Remove unused #include's from backend .c files

as determined by include-what-you-use (IWYU)

While IWYU also suggests to *add* a bunch of #include's (which is its
main purpose), this patch does not do that.  In some cases, a more
specific #include replaces another less specific one.

Some manual adjustments of the automatic result:

- IWYU currently doesn't know about includes that provide global
  variable declarations (like -Wmissing-variable-declarations), so
  those includes are being kept manually.

- All includes for port(ability) headers are being kept for now, to
  play it safe.

- No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the
  patch from exploding in size.

Note that this patch touches just *.c files, so nothing declared in
header files changes in hidden ways.

As a small example, in src/backend/access/transam/rmgr.c, some IWYU
pragma annotations are added to handle a special case there.

Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org

src/backend/access/transam/commit_ts.c

@@ -27,14 +27,11 @@
 #include "access/transam.h"
 #include "access/xloginsert.h"
 #include "access/xlogutils.h"
-#include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
-#include "pg_trace.h"
 #include "storage/shmem.h"
-#include "utils/builtins.h"
+#include "utils/fmgrprotos.h"
 #include "utils/guc_hooks.h"
-#include "utils/snapmgr.h"
 #include "utils/timestamp.h"
 
 /*

src/backend/access/transam/generic_xlog.c

@@ -17,7 +17,6 @@
 #include "access/generic_xlog.h"
 #include "access/xlogutils.h"
 #include "miscadmin.h"
-#include "utils/memutils.h"
 
 /*-------------------------------------------------------------------------
  * Internally, a delta between pages consists of a set of fragments.  Each

src/backend/access/transam/multixact.c

@@ -74,23 +74,21 @@
 #include "access/twophase.h"
 #include "access/twophase_rmgr.h"
 #include "access/xact.h"
+#include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "access/xlogutils.h"
-#include "catalog/pg_type.h"
 #include "commands/dbcommands.h"
 #include "funcapi.h"
 #include "lib/ilist.h"
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "postmaster/autovacuum.h"
-#include "storage/lmgr.h"
 #include "storage/pmsignal.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
-#include "utils/builtins.h"
+#include "utils/fmgrprotos.h"
 #include "utils/guc_hooks.h"
 #include "utils/memutils.h"
-#include "utils/snapmgr.h"
 
 
 /*

src/backend/access/transam/parallel.c

@@ -25,7 +25,6 @@
 #include "catalog/pg_enum.h"
 #include "catalog/storage.h"
 #include "commands/async.h"
-#include "commands/progress.h"
 #include "commands/vacuum.h"
 #include "executor/execParallel.h"
 #include "libpq/libpq.h"
@@ -36,7 +35,6 @@
 #include "pgstat.h"
 #include "storage/ipc.h"
 #include "storage/predicate.h"
-#include "storage/sinval.h"
 #include "storage/spin.h"
 #include "tcop/tcopprot.h"
 #include "utils/combocid.h"
@@ -45,7 +43,6 @@
 #include "utils/memutils.h"
 #include "utils/relmapper.h"
 #include "utils/snapmgr.h"
-#include "utils/typcache.h"
 
 /*
  * We don't want to waste a lot of memory on an error queue which, most of

src/backend/access/transam/rmgr.c

@@ -7,6 +7,18 @@
  */
 #include "postgres.h"
 
+#include "access/rmgr.h"
+#include "access/xlog_internal.h"
+#include "fmgr.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "nodes/execnodes.h"
+#include "utils/builtins.h"
+#include "utils/fmgrprotos.h"
+#include "utils/tuplestore.h"
+
+/* includes needed for "access/rmgrlist.h" */
+/* IWYU pragma: begin_keep */
 #include "access/brin_xlog.h"
 #include "access/clog.h"
 #include "access/commit_ts.h"
@@ -19,20 +31,17 @@
 #include "access/nbtxlog.h"
 #include "access/spgxlog.h"
 #include "access/xact.h"
-#include "access/xlog_internal.h"
 #include "catalog/storage_xlog.h"
 #include "commands/dbcommands_xlog.h"
 #include "commands/sequence.h"
 #include "commands/tablespace.h"
-#include "fmgr.h"
-#include "funcapi.h"
-#include "miscadmin.h"
 #include "replication/decode.h"
 #include "replication/message.h"
 #include "replication/origin.h"
 #include "storage/standby.h"
-#include "utils/builtins.h"
 #include "utils/relmapper.h"
+/* IWYU pragma: end_keep */
+
 
