diff --git a/src/test/regress/expected/gist.out b/src/test/regress/expected/gist.out
index a36b4c9c56..044986433a 100644
--- a/src/test/regress/expected/gist.out
+++ b/src/test/regress/expected/gist.out
@@ -46,6 +46,12 @@ vacuum analyze gist_tbl;
 set enable_seqscan=off;
 set enable_bitmapscan=off;
 set enable_indexonlyscan=on;
+-- Build an index using buffering caused by a index build that don't fit on cache.
+set effective_cache_size = '1MB';
+create index gist_tbl_box_index_buffering on gist_tbl using gist (p, b, c);
+reset effective_cache_size;
+-- Force a index build using buffering.
+create index gist_tbl_box_index_forcing_buffering on gist_tbl using gist (p) with (buffering=on);
 -- Test index-only scan with point opclass
 create index gist_tbl_point_index on gist_tbl using gist (p);
 -- check that the planner chooses an index-only scan
diff --git a/src/test/regress/sql/gist.sql b/src/test/regress/sql/gist.sql
index 3360266370..836ce84d71 100644
--- a/src/test/regress/sql/gist.sql
+++ b/src/test/regress/sql/gist.sql
@@ -55,6 +55,14 @@ set enable_seqscan=off;
 set enable_bitmapscan=off;
 set enable_indexonlyscan=on;
 
+-- Build an index using buffering caused by a index build that don't fit on cache.
+set effective_cache_size = '1MB';
+create index gist_tbl_box_index_buffering on gist_tbl using gist (p, b, c);
+reset effective_cache_size;
+
+-- Force an index build using buffering.
+create index gist_tbl_box_index_forcing_buffering on gist_tbl using gist (p) with (buffering=on);
+
 -- Test index-only scan with point opclass
 create index gist_tbl_point_index on gist_tbl using gist (p);