diff --git a/contrib/pageinspect/expected/gist.out b/contrib/pageinspect/expected/gist.out
index 508f5adb55..5f7d8cea71 100644
--- a/contrib/pageinspect/expected/gist.out
+++ b/contrib/pageinspect/expected/gist.out
@@ -1,3 +1,12 @@
+-- The gist_page_opaque_info() function prints the page's LSN. Normally,
+-- that's constant 1 (GistBuildLSN) on every page of a freshly built GiST
+-- index. But with wal_level=minimal, the whole relation is dumped to WAL at
+-- the end of the transaction if it's smaller than wal_skip_threshold, which
+-- updates the LSNs. Wrap the tests on gist_page_opaque_info() in the
+-- same transaction with the CREATE INDEX so that we see the LSNs before
+-- they are possibly overwritten at end of transaction.
+BEGIN;
+-- Create a test table and GiST index.
 CREATE TABLE test_gist AS SELECT point(i,i) p, i::text t FROM
     generate_series(1,1000) i;
 CREATE INDEX test_gist_idx ON test_gist USING gist (p);
@@ -20,6 +29,7 @@ SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
  0/1 | 0/0 |         1 | {leaf}
 (1 row)
 
+COMMIT;
 SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
  itemoffset |   ctid    | itemlen |       keys        
 ------------+-----------+---------+-------------------
diff --git a/contrib/pageinspect/sql/gist.sql b/contrib/pageinspect/sql/gist.sql
index e6f6e42a5e..1560d1e15c 100644
--- a/contrib/pageinspect/sql/gist.sql
+++ b/contrib/pageinspect/sql/gist.sql
@@ -1,3 +1,13 @@
+-- The gist_page_opaque_info() function prints the page's LSN. Normally,
+-- that's constant 1 (GistBuildLSN) on every page of a freshly built GiST
+-- index. But with wal_level=minimal, the whole relation is dumped to WAL at
+-- the end of the transaction if it's smaller than wal_skip_threshold, which
+-- updates the LSNs. Wrap the tests on gist_page_opaque_info() in the
+-- same transaction with the CREATE INDEX so that we see the LSNs before
+-- they are possibly overwritten at end of transaction.
+BEGIN;
+
+-- Create a test table and GiST index.
 CREATE TABLE test_gist AS SELECT point(i,i) p, i::text t FROM
     generate_series(1,1000) i;
 CREATE INDEX test_gist_idx ON test_gist USING gist (p);
@@ -7,6 +17,8 @@ SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 0));
 SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 1));
 SELECT * FROM gist_page_opaque_info(get_raw_page('test_gist_idx', 2));
 
+COMMIT;
+
 SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 0), 'test_gist_idx');
 SELECT * FROM gist_page_items(get_raw_page('test_gist_idx', 1), 'test_gist_idx') LIMIT 5;