diff --git a/src/include/utils/memutils_memorychunk.h b/src/include/utils/memutils_memorychunk.h
index 685c177b68..1e27d084cd 100644
--- a/src/include/utils/memutils_memorychunk.h
+++ b/src/include/utils/memutils_memorychunk.h
@@ -111,6 +111,14 @@ typedef struct MemoryChunk
 {
 #ifdef MEMORY_CONTEXT_CHECKING
 	Size		requested_size;
+#define MEMORYCHUNK_RAWSIZE		(SIZEOF_SIZE_T + 8)
+#else
+#define MEMORYCHUNK_RAWSIZE		8
+#endif							/* MEMORY_CONTEXT_CHECKING */
+
+	/* ensure proper alignment by adding padding if needed */
+#if (MEMORYCHUNK_RAWSIZE % MAXIMUM_ALIGNOF) != 0
+	char		padding[MAXIMUM_ALIGNOF - MEMORYCHUNK_RAWSIZE % MAXIMUM_ALIGNOF];
 #endif
 
 	/* bitfield for storing details about the chunk */