More SQLite (#871)

* SQLite support for appservice * SQLite support for mediaapi * Copyright notices * SQLite for public rooms API (although with some slight differences in behaviour) * Lazy match aliases, add TODOs
2024-12-27 07:28:27 +00:00 · 2020-02-14 14:12:33 +00:00 · 2020-02-14 14:12:33 +00:00 · 3dabf4d4ed
commit 3dabf4d4ed
parent 409fec2a48
17 changed files with 1034 additions and 111 deletions
--- a/appservice/consumers/roomserver.go
+++ b/appservice/consumers/roomserver.go
@ -34,7 +34,7 @@ import (
 type OutputRoomEventConsumer struct {
 	roomServerConsumer *common.ContinualConsumer
 	db                 accounts.Database
-	asDB               *storage.Database
+	asDB               storage.Database
 	query              api.RoomserverQueryAPI
 	alias              api.RoomserverAliasAPI
 	serverName         string
@ -47,7 +47,7 @@ func NewOutputRoomEventConsumer(
 	cfg *config.Dendrite,
 	kafkaConsumer sarama.Consumer,
 	store accounts.Database,
-	appserviceDB *storage.Database,
+	appserviceDB storage.Database,
 	queryAPI api.RoomserverQueryAPI,
 	aliasAPI api.RoomserverAliasAPI,
 	workerStates []types.ApplicationServiceWorkerState,
--- a/appservice/storage/postgres/appservice_events_table.go
+++ b/appservice/storage/postgres/appservice_events_table.go
@ -1,4 +1,5 @@
 // Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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.
@ -12,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-package storage
+package postgres

 import (
 	"context"
--- a/appservice/storage/postgres/storage.go
+++ b/appservice/storage/postgres/storage.go
@ -0,0 +1,111 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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 postgres
+
+import (
+	"context"
+	"database/sql"
+
+	// Import postgres database driver
+	_ "github.com/lib/pq"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+// Database stores events intended to be later sent to application services
+type Database struct {
+	events eventsStatements
+	txnID  txnStatements
+	db     *sql.DB
+}
+
+// NewDatabase opens a new database
+func NewDatabase(dataSourceName string) (*Database, error) {
+	var result Database
+	var err error
+	if result.db, err = sql.Open("postgres", dataSourceName); err != nil {
+		return nil, err
+	}
+	if err = result.prepare(); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (d *Database) prepare() error {
+	if err := d.events.prepare(d.db); err != nil {
+		return err
+	}
+
+	return d.txnID.prepare(d.db)
+}
+
+// StoreEvent takes in a gomatrixserverlib.Event and stores it in the database
+// for a transaction worker to pull and later send to an application service.
+func (d *Database) StoreEvent(
+	ctx context.Context,
+	appServiceID string,
+	event *gomatrixserverlib.Event,
+) error {
+	return d.events.insertEvent(ctx, appServiceID, event)
+}
+
+// GetEventsWithAppServiceID returns a slice of events and their IDs intended to
+// be sent to an application service given its ID.
+func (d *Database) GetEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+	limit int,
+) (int, int, []gomatrixserverlib.Event, bool, error) {
+	return d.events.selectEventsByApplicationServiceID(ctx, appServiceID, limit)
+}
+
+// CountEventsWithAppServiceID returns the number of events destined for an
+// application service given its ID.
+func (d *Database) CountEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+) (int, error) {
+	return d.events.countEventsByApplicationServiceID(ctx, appServiceID)
+}
+
+// UpdateTxnIDForEvents takes in an application service ID and a
+// and stores them in the DB, unless the pair already exists, in
+// which case it updates them.
+func (d *Database) UpdateTxnIDForEvents(
+	ctx context.Context,
+	appserviceID string,
+	maxID, txnID int,
+) error {
+	return d.events.updateTxnIDForEvents(ctx, appserviceID, maxID, txnID)
+}
+
+// RemoveEventsBeforeAndIncludingID removes all events from the database that
+// are less than or equal to a given maximum ID. IDs here are implemented as a
+// serial, thus this should always delete events in chronological order.
+func (d *Database) RemoveEventsBeforeAndIncludingID(
+	ctx context.Context,
+	appserviceID string,
+	eventTableID int,
+) error {
+	return d.events.deleteEventsBeforeAndIncludingID(ctx, appserviceID, eventTableID)
+}
+
+// GetLatestTxnID returns the latest available transaction id
+func (d *Database) GetLatestTxnID(
+	ctx context.Context,
+) (int, error) {
+	return d.txnID.selectTxnID(ctx)
+}
--- a/appservice/storage/postgres/txn_id_counter_table.go
+++ b/appservice/storage/postgres/txn_id_counter_table.go
@ -1,4 +1,5 @@
 // Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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.
@ -12,7 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.

