diff --git a/src/hnsw.h b/src/hnsw.h
index af39852..1ced9f6 100644
--- a/src/hnsw.h
+++ b/src/hnsw.h
@@ -15,6 +15,10 @@
 #error "Requires PostgreSQL 11+"
 #endif
 
+#if PG_VERSION_NUM < 120000
+#include "access/relscan.h"
+#endif
+
 #define HNSW_MAX_DIM 2000
 
 /* Support functions */
diff --git a/src/hnswbuild.c b/src/hnswbuild.c
index f298611..29fc9b9 100644
--- a/src/hnswbuild.c
+++ b/src/hnswbuild.c
@@ -3,6 +3,7 @@
 #include <math.h>
 
 #include "access/parallel.h"
+#include "access/xact.h"
 #include "catalog/index.h"
 #include "hnsw.h"
 #include "miscadmin.h"