Rebakeはエラーメッセージで中止

[Canapin (Coin-coin le Canapin)]

こんにちは！

rake タスクで投稿を再ベイクしようとすると、次のようなメッセージで停止することがあります。

168858 / 329447 ( 51.3%)WARNING: terminating connection because of crash of another server process
DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
HINT: In a moment you should be able to reconnect to the database and repeat your command.

そして、次のようなテキストの壁の最後に：

/var/www/discourse/vendor/bundle/ruby/2.7.0/gems/activerecord-6.1.4.7/lib/active_record/relation.rb:828:in `exec_queries'
/var/www/discourse/vendor/bundle/ruby/2.7.0/gems/activerecord-6.1.4.7/lib/active_record/relation.rb:631:in `load'
/var/www/discourse/vendor/bundle/ruby/2.7.0/gems/activerecord-6.1.4.7/lib/active_record/relation.rb:249:in `records'
/var/www/discourse/vendor/bundle/ruby/2.7.0/gems/activerecord-6.1.4.7/lib/active_record/relation/delegation.rb:88:in `each'
/var/www/discourse/lib/tasks/posts.rake:124:in `block in rebake_posts'

これがあります：
168859 / 329447 ( 51.3%)rake aborted!
ActiveRecord::ConnectionNotEstablished: connection to server on socket \"/var/run/postgresql/.s.PGSQL.5432\" failed: FATAL: the database system is in recovery mode

---

Discourse ログのエラー：

このトラブルシューティングについて何かアイデアはありますか？

[RGJ (Richard - Communiteq)]

@Canapin

The postmaster has commanded this server process to roll back the current transaction and exit

PostgreSQLのログを確認してください。

[Canapin (Coin-coin le Canapin)]

ありがとう！

正直に言いますが、PostgreSQL は私にとって全く新しい世界で、ほとんど知識がありません。
ログが /var/discourse/shared/standalone/log/var-log/postgres に保存されていることを確認できますか？それとも、特定の エラー ログを別の場所を探す必要がありますか？
このフォルダ内の current ファイルを確認しましたが、Discourse のインターフェースログで示された時刻に特に疑わしいものは見つかりませんでした。

ただし、私が 何 を探すべきか知らない可能性も十分にあります。

---

編集：current ファイルに以下を見つけました：

	
2022-03-12 05:27:51.651 UTC [450818] discourse@discourse LOG:  duration: 258.470 ms  parse <unnamed>: SELECT 1 AS one FROM "permalinks" WHERE "permalinks"."url" = 'images/emoji/twitter/roll_eyes.png' LIMIT 1
2022-03-12 05:27:52.287 UTC [450818] discourse@discourse LOG:  duration: 557.420 ms  bind <unnamed>: SELECT 1 AS one FROM "permalinks" WHERE "permalinks"."url" = 'images/emoji/twitter/roll_eyes.png' LIMIT 1
2022-03-12 05:27:52.500 UTC [450818] discourse@discourse LOG:  duration: 158.213 ms  execute <unnamed>: SELECT 1 AS one FROM "permalinks" WHERE "permalinks"."url" = 'images/emoji/twitter/roll_eyes.png' LIMIT 1
2022-03-12 05:27:53.047 UTC [450818] discourse@discourse LOG:  duration: 301.290 ms  parse <unnamed>: SELECT 1 AS one FROM "permalinks" WHERE "permalinks"."url" = 'images/emoji/twitter/roll_eyes.png' LIMIT 1
2022-03-12 05:27:56.647 UTC [560] LOG:  checkpointer process (PID 180496) was terminated by signal 9: Killed
2022-03-12 05:27:56.650 UTC [560] LOG:  terminating any other active server processes
2022-03-12 05:27:56.652 UTC [455579] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.652 UTC [455579] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.652 UTC [455579] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.652 UTC [455580] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.652 UTC [455580] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.652 UTC [455580] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455573] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455573] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455573] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455560] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455560] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455560] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455476] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455476] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455476] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [180506] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [180506] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [180506] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455477] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455477] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455477] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [180499] WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [180499] DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [180499] HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455581] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455581] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455581] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.653 UTC [455574] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.653 UTC [455574] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.653 UTC [455574] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.654 UTC [427436] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.654 UTC [427436] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.654 UTC [427436] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.657 UTC [455341] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.657 UTC [455341] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.657 UTC [455341] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.661 UTC [455559] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.661 UTC [455559] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.661 UTC [455559] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.698 UTC [450818] discourse@discourse WARNING:  terminating connection because of crash of another server process
2022-03-12 05:27:56.698 UTC [450818] discourse@discourse DETAIL:  The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory.
2022-03-12 05:27:56.698 UTC [450818] discourse@discourse HINT:  In a moment you should be able to reconnect to the database and repeat your command.
2022-03-12 05:27:56.773 UTC [560] LOG:  all server processes terminated; reinitializing
2022-03-12 05:27:56.957 UTC [455632] LOG:  database system was interrupted; last known up at 2022-03-12 05:25:19 UTC
2022-03-12 05:27:56.957 UTC [455634] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.957 UTC [455633] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.958 UTC [455636] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.958 UTC [455635] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.966 UTC [455637] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.966 UTC [455638] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.966 UTC [455639] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.969 UTC [455640] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:56.977 UTC [455641] discourse@discourse FATAL:  the database system is in recovery mode
2022-03-12 05:27:57.331 UTC [455632] LOG:  database system was not properly shut down; automatic recovery in progress
2022-03-12 05:27:57.334 UTC [455632] LOG:  redo starts at E/B99AC028
2022-03-12 05:27:57.371 UTC [455632] LOG:  invalid record length at E/BA16D680: wanted 24, got 0
2022-03-12 05:27:57.371 UTC [455632] LOG:  redo done at E/BA16D640
2022-03-12 05:27:57.467 UTC [560] LOG:  database system is ready to accept connections

