diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a04763207f031c517a45362c743d7ad329fe5890..336fbb06dac9cc481d4bf035eda21dd391953fd1 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8115,11 +8115,13 @@ newsame:;
 
 	if (xlrec->flags & XLOG_HEAP_PREFIX_FROM_OLD)
 	{
+		Assert(samepage);
 		memcpy(&prefixlen, recdata, sizeof(uint16));
 		recdata += sizeof(uint16);
 	}
 	if (xlrec->flags & XLOG_HEAP_SUFFIX_FROM_OLD)
 	{
+		Assert(samepage);
 		memcpy(&suffixlen, recdata, sizeof(uint16));
 		recdata += sizeof(uint16);
 	}