Falha no Rebake: como diagnosticar e corrigir?

Suporte
1

Olá,

Após desativar o CDN no meu fórum, executei rake posts:rebake.
Falhou após algumas dezenas de milhares de rebakes.

Ao pesquisar por uma das mensagens de erro (“PQsocket() can’t get socket descriptor”), encontrei Rake:rebake crashes with errors: PG::ConnectionBad: PQsocket - #8 by j127, onde adicionar swap resolveu o problema.
Não tenho certeza se o problema é o mesmo, mas tentei, e o rebake ainda falha. É possível que ele falhe após mais rebakes do que antes de adicionar swap, mas não anotei quantos rebakes falharam nas primeiras vezes.

O que acontece:

  1. O rebake inicia e falha após cerca de 200.000 posts de um total de 1,6 milhão.
    root@Unicyclist-app:/var/www/discourse# rake posts:rebake
Rebaking post markdown for 'default'
   202930 / 1634878 ( 12.4%)
Failed to rebake (topic_id: 196639, post_id: 1470519)
PQconsumeInput() server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
  2. Após essa mensagem, esse erro é exibido instantaneamente para centenas de posts subsequentes:
       202931 / 1634878 ( 12.4%)
Failed to rebake (topic_id: 196638, post_id: 1470518)
PQsocket() can't get socket descriptor
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `async_exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:167:in `perform_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:556:in `block (2 levels) in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1017:in `block in with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/concurrency/null_lock.rb:9:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:986:in `with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:555:in `block in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/notifications/instrumenter.rb:58:in `instrument'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1137:in `log'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:554:in `raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:591:in `internal_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:547:in `internal_exec_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:693:in `select'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:73:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/query_cache.rb:262:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/querying.rb:68:in `_query_by_sql'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/querying.rb:53:in `block in find_by_sql'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_handling.rb:312:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/querying.rb:52:in `find_by_sql'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/statement_cache.rb:152:in `execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/core.rb:454:in `block in cached_find_by'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_handling.rb:312:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/core.rb:442:in `cached_find_by'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/core.rb:327:in `find_by'
/var/www/discourse/lib/pretty_text/helpers.rb:20:in `avatar_template'
/var/www/discourse/lib/pretty_text.rb:255:in `call'
/var/www/discourse/lib/pretty_text.rb:255:in `eval'
/var/www/discourse/lib/pretty_text.rb:255:in `block in markdown'
/var/www/discourse/lib/pretty_text.rb:695:in `block in protect'
/var/www/discourse/lib/pretty_text.rb:695:in `synchronize'
/var/www/discourse/lib/pretty_text.rb:695:in `protect'
/var/www/discourse/lib/pretty_text.rb:192:in `markdown'
/var/www/discourse/lib/pretty_text.rb:318:in `cook'
/var/www/discourse/app/models/post_analyzer.rb:30:in `cook'
/var/www/discourse/app/models/post.rb:359:in `cook'
/var/www/discourse/app/models/post.rb:836:in `rebake!'
/var/www/discourse/lib/tasks/posts.rake:145:in `rebake_post'
/var/www/discourse/lib/tasks/posts.rake:132:in `block (2 levels) in rebake_posts'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation/delegation.rb:101:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation/delegation.rb:101:in `each'
/var/www/discourse/lib/tasks/posts.rake:131:in `block in rebake_posts'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/lib/tasks/posts.rake:126:in `rebake_posts'
/var/www/discourse/lib/tasks/posts.rake:111:in `block in rebake_posts_all_sites'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:49:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:36:in `each_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management.rb:17:in `each_connection'
/var/www/discourse/lib/tasks/posts.rake:111:in `rebake_posts_all_sites'
/var/www/discourse/lib/tasks/posts.rake:7:in `block in <main>'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:281:in `block in execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:281:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:281:in `execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:199:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:199:in `invoke_with_call_chain'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/task.rb:188:in `invoke'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:188:in `invoke_task'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:138:in `block (2 levels) in top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:138:in `each'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:138:in `block in top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:147:in `run_with_threads'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:132:in `top_level'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:83:in `block in run'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:214:in `standard_exception_handling'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rake-13.3.1/lib/rake/application.rb:80:in `run'
bin/rake:13:in `<top (required)>'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:59:in `load'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:59:in `kernel_load'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli/exec.rb:23:in `run'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:452:in `exec'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/command.rb:28:in `run'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in `invoke_command'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor.rb:538:in `dispatch'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:35:in `dispatch'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/vendor/thor/lib/thor/base.rb:584:in `start'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/cli.rb:29:in `start'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/exe/bundle:28:in `block in <top (required)>'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/lib/bundler/friendly_errors.rb:117:in `with_friendly_errors'
/usr/local/lib/ruby/gems/3.3.0/gems/bundler-2.6.4/exe/bundle:20:in `<top (required)>'
/usr/local/bin/bundle:25:in `load'
/usr/local/bin/bundle:25:in `<main>'
  3. Até que termine várias vezes com isso:
    Caused by:
ActiveRecord::ConnectionNotEstablished: PQsocket() can't get socket descriptor (ActiveRecord::ConnectionNotEstablished)
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `async_exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:167:in `perform_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:556:in `block (2 levels) in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1017:in `block in with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/concurrency/null_lock.rb:9:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:986:in `with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:555:in `block in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/notifications/instrumenter.rb:58:in `instrument'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1137:in `log'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:554:in `raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:591:in `internal_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:547:in `internal_exec_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:693:in `select'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:73:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/query_cache.rb:262:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/querying.rb:68:in `_query_by_sql'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1459:in `block (2 levels) in exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_handling.rb:312:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1458:in `block in exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1480:in `skip_query_cache_if_necessary'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1442:in `exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1420:in `block in exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1480:in `skip_query_cache_if_necessary'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1414:in `exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/goldiloader-6.0.0/lib/goldiloader/active_record_patches.rb:40:in `exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1191:in `load'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:353:in `records'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation/delegation.rb:101:in `each'
/var/www/discourse/lib/tasks/posts.rake:131:in `block in rebake_posts'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/lib/tasks/posts.rake:126:in `rebake_posts'
/var/www/discourse/lib/tasks/posts.rake:111:in `block in rebake_posts_all_sites'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:49:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:36:in `each_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management.rb:17:in `each_connection'
/var/www/discourse/lib/tasks/posts.rake:111:in `rebake_posts_all_sites'
/var/www/discourse/lib/tasks/posts.rake:7:in `block in <main>'
/usr/local/bin/bundle:25:in `load'
/usr/local/bin/bundle:25:in `<main>'