-package storage
+package postgres

 import (
 	"context"
--- a/appservice/storage/sqlite3/appservice_events_table.go
+++ b/appservice/storage/sqlite3/appservice_events_table.go
@ -0,0 +1,249 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"time"
+
+	"github.com/matrix-org/gomatrixserverlib"
+	log "github.com/sirupsen/logrus"
+)
+
+const appserviceEventsSchema = `
+-- Stores events to be sent to application services
+CREATE TABLE IF NOT EXISTS appservice_events (
+	-- An auto-incrementing id unique to each event in the table
+	id INTEGER PRIMARY KEY AUTOINCREMENT,
+	-- The ID of the application service the event will be sent to
+	as_id TEXT NOT NULL,
+	-- JSON representation of the event
+	event_json TEXT NOT NULL,
+	-- The ID of the transaction that this event is a part of
+	txn_id INTEGER NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS appservice_events_as_id ON appservice_events(as_id);
+`
+
+const selectEventsByApplicationServiceIDSQL = "" +
+	"SELECT id, event_json, txn_id " +
+	"FROM appservice_events WHERE as_id = $1 ORDER BY txn_id DESC, id ASC"
+
+const countEventsByApplicationServiceIDSQL = "" +
+	"SELECT COUNT(id) FROM appservice_events WHERE as_id = $1"
+
+const insertEventSQL = "" +
+	"INSERT INTO appservice_events(as_id, event_json, txn_id) " +
+	"VALUES ($1, $2, $3)"
+
+const updateTxnIDForEventsSQL = "" +
+	"UPDATE appservice_events SET txn_id = $1 WHERE as_id = $2 AND id <= $3"
+
+const deleteEventsBeforeAndIncludingIDSQL = "" +
+	"DELETE FROM appservice_events WHERE as_id = $1 AND id <= $2"
+
+const (
+	// A transaction ID number that no transaction should ever have. Used for
+	// checking again the default value.
+	invalidTxnID = -2
+)
+
+type eventsStatements struct {
+	selectEventsByApplicationServiceIDStmt *sql.Stmt
+	countEventsByApplicationServiceIDStmt  *sql.Stmt
+	insertEventStmt                        *sql.Stmt
+	updateTxnIDForEventsStmt               *sql.Stmt
+	deleteEventsBeforeAndIncludingIDStmt   *sql.Stmt
+}
+
+func (s *eventsStatements) prepare(db *sql.DB) (err error) {
+	_, err = db.Exec(appserviceEventsSchema)
+	if err != nil {
+		return
+	}
+
+	if s.selectEventsByApplicationServiceIDStmt, err = db.Prepare(selectEventsByApplicationServiceIDSQL); err != nil {
+		return
+	}
+	if s.countEventsByApplicationServiceIDStmt, err = db.Prepare(countEventsByApplicationServiceIDSQL); err != nil {
+		return
+	}
+	if s.insertEventStmt, err = db.Prepare(insertEventSQL); err != nil {
+		return
+	}
+	if s.updateTxnIDForEventsStmt, err = db.Prepare(updateTxnIDForEventsSQL); err != nil {
+		return
+	}
+	if s.deleteEventsBeforeAndIncludingIDStmt, err = db.Prepare(deleteEventsBeforeAndIncludingIDSQL); err != nil {
+		return
+	}
+
+	return
+}
+
+// selectEventsByApplicationServiceID takes in an application service ID and
+// returns a slice of events that need to be sent to that application service,
+// as well as an int later used to remove these same events from the database
+// once successfully sent to an application service.
+func (s *eventsStatements) selectEventsByApplicationServiceID(
+	ctx context.Context,
+	applicationServiceID string,
+	limit int,
+) (
+	txnID, maxID int,
+	events []gomatrixserverlib.Event,
+	eventsRemaining bool,
+	err error,
+) {
+	// Retrieve events from the database. Unsuccessfully sent events first
+	eventRows, err := s.selectEventsByApplicationServiceIDStmt.QueryContext(ctx, applicationServiceID)
+	if err != nil {
+		return
+	}
+	defer func() {
+		err = eventRows.Close()
+		if err != nil {
+			log.WithFields(log.Fields{
+				"appservice": applicationServiceID,
+			}).WithError(err).Fatalf("appservice unable to select new events to send")
+		}
+	}()
+	events, maxID, txnID, eventsRemaining, err = retrieveEvents(eventRows, limit)
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func retrieveEvents(eventRows *sql.Rows, limit int) (events []gomatrixserverlib.Event, maxID, txnID int, eventsRemaining bool, err error) {
+	// Get current time for use in calculating event age
+	nowMilli := time.Now().UnixNano() / int64(time.Millisecond)
+
+	// Iterate through each row and store event contents
+	// If txn_id changes dramatically, we've switched from collecting old events to
+	// new ones. Send back those events first.
+	lastTxnID := invalidTxnID
+	for eventsProcessed := 0; eventRows.Next(); {
+		var event gomatrixserverlib.Event
+		var eventJSON []byte
+		var id int
+		err = eventRows.Scan(
+			&id,
+			&eventJSON,
+			&txnID,
+		)
+		if err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		// Unmarshal eventJSON
+		if err = json.Unmarshal(eventJSON, &event); err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		// If txnID has changed on this event from the previous event, then we've
+		// reached the end of a transaction's events. Return only those events.
+		if lastTxnID > invalidTxnID && lastTxnID != txnID {
+			return events, maxID, lastTxnID, true, nil
+		}
+		lastTxnID = txnID
+
+		// Limit events that aren't part of an old transaction
+		if txnID == -1 {
+			// Return if we've hit the limit
+			if eventsProcessed++; eventsProcessed > limit {
+				return events, maxID, lastTxnID, true, nil
+			}
+		}
+
+		if id > maxID {
+			maxID = id
+		}
+
+		// Portion of the event that is unsigned due to rapid change
+		// TODO: Consider removing age as not many app services use it
+		if err = event.SetUnsignedField("age", nowMilli-int64(event.OriginServerTS())); err != nil {
+			return nil, 0, 0, false, err
+		}
+
+		events = append(events, event)
+	}
+
+	return
+}
+
+// countEventsByApplicationServiceID inserts an event mapped to its corresponding application service
+// IDs into the db.
+func (s *eventsStatements) countEventsByApplicationServiceID(
+	ctx context.Context,
+	appServiceID string,
+) (int, error) {
