diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c
index ada782f98f5..20ff58aa782 100644
--- a/contrib/amcheck/verify_heapam.c
+++ b/contrib/amcheck/verify_heapam.c
@@ -24,6 +24,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
+#include "storage/lwlock.h"
 #include "storage/procarray.h"
 #include "storage/read_stream.h"
 #include "utils/builtins.h"
diff --git a/src/backend/access/common/relation.c b/src/backend/access/common/relation.c
index 92a6e37d8bd..38b356b8239 100644
--- a/src/backend/access/common/relation.c
+++ b/src/backend/access/common/relation.c
@@ -25,6 +25,7 @@
 #include "catalog/namespace.h"
 #include "pgstat.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "utils/inval.h"
 #include "utils/syscache.h"
 
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 237ab8d0ed9..a6002ae9b07 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -28,6 +28,7 @@
 #include "commands/defrem.h"
 #include "commands/tablespace.h"
 #include "nodes/makefuncs.h"
+#include "storage/lock.h"
 #include "utils/array.h"
 #include "utils/attoptcache.h"
 #include "utils/builtins.h"
diff --git a/src/backend/access/heap/heapam_handler.c b/src/backend/access/heap/heapam_handler.c
index 253a735b6c1..d40878928e1 100644
--- a/src/backend/access/heap/heapam_handler.c
+++ b/src/backend/access/heap/heapam_handler.c
@@ -40,6 +40,7 @@
 #include "storage/bufmgr.h"
 #include "storage/bufpage.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "storage/predicate.h"
 #include "storage/procarray.h"
 #include "storage/smgr.h"
diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c
index 5eb7e99ad3e..fbfc33159eb 100644
--- a/src/backend/access/index/indexam.c
+++ b/src/backend/access/index/indexam.c
@@ -53,6 +53,7 @@
 #include "nodes/execnodes.h"
 #include "pgstat.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "storage/predicate.h"
 #include "utils/ruleutils.h"
 #include "utils/snapmgr.h"
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c
index aed74590cf4..6d870e4ebe7 100644
--- a/src/backend/access/nbtree/nbtree.c
+++ b/src/backend/access/nbtree/nbtree.c
@@ -30,6 +30,7 @@
 #include "storage/indexfsm.h"
 #include "storage/ipc.h"
 #include "storage/lmgr.h"
+#include "storage/lwlock.h"
 #include "storage/read_stream.h"
 #include "utils/datum.h"
 #include "utils/fmgrprotos.h"
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 9b091858997..732bc750c9e 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -24,6 +24,7 @@
 #include "common/int.h"
 #include "lib/qunique.h"
 #include "miscadmin.h"
+#include "storage/lwlock.h"
 #include "utils/datum.h"
 #include "utils/lsyscache.h"
 #include "utils/rel.h"
diff --git a/src/backend/catalog/pg_inherits.c b/src/backend/catalog/pg_inherits.c
index cef80633157..4b9802aafcc 100644
--- a/src/backend/catalog/pg_inherits.c
+++ b/src/backend/catalog/pg_inherits.c
@@ -28,6 +28,7 @@
 #include "storage/lmgr.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
+#include "utils/hsearch.h"
 #include "utils/snapmgr.h"
 #include "utils/syscache.h"
 
diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c
index 3673d4f0bc1..1d140c513d0 100644
--- a/src/backend/catalog/pg_subscription.c
+++ b/src/backend/catalog/pg_subscription.c
@@ -26,6 +26,7 @@
 #include "foreign/foreign.h"
 #include "miscadmin.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "utils/acl.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
diff --git a/src/backend/commands/conversioncmds.c b/src/backend/commands/conversioncmds.c
index 61aa8bb9fd1..5f2022d3072 100644
--- a/src/backend/commands/conversioncmds.c
+++ b/src/backend/commands/conversioncmds.c
@@ -19,6 +19,7 @@
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "commands/conversioncmds.h"
+#include "fmgr.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "parser/parse_func.h"
diff --git a/src/backend/commands/discard.c b/src/backend/commands/discard.c
index 7b5520b9abe..17d172df076 100644
--- a/src/backend/commands/discard.c
+++ b/src/backend/commands/discard.c
@@ -19,6 +19,7 @@
 #include "commands/discard.h"
 #include "commands/prepare.h"
 #include "commands/sequence.h"
+#include "storage/lock.h"
 #include "utils/guc.h"
 #include "utils/portal.h"
 
