恢复后 PostgreSQL 9.2 归档最后重放的 WAL

Question

按照 PostgreSQL 9.2 官方文档，我在我的 postgres.conf 文件上设置了连续归档:

wal_level = archive
archive_mode = on
archive_command = 'test ! -f /.../archive/%f && cp %p /.../archive/%f'

备份和恢复成功后，数据库启动时存档命令失败，因为 PostgreSQL 正在尝试存档最后重放的 WAL 文件，显然，它已经存档了。我的 recovery.conf 文件如下:

restore_command = 'cp /.../archive/%f "%p"'
recovery_target_time = '2013-07-02 15:20:12'

这是我在尝试启动数据库时遇到的错误:

LOG:  database system was interrupted; last known up at 2013-07-02 14:53:37 CEST
LOG:  creating missing WAL directory "pg_xlog/archive_status"
LOG:  starting point-in-time recovery to 2013-07-02 15:20:12+02
LOG:  restored log file "000000010000000000000002" from archive
LOG:  redo starts at 0/2000020
LOG:  consistent recovery state reached at 0/20023D0
LOG:  restored log file "000000010000000000000003" from archive
LOG:  recovery stopping before commit of transaction 4063, time 2013-07-02 15:20:12.211559+02
LOG:  redo done at 0/306D8B8
LOG:  last completed transaction was at log time 2013-07-02 15:20:11.189978+02
cp: cannot stat `/.../archive/00000002.history': No such file or directory
LOG:  selected new timeline ID: 2
cp: cannot stat `/.../archive/00000001.history': No such file or directory
LOG:  archive recovery complete
LOG:  autovacuum launcher started
LOG:  database system is ready to accept connections
LOG:  archive command failed with exit code 1
DETAIL:  The failed archive command was: test ! -f /.../archive/000000010000000000000003 && cp pg_xlog/000000010000000000000003 /.../archive/000000010000000000000003
LOG:  archive command failed with exit code 1
DETAIL:  The failed archive command was: test ! -f /.../archive/000000010000000000000003 && cp pg_xlog/000000010000000000000003 /.../archive/000000010000000000000003
LOG:  archive command failed with exit code 1
DETAIL:  The failed archive command was: test ! -f /.../archive/000000010000000000000003 && cp pg_xlog/000000010000000000000003 /.../archive/000000010000000000000003
WARNING:  transaction log file "000000010000000000000003" could not be archived: too many failures

这是预期的行为吗？恢复后是否应该归档最后重放的 WAL 文件？如果是这样，则存档命令不应失败，以防文件已存档(如文档中所述)。

Answer 1

显然，您应该只存档一次并恢复存档的副本。

我会在恢复期间关闭存档，然后再打开它。