Fulltext implementation using Bleve (#2675)

Based on #2480

This actually indexes events based on their event type. They are removed
from the index if we receive a `m.room.redaction` event on the
`OutputRoomEvent` stream.
An admin endpoint is added to reindex all existing events.


Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>

syncapi/storage/interface.go

@@ -161,6 +161,7 @@ type Database interface {
 	// returns "leave", the topological position and no error. If an error occurs, other than sql.ErrNoRows, returns that and an empty
 	// string as the membership.
 	SelectMembershipForUser(ctx context.Context, roomID, userID string, pos int64) (membership string, topologicalPos int, err error)
+	ReIndex(ctx context.Context, limit, afterID int64) (map[int64]gomatrixserverlib.HeaderedEvent, error)
 }
 
 type Presence interface {

syncapi/storage/postgres/output_room_events_table.go

@@ -166,6 +166,8 @@ const selectContextAfterEventSQL = "" +
 	" AND ( $7::text[] IS NULL OR NOT(type LIKE ANY($7)) )" +
 	" ORDER BY id ASC LIMIT $3"
 
+const selectSearchSQL = "SELECT id, event_id, headered_event_json FROM syncapi_output_room_events WHERE id > $1 AND type = ANY($2) ORDER BY id ASC LIMIT $3"
+
 type outputRoomEventsStatements struct {
 	insertEventStmt               *sql.Stmt
 	selectEventsStmt              *sql.Stmt
@@ -180,6 +182,7 @@ type outputRoomEventsStatements struct {
 	selectContextEventStmt        *sql.Stmt
 	selectContextBeforeEventStmt  *sql.Stmt
 	selectContextAfterEventStmt   *sql.Stmt
+	selectSearchStmt              *sql.Stmt
 }
 
 func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
@@ -215,6 +218,7 @@ func NewPostgresEventsTable(db *sql.DB) (tables.Events, error) {
 		{&s.selectContextEventStmt, selectContextEventSQL},
 		{&s.selectContextBeforeEventStmt, selectContextBeforeEventSQL},
 		{&s.selectContextAfterEventStmt, selectContextAfterEventSQL},
+		{&s.selectSearchStmt, selectSearchSQL},
 	}.Prepare(db)
 }
 
@@ -632,3 +636,27 @@ func rowsToStreamEvents(rows *sql.Rows) ([]types.StreamEvent, error) {
 	}
 	return result, rows.Err()
 }
+
+func (s *outputRoomEventsStatements) ReIndex(ctx context.Context, txn *sql.Tx, limit, afterID int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	rows, err := sqlutil.TxStmt(txn, s.selectSearchStmt).QueryContext(ctx, afterID, pq.StringArray(types), limit)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "rows.close() failed")
+
+	var eventID string
+	var id int64
+	result := make(map[int64]gomatrixserverlib.HeaderedEvent)
+	for rows.Next() {
+		var ev gomatrixserverlib.HeaderedEvent
+		var eventBytes []byte
+		if err = rows.Scan(&id, &eventID, &eventBytes); err != nil {
+			return nil, err
+		}
+		if err = ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+		result[id] = ev
+	}
+	return result, rows.Err()
+}

syncapi/storage/shared/syncserver.go

@@ -1093,3 +1093,11 @@ func (d *Database) MaxStreamPositionForPresence(ctx context.Context) (types.Stre
 func (d *Database) SelectMembershipForUser(ctx context.Context, roomID, userID string, pos int64) (membership string, topologicalPos int, err error) {
 	return d.Memberships.SelectMembershipForUser(ctx, nil, roomID, userID, pos)
 }
+
+func (s *Database) ReIndex(ctx context.Context, limit, afterID int64) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	return s.OutputEvents.ReIndex(ctx, nil, limit, afterID, []string{
+		gomatrixserverlib.MRoomName,
+		gomatrixserverlib.MRoomTopic,
+		"m.room.message",
+	})
+}