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index ed2a93a09db..d91fcf0facf 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -70,6 +70,7 @@
 #include "miscadmin.h"
 #include "postmaster/bgwriter.h"
 #include "storage/fd.h"
+#include "storage/lwlock.h"
 #include "storage/procsignal.h"
 #include "storage/standby.h"
 #include "utils/acl.h"
diff --git a/src/backend/optimizer/util/inherit.c b/src/backend/optimizer/util/inherit.c
index 8d623bf136d..6a7b9edff3f 100644
--- a/src/backend/optimizer/util/inherit.c
+++ b/src/backend/optimizer/util/inherit.c
@@ -14,6 +14,8 @@
  */
 #include "postgres.h"
 
+#include <limits.h>
+
 #include "access/sysattr.h"
 #include "access/table.h"
 #include "catalog/partition.h"
diff --git a/src/backend/parser/parse_oper.c b/src/backend/parser/parse_oper.c
index a6b402f2d7b..2f218c1ab8b 100644
--- a/src/backend/parser/parse_oper.c
+++ b/src/backend/parser/parse_oper.c
@@ -25,6 +25,7 @@
 #include "parser/parse_oper.h"
 #include "parser/parse_type.h"
 #include "utils/builtins.h"
+#include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
diff --git a/src/backend/replication/logical/sequencesync.c b/src/backend/replication/logical/sequencesync.c
index 9c92fddd624..a4fb6783ba9 100644
--- a/src/backend/replication/logical/sequencesync.c
+++ b/src/backend/replication/logical/sequencesync.c
@@ -60,6 +60,7 @@
 #include "postmaster/interrupt.h"
 #include "replication/logicalworker.h"
 #include "replication/worker_internal.h"
+#include "storage/lwlock.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.c
index aca2c8fc742..e5a2289f0b0 100644
--- a/src/backend/utils/activity/wait_event.c
+++ b/src/backend/utils/activity/wait_event.c
@@ -22,8 +22,9 @@
  */
 #include "postgres.h"
 
-#include "storage/lmgr.h"		/* for GetLockNameFromTagType */
-#include "storage/lwlock.h"		/* for GetLWLockIdentifier */
+#include "storage/lmgr.h"
+#include "storage/lwlock.h"
+#include "storage/shmem.h"
 #include "storage/spin.h"
 #include "utils/wait_event.h"
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index 3a4f19e8d58..e19f0d3e51c 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -77,6 +77,7 @@
 #include "rewrite/rowsecurity.h"
 #include "storage/fd.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "storage/smgr.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
diff --git a/src/backend/utils/cache/syscache.c b/src/backend/utils/cache/syscache.c
index 007a9a15d71..f4233f9e31a 100644
--- a/src/backend/utils/cache/syscache.c
+++ b/src/backend/utils/cache/syscache.c
@@ -32,6 +32,7 @@
 #include "lib/qunique.h"
 #include "miscadmin.h"
 #include "storage/lmgr.h"
+#include "storage/lock.h"
 #include "utils/catcache.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
diff --git a/src/backend/utils/cache/ts_cache.c b/src/backend/utils/cache/ts_cache.c
index 744c8e71d71..9e29f1386b0 100644
--- a/src/backend/utils/cache/ts_cache.c
+++ b/src/backend/utils/cache/ts_cache.c
@@ -44,6 +44,7 @@
 #include "utils/catcache.h"
 #include "utils/fmgroids.h"
 #include "utils/guc_hooks.h"
+#include "utils/hsearch.h"
 #include "utils/inval.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
diff --git a/src/include/access/reloptions.h b/src/include/access/reloptions.h
index 0bd17b30ca7..c228147420a 100644
--- a/src/include/access/reloptions.h
+++ b/src/include/access/reloptions.h
@@ -23,7 +23,6 @@
 #include "access/htup.h"
 #include "access/tupdesc.h"
 #include "nodes/pg_list.h"
-#include "storage/lock.h"
 
