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

3 files changed, 96 insertions, 3 deletions

diff --git a/syncapi/storage/postgres/deltas/20201211125500_sequences.go b/syncapi/storage/postgres/deltas/20201211125500_sequences.go
new file mode 100644
index 00000000..a51df26f
--- /dev/null
+++ b/syncapi/storage/postgres/deltas/20201211125500_sequences.go
@@ -0,0 +1,66 @@
+// 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;
+
+		-- Use the new syncapi_receipts_id sequence.
+		CREATE SEQUENCE IF NOT EXISTS syncapi_receipt_id;
+		ALTER SEQUENCE IF EXISTS syncapi_receipt_id RESTART WITH 1;
+		ALTER TABLE syncapi_receipts ALTER COLUMN id SET DEFAULT nextval('syncapi_receipt_id');
+	`)
+	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;
+
+		-- Revert back to using the syncapi_stream_id sequence.
+		DROP SEQUENCE IF EXISTS syncapi_receipt_id;
+		ALTER TABLE syncapi_receipts ALTER COLUMN id SET DEFAULT nextval('syncapi_stream_id');
+	`)
+	if err != nil {
+		return fmt.Errorf("failed to execute downgrade: %w", err)
+	}
+	return nil
+}
diff --git a/syncapi/storage/postgres/receipt_table.go b/syncapi/storage/postgres/receipt_table.go
index c5ec6cbc..23c66910 100644
--- a/syncapi/storage/postgres/receipt_table.go
+++ b/syncapi/storage/postgres/receipt_table.go
@@ -30,11 +30,12 @@ import (
 )
 
 const receiptsSchema = `
-CREATE SEQUENCE IF NOT EXISTS syncapi_stream_id;
+CREATE SEQUENCE IF NOT EXISTS syncapi_receipt_id;
+
 -- Stores data about receipts
 CREATE TABLE IF NOT EXISTS syncapi_receipts (
 	-- The ID
-	id BIGINT PRIMARY KEY DEFAULT nextval('syncapi_stream_id'),
+	id BIGINT PRIMARY KEY DEFAULT nextval('syncapi_receipt_id'),
 	room_id TEXT NOT NULL,
 	receipt_type TEXT NOT NULL,
 	user_id TEXT NOT NULL,
@@ -50,7 +51,7 @@ const upsertReceipt = "" +
 	" (room_id, receipt_type, user_id, event_id, receipt_ts)" +
 	" VALUES ($1, $2, $3, $4, $5)" +
 	" ON CONFLICT (room_id, receipt_type, user_id)" +
-	" DO UPDATE SET id = nextval('syncapi_stream_id'), event_id = $4, receipt_ts = $5" +
+	" DO UPDATE SET id = nextval('syncapi_receipt_id'), event_id = $4, receipt_ts = $5" +
 	" RETURNING id"
 
 const selectRoomReceipts = "" +
@@ -58,10 +59,14 @@ const selectRoomReceipts = "" +
 	" FROM syncapi_receipts" +
 	" WHERE room_id = ANY($1) AND id > $2"
 
+const selectMaxReceiptIDSQL = "" +
+	"SELECT MAX(id) FROM syncapi_receipts"
+
 type receiptStatements struct {
 	db                 *sql.DB
 	upsertReceipt      *sql.Stmt
 	selectRoomReceipts *sql.Stmt
+	selectMaxReceiptID *sql.Stmt
 }
 
 func NewPostgresReceiptsTable(db *sql.DB) (tables.Receipts, error) {
@@ -78,6 +83,9 @@ func NewPostgresReceiptsTable(db *sql.DB) (tables.Receipts, error) {
 	if r.selectRoomReceipts, err = db.Prepare(selectRoomReceipts); err != nil {
 		return nil, fmt.Errorf("unable to prepare selectRoomReceipts statement: %w", err)
 	}
+	if r.selectMaxReceiptID, err = db.Prepare(selectMaxReceiptIDSQL); err != nil {
+		return nil, fmt.Errorf("unable to prepare selectRoomReceipts statement: %w", err)
+	}
 	return r, nil
 }
 
@@ -104,3 +112,15 @@ func (r *receiptStatements) SelectRoomReceiptsAfter(ctx context.Context, roomIDs
 	}
 	return res, rows.Err()
 }
+
+func (s *receiptStatements) SelectMaxReceiptID(
+	ctx context.Context, txn *sql.Tx,
+) (id int64, err error) {
+	var nullableID sql.NullInt64
+	stmt := sqlutil.TxStmt(txn, s.selectMaxReceiptID)
+	err = stmt.QueryRowContext(ctx).Scan(&nullableID)
+	if nullableID.Valid {
+		id = nullableID.Int64
+	}
+	return
+}
diff --git a/syncapi/storage/postgres/syncserver.go b/syncapi/storage/postgres/syncserver.go
index a77c0ec0..60d67ac0 100644
--- a/syncapi/storage/postgres/syncserver.go
+++ b/syncapi/storage/postgres/syncserver.go
@@ -23,6 +23,7 @@ import (
 	"github.com/matrix-org/dendrite/eduserver/cache"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/setup/config"
+	"github.com/matrix-org/dendrite/syncapi/storage/postgres/deltas"
 	"github.com/matrix-org/dendrite/syncapi/storage/shared"
 )
 
@@ -36,6 +37,7 @@ type SyncServerDatasource struct {
 }
 
 // NewDatabase creates a new sync server database
+// nolint:gocyclo
 func NewDatabase(dbProperties *config.DatabaseOptions) (*SyncServerDatasource, error) {
 	var d SyncServerDatasource
 	var err error
@@ -86,6 +88,11 @@ func NewDatabase(dbProperties *config.DatabaseOptions) (*SyncServerDatasource, e
 	if err != nil {
 		return nil, err
 	}
+	m := sqlutil.NewMigrations()
+	deltas.LoadFixSequences(m)
+	if err = m.RunDeltas(d.db, dbProperties); err != nil {
+		return nil, err
+	}
 	d.Database = shared.Database{
 		DB:                  d.db,
 		Writer:              d.writer,