syncapi/storage/sqlite3/output_room_events_table.go

@@ -115,6 +115,8 @@ const selectContextAfterEventSQL = "" +
 
 // WHEN, ORDER BY and LIMIT are appended by prepareWithFilters
 
+const selectSearchSQL = "SELECT id, event_id, headered_event_json FROM syncapi_output_room_events WHERE type IN ($1) AND id > $2 LIMIT $3 ORDER BY id ASC"
+
 type outputRoomEventsStatements struct {
 	db                           *sql.DB
 	streamIDStatements           *StreamIDStatements
@@ -125,6 +127,7 @@ type outputRoomEventsStatements struct {
 	selectContextEventStmt       *sql.Stmt
 	selectContextBeforeEventStmt *sql.Stmt
 	selectContextAfterEventStmt  *sql.Stmt
+	//selectSearchStmt             *sql.Stmt - prepared at runtime
 }
 
 func NewSqliteEventsTable(db *sql.DB, streamID *StreamIDStatements) (tables.Events, error) {
@@ -157,6 +160,7 @@ func NewSqliteEventsTable(db *sql.DB, streamID *StreamIDStatements) (tables.Even
 		{&s.selectContextEventStmt, selectContextEventSQL},
 		{&s.selectContextBeforeEventStmt, selectContextBeforeEventSQL},
 		{&s.selectContextAfterEventStmt, selectContextAfterEventSQL},
+		//{&s.selectSearchStmt, selectSearchSQL}, - prepared at runtime
 	}.Prepare(db)
 }
 
@@ -628,3 +632,40 @@ func unmarshalStateIDs(addIDsJSON, delIDsJSON string) (addIDs []string, delIDs [
 	}
 	return
 }
+
+func (s *outputRoomEventsStatements) ReIndex(ctx context.Context, txn *sql.Tx, limit, afterID int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error) {
+	params := make([]interface{}, len(types))
+	for i := range types {
+		params[i] = types[i]
+	}
+	params = append(params, afterID)
+	params = append(params, limit)
+	selectSQL := strings.Replace(selectSearchSQL, "($1)", sqlutil.QueryVariadic(len(types)), 1)
+
+	stmt, err := s.db.Prepare(selectSQL)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, stmt, "selectEvents: stmt.close() failed")
+	rows, err := stmt.QueryContext(ctx, params...)
+	if err != nil {
+		return nil, err
+	}
+	defer internal.CloseAndLogIfError(ctx, rows, "rows.close() failed")
+
+	var eventID string
+	var id int64
+	result := make(map[int64]gomatrixserverlib.HeaderedEvent)
+	for rows.Next() {
+		var ev gomatrixserverlib.HeaderedEvent
+		var eventBytes []byte
+		if err = rows.Scan(&id, &eventID, &eventBytes); err != nil {
+			return nil, err
+		}
+		if err = ev.UnmarshalJSONWithEventID(eventBytes, eventID); err != nil {
+			return nil, err
+		}
+		result[id] = ev
+	}
+	return result, rows.Err()
+}

syncapi/storage/tables/interface.go

@@ -75,6 +75,7 @@ type Events interface {
 	SelectContextEvent(ctx context.Context, txn *sql.Tx, roomID, eventID string) (int, gomatrixserverlib.HeaderedEvent, error)
 	SelectContextBeforeEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) ([]*gomatrixserverlib.HeaderedEvent, error)
 	SelectContextAfterEvent(ctx context.Context, txn *sql.Tx, id int, roomID string, filter *gomatrixserverlib.RoomEventFilter) (int, []*gomatrixserverlib.HeaderedEvent, error)
+	ReIndex(ctx context.Context, txn *sql.Tx, limit, offset int64, types []string) (map[int64]gomatrixserverlib.HeaderedEvent, error)
 }
 
 // Topology keeps track of the depths and stream positions for all events.