 /* types supported by reloptions */
 typedef enum relopt_type
diff --git a/src/include/access/twophase.h b/src/include/access/twophase.h
index e312514ba87..761d56a5f3d 100644
--- a/src/include/access/twophase.h
+++ b/src/include/access/twophase.h
@@ -17,7 +17,12 @@
 #include "access/xact.h"
 #include "access/xlogdefs.h"
 #include "datatype/timestamp.h"
-#include "storage/lock.h"
+
+/*
+ * forward references in this file
+ */
+typedef struct PGPROC PGPROC;
+typedef struct VirtualTransactionId VirtualTransactionId;
 
 /*
  * GlobalTransactionData is defined in twophase.c; other places have no
diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index 1a25973685c..9453a3e4932 100644
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -15,7 +15,7 @@
 #define NAMESPACE_H
 
 #include "nodes/primnodes.h"
-#include "storage/lock.h"
+#include "storage/lockdefs.h"
 #include "storage/procnumber.h"
 
 
diff --git a/src/include/catalog/pg_inherits.h b/src/include/catalog/pg_inherits.h
index 7a36241d7b3..cc874abaabb 100644
--- a/src/include/catalog/pg_inherits.h
+++ b/src/include/catalog/pg_inherits.h
@@ -22,7 +22,7 @@
 #include "catalog/pg_inherits_d.h"	/* IWYU pragma: export */
 
 #include "nodes/pg_list.h"
-#include "storage/lock.h"
+#include "storage/lockdefs.h"
 
 /* ----------------
  *		pg_inherits definition.  cpp turns this into
diff --git a/src/include/catalog/toasting.h b/src/include/catalog/toasting.h
index 7e0a9f8e9bf..0bc61a8fee9 100644
--- a/src/include/catalog/toasting.h
+++ b/src/include/catalog/toasting.h
@@ -14,7 +14,7 @@
 #ifndef TOASTING_H
 #define TOASTING_H
 
-#include "storage/lock.h"
+#include "storage/lockdefs.h"
 
 /*
  * toasting.c prototypes
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index 28741988478..c79cd2d0e19 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -15,7 +15,7 @@
 
 #include "nodes/parsenodes.h"
 #include "parser/parse_node.h"
-#include "storage/lock.h"
+#include "storage/lockdefs.h"
 #include "utils/relcache.h"
 
 
diff --git a/src/include/commands/tablecmds.h b/src/include/commands/tablecmds.h
index ed38b311ddf..c3d8518cb62 100644
--- a/src/include/commands/tablecmds.h
+++ b/src/include/commands/tablecmds.h
@@ -18,7 +18,7 @@
 #include "catalog/dependency.h"
 #include "catalog/objectaddress.h"
 #include "nodes/parsenodes.h"
-#include "storage/lock.h"
+#include "storage/lockdefs.h"
 #include "utils/relcache.h"
 
 typedef struct AlterTableUtilityContext AlterTableUtilityContext;	/* avoid including
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index 953a506181e..1f45bca015c 100644
--- a/src/include/commands/vacuum.h
+++ b/src/include/commands/vacuum.h
@@ -23,7 +23,6 @@
 #include "catalog/pg_type.h"
 #include "parser/parse_node.h"
 #include "storage/buf.h"
-#include "storage/lock.h"
 #include "utils/relcache.h"
 