Caused by:
PG::ConnectionBad: PQsocket() can't get socket descriptor (PG::ConnectionBad)
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rack-mini-profiler-4.0.1/lib/patches/db/pg/alias_method.rb:109:in `async_exec'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/postgresql/database_statements.rb:167:in `perform_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:556:in `block (2 levels) in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1017:in `block in with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/concurrency/null_lock.rb:9:in `synchronize'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:986:in `with_raw_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:555:in `block in raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/notifications/instrumenter.rb:58:in `instrument'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract_adapter.rb:1137:in `log'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:554:in `raw_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:591:in `internal_execute'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:547:in `internal_exec_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:693:in `select'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/database_statements.rb:73:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/query_cache.rb:262:in `select_all'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/querying.rb:68:in `_query_by_sql'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1459:in `block (2 levels) in exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_adapters/abstract/connection_pool.rb:416:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/connection_handling.rb:312:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1458:in `block in exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1480:in `skip_query_cache_if_necessary'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1442:in `exec_main_query'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1420:in `block in exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1480:in `skip_query_cache_if_necessary'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1414:in `exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/goldiloader-6.0.0/lib/goldiloader/active_record_patches.rb:40:in `exec_queries'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:1191:in `load'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation.rb:353:in `records'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activerecord-8.0.4/lib/active_record/relation/delegation.rb:101:in `each'
/var/www/discourse/lib/tasks/posts.rake:131:in `block in rebake_posts'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/activesupport-8.0.4/lib/active_support/core_ext/range/each.rb:14:in `step'
/var/www/discourse/lib/tasks/posts.rake:126:in `rebake_posts'
/var/www/discourse/lib/tasks/posts.rake:111:in `block in rebake_posts_all_sites'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:49:in `with_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management/null_instance.rb:36:in `each_connection'
/var/www/discourse/vendor/bundle/ruby/3.3.0/gems/rails_multisite-7.0.0/lib/rails_multisite/connection_management.rb:17:in `each_connection'
/var/www/discourse/lib/tasks/posts.rake:111:in `rebake_posts_all_sites'
/var/www/discourse/lib/tasks/posts.rake:7:in `block in <main>'
/usr/local/bin/bundle:25:in `load'
/usr/local/bin/bundle:25:in `<main>'
Tasks: TOP => posts:rebake
(See full trace by running task with --trace)
root@Unicyclist-app:/var/www/discourse#

Aqui está a saída de free -h durante o rebake (os valores são aproximadamente os mesmos em qualquer momento durante o rebake):

               total        used        free      shared  buff/cache   available
Mem:           7.6Gi       4.6Gi       231Mi       2.1Gi       2.8Gi       709Mi
Swap:          2.0Gi       1.8Gi       194Mi

Também tenho bastante espaço livre (não tinha nas primeiras vezes, mas liberei espaço só para garantir, e isso não mudou nada).

Já rebakeei todos os posts deste fórum algumas vezes ao longo dos últimos anos e nunca enfrentei problemas. O fórum não cresceu muito, e as especificações do servidor são as mesmas de antes.

