diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 6e1d2b14bc4..82d7215b05b 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -36,6 +36,7 @@
 #include "parser/parse_relation.h"
 #include "partitioning/partdesc.h"
 #include "partitioning/partprune.h"
+#include "utils/injection_point.h"
 #include "utils/rel.h"
 
 
@@ -334,6 +335,10 @@ expand_partitioned_rtentry(PlannerInfo *root, RelOptInfo *relinfo,
 	partdesc = PartitionDirectoryLookup(root->glob->partition_directory,
 										parentrel);
 
+	/* test-only: pause after a sub-partitioned table's PartitionDesc is read */
+	if (parentrel->rd_rel->relispartition)
+		INJECTION_POINT("expand-subpartdesc-read", NULL);
+
 	/* A partitioned table should always have a partition descriptor. */
 	Assert(partdesc);
 
diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 22e0e8b11f8..38258771b0c 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -49,6 +49,7 @@
 #include "storage/bufmgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
+#include "utils/injection_point.h"
 #include "utils/lsyscache.h"
 #include "utils/partcache.h"
 #include "utils/rel.h"
@@ -134,6 +135,9 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent,
 	 */
 	relation = table_open(relationObjectId, NoLock);
 
+	/* test-only: pause after expression preprocessing (inlining), before index_open() */
+	INJECTION_POINT("get-relation-info-start", NULL);
+
 	/*
 	 * Relations without a table AM can be used in a query only if they are of
 	 * special-cased relkinds.  This check prevents us from crashing later if,