diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 3d752c6418c83c74b6fd25a1345f282e9c565d36..d675560894e24c5b5d2b32814ec4e8bb147ddbc9 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8318,7 +8318,7 @@ CreateCheckPoint(int flags)
  * CreateRestartPoint() allows for the case where recovery may end before
  * the restartpoint completes so there is no concern of concurrent behaviour.
  */
-void
+static void
 CreateEndOfRecoveryRecord(void)
 {
 	xl_end_of_recovery xlrec;
diff --git a/src/backend/replication/logical/reorderbuffer.c b/src/backend/replication/logical/reorderbuffer.c
index f96e3e1d93bd8b6b1703d10ff7b1d29b2275fca7..12960f4997b00a17ecda4f5918e7a4853d780142 100644
--- a/src/backend/replication/logical/reorderbuffer.c
+++ b/src/backend/replication/logical/reorderbuffer.c
@@ -322,7 +322,7 @@ ReorderBufferGetTXN(ReorderBuffer *rb)
  * Deallocation might be delayed for efficiency purposes, for details check
  * the comments above max_cached_changes's definition.
  */
-void
+static void
 ReorderBufferReturnTXN(ReorderBuffer *rb, ReorderBufferTXN *txn)
 {
 	/* clean the lookup cache if we were cached (quite likely) */
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 1ffa24356b39fca6164818bc4cc2e6a3d5f696fe..0d3ef20c0666b9f36dbc2b8c1c833cf7165b2f47 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -2381,7 +2381,7 @@ RelationCloseSmgrByOid(Oid relationId)
 	RelationCloseSmgr(relation);
 }
 
-void
+static void
 RememberToFreeTupleDescAtEOX(TupleDesc td)
 {
 	if (EOXactTupleDescArray == NULL)
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fdd5b638cd65f8424fdd900b6f1ef5ac0e4e2898..1d094f00c61062876986edbd53a54a2b77d9609a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -5340,7 +5340,7 @@ config_enum_get_options(struct config_enum * record, const char *prefix,
  *	1: the value is valid
  *	0: the name or value is invalid
  */
-bool
+static bool
 validate_conf_option(struct config_generic * record, const char *name,
 					 const char *value, GucSource source, int elevel,
 					 bool freemem, void *newval, void **newextra)
diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 899f4323b276cff19db561adf55dda411d7bbd87..9a6ade935f8df2fd06b145ddf851593e64208390 100644
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -399,7 +399,7 @@ readfile(const char *path)
 /*
  * Free memory allocated for optlines through readfile()
  */
-void
+static void
 free_readfile(char **optlines)
 {
 	char	   *curr_line = NULL;