一部のタグを使用時に内部サーバーエラーが発生（ERROR: duplicate key value violates unique constraint "index_tags_on_name"）

[AstonJ]

これは奇妙な問題のようです。一部のタグにのみ影響しており、タグ付きのトピックを作成しようとすると、ユーザーに「Internal Server Message」（内部サーバーエラー）が表示されます。場合によっては、その段階を通過した後、レビューキューシステムを介して同じメッセージが表示されることがあります。これらの影響を受けたタグのページにアクセスすると、「Oops! That page doesn’t exist or is private.」（おっと！そのページは存在しないか、プライベートです。）と表示されます。

以下にログを示します：

ActiveRecord::RecordNotUnique (PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "index_tags_on_name"
DETAIL:  Key (name)=(ecommerce) already exists.
)
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/patches/db/pg.rb:72:in `async_exec_params'

/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/patches/db/pg.rb:72:in `async_exec_params'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/patches/db/pg.rb:72:in `exec_params'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:668:in `block (2 levels) in exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:667:in `block in exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:707:in `block (2 levels) in log'
/usr/local/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:706:in `block in log'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:697:in `log'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:666:in `exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:647:in `execute_and_clear'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:96:in `exec_query'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:135:in `exec_insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:130:in `exec_insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:162:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/query_cache.rb:22:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:375:in `_insert_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:933:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/counter_cache.rb:163:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/locking/optimistic.rb:70:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/attribute_methods/dirty.rb:211:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:332:in `block in _create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:827:in `_run_create_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:332:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/timestamp.rb:111:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:906:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:328:in `block in create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:827:in `_run_save_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:328:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/timestamp.rb:129:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:470:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/validations.rb:47:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:315:in `block in save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:375:in `block in with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:275:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:366:in `with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:315:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/suppressor.rb:44:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:38:in `create'
/var/www/discourse/lib/discourse_tagging.rb:62:in `block in tag_topic_by_names'
/var/www/discourse/lib/discourse_tagging.rb:60:in `each'
/var/www/discourse/lib/discourse_tagging.rb:60:in `tag_topic_by_names'
/var/www/discourse/lib/topic_creator.rb:158:in `setup_tags'
/var/www/discourse/lib/topic_creator.rb:37:in `create'
/var/www/discourse/lib/post_creator.rb:421:in `create_topic'
/var/www/discourse/lib/post_creator.rb:168:in `block in create'
/var/www/discourse/lib/post_creator.rb:345:in `block in transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:275:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/lib/post_creator.rb:344:in `transaction'
/var/www/discourse/lib/post_creator.rb:166:in `create'
/var/www/discourse/app/models/reviewable_queued_post.rb:80:in `perform_approve_post'
/var/www/discourse/app/models/reviewable.rb:319:in `public_send'
/var/www/discourse/app/models/reviewable.rb:319:in `block in perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:277:in `block in transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/transaction.rb:280:in `block in within_new_transaction'
/usr/local/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/transaction.rb:278:in `within_new_transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:277:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/app/models/reviewable.rb:317:in `perform'
/var/www/discourse/app/controllers/reviewables_controller.rb:184:in `perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/base.rb:196:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/rendering.rb:30:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/abstract_controller/callbacks.rb:42:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/callbacks.rb:41:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/rescue.rb:22:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/instrumentation.rb:33:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications.rb:180:in `block in instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications.rb:180:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/railties/controller_runtime.rb:27:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/base.rb:136:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionview-6.0.0/lib/action_view/rendering.rb:39:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/mini_profiler/profiling_methods.rb:104:in `block in profile_method'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal.rb:191:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal.rb:252:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:51:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:33:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:49:in `block in serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:32:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:32:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:837:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-protection-2.0.7/lib/rack/protection/frame_options.rb:31:in `call'
/var/www/discourse/lib/middleware/omniauth_bypass_middleware.rb:68:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/tempfile_reaper.rb:15:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/conditional_get.rb:38:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/head.rb:12:in `call'
/var/www/discourse/lib/content_security_policy/middleware.rb:12:in `call'
/var/www/discourse/lib/middleware/anonymous_cache.rb:274:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/session/abstract/id.rb:232:in `context'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/session/abstract/id.rb:226:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/cookies.rb:648:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:101:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/debug_exceptions.rb:32:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/logster-2.3.3/lib/logster/middleware/reporter.rb:43:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/rack/logger.rb:38:in `call_app'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/rack/logger.rb:28:in `call'
/var/www/discourse/config/initializers/100-quiet_logger.rb:18:in `call'
/var/www/discourse/config/initializers/100-silence_logger.rb:31:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/request_id.rb:27:in `call'
/var/www/discourse/lib/middleware/enforce_hostname.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/method_override.rb:22:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/executor.rb:14:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/sendfile.rb:111:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/host_authorization.rb:77:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/mini_profiler/profiler.rb:296:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-2.2.2/lib/message_bus/rack/middleware.rb:57:in `call'
/var/www/discourse/lib/middleware/request_tracker.rb:176:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/engine.rb:526:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/railtie.rb:190:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/railtie.rb:190:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:68:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:53:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:53:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:605:in `process_client'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:700:in `worker_loop'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:548:in `spawn_missing_workers'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:144:in `start'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/bin/unicorn:128:in `<top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `load'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `<main>'