+	var count int
+	err := s.countEventsByApplicationServiceIDStmt.QueryRowContext(ctx, appServiceID).Scan(&count)
+	if err != nil && err != sql.ErrNoRows {
+		return 0, err
+	}
+
+	return count, nil
+}
+
+// insertEvent inserts an event mapped to its corresponding application service
+// IDs into the db.
+func (s *eventsStatements) insertEvent(
+	ctx context.Context,
+	appServiceID string,
+	event *gomatrixserverlib.Event,
+) (err error) {
+	// Convert event to JSON before inserting
+	eventJSON, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.insertEventStmt.ExecContext(
+		ctx,
+		appServiceID,
+		eventJSON,
+		-1, // No transaction ID yet
+	)
+	return
+}
+
+// updateTxnIDForEvents sets the transactionID for a collection of events. Done
+// before sending them to an AppService. Referenced before sending to make sure
+// we aren't constructing multiple transactions with the same events.
+func (s *eventsStatements) updateTxnIDForEvents(
+	ctx context.Context,
+	appserviceID string,
+	maxID, txnID int,
+) (err error) {
+	_, err = s.updateTxnIDForEventsStmt.ExecContext(ctx, txnID, appserviceID, maxID)
+	return
+}
+
+// deleteEventsBeforeAndIncludingID removes events matching given IDs from the database.
+func (s *eventsStatements) deleteEventsBeforeAndIncludingID(
+	ctx context.Context,
+	appserviceID string,
+	eventTableID int,
+) (err error) {
+	_, err = s.deleteEventsBeforeAndIncludingIDStmt.ExecContext(ctx, appserviceID, eventTableID)
+	return
+}
--- a/appservice/storage/sqlite3/storage.go
+++ b/appservice/storage/sqlite3/storage.go
@ -0,0 +1,111 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+
+	// Import SQLite database driver
+	"github.com/matrix-org/gomatrixserverlib"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// Database stores events intended to be later sent to application services
+type Database struct {
+	events eventsStatements
+	txnID  txnStatements
+	db     *sql.DB
+}
+
+// NewDatabase opens a new database
+func NewDatabase(dataSourceName string) (*Database, error) {
+	var result Database
+	var err error
+	if result.db, err = sql.Open("sqlite3", dataSourceName); err != nil {
+		return nil, err
+	}
+	if err = result.prepare(); err != nil {
+		return nil, err
+	}
+	return &result, nil
+}
+
+func (d *Database) prepare() error {
+	if err := d.events.prepare(d.db); err != nil {
+		return err
+	}
+
+	return d.txnID.prepare(d.db)
+}
+
+// StoreEvent takes in a gomatrixserverlib.Event and stores it in the database
+// for a transaction worker to pull and later send to an application service.
+func (d *Database) StoreEvent(
+	ctx context.Context,
+	appServiceID string,
+	event *gomatrixserverlib.Event,
+) error {
+	return d.events.insertEvent(ctx, appServiceID, event)
+}
+
+// GetEventsWithAppServiceID returns a slice of events and their IDs intended to
+// be sent to an application service given its ID.
+func (d *Database) GetEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+	limit int,
+) (int, int, []gomatrixserverlib.Event, bool, error) {
+	return d.events.selectEventsByApplicationServiceID(ctx, appServiceID, limit)
+}
+
+// CountEventsWithAppServiceID returns the number of events destined for an
+// application service given its ID.
+func (d *Database) CountEventsWithAppServiceID(
+	ctx context.Context,
+	appServiceID string,
+) (int, error) {
+	return d.events.countEventsByApplicationServiceID(ctx, appServiceID)
+}
+
+// UpdateTxnIDForEvents takes in an application service ID and a
+// and stores them in the DB, unless the pair already exists, in
+// which case it updates them.
+func (d *Database) UpdateTxnIDForEvents(
+	ctx context.Context,
+	appserviceID string,
+	maxID, txnID int,
+) error {
+	return d.events.updateTxnIDForEvents(ctx, appserviceID, maxID, txnID)
+}
+
+// RemoveEventsBeforeAndIncludingID removes all events from the database that
+// are less than or equal to a given maximum ID. IDs here are implemented as a
+// serial, thus this should always delete events in chronological order.
+func (d *Database) RemoveEventsBeforeAndIncludingID(
+	ctx context.Context,
+	appserviceID string,
+	eventTableID int,
+) error {
+	return d.events.deleteEventsBeforeAndIncludingID(ctx, appserviceID, eventTableID)
+}
+
+// GetLatestTxnID returns the latest available transaction id
+func (d *Database) GetLatestTxnID(
+	ctx context.Context,
+) (int, error) {
+	return d.txnID.selectTxnID(ctx)
+}
--- a/appservice/storage/sqlite3/txn_id_counter_table.go
+++ b/appservice/storage/sqlite3/txn_id_counter_table.go
@ -0,0 +1,60 @@
+// Copyright 2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+)
+
+const txnIDSchema = `
+-- Keeps a count of the current transaction ID
+CREATE TABLE IF NOT EXISTS appservice_counters (
+  name TEXT PRIMARY KEY NOT NULL,
+  last_id INTEGER DEFAULT 1
+);
+INSERT OR IGNORE INTO appservice_counters (name, last_id) VALUES('txn_id', 1);
+`
+
+const selectTxnIDSQL = `
+  SELECT last_id FROM appservice_counters WHERE name='txn_id';
+  UPDATE appservice_counters SET last_id=last_id+1 WHERE name='txn_id';
+`
+
+type txnStatements struct {
+	selectTxnIDStmt *sql.Stmt
+}
+
+func (s *txnStatements) prepare(db *sql.DB) (err error) {
+	_, err = db.Exec(txnIDSchema)
+	if err != nil {
+		return
+	}
+
+	if s.selectTxnIDStmt, err = db.Prepare(selectTxnIDSQL); err != nil {
+		return
+	}
+
+	return
+}
+
+// selectTxnID selects the latest ascending transaction ID
+func (s *txnStatements) selectTxnID(
+	ctx context.Context,
+) (txnID int, err error) {
+	err = s.selectTxnIDStmt.QueryRowContext(ctx).Scan(&txnID)
+	return
+}
--- a/appservice/storage/storage.go
+++ b/appservice/storage/storage.go
@ -1,4 +1,4 @@
-// Copyright 2018 New Vector Ltd
+// 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.
@ -16,95 +16,33 @@ package storage