2

Ainda estou procurando ajuda com isto :face_with_tongue:

3

Aumentei o tamanho da troca (swap) de 2 para 4 GB, e o rebake funcionou.

Então, acho que era sobre memória, embora eu esteja um pouco surpreso com o quanto ele pede (8 GB de RAM + 4 GB de swap), especialmente porque rebakes mais antigos não apresentavam problemas sem swap e com a mesma quantidade de RAM.

O que devo fazer se eu quiser monitorar o uso de RAM e verificar se há algum problema? Qual métrica deve importar para estimar os requisitos de memória? Visualizações de página por dia (5000-8000 + picos de bot uma ou duas vezes por mês)? Tamanho do banco de dados (23 GB)? :person_shrugging: :face_with_raised_eyebrow:

4

O uso de memória é muito maior durante uma reconstrução do que durante a operação normal. Parece que o “rebaking” (reprocessamento), de forma semelhante, exige muito. Se for esse o caso, qualquer tipo de monitoramento regular não agregaria muito valor: o monitoramento seria necessário durante esses picos, que felizmente ocorrem quando o administrador realiza alguma ação específica.

Quando eu estava rodando em uma configuração de máquina menor e mais marginal, eu costumava deixar uma segunda janela de terminal aberta, conectada via ssh ao meu servidor e executando
vmstat 5
o que fornece um registro do uso de memória à medida que ele sobe e desce. Observe a coluna swpd e compare com o seu espaço de swap configurado. Comumente a falha ocorrerá de repente, não gradualmente, então mesmo observar tendências de curto prazo não ajuda muito.

Se você tiver espaço em disco, não há mal algum em ter muito swap — metade da RAM, ou até mesmo o mesmo que a RAM. Ele está lá neste caso para lidar com os picos. Você não quer ver atividade de swapping/paging durante o uso normal. Novamente, pode-se usar vmstat 5 5 para obter uma visão de curto prazo da atividade de paginação (nas colunas si e so).

Aqui está um exemplo:

# vmstat 5 5
procs -----------memory----------   ---swap--  -----io---- -system--  ------cpu-----
 r  b   swpd   free   buff  cache     si    so    bi    bo   in    cs us sy id wa st
 3  0 1392140  61200  11632  76432    41    32   117    93    0     1  2  1 97  0  0
 1  1 1467220  63416    324  67284  8786 20499 13178 20567 2539  8924 77 13  0 10  0
 0  2 1593340  57916   1096  53832 24262 46868 29986 46889 5377 18534 44 22  0 34  0
 4  0 1155632 120680   2772  86280 39111 35424 54768 37824 6987 25174 38 27  0 35  0
 3  0 1102988  74096   2852  85276 11261   246 12610   271 1879  6365 86  6  0  8  0

Você vê que a coluna swpd atingiu o pico em mais de 1,5G, em comparação com os meus 2,0G configurados. Você vê que a atividade de swapout (so) atingiu o pico na mesma janela de 5 segundos, e o swapin (si) atingiu o pico na janela seguinte.

(Edição: Eu posso ver que eu tinha 2,0G de swap configurado porque eu havia executado free anteriormente:

# free
              total        used        free      shared  buff/cache   available
Mem:        1009140      696504       78544       51784      234092      118436
Swap:       2097144      154628     1942516

nós também vemos que eu estava na época conseguindo rodar o discourse com apenas 1G de RAM.)

5

Interessante. Estou com pouco espaço em disco há algum tempo. Atualmente estou tentando reescalonar para outros planos (criarei um tópico sobre isso) e ver como o desempenho se compara, mas em vez de fazer isso, você acha que seria uma ideia melhor – no papel, pelo menos – manter meu plano, mover meus backups para um volume adicional barato[1] e adicionar vários GB de swap?

  1. Bem, preciso ver se há tanta diferença entre adicionar um volume ou mudar meu plano para outro que também ofereça mais espaço em disco) ↩︎

6

Essa é uma troca possível. Uma das primeiras coisas que fiz foi limitar o número (e ajustar a frequência) de backups. Eu ainda não mudei para armazenamento em bloco para backups ou uploads, mas isso pode ser uma vantagem, se estender a vida útil de uma configuração com RAM limitada.

(Outra coisa que fiz, perto do final do meu tempo nas máquinas de configuração menores, foi redimensionar temporariamente para uma instância com mais RAM apenas pelo tempo necessário para fazer uma atualização e depois redimensionar de volta. Custou apenas centavos, mesmo que a instância maior possa custar o dobro do custo mensal. Mas isso exige um pouco de tempo de inatividade, e um pouco de tempo e cuidado. E requer que seu provedor tenha uma máquina maior com a mesma capacidade de disco - aumentar a escala para uma configuração com disco maior geralmente é um caminho sem volta.)

7

Meu provedor permite o escalonamento vertical mantendo o mesmo espaço em disco, o que permite o escalonamento vertical para baixo, se necessário :slight_smile: