diff --git a/src/test/regress/expected/test_setup.out b/src/test/regress/expected/test_setup.out
index 98e08cb6eb..e667412fd4 100644
--- a/src/test/regress/expected/test_setup.out
+++ b/src/test/regress/expected/test_setup.out
@@ -7,6 +7,13 @@
 \getenv dlsuffix PG_DLSUFFIX
 \set regresslib :libdir '/regress' :dlsuffix
 --
+-- synchronous_commit setting affects the time when hint bits are set which
+-- in its turn has an effect on the query plans. This means that in the
+-- general case we can't guarantee that all the tests will pass regardless of
+-- synchronous_commit value in postgresql.conf.
+--
+SET synchronous_commit = on;
+--
 -- Postgres formerly made the public schema read/write by default,
 -- and most of the core regression tests still expect that.
 --
diff --git a/src/test/regress/sql/test_setup.sql b/src/test/regress/sql/test_setup.sql
index d0a73c473d..ea2ac22b52 100644
--- a/src/test/regress/sql/test_setup.sql
+++ b/src/test/regress/sql/test_setup.sql
@@ -9,6 +9,14 @@
 
 \set regresslib :libdir '/regress' :dlsuffix
 
+--
+-- synchronous_commit setting affects the time when hint bits are set which
+-- in its turn has an effect on the query plans. This means that in the
+-- general case we can't guarantee that all the tests will pass regardless of
+-- synchronous_commit value in postgresql.conf.
+--
+SET synchronous_commit = on;
+
 --
 -- Postgres formerly made the public schema read/write by default,
 -- and most of the core regression tests still expect that.