owpengram-server/deploy/migrations/0070_dispatch_outbox_head_readiness.up.sql

82 lines
3.1 KiB
PL/PgSQL

-- Keep claim readiness on the one-row-per-user head itself. Otherwise PostgreSQL may
-- legally reorder the head/outbox join and start from every eligible backlog row,
-- reintroducing the full-backlog scan that 0069 is meant to remove.
LOCK TABLE dispatch_outbox IN SHARE ROW EXCLUSIVE MODE;
ALTER TABLE dispatch_outbox_user_heads
ADD COLUMN status varchar(16) NOT NULL DEFAULT 'pending'
CHECK (status IN ('pending', 'dispatching', 'failed')),
ADD COLUMN next_attempt_at timestamptz NOT NULL DEFAULT now(),
ADD COLUMN updated_at timestamptz NOT NULL DEFAULT now();
UPDATE dispatch_outbox_user_heads h
SET status = d.status,
next_attempt_at = d.next_attempt_at,
updated_at = d.updated_at
FROM dispatch_outbox d
WHERE d.target_user_id = h.target_user_id
AND d.id = h.head_id;
CREATE OR REPLACE FUNCTION dispatch_outbox_maintain_user_head()
RETURNS trigger
LANGUAGE plpgsql
AS $$
DECLARE
removed_head bigint;
BEGIN
IF TG_OP = 'INSERT' THEN
INSERT INTO dispatch_outbox_user_heads (
target_user_id, head_id, head_pts, status, next_attempt_at, updated_at
) VALUES (
NEW.target_user_id, NEW.id, NEW.pts, NEW.status, NEW.next_attempt_at, NEW.updated_at
)
ON CONFLICT (target_user_id) DO UPDATE
SET head_id = EXCLUDED.head_id,
head_pts = EXCLUDED.head_pts,
status = EXCLUDED.status,
next_attempt_at = EXCLUDED.next_attempt_at,
updated_at = EXCLUDED.updated_at
WHERE (EXCLUDED.head_pts, EXCLUDED.head_id) <
(dispatch_outbox_user_heads.head_pts, dispatch_outbox_user_heads.head_id);
RETURN NULL;
ELSIF TG_OP = 'UPDATE' THEN
UPDATE dispatch_outbox_user_heads
SET status = NEW.status,
next_attempt_at = NEW.next_attempt_at,
updated_at = NEW.updated_at
WHERE target_user_id = NEW.target_user_id
AND head_id = NEW.id;
RETURN NULL;
END IF;
DELETE FROM dispatch_outbox_user_heads
WHERE target_user_id = OLD.target_user_id
AND head_id = OLD.id
RETURNING head_id INTO removed_head;
IF removed_head IS NOT NULL THEN
INSERT INTO dispatch_outbox_user_heads (
target_user_id, head_id, head_pts, status, next_attempt_at, updated_at
)
SELECT target_user_id, id, pts, status, next_attempt_at, updated_at
FROM dispatch_outbox
WHERE target_user_id = OLD.target_user_id
ORDER BY pts ASC, id ASC
LIMIT 1
ON CONFLICT (target_user_id) DO UPDATE
SET head_id = EXCLUDED.head_id,
head_pts = EXCLUDED.head_pts,
status = EXCLUDED.status,
next_attempt_at = EXCLUDED.next_attempt_at,
updated_at = EXCLUDED.updated_at
WHERE (EXCLUDED.head_pts, EXCLUDED.head_id) <
(dispatch_outbox_user_heads.head_pts, dispatch_outbox_user_heads.head_id);
END IF;
RETURN NULL;
END;
$$;
CREATE TRIGGER dispatch_outbox_update_user_head
AFTER UPDATE OF status, next_attempt_at, updated_at ON dispatch_outbox
FOR EACH ROW
EXECUTE FUNCTION dispatch_outbox_maintain_user_head();