Give receipts their own stream ID in the database (#1631)

* Give read recipts their own database sequence

* Give receipts their own stream ID

* Change migration names

* Reset sequences

* Add max receipt queries, missing stream_id table entry for SQLite

syncapi/storage/sqlite3/deltas/20201211125500_sequences.go

@@ -0,0 +1,58 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package deltas
+
+import (
+	"database/sql"
+	"fmt"
+
+	"github.com/matrix-org/dendrite/internal/sqlutil"
+	"github.com/pressly/goose"
+)
+
+func LoadFromGoose() {
+	goose.AddMigration(UpFixSequences, DownFixSequences)
+}
+
+func LoadFixSequences(m *sqlutil.Migrations) {
+	m.AddMigration(UpFixSequences, DownFixSequences)
+}
+
+func UpFixSequences(tx *sql.Tx) error {
+	_, err := tx.Exec(`
+		-- We need to delete all of the existing receipts because the indexes
+		-- will be wrong, and we'll get primary key violations if we try to
+		-- reuse existing stream IDs from a different sequence.
+		DELETE FROM syncapi_receipts;
+		UPDATE syncapi_stream_id SET stream_id=1 WHERE stream_name="receipt";
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute upgrade: %w", err)
+	}
+	return nil
+}
+
+func DownFixSequences(tx *sql.Tx) error {
+	_, err := tx.Exec(`
+		-- We need to delete all of the existing receipts because the indexes
+		-- will be wrong, and we'll get primary key violations if we try to
+		-- reuse existing stream IDs from a different sequence.
+		DELETE FROM syncapi_receipts;
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	return nil
+}