*** a/doc/src/sgml/ref/pg_rewind.sgml
--- b/doc/src/sgml/ref/pg_rewind.sgml
***************
*** 50,61 **** PostgreSQL documentation
    <para>
     The result is equivalent to replacing the target data directory with the
     source one. Only changed blocks from relation files are copied;
!    all other files are copied in full, including configuration files. The
!    advantage of <application>pg_rewind</> over taking a new base backup, or
!    tools like <application>rsync</>, is that <application>pg_rewind</> does
!    not require reading through unchanged blocks in the cluster. This makes
!    it a lot faster when the database is large and only a small
!    fraction of blocks differ between the clusters.
    </para>
  
    <para>
--- 50,63 ----
    <para>
     The result is equivalent to replacing the target data directory with the
     source one. Only changed blocks from relation files are copied;
!    all other files except WAL are copied in full, including configuration
!    files. Only the WAL files between the point of divergence and the current
!    WAL insert location of the source server are copied, other WAL files are
!    useless for the target server. The advantage of <application>pg_rewind</>
!    over taking a new base backup, or tools like <application>rsync</>, 
!    is that <application>pg_rewind</> does not require reading through unchanged
!    blocks in the cluster. This makes it a lot faster when the database is
!    large and only a small fraction of blocks differ between the clusters.
    </para>
  
    <para>
***************
*** 231,237 **** PostgreSQL documentation
       <para>
        Copy all other files such as <filename>pg_xact</filename> and
        configuration files from the source cluster to the target cluster
!       (everything except the relation files).
       </para>
      </step>
      <step>
--- 233,239 ----
       <para>
        Copy all other files such as <filename>pg_xact</filename> and
        configuration files from the source cluster to the target cluster
!       (everything except the relation files and some WAL files).
       </para>
      </step>
      <step>
*** a/src/bin/pg_rewind/filemap.c
--- b/src/bin/pg_rewind/filemap.c
***************
*** 21,26 ****
--- 21,27 ----
  #include "common/string.h"
  #include "catalog/pg_tablespace.h"
  #include "storage/fd.h"
+ #include "access/xlog_internal.h"
  
  filemap_t  *filemap = NULL;
  
***************
*** 67,72 **** process_source_file(const char *path, file_type_t type, size_t newsize,
--- 68,75 ----
  	file_action_t action = FILE_ACTION_NONE;
  	size_t		oldsize = 0;
  	file_entry_t *entry;
+ 	uint32		tli;
+ 	XLogSegNo	segno;
  
  	Assert(map->array == NULL);
  
***************
*** 168,179 **** process_source_file(const char *path, file_type_t type, size_t newsize,
--- 171,201 ----
  				 *
  				 * An exception: PG_VERSIONs should be identical, but avoid
  				 * overwriting it for paranoia.
+ 				 *
+ 				 * Another exception: Do not copy WAL files before the
+ 				 * divergence and the WAL files after the current WAL insert
+ 				 * location of the source server for performance reasons.
  				 */
  				if (pg_str_endswith(path, "PG_VERSION"))
  				{
  					action = FILE_ACTION_NONE;
  					oldsize = statbuf.st_size;
  				}
+ 				else if (strncmp(path, XLOGDIR "/", strlen(XLOGDIR "/")) == 0 &&
+ 						 IsXLogFileName(path + strlen(XLOGDIR "/")))
+ 				{
+ 					XLogFromFileName(path + strlen(XLOGDIR "/"), &tli, &segno, WalSegSz);
+ 					if (segno >= divergence_segno && segno <= last_source_segno)
+ 					{
+ 						action = FILE_ACTION_COPY;
+ 						oldsize = 0;
+ 					}
+ 					else
+ 					{
+ 						action = FILE_ACTION_NONE;
+ 						oldsize = exists ? statbuf.st_size : 0;
+ 					}
+ 				}
  				else
  				{
  					action = FILE_ACTION_COPY;
***************
*** 258,263 **** process_target_file(const char *path, file_type_t type, size_t oldsize,
--- 280,288 ----
  	file_entry_t *key_ptr;
  	filemap_t  *map = filemap;
  	file_entry_t *entry;
+ 	bool		reserve = false;
+ 	uint32		tli;
+ 	XLogSegNo	segno;
  
  	snprintf(localpath, sizeof(localpath), "%s/%s", datadir_target, path);
  	if (lstat(localpath, &statbuf) < 0)
***************
*** 303,310 **** process_target_file(const char *path, file_type_t type, size_t oldsize,
  	exists = (bsearch(&key_ptr, map->array, map->narray, sizeof(file_entry_t *),
  					  path_cmp) != NULL);
  