 /*
diff --git a/src/include/replication/worker_internal.h b/src/include/replication/worker_internal.h
index 4ecbdcfadac..745b7d9e969 100644
--- a/src/include/replication/worker_internal.h
+++ b/src/include/replication/worker_internal.h
@@ -20,7 +20,6 @@
 #include "replication/walreceiver.h"
 #include "storage/buffile.h"
 #include "storage/fileset.h"
-#include "storage/lock.h"
 #include "storage/shm_mq.h"
 #include "storage/shm_toc.h"
 #include "storage/spin.h"
diff --git a/src/include/storage/lmgr.h b/src/include/storage/lmgr.h
index 74a398ffc00..2a985ce5e15 100644
--- a/src/include/storage/lmgr.h
+++ b/src/include/storage/lmgr.h
@@ -16,7 +16,7 @@
 
 #include "lib/stringinfo.h"
 #include "storage/itemptr.h"
-#include "storage/lock.h"
+#include "storage/locktag.h"
 #include "utils/rel.h"
 
 
diff --git a/src/include/storage/lock.h b/src/include/storage/lock.h
index 9505701a805..fa68e6ecece 100644
--- a/src/include/storage/lock.h
+++ b/src/include/storage/lock.h
@@ -59,7 +59,7 @@ extern PGDLLIMPORT bool Debug_deadlocks;
  * coding errors from trying to use struct assignment with it; instead use
  * GET_VXID_FROM_PGPROC().
  */
-typedef struct
+typedef struct VirtualTransactionId
 {
 	ProcNumber	procNumber;		/* proc number of the PGPROC */
 	LocalTransactionId localTransactionId;	/* lxid from PGPROC */
diff --git a/src/include/storage/predicate.h b/src/include/storage/predicate.h
index 607d7d84596..a5ac55b8f7e 100644
--- a/src/include/storage/predicate.h
+++ b/src/include/storage/predicate.h
@@ -14,11 +14,16 @@
 #ifndef PREDICATE_H
 #define PREDICATE_H
 
+#include "access/transam.h"
 #include "storage/itemptr.h"
-#include "storage/lock.h"
 #include "utils/relcache.h"
 #include "utils/snapshot.h"
 
+/*
+ * forward references in this file
+ */
+typedef struct VirtualTransactionId VirtualTransactionId;
+
 
 /*
  * GUC variables
diff --git a/src/include/storage/procarray.h b/src/include/storage/procarray.h
index c5ab1574fe3..abdf021e66e 100644
--- a/src/include/storage/procarray.h
+++ b/src/include/storage/procarray.h
@@ -14,7 +14,6 @@
 #ifndef PROCARRAY_H
 #define PROCARRAY_H
 
-#include "storage/lock.h"
 #include "storage/standby.h"
 #include "utils/relcache.h"
 #include "utils/snapshot.h"
diff --git a/src/include/storage/sinvaladt.h b/src/include/storage/sinvaladt.h
index a1694500a85..122dbcdf19f 100644
--- a/src/include/storage/sinvaladt.h
+++ b/src/include/storage/sinvaladt.h
@@ -22,7 +22,6 @@
 #ifndef SINVALADT_H
 #define SINVALADT_H
 
-#include "storage/lock.h"
 #include "storage/sinval.h"
 
 /*
diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h
index c63a4f2cc6a..6a314c693cd 100644
--- a/src/include/storage/standby.h
+++ b/src/include/storage/standby.h
@@ -15,10 +15,13 @@
 #define STANDBY_H
 
 #include "datatype/timestamp.h"
-#include "storage/lock.h"
+#include "storage/locktag.h"
 #include "storage/relfilelocator.h"
 #include "storage/standbydefs.h"
 
+typedef struct PGPROC PGPROC;
+typedef struct VirtualTransactionId VirtualTransactionId;
+
 /* User-settable GUC parameters */
 extern PGDLLIMPORT int max_standby_archive_delay;
 extern PGDLLIMPORT int max_standby_streaming_delay;