如何将 PostgreSQL 从版本 11 升级到版本 13？

Question

我尝试在 Debian 系统上将 PostgreSQL 从 11 升级到 13，但失败了。我有一个需要升级的集群：

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$ sudo -u postgres pg_lsclusters\nVer Cluster Port Status Owner    Data directory               Log file\n11  main    5432 online postgres /var/lib/postgresql/11/main  /var/log/postgresql/postgresql-11-main.log\n

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这是我尝试升级的方法：

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$ sudo -u postgres pg_upgradecluster 11 main\nStopping old cluster...\nWarning: stopping the cluster using pg_ctlcluster will mark the systemd unit as failed. Consider using systemctl:\n  sudo systemctl stop postgresql@11-main\nRestarting old cluster with restricted connections...\nNotice: extra pg_ctl/postgres options given, bypassing systemctl for start operation\nError: cluster configuration already exists\nError: Could not create target cluster\n

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此后，系统将处于不可用状态：

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$ sudo systemctl status postgresql@11-main.service \n\xe2\x97\x8f postgresql@11-main.service - PostgreSQL Cluster 11-main\n     Loaded: loaded (/lib/systemd/system/postgresql@.service; enabled-runtime; vendor preset: enabled)\n     Active: failed (Result: exit-code) since Tue 2022-06-14 06:48:20 CEST; 19s ago\n    Process: 597 ExecStart=/usr/bin/pg_ctlcluster --skip-systemctl-redirect 11-main start (code=exited, status=0/SUCCE>\n    Process: 4508 ExecStop=/usr/bin/pg_ctlcluster --skip-systemctl-redirect -m fast 11-main stop (code=exited, status=>\n   Main PID: 684 (code=exited, status=0/SUCCESS)\n        CPU: 1.862s\n\nJun 14 06:47:23 argos systemd[1]: Starting PostgreSQL Cluster 11-main...\nJun 14 06:47:27 argos systemd[1]: Started PostgreSQL Cluster 11-main.\nJun 14 06:48:20 argos postgresql@11-main[4508]: Cluster is not running.\nJun 14 06:48:20 argos systemd[1]: postgresql@11-main.service: Control process exited, code=exited, status=2/INVALIDARG>\nJun 14 06:48:20 argos systemd[1]: postgresql@11-main.service: Failed with result 'exit-code'.\nJun 14 06:48:20 argos systemd[1]: postgresql@11-main.service: Consumed 1.862s CPU time.\n\n$ sudo systemctl start postgresql@11-main.service \nJob for postgresql@11-main.service failed because the service did not take the steps required by its unit configuration.\nSee "systemctl status postgresql@11-main.service" and "journalctl -xe" for details.\n

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幸运的是，重新启动系统使旧集群重新上线，但没有任何升级。为什么升级失败？“其单元配置所需的步骤”是什么？如何以最短的停机时间升级 PostgreSQL？

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Answer 1

我找到了问题的根源：错误的用户（root而不是postgres）拥有的配置文件无法通过pg_dropcluster命令删除，因为我以用户身份运行它postgres。

为了供将来参考，以下是将 PostgreSQL 集群从 11 升级到 13 的正确步骤：

• 验证当前集群是否仍然是旧版本：

  $ pg_lsclusters
  Ver Cluster Port Status Owner    Data directory               Log file
  11  main    5432 online postgres /var/lib/postgresql/11/main  /var/log/postgresql/postgresql-11-main.log
  13  main    5434 down   postgres /var/lib/postgresql/13/main  /var/log/postgresql/postgresql-13-main.log
  

• pg_dropcluster 13 main以用户身份运行postgres：

  $ sudo -u postgres pg_dropcluster 13 main
  Warning: systemd was not informed about the removed cluster yet. 
  Operations like "service postgresql start" might fail. To fix, run:
  sudo systemctl daemon-reload
  

• pg_upgradecluster以用户身份运行命令postgres：

  $ sudo -u postgres pg_upgradecluster 11 main
  

• 验证一切正常，并且唯一的在线集群现在是 13：

  $ pg_lsclusters 
  Ver Cluster Port Status Owner    Data directory               Log file
  11  main    5434 down   postgres /var/lib/postgresql/11/main  /var/log/postgresql/postgresql-11-main.log
  13  main    5432 online postgres /var/lib/postgresql/13/main  /var/log/postgresql/postgresql-13-main.log
  

• 删除旧集群：

  $ sudo -u postgres pg_dropcluster 11 main
  

• 卸载以前版本的 PostgreSQL：

  $ sudo apt remove 'postgresql*11'