Remove materialized view and use a recursive CTE instead to get unique

event_types
This commit is contained in:
Till Faelligen 2024-05-21 16:16:17 +02:00
parent 9eee30b152
commit ce15a2800c
No known key found for this signature in database
GPG Key ID: ACCDC9606D472758
2 changed files with 9 additions and 16 deletions

View File

@ -141,11 +141,6 @@ func NewEventTable(db *sqlx.DB) *EventTable {
CREATE INDEX IF NOT EXISTS syncv3_nid_room_state_idx ON syncv3_events(room_id, event_nid, is_state);
CREATE UNIQUE INDEX IF NOT EXISTS syncv3_events_room_event_nid_type_skey_idx ON syncv3_events(event_nid, event_type, state_key);
-- Create a materialized view for event_types (used on startup to get the latest events in each room)
CREATE MATERIALIZED VIEW IF NOT EXISTS event_types as
SELECT DISTINCT event_type
FROM syncv3_events;
`)
return &EventTable{db}
}
@ -447,13 +442,20 @@ func (t *EventTable) SelectLatestEventsBetween(txn *sqlx.Tx, roomID string, lowe
func (t *EventTable) selectLatestEventByTypeInAllRooms(txn *sqlx.Tx) ([]Event, error) {
result := []Event{}
// What the following query does:
// 1. Gets all event types from a materialized view (updated on startup in `PrepareSnapshot`) as the `event_types` CTE
// 1. Gets all event types from a recursive CTE as the `event_types` CTE
// 2. Gets all rooms as the `room_ids` CTE
// 3. Gets the latest event_nid for each event_type and room as the `max_by_ev_type` CTE
// 4. Queries the required data using the event_nids provided by the `max_by_ev_type` CTE
rows, err := txn.Query(`
WITH event_types AS (
SELECT * FROM event_types
WITH RECURSIVE t AS (
(SELECT event_type FROM syncv3_events ORDER BY event_type LIMIT 1) -- parentheses required
UNION ALL
SELECT (SELECT event_type FROM syncv3_events WHERE event_type > t.event_type ORDER BY event_type LIMIT 1)
FROM t
WHERE t.event_type IS NOT NULL
)
SELECT event_type FROM t WHERE event_type IS NOT NULL
), room_ids AS (
SELECT DISTINCT room_id FROM syncv3_rooms
), max_by_ev_type AS (

View File

@ -171,15 +171,6 @@ func (s *Storage) PrepareSnapshot(txn *sqlx.Tx) (tableName string, err error) {
`SELECT UNNEST(membership_events) AS membership_nid INTO TEMP ` + tempTableName + ` FROM syncv3_snapshots
JOIN syncv3_rooms ON syncv3_snapshots.snapshot_id = syncv3_rooms.current_snapshot_id`,
)
if err != nil {
return "", err
}
// Refresh the materialized view, so getting latest events by type per room
// can use a fresh view of the event_types.
_, err = txn.Exec("REFRESH MATERIALIZED VIEW event_types;")
if err != nil {
return "", err
}
return tempTableName, nil
}