 import (
 	"context"
-	"database/sql"
+	"net/url"

-	// Import postgres database driver
-	_ "github.com/lib/pq"
+	"github.com/matrix-org/dendrite/appservice/storage/postgres"
+	"github.com/matrix-org/dendrite/appservice/storage/sqlite3"
 	"github.com/matrix-org/gomatrixserverlib"
 )

-// Database stores events intended to be later sent to application services
-type Database struct {
-	events eventsStatements
-	txnID  txnStatements
-	db     *sql.DB
+type Database interface {
+	StoreEvent(ctx context.Context, appServiceID string, event *gomatrixserverlib.Event) error
+	GetEventsWithAppServiceID(ctx context.Context, appServiceID string, limit int) (int, int, []gomatrixserverlib.Event, bool, error)
+	CountEventsWithAppServiceID(ctx context.Context, appServiceID string) (int, error)
+	UpdateTxnIDForEvents(ctx context.Context, appserviceID string, maxID, txnID int) error
+	RemoveEventsBeforeAndIncludingID(ctx context.Context, appserviceID string, eventTableID int) error
+	GetLatestTxnID(ctx context.Context) (int, error)
 }

-// NewDatabase opens a new database
-func NewDatabase(dataSourceName string) (*Database, error) {
-	var result Database
-	var err error
-	if result.db, err = sql.Open("postgres", dataSourceName); err != nil {
-		return nil, err
+func NewDatabase(dataSourceName string) (Database, error) {
+	uri, err := url.Parse(dataSourceName)
+	if err != nil {
+		return postgres.NewDatabase(dataSourceName)
 	}
-	if err = result.prepare(); err != nil {
-		return nil, err
+	switch uri.Scheme {
+	case "postgres":
+		return postgres.NewDatabase(dataSourceName)
+	case "file":
+		return sqlite3.NewDatabase(dataSourceName)
+	default:
+		return postgres.NewDatabase(dataSourceName)
 	}
-	return &result, nil
-}
-
-func (d *Database) prepare() error {
-	if err := d.events.prepare(d.db); err != nil {
-		return err
-	}
-
-	return d.txnID.prepare(d.db)
-}
-
-// StoreEvent takes in a gomatrixserverlib.Event and stores it in the database
-// for a transaction worker to pull and later send to an application service.
-func (d *Database) StoreEvent(
-	ctx context.Context,
-	appServiceID string,
-	event *gomatrixserverlib.Event,
-) error {
-	return d.events.insertEvent(ctx, appServiceID, event)
-}
-
-// GetEventsWithAppServiceID returns a slice of events and their IDs intended to
-// be sent to an application service given its ID.
-func (d *Database) GetEventsWithAppServiceID(
-	ctx context.Context,
-	appServiceID string,
-	limit int,
-) (int, int, []gomatrixserverlib.Event, bool, error) {
-	return d.events.selectEventsByApplicationServiceID(ctx, appServiceID, limit)
-}
-
-// CountEventsWithAppServiceID returns the number of events destined for an
-// application service given its ID.
-func (d *Database) CountEventsWithAppServiceID(
-	ctx context.Context,
-	appServiceID string,
-) (int, error) {
-	return d.events.countEventsByApplicationServiceID(ctx, appServiceID)
-}
-
-// UpdateTxnIDForEvents takes in an application service ID and a
-// and stores them in the DB, unless the pair already exists, in
-// which case it updates them.
-func (d *Database) UpdateTxnIDForEvents(
-	ctx context.Context,
-	appserviceID string,
-	maxID, txnID int,
-) error {
-	return d.events.updateTxnIDForEvents(ctx, appserviceID, maxID, txnID)
-}
-
-// RemoveEventsBeforeAndIncludingID removes all events from the database that
-// are less than or equal to a given maximum ID. IDs here are implemented as a
-// serial, thus this should always delete events in chronological order.
-func (d *Database) RemoveEventsBeforeAndIncludingID(
-	ctx context.Context,
-	appserviceID string,
-	eventTableID int,
-) error {
-	return d.events.deleteEventsBeforeAndIncludingID(ctx, appserviceID, eventTableID)
-}
-
-// GetLatestTxnID returns the latest available transaction id
-func (d *Database) GetLatestTxnID(
-	ctx context.Context,
-) (int, error) {
-	return d.txnID.selectTxnID(ctx)
 }
--- a/appservice/workers/transaction_scheduler.go
+++ b/appservice/workers/transaction_scheduler.go
@ -43,7 +43,7 @@ var (
 // size), then send that off to the AS's /transactions/{txnID} endpoint. It also
 // handles exponentially backing off in case the AS isn't currently available.
 func SetupTransactionWorkers(
-	appserviceDB *storage.Database,
+	appserviceDB storage.Database,
 	workerStates []types.ApplicationServiceWorkerState,
 ) error {
 	// Create a worker that handles transmitting events to a single homeserver
@ -58,7 +58,7 @@ func SetupTransactionWorkers(