! 	/* Remove any file or folder that doesn't exist in the source system. */
! 	if (!exists)
  	{
  		entry = pg_malloc(sizeof(file_entry_t));
  		entry->path = pg_strdup(path);
--- 328,346 ----
  	exists = (bsearch(&key_ptr, map->array, map->narray, sizeof(file_entry_t *),
  					  path_cmp) != NULL);
  
! 	if(strncmp(path, XLOGDIR "/", strlen(XLOGDIR "/")) == 0 &&
! 		IsXLogFileName(path + strlen(XLOGDIR "/")))
! 	{
! 		XLogFromFileName(path + strlen(XLOGDIR "/"), &tli, &segno, WalSegSz);
! 		if(segno < divergence_segno)
! 			reserve = true;
! 	}
! 
! 	/*
! 	 * Remove any file or folder that doesn't exist in the source system
! 	 * except the WAL files before the divergence.
! 	 */
! 	if (!exists && !reserve)
  	{
  		entry = pg_malloc(sizeof(file_entry_t));
  		entry->path = pg_strdup(path);
*** a/src/bin/pg_rewind/pg_rewind.c
--- b/src/bin/pg_rewind/pg_rewind.c
***************
*** 27,32 ****
--- 27,33 ----
  #include "common/restricted_token.h"
  #include "getopt_long.h"
  #include "storage/bufpage.h"
+ #include "access/xlog_internal.h"
  
  static void usage(const char *progname);
  
***************
*** 59,64 **** bool		dry_run = false;
--- 60,69 ----
  TimeLineHistoryEntry *targetHistory;
  int			targetNentries;
  
+ /* WAL location */
+ XLogSegNo	divergence_segno;
+ XLogSegNo	last_source_segno;
+ 
  static void
  usage(const char *progname)
  {
***************
*** 281,286 **** main(int argc, char **argv)
--- 286,313 ----
  		   chkpttli);
  
  	/*
+ 	 * Save the WAL segment numbers of the divergence and the current WAL insert
+ 	 * location of the source server. Later only the WAL files between those
+ 	 * would be copied to the target data directory.
+ 	 * 
+ 	 * Note: The later generated WAL files in the source server before the end
+ 	 * of the copy of the data files must be made available when the target
+ 	 * server is started. This can be done by configuring the target server as
+ 	 * a standby of the source server.
+ 	 */
+ 	if (connstr_source)
+ 	{
+ 		endrec = libpqGetCurrentXlogInsertLocation();
+ 	}
+ 	else
+ 	{
+ 		endrec = ControlFile_source.checkPoint;
+ 	}
+ 
+ 	XLByteToSeg(divergerec, divergence_segno, WalSegSz);
+ 	XLByteToPrevSeg(endrec, last_source_segno, WalSegSz);
+ 
+ 	/*
  	 * Build the filemap, by comparing the source and target data directories.
  	 */
  	filemap_create();
*** a/src/bin/pg_rewind/pg_rewind.h
--- b/src/bin/pg_rewind/pg_rewind.h
***************
*** 30,35 **** extern int	WalSegSz;
--- 30,39 ----
  extern TimeLineHistoryEntry *targetHistory;
  extern int	targetNentries;
  
