-- A Ref DCL pool's state and swap whitelist, kept when they change.
-- blackbeard/observer#45.
--
-- Both are read every minute (refdcl::pools) and were only ever held in memory,
-- so a pool paused, or a solver dropped from its whitelist, during a stretch
-- with no quotes would leave no trace afterwards. That is exactly the context
-- a pause needs: "the pool stopped" and "the quotes stopped while the pool ran"
-- are different events. A row is written only when either differs from the
-- latest one for the pool, so the table is a list of changes, and the first
-- row is the state as first seen.
create table ref_pool_settings (
    chain      text        not null references chain (id) on delete cascade,
    pool_id    text        not null,
    at         timestamptz not null,
    state      text        not null,
    -- Sorted, so equal whitelists compare equal.
    whitelist  jsonb       not null,
    primary key (chain, pool_id, at)
);