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priv/event_store/migrations/v0.14.0.sql

BEGIN;
-- seed `$all` stream using event counter as its stream version
INSERT INTO streams (stream_id, stream_uuid, stream_version)
SELECT 0, '$all', event_number
FROM event_counter;
-- create `stream_events` table
CREATE TABLE stream_events
(
event_id uuid NOT NULL REFERENCES events (event_id),
stream_id bigint NOT NULL REFERENCES streams (stream_id),
stream_version bigint NOT NULL,
original_stream_id bigint REFERENCES streams (stream_id),
original_stream_version bigint,
PRIMARY KEY(event_id, stream_id)
);
CREATE UNIQUE INDEX ix_stream_events ON stream_events (stream_id, stream_version);
CREATE RULE no_update_stream_events AS ON UPDATE TO stream_events DO INSTEAD NOTHING;
CREATE RULE no_delete_stream_events AS ON DELETE TO stream_events DO INSTEAD NOTHING;
-- seed stream events
INSERT INTO stream_events (event_id, stream_id, stream_version, original_stream_id, original_stream_version)
SELECT event_id, stream_id, stream_version, stream_id, stream_version
FROM events;
-- seed `$all` stream events
INSERT INTO stream_events (event_id, stream_id, stream_version, original_stream_id, original_stream_version)
SELECT event_id, 0, event_number, stream_id, stream_version
FROM events;
DROP INDEX ix_events_event_number;
DROP INDEX ix_events_stream_id;
DROP INDEX ix_events_stream_id_stream_version;
ALTER TABLE events
DROP COLUMN event_number,
DROP COLUMN stream_id,
DROP COLUMN stream_version;
-- subscriptions now use single `last_seen` pointer
ALTER TABLE subscriptions ADD COLUMN last_seen bigint;
UPDATE subscriptions
SET last_seen = COALESCE(last_seen_event_number, last_seen_stream_version);
ALTER TABLE subscriptions
DROP COLUMN last_seen_event_number,
DROP COLUMN last_seen_stream_version;
-- event pub/sub notification function
CREATE OR REPLACE FUNCTION notify_events()
RETURNS trigger AS $$
DECLARE
payload text;
BEGIN
payload := NEW.stream_uuid || ',' || NEW.stream_id || ',' || (OLD.stream_version + 1) || ',' || NEW.stream_version;
-- Notify events to listeners
PERFORM pg_notify('events', payload);
RETURN NULL;
END;
$$ LANGUAGE plpgsql;
-- event pub/sub table trigger
CREATE TRIGGER event_notification
AFTER UPDATE ON streams
FOR EACH ROW EXECUTE PROCEDURE notify_events();
-- stream version of `$all` stream events are used instead of event counter
DROP TABLE event_counter;
-- record schema migration
INSERT INTO schema_migrations (major_version, minor_version, patch_version) VALUES (0, 14, 0);
COMMIT;