition indices (remember we do not support ON CONFLICT in
-		 * case of partitioned tables, so we do not need support information
-		 * for speculative insertion)
+		 * Open partition indices.  The user may have asked to check for
+		 * conflicts within this leaf partition and do "nothing" instead of
+		 * throwing an error.  Be prepared in that case by initializing the
+		 * index information needed by ExecInsert() to perform speculative
+		 * insertions.
 		 */
 		if (leaf_part_rri->ri_RelationDesc->rd_rel->relhasindex &&
 			leaf_part_rri->ri_IndexRelationDescs == NULL)
-			ExecOpenIndices(leaf_part_rri, false);
+			ExecOpenIndices(leaf_part_rri,
+							mtstate != NULL &&
+							mtstate->mt_onconflict != ONCONFLICT_NONE);
 
 		estate->es_leaf_result_relations =
 			lappend(estate->es_leaf_result_relations, leaf_part_rri);
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 1e3ece9b34c..afb83ed3ae1 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -1953,7 +1953,8 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
 		int			num_parted,
 					num_partitions;
 
-		ExecSetupPartitionTupleRouting(rel,
+		ExecSetupPartitionTupleRouting(mtstate,
+									   rel,
 									   node->nominalRelation,
 									   estate,
 									   &partition_dispatch_info,
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 757a4a8fd12..d680d2285c6 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -847,16 +847,8 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
 
 	/* Process ON CONFLICT, if any. */
 	if (stmt->onConflictClause)
-	{
-		/* Bail out if target relation is partitioned table */
-		if (pstate->p_target_rangetblentry->relkind == RELKIND_PARTITIONED_TABLE)
-			ereport(ERROR,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("ON CONFLICT clause is not supported with partitioned tables")));
-
 		qry->onConflict = transformOnConflictClause(pstate,
 													stmt->onConflictClause);
-	}
 
 	/*
 	 * If we have a RETURNING clause, we need to add the target relation to