---

Failed to handle exception in exception app middleware : PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "index_tags_on_name"
DETAIL:  Key (name)=(ecommerce) already exists.

/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/patches/db/pg.rb:72:in `async_exec_params'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/patches/db/pg.rb:72:in `exec_params'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:668:in `block (2 levels) in exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/dependencies/interlock.rb:48:in `block in permit_concurrent_loads'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/concurrency/share_lock.rb:187:in `yield_shares'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/dependencies/interlock.rb:47:in `permit_concurrent_loads'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:667:in `block in exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:707:in `block (2 levels) in log'
/usr/local/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:706:in `block in log'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract_adapter.rb:697:in `log'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:666:in `exec_no_cache'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql_adapter.rb:647:in `execute_and_clear'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:96:in `exec_query'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:135:in `exec_insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/postgresql/database_statements.rb:130:in `exec_insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:162:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/query_cache.rb:22:in `insert'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:375:in `_insert_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:933:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/counter_cache.rb:163:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/locking/optimistic.rb:70:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/attribute_methods/dirty.rb:211:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:332:in `block in _create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:827:in `_run_create_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:332:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/timestamp.rb:111:in `_create_record'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:906:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:328:in `block in create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:827:in `_run_save_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/callbacks.rb:328:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/timestamp.rb:129:in `create_or_update'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:470:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/validations.rb:47:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:315:in `block in save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:375:in `block in with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:275:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:366:in `with_transaction_returning_status'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:315:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/suppressor.rb:44:in `save'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/persistence.rb:38:in `create'
/var/www/discourse/lib/discourse_tagging.rb:62:in `block in tag_topic_by_names'
/var/www/discourse/lib/discourse_tagging.rb:60:in `each'
/var/www/discourse/lib/discourse_tagging.rb:60:in `tag_topic_by_names'
/var/www/discourse/lib/topic_creator.rb:158:in `setup_tags'
/var/www/discourse/lib/topic_creator.rb:37:in `create'
/var/www/discourse/lib/post_creator.rb:421:in `create_topic'
/var/www/discourse/lib/post_creator.rb:168:in `block in create'
/var/www/discourse/lib/post_creator.rb:345:in `block in transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:275:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/lib/post_creator.rb:344:in `transaction'
/var/www/discourse/lib/post_creator.rb:166:in `create'
/var/www/discourse/app/models/reviewable_queued_post.rb:80:in `perform_approve_post'
/var/www/discourse/app/models/reviewable.rb:319:in `public_send'
/var/www/discourse/app/models/reviewable.rb:319:in `block in perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:277:in `block in transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/transaction.rb:280:in `block in within_new_transaction'
/usr/local/lib/ruby/2.6.0/monitor.rb:235:in `mon_synchronize'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/transaction.rb:278:in `within_new_transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/connection_adapters/abstract/database_statements.rb:277:in `transaction'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/transactions.rb:212:in `transaction'
/var/www/discourse/app/models/reviewable.rb:317:in `perform'