 // worker is a goroutine that sends any queued events to the application service
 // it is given.
-func worker(db *storage.Database, ws types.ApplicationServiceWorkerState) {
+func worker(db storage.Database, ws types.ApplicationServiceWorkerState) {
 	log.WithFields(log.Fields{
 		"appservice": ws.AppService.ID,
 	}).Info("starting application service")
@ -149,7 +149,7 @@ func backoff(ws *types.ApplicationServiceWorkerState, err error) {
 // transaction, and JSON-encodes the results.
 func createTransaction(
 	ctx context.Context,
-	db *storage.Database,
+	db storage.Database,
 	appserviceID string,
 ) (
 	transactionJSON []byte,
--- a/mediaapi/storage/sqlite3/media_repository_table.go
+++ b/mediaapi/storage/sqlite3/media_repository_table.go
@ -0,0 +1,115 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const mediaSchema = `
+-- The media_repository table holds metadata for each media file stored and accessible to the local server,
+-- the actual file is stored separately.
+CREATE TABLE IF NOT EXISTS mediaapi_media_repository (
+    -- The id used to refer to the media.
+    -- For uploads to this server this is a base64-encoded sha256 hash of the file data
+    -- For media from remote servers, this can be any unique identifier string
+    media_id TEXT NOT NULL,
+    -- The origin of the media as requested by the client. Should be a homeserver domain.
+    media_origin TEXT NOT NULL,
+    -- The MIME-type of the media file as specified when uploading.
+    content_type TEXT NOT NULL,
+    -- Size of the media file in bytes.
+    file_size_bytes INTEGER NOT NULL,
+    -- When the content was uploaded in UNIX epoch ms.
+    creation_ts INTEGER NOT NULL,
+    -- The file name with which the media was uploaded.
+    upload_name TEXT NOT NULL,
+    -- Alternate RFC 4648 unpadded base64 encoding string representation of a SHA-256 hash sum of the file data.
+    base64hash TEXT NOT NULL,
+    -- The user who uploaded the file. Should be a Matrix user ID.
+    user_id TEXT NOT NULL
+);
+CREATE UNIQUE INDEX IF NOT EXISTS mediaapi_media_repository_index ON mediaapi_media_repository (media_id, media_origin);
+`
+
+const insertMediaSQL = `
+INSERT INTO mediaapi_media_repository (media_id, media_origin, content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id)
+    VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+`
+
+const selectMediaSQL = `
+SELECT content_type, file_size_bytes, creation_ts, upload_name, base64hash, user_id FROM mediaapi_media_repository WHERE media_id = $1 AND media_origin = $2
+`
+
+type mediaStatements struct {
+	insertMediaStmt *sql.Stmt
+	selectMediaStmt *sql.Stmt
+}
+
+func (s *mediaStatements) prepare(db *sql.DB) (err error) {
+	_, err = db.Exec(mediaSchema)
+	if err != nil {
+		return
+	}
+
+	return statementList{
+		{&s.insertMediaStmt, insertMediaSQL},
+		{&s.selectMediaStmt, selectMediaSQL},
+	}.prepare(db)
+}
+
+func (s *mediaStatements) insertMedia(
+	ctx context.Context, mediaMetadata *types.MediaMetadata,
+) error {
+	mediaMetadata.CreationTimestamp = types.UnixMs(time.Now().UnixNano() / 1000000)
+	_, err := s.insertMediaStmt.ExecContext(
+		ctx,
+		mediaMetadata.MediaID,
+		mediaMetadata.Origin,
+		mediaMetadata.ContentType,
+		mediaMetadata.FileSizeBytes,
+		mediaMetadata.CreationTimestamp,
+		mediaMetadata.UploadName,
+		mediaMetadata.Base64Hash,
+		mediaMetadata.UserID,
+	)
+	return err
+}
+
+func (s *mediaStatements) selectMedia(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata := types.MediaMetadata{
+		MediaID: mediaID,
+		Origin:  mediaOrigin,
+	}
+	err := s.selectMediaStmt.QueryRowContext(
+		ctx, mediaMetadata.MediaID, mediaMetadata.Origin,
+	).Scan(
+		&mediaMetadata.ContentType,
+		&mediaMetadata.FileSizeBytes,
+		&mediaMetadata.CreationTimestamp,
+		&mediaMetadata.UploadName,
+		&mediaMetadata.Base64Hash,
+		&mediaMetadata.UserID,
+	)
+	return &mediaMetadata, err
+}
--- a/mediaapi/storage/sqlite3/prepare.go
+++ b/mediaapi/storage/sqlite3/prepare.go
@ -0,0 +1,38 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 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.
+
+// FIXME: This should be made common!
+
+package sqlite3
+
+import (
+	"database/sql"
+)
+
+// a statementList is a list of SQL statements to prepare and a pointer to where to store the resulting prepared statement.
+type statementList []struct {
+	statement **sql.Stmt
+	sql       string
+}
+
+// prepare the SQL for each statement in the list and assign the result to the prepared statement.
+func (s statementList) prepare(db *sql.DB) (err error) {
+	for _, statement := range s {
+		if *statement.statement, err = db.Prepare(statement.sql); err != nil {
+			return
+		}
+	}
+	return
+}
--- a/mediaapi/storage/sqlite3/sql.go
+++ b/mediaapi/storage/sqlite3/sql.go
@ -0,0 +1,36 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"database/sql"
+)
+
+type statements struct {
+	media     mediaStatements
+	thumbnail thumbnailStatements
+}
+
+func (s *statements) prepare(db *sql.DB) (err error) {
+	if err = s.media.prepare(db); err != nil {
+		return
+	}
+	if err = s.thumbnail.prepare(db); err != nil {
+		return
+	}
+
+	return
+}
--- a/mediaapi/storage/sqlite3/storage.go
+++ b/mediaapi/storage/sqlite3/storage.go
@ -0,0 +1,106 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+
+	// Import the postgres database driver.
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+	_ "github.com/mattn/go-sqlite3"
+)
+
+// Database is used to store metadata about a repository of media files.
+type Database struct {
+	statements statements
+	db         *sql.DB
+}
+
+// Open opens a postgres database.
+func Open(dataSourceName string) (*Database, error) {
+	var d Database
+	var err error
+	if d.db, err = sql.Open("sqlite3", dataSourceName); err != nil {
+		return nil, err
+	}
+	if err = d.statements.prepare(d.db); err != nil {
+		return nil, err
+	}
+	return &d, nil
+}
+
+// StoreMediaMetadata inserts the metadata about the uploaded media into the database.
+// Returns an error if the combination of MediaID and Origin are not unique in the table.
+func (d *Database) StoreMediaMetadata(
+	ctx context.Context, mediaMetadata *types.MediaMetadata,
+) error {
+	return d.statements.media.insertMedia(ctx, mediaMetadata)
+}
+
+// GetMediaMetadata returns metadata about media stored on this server.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there is no metadata associated with this media.
+func (d *Database) GetMediaMetadata(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) (*types.MediaMetadata, error) {
+	mediaMetadata, err := d.statements.media.selectMedia(ctx, mediaID, mediaOrigin)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return mediaMetadata, err
