-- Order and one writer (novox/hq to-be 45 §6, Phase 2).
--
-- The controller acts only while it holds its lease, and every act carries the lease's epoch: a
-- declaration, a plan write. A report carries the order of the declaration it accounts for, and the
-- controller keeps the highest per machine, refusing an older account rather than letting the last
-- one written win (issue 267). These are the records each of those needs.

-- Every epoch the mesh issued: which controller instance held it, from when, and how it ended —
-- given back, or lost (its key expired, or a renewal was refused). The highest one is the floor no
-- new epoch may be at or under, even when the lease's bucket was raised again from nothing; and a
-- stale refusal names its writer from here.
create table controller_epoch (
    epoch    bigint      primary key,
    instance text        not null,
    host     text        not null default '',
    build    text        not null default '',
    taken    timestamptz not null default now(),
    ended    timestamptz,
    -- how: 'released' (given back), 'lost' (its own renewal was refused or failed), 'expired'
    -- (found expired by the next holder: it stopped renewing without saying so).
    how      text        not null default ''
);

-- The epoch a machine was last sent, so what the mesh WOULD send is composed with it and reads as
-- byte for byte what it DID send when nothing else changed — a new holder's epoch is not a change
-- of the machine. Null for a declaration sent without one.
alter table node add column sent_epoch bigint;
-- Whether the machine's node-engine said it reads an epoch in a declaration (its report's `reads`):
-- until it has, it is sent none, because an older node-engine refuses a key it does not know, whole.
alter table node add column reads_epoch boolean not null default false;

-- The order of the account kept for each machine: the declaration's sequence and epoch it is about
-- and the node-engine's own report sequence. Null where the kept account carried none.
alter table node_report add column reported_sequence bigint;
alter table node_report add column reported_epoch bigint;
alter table node_report add column report_sequence bigint;

-- A plan is written by compare-and-set on its revision, and says the epoch that wrote it last.
alter table release_plan add column revision bigint not null default 0;
alter table release_plan add column epoch bigint;