chore: configurable delete retention interval (#10030)

Command line flag, as it also needs to be able to take effect during
migration.

internal/db/sqlite/db.go

@@ -17,10 +17,12 @@ import (
 )
 
 type DB struct {
-	sql            *sqlx.DB
-	localDeviceIdx int64
-	updateLock     sync.Mutex
-	updatePoints   int
+	sql             *sqlx.DB
+	localDeviceIdx  int64
+	deleteRetention time.Duration
+
+	updateLock   sync.Mutex
+	updatePoints int
 
 	statementsMut sync.RWMutex
 	statements    map[string]*sqlx.Stmt
@@ -29,6 +31,14 @@ type DB struct {
 
 var _ db.DB = (*DB)(nil)
 
+type Option func(*DB)
+
+func WithDeleteRetention(d time.Duration) Option {
+	return func(s *DB) {
+		s.deleteRetention = d
+	}
+}
+
 func (s *DB) Close() error {
 	s.updateLock.Lock()
 	s.statementsMut.Lock()

internal/db/sqlite/db_open.go

@@ -21,7 +21,7 @@ import (
 
 const maxDBConns = 128
 
-func Open(path string) (*DB, error) {
+func Open(path string, opts ...Option) (*DB, error) {
 	// Open the database with options to enable foreign keys and recursive
 	// triggers (needed for the delete+insert triggers on row replace).
 	sqlDB, err := sqlx.Open(dbDriver, "file:"+path+"?"+commonOptions)
@@ -36,7 +36,7 @@ func Open(path string) (*DB, error) {
 		// https://www.sqlite.org/pragma.html#pragma_optimize
 		return nil, wrap(err, "PRAGMA optimize")
 	}
-	return openCommon(sqlDB)
+	return openCommon(sqlDB, opts...)
 }
 
 // Open the database with options suitable for the migration inserts. This
@@ -73,7 +73,7 @@ func OpenTemp() (*DB, error) {
 	return Open(path)
 }
 
-func openCommon(sqlDB *sqlx.DB) (*DB, error) {
+func openCommon(sqlDB *sqlx.DB, opts ...Option) (*DB, error) {
 	if _, err := sqlDB.Exec(`PRAGMA auto_vacuum = INCREMENTAL`); err != nil {
 		return nil, wrap(err, "PRAGMA auto_vacuum")
 	}
@@ -85,8 +85,15 @@ func openCommon(sqlDB *sqlx.DB) (*DB, error) {
 	}
 
 	db := &DB{
-		sql:        sqlDB,
-		statements: make(map[string]*sqlx.Stmt),
+		sql:             sqlDB,
+		deleteRetention: defaultDeleteRetention,
+		statements:      make(map[string]*sqlx.Stmt),
+	}
+	for _, opt := range opts {
+		opt(db)
+	}
+	if db.deleteRetention > 0 && db.deleteRetention < minDeleteRetention {
+		db.deleteRetention = minDeleteRetention
 	}
 
 	if err := db.runScripts("sql/schema/*"); err != nil {

internal/db/sqlite/db_service.go

@@ -15,9 +15,10 @@ import (
 )
 
 const (
-	internalMetaPrefix = "dbsvc"
-	lastMaintKey       = "lastMaint"
-	MaxDeletedFileAge  = 180 * 24 * time.Hour
+	internalMetaPrefix     = "dbsvc"
+	lastMaintKey           = "lastMaint"
+	defaultDeleteRetention = 180 * 24 * time.Hour
+	minDeleteRetention     = 24 * time.Hour
 )
 
 type Service struct {
@@ -101,12 +102,18 @@ func (s *Service) periodic(ctx context.Context) error {
 }
 
 func (s *Service) garbageCollectOldDeletedLocked() error {
+	if s.sdb.deleteRetention <= 0 {
+		l.Debugln("Delete retention is infinite, skipping cleanup")
+		return nil
+	}
+
 	// Remove deleted files that are marked as not needed (we have processed
 	// them) and they were deleted more than MaxDeletedFileAge ago.
+	l.Debugln("Forgetting deleted files older than", s.sdb.deleteRetention)
 	res, err := s.sdb.stmt(`
 		DELETE FROM files
 		WHERE deleted AND modified < ? AND local_flags & {{.FlagLocalNeeded}} == 0
-	`).Exec(time.Now().Add(-MaxDeletedFileAge).UnixNano())
+	`).Exec(time.Now().Add(-s.sdb.deleteRetention).UnixNano())
 	if err != nil {
 		return wrap(err)
 	}