+}
+
+// StoreThumbnail inserts the metadata about the thumbnail into the database.
+// Returns an error if the combination of MediaID and Origin are not unique in the table.
+func (d *Database) StoreThumbnail(
+	ctx context.Context, thumbnailMetadata *types.ThumbnailMetadata,
+) error {
+	return d.statements.thumbnail.insertThumbnail(ctx, thumbnailMetadata)
+}
+
+// GetThumbnail returns metadata about a specific thumbnail.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there is no metadata associated with this thumbnail.
+func (d *Database) GetThumbnail(
+	ctx context.Context,
+	mediaID types.MediaID,
+	mediaOrigin gomatrixserverlib.ServerName,
+	width, height int,
+	resizeMethod string,
+) (*types.ThumbnailMetadata, error) {
+	thumbnailMetadata, err := d.statements.thumbnail.selectThumbnail(
+		ctx, mediaID, mediaOrigin, width, height, resizeMethod,
+	)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return thumbnailMetadata, err
+}
+
+// GetThumbnails returns metadata about all thumbnails for a specific media stored on this server.
+// The media could have been uploaded to this server or fetched from another server and cached here.
+// Returns nil metadata if there are no thumbnails associated with this media.
+func (d *Database) GetThumbnails(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) ([]*types.ThumbnailMetadata, error) {
+	thumbnails, err := d.statements.thumbnail.selectThumbnails(ctx, mediaID, mediaOrigin)
+	if err != nil && err == sql.ErrNoRows {
+		return nil, nil
+	}
+	return thumbnails, err
+}
--- a/mediaapi/storage/sqlite3/thumbnail_table.go
+++ b/mediaapi/storage/sqlite3/thumbnail_table.go
@ -0,0 +1,162 @@
+// Copyright 2017-2018 New Vector Ltd
+// Copyright 2019-2020 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 sqlite3
+
+import (
+	"context"
+	"database/sql"
+	"time"
+
+	"github.com/matrix-org/dendrite/mediaapi/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+const thumbnailSchema = `
+-- The mediaapi_thumbnail table holds metadata for each thumbnail file stored and accessible to the local server,
+-- the actual file is stored separately.
+CREATE TABLE IF NOT EXISTS mediaapi_thumbnail (
+    media_id TEXT NOT NULL,
+    media_origin TEXT NOT NULL,
+    content_type TEXT NOT NULL,
+    file_size_bytes INTEGER NOT NULL,
+    creation_ts INTEGER NOT NULL,
+    width INTEGER NOT NULL,
+    height INTEGER NOT NULL,
+    resize_method TEXT NOT NULL
+);
+CREATE UNIQUE INDEX IF NOT EXISTS mediaapi_thumbnail_index ON mediaapi_thumbnail (media_id, media_origin, width, height, resize_method);
+`
+
+const insertThumbnailSQL = `
+INSERT INTO mediaapi_thumbnail (media_id, media_origin, content_type, file_size_bytes, creation_ts, width, height, resize_method)
+    VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+`
+
+// Note: this selects one specific thumbnail
+const selectThumbnailSQL = `
+SELECT content_type, file_size_bytes, creation_ts FROM mediaapi_thumbnail WHERE media_id = $1 AND media_origin = $2 AND width = $3 AND height = $4 AND resize_method = $5
+`
+
+// Note: this selects all thumbnails for a media_origin and media_id
+const selectThumbnailsSQL = `
+SELECT content_type, file_size_bytes, creation_ts, width, height, resize_method FROM mediaapi_thumbnail WHERE media_id = $1 AND media_origin = $2
+`
+
+type thumbnailStatements struct {
+	insertThumbnailStmt  *sql.Stmt
+	selectThumbnailStmt  *sql.Stmt
+	selectThumbnailsStmt *sql.Stmt
+}
+
+func (s *thumbnailStatements) prepare(db *sql.DB) (err error) {
+	_, err = db.Exec(thumbnailSchema)
+	if err != nil {
+		return
+	}
+
+	return statementList{
+		{&s.insertThumbnailStmt, insertThumbnailSQL},
+		{&s.selectThumbnailStmt, selectThumbnailSQL},
+		{&s.selectThumbnailsStmt, selectThumbnailsSQL},
+	}.prepare(db)
+}
+
+func (s *thumbnailStatements) insertThumbnail(
+	ctx context.Context, thumbnailMetadata *types.ThumbnailMetadata,
+) error {
+	thumbnailMetadata.MediaMetadata.CreationTimestamp = types.UnixMs(time.Now().UnixNano() / 1000000)
+	_, err := s.insertThumbnailStmt.ExecContext(
+		ctx,
+		thumbnailMetadata.MediaMetadata.MediaID,
+		thumbnailMetadata.MediaMetadata.Origin,
+		thumbnailMetadata.MediaMetadata.ContentType,
+		thumbnailMetadata.MediaMetadata.FileSizeBytes,
+		thumbnailMetadata.MediaMetadata.CreationTimestamp,
+		thumbnailMetadata.ThumbnailSize.Width,
+		thumbnailMetadata.ThumbnailSize.Height,
+		thumbnailMetadata.ThumbnailSize.ResizeMethod,
+	)
+	return err
+}
+
+func (s *thumbnailStatements) selectThumbnail(
+	ctx context.Context,
+	mediaID types.MediaID,
+	mediaOrigin gomatrixserverlib.ServerName,
+	width, height int,
+	resizeMethod string,
+) (*types.ThumbnailMetadata, error) {
+	thumbnailMetadata := types.ThumbnailMetadata{
+		MediaMetadata: &types.MediaMetadata{
+			MediaID: mediaID,
+			Origin:  mediaOrigin,
+		},
+		ThumbnailSize: types.ThumbnailSize{
+			Width:        width,
+			Height:       height,
+			ResizeMethod: resizeMethod,
+		},
+	}
+	err := s.selectThumbnailStmt.QueryRowContext(
+		ctx,
+		thumbnailMetadata.MediaMetadata.MediaID,
+		thumbnailMetadata.MediaMetadata.Origin,
+		thumbnailMetadata.ThumbnailSize.Width,
+		thumbnailMetadata.ThumbnailSize.Height,
+		thumbnailMetadata.ThumbnailSize.ResizeMethod,
+	).Scan(
+		&thumbnailMetadata.MediaMetadata.ContentType,
+		&thumbnailMetadata.MediaMetadata.FileSizeBytes,
+		&thumbnailMetadata.MediaMetadata.CreationTimestamp,
+	)
+	return &thumbnailMetadata, err
+}
+
+func (s *thumbnailStatements) selectThumbnails(
+	ctx context.Context, mediaID types.MediaID, mediaOrigin gomatrixserverlib.ServerName,
+) ([]*types.ThumbnailMetadata, error) {
+	rows, err := s.selectThumbnailsStmt.QueryContext(
+		ctx, mediaID, mediaOrigin,
+	)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close() // nolint: errcheck
+
+	var thumbnails []*types.ThumbnailMetadata
+	for rows.Next() {
+		thumbnailMetadata := types.ThumbnailMetadata{
+			MediaMetadata: &types.MediaMetadata{
+				MediaID: mediaID,
+				Origin:  mediaOrigin,
+			},
+		}
+		err = rows.Scan(
+			&thumbnailMetadata.MediaMetadata.ContentType,
+			&thumbnailMetadata.MediaMetadata.FileSizeBytes,
+			&thumbnailMetadata.MediaMetadata.CreationTimestamp,
+			&thumbnailMetadata.ThumbnailSize.Width,
+			&thumbnailMetadata.ThumbnailSize.Height,
+			&thumbnailMetadata.ThumbnailSize.ResizeMethod,
+		)
+		if err != nil {
+			return nil, err
+		}
+		thumbnails = append(thumbnails, &thumbnailMetadata)
+	}
+
+	return thumbnails, rows.Err()
+}
--- a/mediaapi/storage/storage.go
+++ b/mediaapi/storage/storage.go
@ -19,6 +19,7 @@ import (
 	"net/url"