/var/www/discourse/app/controllers/reviewables_controller.rb:184:in `perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/base.rb:196:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/rendering.rb:30:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/abstract_controller/callbacks.rb:42:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:135:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/callbacks.rb:41:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/rescue.rb:22:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/instrumentation.rb:33:in `block in process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications.rb:180:in `block in instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications/instrumenter.rb:24:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/notifications.rb:180:in `instrument'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/instrumentation.rb:32:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal/params_wrapper.rb:245:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activerecord-6.0.0/lib/active_record/railties/controller_runtime.rb:27:in `process_action'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/abstract_controller/base.rb:136:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionview-6.0.0/lib/action_view/rendering.rb:39:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/mini_profiler/profiling_methods.rb:104:in `block in profile_method'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal.rb:191:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_controller/metal.rb:252:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:51:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:33:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:49:in `block in serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:32:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/journey/router.rb:32:in `serve'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/routing/route_set.rb:837:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-protection-2.0.7/lib/rack/protection/frame_options.rb:31:in `call'
/var/www/discourse/lib/middleware/omniauth_bypass_middleware.rb:68:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/tempfile_reaper.rb:15:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/conditional_get.rb:38:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/head.rb:12:in `call'
/var/www/discourse/lib/content_security_policy/middleware.rb:12:in `call'
/var/www/discourse/lib/middleware/anonymous_cache.rb:274:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/session/abstract/id.rb:232:in `context'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/session/abstract/id.rb:226:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/cookies.rb:648:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/activesupport-6.0.0/lib/active_support/callbacks.rb:101:in `run_callbacks'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/callbacks.rb:26:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/debug_exceptions.rb:32:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/show_exceptions.rb:33:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/logster-2.3.3/lib/logster/middleware/reporter.rb:43:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/rack/logger.rb:38:in `call_app'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/rack/logger.rb:28:in `call'
/var/www/discourse/config/initializers/100-quiet_logger.rb:18:in `call'
/var/www/discourse/config/initializers/100-silence_logger.rb:31:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/remote_ip.rb:81:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/request_id.rb:27:in `call'
/var/www/discourse/lib/middleware/enforce_hostname.rb:17:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/method_override.rb:22:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/executor.rb:14:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/sendfile.rb:111:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/actionpack-6.0.0/lib/action_dispatch/middleware/host_authorization.rb:77:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.0/lib/mini_profiler/profiler.rb:296:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/message_bus-2.2.2/lib/message_bus/rack/middleware.rb:57:in `call'
/var/www/discourse/lib/middleware/request_tracker.rb:176:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/engine.rb:526:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/railtie.rb:190:in `public_send'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/railties-6.0.0/lib/rails/railtie.rb:190:in `method_missing'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:68:in `block in call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:53:in `each'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-2.0.7/lib/rack/urlmap.rb:53:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:605:in `process_client'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:700:in `worker_loop'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:548:in `spawn_missing_workers'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/lib/unicorn/http_server.rb:144:in `start'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/unicorn-5.5.1/bin/unicorn:128:in `<top (required)>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `load'
/var/www/discourse/vendor/bundle/ruby/2.6.0/bin/unicorn:23:in `<main>'

なぜこれが起こるのか、ご存知ですか？既存のタグを作成しようとしているように見えます。

更新:

同じ問題が発生していたタグの一つでは、結局ユーザーにタグなしで再投稿を依頼し、その後編集時にタグを追加することができました（また、タグのページに問題なくアクセスできました）。以前は、ユーザーは実際にトピックを投稿できていましたが、レビューキュー（最初の投稿/トピックはすべてレビューするため）に入り、トピックを承認しようとした際に内部サーバーエラーが発生していました。

ただし、他のタグ（ecommerce）については追加できず、依然として内部サーバーエラーが報告されています。

[AstonJ]

別のタグでも同じ問題が発生しています:

ActiveRecord::RecordNotUnique (PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint "index_tags_on_name"
DETAIL:  Key (name)=(file-uploading) already exists.
)
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rack-mini-profiler-1.1.2/lib/patches/db/pg.rb:72:in `async_exec_params'

これは Discourse のバグでしょうか、それとも AR/Rails のバグでしょうか？既存のタグにもかかわらず、再度タグを作成しようとしているように見えます。

[sam (Sam Saffron)]