最も重要な行は次のものだと思われます：

2022-03-12 05:27:56.647 UTC [560] LOG:  checkpointer process (PID 180496) was terminated by signal 9: Killed
2022-03-12 05:27:56.650 UTC [560] LOG:  terminating any other active server processes

フォーラムのアクティビティ：

300,000 件の投稿を再レンダリングする必要があります（ただし、エラーは 150,000 件後や 1,000 件の再レンダリング後に発生することがあり、かなりランダムです）。

サーバー仕様：
Hetzner の CPX21：https://www.hetzner.com/cloud-fr

• 3 vCPU
• 4 GB RAM
• 80 GB ディスク（50% 空き）

また、dmesg コマンドが追加情報を表示することを知りました。このコマンドの末尾は以下の通りです：

[590461.105649] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=2f5e8cd98980f017bab02228d6af1cfbbd0068935aedea9ab3680470befa2030,mems_allowed=0,global_oom,task_memcg=/docker/2f5e8cd98980f017bab02228d6af1cfbbd0068935aedea9ab3680470befa2030,task=postmaster,pid=1135915,uid=105
[590461.105673] Out of memory: Killed process 1135915 (postmaster) total-vm:1172132kB, anon-rss:7244kB, file-rss:0kB, shmem-rss:839588kB, UID:105 pgtables:2104kB oom_score_adj:0
[590461.109673] oom_reaper: reaped process 1135915 (postmaster), now anon-rss:0kB, file-rss:0kB, shmem-rss:839588kB
[592120.454582] Process accounting resumed
[592121.145664] Process accounting resumed

これは何か役に立ちますか？

[RGJ (Richard - Communiteq)]

@Canapin

Out of memory

これです。
サーバーの（仮想）メモリが不足すると、オペレーティングシステムはシステム全体が利用できなくなるのを防ぐためにプロセスを終了させ始めます。

これはリベイク中にのみ発生するため、実際のメモリを増やす必要はなく、スワップファイルを拡大することで達成できる仮想メモリを増やすだけでよい場合があります。

[Canapin (Coin-coin le Canapin)]

承知しました！

しかし、リベイクの途中でメモリ不足になることには少し驚いています。ランダムな「ステージ」で発生し、各リベイクバッチ間でメモリが解放されているように見え、デフォルトのリベイクバッチはデフォルトでかなり小さい（150投稿程度？）からです。

---

このガイドに従って、2GBのスワップファイルを作成しました。これで大丈夫だといいのですが。

Create a swapfile for your Linux server

For servers with <= 2GB of RAM, running ./discourse-setup will prompt for and automatically create a 2GB swapfile. Most cloud virtual machine providers do not set up swapfiles as part of their server provisioning. In particular, upgrading Discourse produces a lot of memory pressure. With a swap file, rather than randomly terminating processes with an out of memory error, things will slow down instead. Having a swap file is a cheap insurance policy that protects you from many other lo…