 	"github.com/matrix-org/dendrite/mediaapi/storage/postgres"
+	"github.com/matrix-org/dendrite/mediaapi/storage/sqlite3"
 	"github.com/matrix-org/dendrite/mediaapi/types"
 	"github.com/matrix-org/gomatrixserverlib"
 )
@ -40,6 +41,8 @@ func Open(dataSourceName string) (Database, error) {
 	switch uri.Scheme {
 	case "postgres":
 		return postgres.Open(dataSourceName)
+	case "file":
+		return sqlite3.Open(dataSourceName)
 	default:
 		return postgres.Open(dataSourceName)
 	}
--- a/publicroomsapi/storage/sqlite3/public_rooms_table.go
+++ b/publicroomsapi/storage/sqlite3/public_rooms_table.go
@ -39,26 +39,15 @@ var editableAttributes = []string{
 const publicRoomsSchema = `
 -- Stores all of the rooms with data needed to create the server's room directory
 CREATE TABLE IF NOT EXISTS publicroomsapi_public_rooms(
-	-- The room's ID
 	room_id TEXT NOT NULL PRIMARY KEY,
-	-- Number of joined members in the room
 	joined_members INTEGER NOT NULL DEFAULT 0,
-	-- Aliases of the room (empty array if none)
-	aliases TEXT[] NOT NULL DEFAULT '{}'::TEXT[],
-	-- Canonical alias of the room (empty string if none)
+	aliases TEXT NOT NULL DEFAULT '',
 	canonical_alias TEXT NOT NULL DEFAULT '',
-	-- Name of the room (empty string if none)
 	name TEXT NOT NULL DEFAULT '',
-	-- Topic of the room (empty string if none)
 	topic TEXT NOT NULL DEFAULT '',
-	-- Is the room world readable?
 	world_readable BOOLEAN NOT NULL DEFAULT false,
-	-- Can guest join the room?
 	guest_can_join BOOLEAN NOT NULL DEFAULT false,
-	-- URL of the room avatar (empty string if none)
 	avatar_url TEXT NOT NULL DEFAULT '',
-	-- Visibility of the room: true means the room is publicly visible, false
-	-- means the room is private
 	visibility BOOLEAN NOT NULL DEFAULT false
 );
 `
@ -71,13 +60,13 @@ const selectPublicRoomsSQL = "" +
 	"SELECT room_id, joined_members, aliases, canonical_alias, name, topic, world_readable, guest_can_join, avatar_url" +
 	" FROM publicroomsapi_public_rooms WHERE visibility = true" +
 	" ORDER BY joined_members DESC" +
-	" OFFSET $1"
+	" LIMIT 30 OFFSET $1"

