Enable WAL mode, add changelog

docs/releases.md

@@ -6,8 +6,14 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 ## ntfy server v1.27.0 (UNRELEASED)
 
+!!! info
+    The message cache database (typically `cache.db`) now enables the write-ahead log (WAL) in SQLite.
+    WAL mode will create two additional files (`cache.db-wal` and `cache.db-shm`). This is perfectly normal.
+    Do not delete or modify these files, as that can lead to database corruption.
+
 **Features:**
 
+* Greatly improve SQLite performance for the message cache by enabling WAL mode (no ticket)
 * ntfy CLI can now [wait for a command or PID](https://ntfy.sh/docs/subscribe/cli/#wait-for-pidcommand) before publishing ([#263](https://github.com/binwiederhier/ntfy/issues/263), thanks to the [original ntfy](https://github.com/dschep/ntfy) for the idea) 
 * Trace: Log entire HTTP request to simplify debugging (no ticket)
 * Allow setting user password via `NTFY_PASSWORD` env variable ([#327](https://github.com/binwiederhier/ntfy/pull/327), thanks to [@Kenix3](https://github.com/Kenix3))

server/message_cache.go

@@ -88,6 +88,18 @@ const (
 	selectAttachmentsExpiredQuery   = `SELECT mid FROM messages WHERE attachment_expires > 0 AND attachment_expires < ?`
 )
 
+// Performance & setup queries (see https://phiresky.github.io/blog/2020/sqlite-performance-tuning/)
+// - Write-ahead log (speeds up reads)
+// - Only sync on WAL checkpoint
+// - Temporary indices in memory
+const (
+	setupQueries = `
+		pragma journal_mode = WAL;
+		pragma synchronous = normal;
+		pragma temp_store = memory;
+	`
+)
+
 // Schema management queries
 const (
 	currentSchemaVersion          = 7
@@ -222,12 +234,22 @@ func createMemoryFilename() string {
 }
 
 func (c *messageCache) AddMessage(m *message) error {
-	if m.Event != messageEvent {
-		return errUnexpectedMessageType
+	return c.addMessages([]*message{m})
 }
+
+func (c *messageCache) addMessages(ms []*message) error {
 	if c.nop {
 		return nil
 	}
+	tx, err := c.db.Begin()
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+	for _, m := range ms {
+		if m.Event != messageEvent {
+			return errUnexpectedMessageType
+		}
 		published := m.Time <= time.Now().Unix()
 		tags := strings.Join(m.Tags, ",")
 		var attachmentName, attachmentType, attachmentURL string
@@ -247,7 +269,7 @@ func (c *messageCache) AddMessage(m *message) error {
 			}
 			actionsStr = string(actionsBytes)
 		}
-	_, err := c.db.Exec(
+		_, err := tx.Exec(
 			insertMessageQuery,
 			m.ID,
 			m.Time,
@@ -267,8 +289,12 @@ func (c *messageCache) AddMessage(m *message) error {
 			m.Encoding,
 			published,
 		)
+		if err != nil {
 			return err
 		}
+	}
+	return tx.Commit()
+}
 
 func (c *messageCache) Messages(topic string, since sinceMarker, scheduled bool) ([]*message, error) {
 	if since.IsNone() {
@@ -486,6 +512,11 @@ func readMessages(rows *sql.Rows) ([]*message, error) {
 }
 
 func setupCacheDB(db *sql.DB) error {
+	// Performance: WAL mode, only sync on WAL checkpoints
+	if _, err := db.Exec(setupQueries); err != nil {
+		return err
+	}
+
 	// If 'messages' table does not exist, this must be a new database
 	rowsMC, err := db.Query(selectMessagesCountQuery)
 	if err != nil {

server/server_test.go

@@ -6,6 +6,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"github.com/stretchr/testify/assert"
 	"io"
 	"log"
 	"math/rand"
@@ -1411,15 +1412,22 @@ func TestServer_Visitor_XForwardedFor_Multiple(t *testing.T) {
 }
 
 func TestServer_PublishWhileUpdatingStatsWithLotsOfMessages(t *testing.T) {
-	count := 1000
-	s := newTestServer(t, newTestConfig(t))
+	count := 50000
+	c := newTestConfig(t)
+	c.TotalTopicLimit = 50001
+	s := newTestServer(t, c)
 
 	// Add lots of messages
 	log.Printf("Adding %d messages", count)
 	start := time.Now()
+	messages := make([]*message, 0)
 	for i := 0; i < count; i++ {
-		require.Nil(t, s.messageCache.AddMessage(newDefaultMessage(fmt.Sprintf("topic%d", i), "some message")))
+		topicID := fmt.Sprintf("topic%d", i)
+		_, err := s.topicsFromIDs(topicID) // Add topic to internal s.topics array
+		require.Nil(t, err)
+		messages = append(messages, newDefaultMessage(topicID, "some message"))
 	}
+	require.Nil(t, s.messageCache.addMessages(messages))
 	log.Printf("Done: Adding %d messages; took %s", count, time.Since(start).Round(time.Millisecond))
 
 	// Update stats
@@ -1438,11 +1446,13 @@ func TestServer_PublishWhileUpdatingStatsWithLotsOfMessages(t *testing.T) {
 	start = time.Now()
 	response := request(t, s, "PUT", "/mytopic", "some body", nil)
 	m := toMessage(t, response.Body.String())
-	require.Equal(t, "some body", m.Message)
-	require.True(t, time.Since(start) < 500*time.Millisecond)
+	assert.Equal(t, "some body", m.Message)
+	assert.True(t, time.Since(start) < 100*time.Millisecond)
 	log.Printf("Done: Publishing message; took %s", time.Since(start).Round(time.Millisecond))
 
+	// Wait for all goroutines
 	<-statsChan
+	log.Printf("Done: Waiting for all locks")
 }
 
 func newTestConfig(t *testing.T) *Config {