データエクスプローラーの tags テーブルを確認していただけますか？もしかすると、Ecommerce と ecommerce の間で大文字小文字の問題があるかもしれません。

[AstonJ]

こんにちは、サムさん。
テーブルを確認したところ、以下の項目があります：

ecommerce
e-commerce

2番目の項目（file-uploading）については：

file-downloading
file-uploading

どちらもハイフンが含まれているので、それが原因かもしれませんか？

設定では「タグを強制的に小文字にする」がチェックされていますが、これも何らかの競合を引き起こしている可能性がありますか？

他に確認が必要なことがあれば、お知らせください

[sam (Sam Saffron)]

100% 確信はありませんが、1 日ほどお待ちください。@neil はタグシステムに非常に精通しており、ここでいくつかのアイデアを持っているかもしれません。

[AstonJ]

わかりました、サムさん、ありがとう

[neil (Neil Lalonde)]

大文字小文字が混在するタグ名やハイフンを含むタグで遊んでみたのですが、このエラーを再現できません。使用している Discourse の正確なバージョンはどれですか？タグ制限が設定されたカテゴリで発生していますか？他のタグ設定は何を使用していますか？

[AstonJ]

こんにちは、Neil さん。私は 2.4.0.beta6 (8ca5aad1e2) を使用しています。

手動で Rails コンソールからタグ名を変更することで問題を解決できました。面白いことに、e.commerce タグは存在していたにもかかわらず nil を返していました！ID で見つけてから名前を変更したところ、現在正常に動作しています。

これは大文字小文字の区別が導入された際に発生し始めたのではないかと思っています（問題が発生してからはしばらく経っていますが、通常は新しいリリースがいくつか出るまで待ちます。あなたは非常に迅速に問題を解決してくれるので）。他に調査が必要なことがあればお知らせください。それ以外の場合は、すべてのタグ（またはエラーログ）を確認し、壊れている他のタグを特定してそれぞれ対応します。参考になればと思い、あなたの質問への回答を以下に記します：

@neil

これはタグ制限が設定されているカテゴリで発生していますか？

いいえ、ただしすべてのカテゴリには少なくとも 1 つのタグが必要です。

@neil

他のタグ設定はどのようなものを使用していますか？

[neil (Neil Lalonde)]

何が問題だったのか分かりません。「e.commerce」を何から何に名前を変更したのですか？タグを大文字小文字混合で使いつつ、小文字強制設定の有効・無効をテストしましたが、重複タグの作成は試みられませんでした。

[AstonJ]

tag-name を tag-name2 に名前を変更し、その後再び tag-name に戻しました。

名前での検索を使用してそれらを検索しました。

Tag.find_by name: "tag-name"

しかし、e-commerce については機能しませんでした。ID で検索する必要がありましたが、これは奇妙に思えます。なぜそのようなことが起こるのかよくわかりません。

他に考えられるのは、ある時点で大量のスレッドにタグを付与するために、検索を実行し、いくつかのトピックをクリックしてから、オプションから「タグを追加」を選択したことです。それが影響を与えるかどうかはわかりませんが。: /

[AstonJ]

申し訳ありません、@neil さん。おそらく関連する別の問題が発生しました。

同じ名前のタグが 2 つ存在しますが、今回の手動修正は機能しません。

[1] pry(main)> Tag.find_by(name: "liveview")
=> #<Tag:0x000055646b510750
 id: 1843,
 name: "liveview",
 topic_count: 25,
 created_at: Tue, 01 Oct 2019 07:42:44 UTC +00:00,
 updated_at: Tue, 01 Oct 2019 07:42:44 UTC +00:00,
 pm_topic_count: 0>
[2] pry(main)> t=Tag.find_by(id: 1036)
=> #<Tag:0x000055646b653978
 id: 1036,
 name: "liveview",
 topic_count: 150,
 created_at: Sun, 09 Sep 2018 16:19:15 UTC +00:00,
 updated_at: Sun, 09 Sep 2018 16:19:15 UTC +00:00,
 pm_topic_count: 0>
[3] pry(main)> t2=Tag.find_by(id: 1843)
=> #<Tag:0x000055646b6af7a0
 id: 1843,
 name: "liveview",
 topic_count: 25,
 created_at: Tue, 01 Oct 2019 07:42:44 UTC +00:00,
 updated_at: Tue, 01 Oct 2019 07:42:44 UTC +00:00,
 pm_topic_count: 0>
[4] pry(main)> t2.name = "liveview2"
=> "liveview2"
[5] pry(main)> t2.save
=> true
[6] pry(main)> t.name = "liveview1"
=> "liveview1"
[7] pry(main)> t.save
=> true
[8] pry(main)> t.name = "liveview"
=> "liveview"
[9] pry(main)> t.save
=> true
[10] pry(main)> t.name = "liveview1"
=> "liveview1"
[11] pry(main)> 