 /* must be kept in sync with RmgrData definition in xlog_internal.h */
 #define PG_RMGR(symname,name,redo,desc,identify,startup,cleanup,mask,decode) \

src/backend/access/transam/twophase.c

@@ -96,15 +96,12 @@
 #include "pgstat.h"
 #include "replication/origin.h"
 #include "replication/syncrep.h"
-#include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/md.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
-#include "storage/sinvaladt.h"
-#include "storage/smgr.h"
 #include "utils/builtins.h"
 #include "utils/memutils.h"
 #include "utils/timestamp.h"

src/backend/access/transam/xact.c

@@ -51,7 +51,6 @@
 #include "replication/origin.h"
 #include "replication/snapbuild.h"
 #include "replication/syncrep.h"
-#include "replication/walsender.h"
 #include "storage/condition_variable.h"
 #include "storage/fd.h"
 #include "storage/lmgr.h"
@@ -62,7 +61,6 @@
 #include "storage/sinvaladt.h"
 #include "storage/smgr.h"
 #include "utils/builtins.h"
-#include "utils/catcache.h"
 #include "utils/combocid.h"
 #include "utils/guc.h"
 #include "utils/inval.h"

src/backend/access/transam/xlog.c

@@ -59,7 +59,6 @@
 #include "access/xlog_internal.h"
 #include "access/xlogarchive.h"
 #include "access/xloginsert.h"
-#include "access/xlogprefetcher.h"
 #include "access/xlogreader.h"
 #include "access/xlogrecovery.h"
 #include "access/xlogutils.h"
@@ -79,7 +78,6 @@
 #include "postmaster/startup.h"
 #include "postmaster/walsummarizer.h"
 #include "postmaster/walwriter.h"
-#include "replication/logical.h"
 #include "replication/origin.h"
 #include "replication/slot.h"
 #include "replication/snapbuild.h"
@@ -90,12 +88,10 @@
 #include "storage/ipc.h"
 #include "storage/large_object.h"
 #include "storage/latch.h"
-#include "storage/pmsignal.h"
 #include "storage/predicate.h"
 #include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/reinit.h"
-#include "storage/smgr.h"
 #include "storage/spin.h"
 #include "storage/sync.h"
 #include "utils/guc_hooks.h"
@@ -104,7 +100,6 @@
 #include "utils/memutils.h"
 #include "utils/ps_status.h"
 #include "utils/relmapper.h"
-#include "utils/pg_rusage.h"
 #include "utils/snapmgr.h"
 #include "utils/timeout.h"
 #include "utils/timestamp.h"

src/backend/access/transam/xlogarchive.c

@@ -31,7 +31,6 @@
 #include "replication/walsender.h"
 #include "storage/fd.h"
 #include "storage/ipc.h"
-#include "storage/lwlock.h"
 
 /*
  * Attempt to retrieve the specified file from off-line archival storage.

src/backend/access/transam/xlogfuncs.c

@@ -22,23 +22,17 @@
 #include "access/xlog_internal.h"
 #include "access/xlogbackup.h"
 #include "access/xlogrecovery.h"
-#include "access/xlogutils.h"
 #include "catalog/pg_type.h"
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "replication/walreceiver.h"
 #include "storage/fd.h"
-#include "storage/ipc.h"
-#include "storage/smgr.h"
 #include "storage/standby.h"
 #include "utils/builtins.h"
-#include "utils/guc.h"
 #include "utils/memutils.h"
-#include "utils/numeric.h"
 #include "utils/pg_lsn.h"
 #include "utils/timestamp.h"
-#include "utils/tuplestore.h"
 
 /*
  * Backup-related variables.

src/backend/access/transam/xloginsert.c

@@ -33,7 +33,6 @@
 #include "access/xloginsert.h"
 #include "catalog/pg_control.h"
 #include "common/pg_lzcompress.h"
-#include "executor/instrument.h"
 #include "miscadmin.h"
 #include "pg_trace.h"
 #include "replication/origin.h"

src/backend/access/transam/xlogprefetcher.c

@@ -27,18 +27,14 @@
 
 #include "postgres.h"
 
-#include "access/xlog.h"
 #include "access/xlogprefetcher.h"
 #include "access/xlogreader.h"
-#include "access/xlogutils.h"
-#include "catalog/pg_class.h"
 #include "catalog/pg_control.h"
 #include "catalog/storage_xlog.h"
 #include "commands/dbcommands_xlog.h"
 #include "utils/fmgrprotos.h"
 #include "utils/timestamp.h"
 #include "funcapi.h"
-#include "pgstat.h"
 #include "miscadmin.h"
 #include "port/atomics.h"
 #include "storage/bufmgr.h"

src/backend/access/transam/xlogreader.c

@@ -34,9 +34,7 @@
 #include "replication/origin.h"
 
 #ifndef FRONTEND
-#include "miscadmin.h"
 #include "pgstat.h"
-#include "utils/memutils.h"
 #else
 #include "common/logging.h"
 #endif

src/backend/access/transam/xlogrecovery.c

@@ -55,11 +55,10 @@
 #include "storage/ipc.h"
 #include "storage/latch.h"
 #include "storage/pmsignal.h"
-#include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/spin.h"
-#include "utils/builtins.h"
 #include "utils/datetime.h"
+#include "utils/fmgrprotos.h"
 #include "utils/guc_hooks.h"
 #include "utils/pg_lsn.h"
 #include "utils/ps_status.h"

src/backend/access/transam/xlogutils.c

@@ -22,13 +22,10 @@
 #include "access/timeline.h"
 #include "access/xlogrecovery.h"
 #include "access/xlog_internal.h"
-#include "access/xlogprefetcher.h"
 #include "access/xlogutils.h"
 #include "miscadmin.h"
-#include "pgstat.h"
 #include "storage/fd.h"
 #include "storage/smgr.h"
-#include "utils/guc.h"
 #include "utils/hsearch.h"
 #include "utils/rel.h"