Update database dictionary

See https://gitlab.com/gitlab-org/gitlab/-/issues/359362

db/docs/postgres_async_indexes.yml

@@ -4,6 +4,8 @@ classes:
 - Gitlab::Database::AsyncIndexes::PostgresAsyncIndex
 feature_categories:
 - database
-description: TODO
+description: >-
+  Contains a queue-like structure for database indexes scheduled to be created asynchronously.
+  See https://docs.gitlab.com/ee/development/adding_database_indexes.html#create-indexes-asynchronously for more details.
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/66478
 milestone: '14.2'

db/docs/postgres_reindex_actions.yml

@@ -4,6 +4,9 @@ classes:
 - Gitlab::Database::Reindexing::ReindexAction
 feature_categories:
 - database
-description: TODO
+description: >-
+  Captures details about reindexing operations on a per-index basis.
+  See https://docs.gitlab.com/ee/administration/raketasks/maintenance.html#rebuild-database-indexes
+  for details about reindexing.
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/43156
 milestone: '13.5'

db/docs/postgres_reindex_queued_actions.yml

@@ -4,6 +4,8 @@ classes:
 - Gitlab::Database::Reindexing::QueuedAction
 feature_categories:
 - database
-description: TODO
+description: >-
+  Contains a queue-like structure for reindexing actions.
+  Actions in this queue will be prioritized over regular reindexing actions.
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/73480
 milestone: '14.5'