liveview2 は機能しますが、単独の liveview は機能しません。ただし、名前を liveview1 にすると機能しますが、名前を再び liveview に戻すと「Oops! That page doesn’t exist or is private.」というエラーになります。インデックス関連の問題でしょうか？

（/logs にも何も記録されていません）

[neil (Neil Lalonde)]

このケースに対処するために、2 つのインデックスが用意されています。データベースにこれらのインデックスは存在しますか？

$ bin/rails db

discourse_development=# \d tags
                                          Table "public.tags"
     Column     |            Type             | Collation | Nullable |             Default              
----------------+-----------------------------+-----------+----------+----------------------------------
 id             | integer                     |           | not null | nextval('tags_id_seq'::regclass)
 name           | character varying           |           | not null | 
 topic_count    | integer                     |           | not null | 0
 created_at     | timestamp without time zone |           | not null | 
 updated_at     | timestamp without time zone |           | not null | 
 pm_topic_count | integer                     |           | not null | 0
Indexes:
    "tags_pkey" PRIMARY KEY, btree (id)
    "index_tags_on_lower_name" UNIQUE, btree (lower(name::text))
    "index_tags_on_name" UNIQUE, btree (name)

2018 年 9 月 28 日付のマイグレーションにより、重複する名前を持つタグが修正され、その後、インデックスのいずれかが作成されるはずです。他のフォーラムソフトウェアからサイトをインポートしましたか？もしそうであれば、重複する行が作成された後、インデックスの作成に失敗している可能性があります。

[AstonJ]

     Column     |            Type             | Collation | Nullable |             Default              
----------------+-----------------------------+-----------+----------+----------------------------------
 id             | integer                     |           | not null | nextval('tags_id_seq'::regclass)
 name           | character varying           |           | not null | 
 topic_count    | integer                     |           | not null | 0
 created_at     | timestamp without time zone |           |          | 
 updated_at     | timestamp without time zone |           |          | 
 pm_topic_count | integer                     |           | not null | 0
Indexes:
    "tags_pkey" PRIMARY KEY, btree (id)
    "index_tags_on_lower_name" UNIQUE, btree (lower(name::text))
    "index_tags_on_name" UNIQUE, btree (name)

@neil

他のフォーラムソフトウェアからサイトをインポートしましたか？

いいえ、これは最初から Discourse フォーラムです。行ったのは別のサーバーへの移行だけで、それには新規インストールとバックアップからのインポートが必要でした。これは去年の 8 月頃に行われたと思います。それが原因でしょうか？

Neil さん、REINDEX TABLE tags; のようなコマンドを実行してインデックスを再構築すべきでしょうか？

編集：created_at と updated_at の Nullable 欄に not null が指定されていないことに気づきました。これは問題になりますか？

編集 2：同じタグが 2 つ存在することに気づきました。

1862	live-view
1486	live-view

[neil (Neil Lalonde)]

はい、テーブルの再インデックス化が必要だと思います。ただし、まず重複する名前のタグをリネームする必要があります。そうしないと再インデックス化が失敗します。そして、この問題がタグテーブルだけにあることを願うしかありません…

@AstonJ

いいえ、これは以前からDiscourseフォーラムでした。私が行ったのは別のサーバーへ移行しただけで、そのため新規インストール後にバックアップからインポートしました。これは昨年8月頃に行われたと思います。それが原因だったのでしょうか？

復元操作がこの問題を引き起こすとは考えられません。インデックスは存在しますが、明らかに機能していません。

[AstonJ]