+ /* WAL location */
+ extern XLogSegNo divergence_segno;
+ extern XLogSegNo last_source_segno;
+ 
  /* in parsexlog.c */
  extern void extractPageMap(const char *datadir, XLogRecPtr startpoint,
  			   int tliIndex, XLogRecPtr endpoint);
*** /dev/null
--- b/src/bin/pg_rewind/t/006_wal_copy.pl
***************
*** 0 ****
--- 1,129 ----
+ #
+ # Test pg_rewind only copy needed WALs from the source.
+ #
+ use strict;
+ use warnings;
+ use TestLib;
+ use Test::More tests => 12;
+ 
+ use RewindTest;
+ 
+ sub run_test
+ {
+ 	my $test_mode = shift;
+ 
+ 	RewindTest::setup_cluster($test_mode);
+ 	RewindTest::start_master();
+ 
+ 	# Setup parameters for WAL reclaim 
+ 	master_psql("ALTER SYSTEM SET checkpoint_timeout = '1d'");
+ 	master_psql("ALTER SYSTEM SET min_wal_size = '80MB'");
+ 	master_psql("ALTER SYSTEM SET wal_keep_segments = 4");
+ 	master_psql("ALTER SYSTEM SET log_checkpoints = on");
+ 	master_psql("SELECT pg_reload_conf()");
+ 
+ 	RewindTest::create_standby($test_mode);
+ 
+ 	# Create a test table and insert rows in master.
+ 	master_psql("CREATE TABLE tbl1 (d text)");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 1')");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 2')");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 3')");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 4')");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 5, checkpoint')");
+ 	master_psql("CHECKPOINT");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 6, before promotion')");
+ 
+ 	# Promote standby
+ 	my $master_divergence_wal = $node_master->safe_psql("postgres",
+ 		"SELECT pg_walfile_name(pg_current_wal_insert_lsn())");
+ 	RewindTest::promote_standby();
+ 
+ 	# Insert rows in master after promotion
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 6, after promotion')");
+ 
+ 	master_psql("SELECT pg_switch_wal()");
+ 	master_psql("INSERT INTO tbl1 VALUES ('in master, wal 7, after promotion')");
+ 
+ 	master_psql("CHECKPOINT");
+ 
+ 	# Insert rows in standby after promotion
+ 	standby_psql("INSERT INTO tbl1 VALUES ('in standby, wal 6, after promotion')");
+ 
+ 	standby_psql("SELECT pg_switch_wal()");
+ 	standby_psql("INSERT INTO tbl1 VALUES ('in standby, wal 7, after promotion')");
+ 
+ 	standby_psql("SELECT pg_switch_wal()");
+ 	standby_psql("INSERT INTO tbl1 VALUES ('in standby, wal 8, after promotion')");	
+ 
+ 	standby_psql("CHECKPOINT");
+ 
+ 	# Check WALs before running pg_rewind
+ 	master_psql("SELECT * from pg_ls_waldir()");
+ 	print("master_divergence_wal: $master_divergence_wal\n");
+ 	my $master_wal_count_before_divergence = $node_master->safe_psql("postgres",
+ 		"SELECT count(*) FROM pg_ls_waldir() WHERE name ~ '^[0-9A-F]{24}\$' AND name < '$master_divergence_wal'");
+ 	ok( $master_wal_count_before_divergence > 0, 'master_wal_count_before_divergence > 0');
+ 
+ 	standby_psql("SELECT * from pg_ls_waldir()");
+ 	my $standby_current_wal = $node_standby->safe_psql("postgres",
+ 		"SELECT pg_walfile_name(pg_current_wal_insert_lsn())");
+ 	print("standby_current_wal: $standby_current_wal\n");
+ 	my $standby_reclaimed_wal_count = $node_standby->safe_psql("postgres",
+ 		"SELECT count(*) FROM pg_ls_waldir() WHERE name ~ '^[0-9A-F]{24}\$' AND name > '$standby_current_wal'");
+ 	ok( $standby_reclaimed_wal_count > 0, 'standby_reclaimed_wal_count > 0');
+ 
+ 	# The accuracy of imodification from pg_ls_waldir() is seconds, so sleep one second
+ 	sleep(1);
+ 	my $pg_rewind_time = $node_master->safe_psql("postgres", "SELECT now()");
+ 	print("pg_rewind_time: $pg_rewind_time\n");
+ 
+ 	# Run pg_rewind and check
+ 	RewindTest::run_pg_rewind($test_mode);
+ 
+ 	master_psql("SELECT * from pg_ls_waldir()");
+ 
+ 	check_query(
+ 		'SELECT * FROM tbl1',
+ 		qq(in master, wal 1
+ in master, wal 2
+ in master, wal 3
+ in master, wal 4
+ in master, wal 5, checkpoint
+ in master, wal 6, before promotion
+ in standby, wal 6, after promotion
+ in standby, wal 7, after promotion
+ in standby, wal 8, after promotion
+ ),
+ 		'table content');
+ 
+ 	check_query(
+ 		"SELECT count(*) FROM pg_ls_waldir() WHERE name ~ '^[0-9A-F]{24}\$' AND name < '$master_divergence_wal' AND modification >= '$pg_rewind_time'",
+ 		qq(0
+ ),
+ 		'do not copy WALs before divergence');
+ 
+ 	check_query(
+ 		"SELECT count(*) FROM pg_ls_waldir() WHERE name ~ '^[0-9A-F]{24}\$' AND name > '$standby_current_wal' AND modification >= '$pg_rewind_time'",
+ 		qq(0
+ ),
+ 		'do not copy reclaimed WALs from the source server');
+ 
+ 	RewindTest::clean_rewind_test();
+ }
+ 
+ # Run the test in both modes
+ run_test('local');
+ run_test('remote');
+ 
+ exit(0);