部署流复制备库的数据复制环节主要包括以下3个步骤：
1.pg_stat_backup('francs_bk1');

2.拷贝主节点$PGDATA数据文件和表空间文件到备节点；

3.pg_stop_backup();

pg_basebackup工具对数据库实例级别进行物理备份，此工具需要超级用户权限或者replication权限，注意max_wal_sender的参数配置，因为pg_basebackup将至少消耗一个wal发送进程

在备库做一个基准备份

[postgres@localhost pg10]$ pg_basebackup -D /database/pg10/pg_root -Fp -Xs -v -P -h 192.168.12.10 -p 1921 -U repuser
pg_basebackup: initiating base backup, waiting for checkpoint to complete
pg_basebackup: checkpoint completed
pg_basebackup: write-ahead log start point: 0/E000028 on timeline 1
pg_basebackup: starting background WAL receiver
23784/23784 kB (100%), 1/1 tablespace
pg_basebackup: write-ahead log end point: 0/E0000F8
pg_basebackup: waiting for background process to finish streaming ...
pg_basebackup: base backup completed

pg_basebackup命令详解Options controlling the output:

-D, --pgdata=DIRECTORY receive base backup into directory　　#指定备节点接收主数据库的目标路径，与主库保持一致
  -F, --format=p|t       output format (plain (default), tar)　　#生成的备份数据格式，p(plain)格式（完全一样）和t(tar)格式（被打包成.tar）
  -r, --max-rate=RATE    maximum transfer rate to transfer data directory
                         (in kB/s, or use suffix "k" or "M")
  -R, --write-recovery-conf
                         write recovery.conf for replication
  -S, --slot=SLOTNAME    replication slot to use
      --no-slot          prevent creation of temporary replication slot
  -T, --tablespace-mapping=OLDDIR=NEWDIR
                         relocate tablespace in OLDDIR to NEWDIR
  -X, --wal-method=none|fetch|stream　　　　　　　　　　　　　　　　　　
#在备份工程中产生的wal日志包含在备份中的方式：
f(fetch)wal日志在基准备份完成后被传送到备节点，这是主库上的wal_keep_segments参数必须设置的较大，以免备份过程中的wal还没发送到备节点之前就被主库覆盖掉，主库只启动一个基准备份wal发送进程
s(stream),主库除了启动一个基准备份wal发送进程还会额外另起一个发送进程用于发送主库生产的wal增量日志流，避免主库中wal被覆盖（生产库推荐此方式特别是大库）
　　　　include required WAL files with specified method
      --waldir=WALDIR    location for the write-ahead log directory
  -z, --gzip             compress tar output
  -Z, --compress=0-9     compress tar output with given compression level

General options:
  -c, --checkpoint=fast|spread
                         set fast or spread checkpointing
  -l, --label=LABEL      set backup label
  -n, --no-clean         do not clean up after errors
  -N, --no-sync          do not wait for changes to be written safely to disk
  -P, --progress         show progress information　　　　#显示数据文件、表空间文件近似传输百分比
  -v, --verbose          output verbose messages　　　　#打印各阶段的日志
  -V, --version          output version information, then exit
  -?, --help             show this help, then exit

Connection options:
  -d, --dbname=CONNSTR   connection string
  -h, --host=HOSTNAME    database server host or socket directory
  -p, --port=PORT        database server port number
  -s, --status-interval=INTERVAL
                         time between status packets sent to server (in seconds)
  -U, --username=NAME    connect as specified database user
  -w, --no-password      never prompt for password
  -W, --password         force password prompt (should happen automatically)

Report bugs to <pgsql-bugs@postgresql.org>.