OK、完了です

もし他にも重複タグを検索するクエリが必要な方がいれば、それは以下の通りです：

SELECT name, COUNT(*)
FROM tags
GROUP BY name
HAVING COUNT(*) > 1

@neil

そして、この問題が tags テーブルにのみ存在することを願っています…

Neil、もう怖がらせないで！

categories テーブルも少し確認しましたが、問題なさそうです（名前ベースでいくつかの重複エントリがありますが、それらはサブカテゴリです）。

@sam と @neil のご協力に感謝します

（ただし、再インデックスはこの 問題 には影響しませんでしたね、Neil）

[sam (Sam Saffron)]

以下のインデックスがあります：

app/models/tag.rb

そのインデックスがテーブルに存在していることは100%確実ですか？ご説明の内容は、Postgresが完全に破損していることを意味しますが、それは極めてあり得ません。もしそうなら、コミュニティ全体に衝撃が走ることになるでしょう。

より可能性が高いのは、何らかの理由で人間の手によってそのインデックスが削除されたケースです。

少なくとも、create unique index on tags (name)を実行することを推奨します。他に何が不足している可能性がありますか？

[AstonJ]

こんにちは、Samさん。

私は以下の状況にあります。

discourse=> \d tags
                                          Table "public.tags"
     Column     |            Type             | Collation | Nullable |             Default              
----------------+-----------------------------+-----------+----------+----------------------------------
 id             | integer                     |           | not null | nextval('tags_id_seq'::regclass)
 name           | character varying           |           | not null | 
 topic_count    | integer                     |           | not null | 0
 created_at     | timestamp without time zone |           |          | 
 updated_at     | timestamp without time zone |           |          | 
 pm_topic_count | integer                     |           | not null | 0
Indexes:
    "tags_pkey" PRIMARY KEY, btree (id)
    "index_tags_on_lower_name" UNIQUE, btree (lower(name::text))
    "index_tags_on_name" UNIQUE, btree (name)

インデックスを再構築するために以下の手順を踏みました。

• 重複するタグの名前を変更しました（例：tag_name_1、tag_name_2 など）
• 上記の投稿にあるクエリを実行し、重複タグがもう存在しないことを確認しました
• rails db にアクセスし、以下のコマンドを実行しました：

discourse=> REINDEX TABLE tags;
REINDEX

Samさん、これ以外に何か追加で必要なことはありますか？

[sam (Sam Saffron)]

重複タグを挿入して、インデックスが正常に動作し、重複データの許容を止めているか確認してみてはどうでしょうか？

[AstonJ]

Sam、問題なさそうです：

[1] pry(main)> t=Tag.new
=> #<Tag:0x000055fe76499830 id: nil, name: nil, topic_count: 0, created_at: nil, updated_at: nil, pm_topic_count: 0>
[2] pry(main)> t
=> #<Tag:0x000055fe76499830 id: nil, name: nil, topic_count: 0, created_at: nil, updated_at: nil, pm_topic_count: 0>
[3] pry(main)> t.name ="test-five"
=> "test-five"
[4] pry(main)> t.save
=> true

[5] pry(main)> Tag.last
=> #<Tag:0x000055fe7671ce90
 id: 1995,
 name: "test-five",
 topic_count: 0,
 created_at: Fri, 08 Nov 2019 02:44:36 UTC +00:00,
 updated_at: Fri, 08 Nov 2019 02:44:36 UTC +00:00,
 pm_topic_count: 0

[6] pry(main)> t=Tag.new
=> #<Tag:0x000055fe76763a70 id: nil, name: nil, topic_count: 0, created_at: nil, updated_at: nil, pm_topic_count: 0>
[7] pry(main)> t.name ="test-five"
=> "test-five"
[8] pry(main)> t.save
=> false
[9] pry(main)> 

また、フォーラムのトピックからも試してみました：

他に試すべきことがあれば、お知らせください

[AstonJ]

@sam

どこかの時点で、人間の操作により何らかの理由でインデックスが削除された可能性の方がはるかに高いでしょう…

また確認ですが、コンソールを通じてデータベースに対して他の操作は行っていないため、なぜこのようなことが起きたのか分かりません。おそらく、大文字小文字の区別が導入された後に発生し始めたのではないかと思っていますが、確証はありません。問題の根本原因を特定するために他に確認すべきことがあれば、サムまでお知らせください。