0611 — table names are `<root>_<kind>`

Context

Table names grew one at a time and the seams show: topic holds config while message_log holds data, delivery reads as the mainline path though the mainline never writes it (success and superseded write only delivery_log rows), and lease vs key_lease leaves the difference to a schema read. Reviewed on a live tbls/Liam ERD snapshot (just schema-diagram).

Decision

Every table name is <root>_<kind>: the leading words name the resource a row is about, the trailing word the table’s kind — _config (declared state, written by declaration verbs), _config_log (that config table’s declaration trail), _log (append-only event history; an event root stands alone with no sibling table — message_log, delivery_log, migration_log), _queue (mutable work rows), _lease (expiring locks, prefixed by what is leased), _instance (live copies), _cursor/_head (singleton runtime state). A table 1:1 with another resource’s rows carries that owner’s name (consumer_group_cursor). FK columns keep the resource’s noun (topic_id), never the table’s name.

Renames: system→system_config, topic→topic_config, topic_log→topic_config_log, consumer_group→ consumer_group_config, worker→worker_config, worker_log→ worker_config_log, cron_job→cron_job_config (its next_scheduled_time/last_scheduled_time and the due index split out to a new 1:1 cron_job_cursor — the scheduler’s position in the schedule, sibling of consumer_group_cursor), delivery→ exception_queue (rows are deliveries off the mainline path — ready-to-retry, deferred, dead; the exception consumer’s own noun), cursor→consumer_group_cursor, lease→claim_lease, key_lease→message_key_lease (rides on [0612]), binding→ binding_config, binding_log→binding_config_log. Unchanged: worker_instance, migration_log, message_log, delivery_log, idempotency_key, compaction_head.

Consequences

• message_key_lease ships only with [0612]‘s column/API rename; until both land the table stays key_lease.
• CONVENTIONS ## Tables gains the naming rule when the rename ships, not before. Sweep: internal/topic table-name funcs, every SQL literal, labs’ inline interpolations, scripts/database/tbls.yml, doc-site prose. Pre-v1: baseline DDL edited in place.
• system_config/consumer_group_config are identity-only today; uniformity chosen over precision.
• The cron_job_cursor split changes scheduler SQL: the due scan joins back to config for schedule/suspended, and a schedule edit becomes a two-table write (recompute next). Per-fire churn moves off the near-static config rows.