PostgreSQL数据中`pg_logical`目录的用途是什么？

Question

我在测试我设置的PostgreSQL 9.4集群的故障转移时偶然发现了这个错误.在这里,我正在努力推动奴隶成为新的主人:

$ repmgr -f /etc/repmgr/repmgr.conf --verbose standby promote

2014-09-22 10:46:37 UTC LOG:  database system shutdown was interrupted; last known up at 2014-09-22 10:44:02 UTC
2014-09-22 10:46:37 UTC LOG:  database system was not properly shut down; automatic recovery in progress
2014-09-22 10:46:37 UTC LOG:  redo starts at 0/18000028
2014-09-22 10:46:37 UTC LOG:  consistent recovery state reached at 0/19000600
2014-09-22 10:46:37 UTC LOG:  record with zero length at 0/1A000090
2014-09-22 10:46:37 UTC LOG:  redo done at 0/1A000028
2014-09-22 10:46:37 UTC LOG:  last completed transaction was at log time 2014-09-22 10:36:22.679806+00
2014-09-22 10:46:37 UTC FATAL:  could not open directory "pg_logical/snapshots": No such file or directory
2014-09-22 10:46:37 UTC LOG:  startup process (PID 2595) exited with exit code 1
2014-09-22 10:46:37 UTC LOG:  aborting startup due to startup process failure

pg_logical/snapshots dir实际上存在于主节点上,它是空的.

UPD:我只是手动创建了空目录pg_logical/snapshots,pg_logical/mappings并且服务器已经启动而没有抱怨.repmgr standby clone似乎在同步时省略了这个目录.但问题仍然存在,因为我只是好奇这个目录是什么,也许我在设置中遗漏了一些东西.简单谷歌搜索它没有产生任何有意义的结果.

Answer 1

它用于9.4 中新的逻辑变更集提取/逻辑复制功能。

不过，这不应该发生......它表明某个地方存在重大错误，可能是 repmgr。我将等待详细信息（repmgr 版本等）。

更新：已确认，这是一个 repmgr 错误。它已经在 git master 中修复了（并且在本报告之前），并将在下一个版本中修复。鉴于这个问题的重要性，最好尽快。