 const selectPublicRoomsWithLimitSQL = "" +
 	"SELECT room_id, joined_members, aliases, canonical_alias, name, topic, world_readable, guest_can_join, avatar_url" +
 	" FROM publicroomsapi_public_rooms WHERE visibility = true" +
 	" ORDER BY joined_members DESC" +
-	" OFFSET $1 LIMIT $2"
+	" LIMIT $2 OFFSET $1"

 const selectPublicRoomsWithFilterSQL = "" +
 	"SELECT room_id, joined_members, aliases, canonical_alias, name, topic, world_readable, guest_can_join, avatar_url" +
@ -85,9 +74,9 @@ const selectPublicRoomsWithFilterSQL = "" +
 	" WHERE visibility = true" +
 	" AND (LOWER(name) LIKE LOWER($1)" +
 	" OR LOWER(topic) LIKE LOWER($1)" +
-	" OR LOWER(ARRAY_TO_STRING(aliases, ',')) LIKE LOWER($1))" +
+	" OR LOWER(aliases) LIKE LOWER($1))" + // TODO: Is there a better way to search aliases?
 	" ORDER BY joined_members DESC" +
-	" OFFSET $2"
+	" LIMIT 30 OFFSET $2"

 const selectPublicRoomsWithLimitAndFilterSQL = "" +
 	"SELECT room_id, joined_members, aliases, canonical_alias, name, topic, world_readable, guest_can_join, avatar_url" +
@ -95,9 +84,9 @@ const selectPublicRoomsWithLimitAndFilterSQL = "" +
 	" WHERE visibility = true" +
 	" AND (LOWER(name) LIKE LOWER($1)" +
 	" OR LOWER(topic) LIKE LOWER($1)" +
-	" OR LOWER(ARRAY_TO_STRING(aliases, ',')) LIKE LOWER($1))" +
+	" OR LOWER(aliases) LIKE LOWER($1))" + // TODO: Is there a better way to search aliases?
 	" ORDER BY joined_members DESC" +
-	" OFFSET $2 LIMIT $3"
+	" LIMIT $3 OFFSET $2"

 const selectRoomVisibilitySQL = "" +
 	"SELECT visibility FROM publicroomsapi_public_rooms" +
@ -187,7 +176,7 @@ func (s *publicRoomsStatements) selectPublicRooms(
 			)
 		} else {
 			rows, err = s.selectPublicRoomsWithLimitAndFilterStmt.QueryContext(
-				ctx, pattern, offset, limit,
+				ctx, pattern, limit, offset,
 			)
 		}
 	} else {
@ -195,7 +184,7 @@ func (s *publicRoomsStatements) selectPublicRooms(
 			rows, err = s.selectPublicRoomsStmt.QueryContext(ctx, offset)
 		} else {
 			rows, err = s.selectPublicRoomsWithLimitStmt.QueryContext(
-				ctx, offset, limit,
+				ctx, limit, offset,
 			)
 		}
 	}
--- a/publicroomsapi/storage/storage.go
+++ b/publicroomsapi/storage/storage.go
@ -20,6 +20,7 @@ import (

 	"github.com/matrix-org/dendrite/common"
 	"github.com/matrix-org/dendrite/publicroomsapi/storage/postgres"
+	"github.com/matrix-org/dendrite/publicroomsapi/storage/sqlite3"
 	"github.com/matrix-org/dendrite/publicroomsapi/types"
 	"github.com/matrix-org/gomatrixserverlib"
 )
@ -43,6 +44,8 @@ func NewPublicRoomsServerDatabase(dataSourceName string) (Database, error) {
 	switch uri.Scheme {
 	case "postgres":
 		return postgres.NewPublicRoomsServerDatabase(dataSourceName)
+	case "file":
+		return sqlite3.NewPublicRoomsServerDatabase(dataSourceName)
 	default:
 		return postgres.NewPublicRoomsServerDatabase(dataSourceName)
 	}