dgraph-io/badger · error

Cannot use NewTransactionAt with managedDB=false. Use NewTra

Error message

Cannot use NewTransactionAt with managedDB=false. Use NewTransaction instead.

What it means

This panic is thrown by Badger's DB.NewTransactionAt when the database was opened without managed transaction mode (badger.DefaultOptions has managedDb=false / WithManagedTxns(false)). NewTransactionAt exists only for databases layered on Badger (e.g. Dgraph) that supply their own read timestamps; regular users must use NewTransaction. The library panics instead of returning an error because this is a programming/API-misuse error detected at the call site.

Source

Thrown at managed_db.go:25

// OpenManaged returns a new DB, which allows more control over setting
// transaction timestamps, aka managed mode.
//
// This is only useful for databases built on top of Badger (like Dgraph), and
// can be ignored by most users.
func OpenManaged(opts Options) (*DB, error) {
	opts.managedTxns = true
	return Open(opts)
}

// NewTransactionAt follows the same logic as DB.NewTransaction(), but uses the
// provided read timestamp.
//
// This is only useful for databases built on top of Badger (like Dgraph), and
// can be ignored by most users.
func (db *DB) NewTransactionAt(readTs uint64, update bool) *Txn {
	if !db.opt.managedTxns {
		panic("Cannot use NewTransactionAt with managedDB=false. Use NewTransaction instead.")
	}
	txn := db.newTransaction(update, true)
	txn.readTs = readTs
	return txn
}

// NewWriteBatchAt is similar to NewWriteBatch but it allows user to set the commit timestamp.
// NewWriteBatchAt is supposed to be used only in the managed mode.
func (db *DB) NewWriteBatchAt(commitTs uint64) *WriteBatch {
	if !db.opt.managedTxns {
		panic("cannot use NewWriteBatchAt with managedDB=false. Use NewWriteBatch instead")
	}

	wb := db.newWriteBatch(true)
	wb.commitTs = commitTs
	wb.txn.commitTs = commitTs
	return wb
}

View on GitHub (pinned to 2a001d466f)

Solutions

1. Open the DB with WithManagedTxns(true): opts := badger.DefaultOptions(dir).WithManagedTxns(true); db, err := badger.Open(opts).
2. If managed mode is not needed, replace NewTransactionAt(readTs, update) with db.NewTransaction(update) and drop the explicit readTs.
3. Centralize DB opening in one helper so the managed flag and the At-style APIs stay consistent.
4. Wrap the call in a function with defer/recover if you must probe behavior, though fixing the options is the real fix.

Example fix

// before
opts := badger.DefaultOptions(dir)
db, _ := badger.Open(opts)
txn := db.NewTransactionAt(100, true)
// after
opts := badger.DefaultOptions(dir).WithManagedTxns(true)
db, _ := badger.Open(opts)
txn := db.NewTransactionAt(100, true)
// ...or, without managed mode:
txn := db.NewTransaction(true)

if !db.Opts().ManagedTxns { // or track the option you passed to badger.Open
    txn := db.NewTransaction(update)
} else {
    txn := db.NewTransactionAt(readTs, update)
}

func isManagedDB(db *badger.DB, openedManaged bool) bool { return openedManaged }

func safeNewTransactionAt(db *badger.DB, readTs uint64, update bool) (txn *badger.Txn, err error) {
    defer func() {
        if r := recover(); r != nil {
            err = fmt.Errorf("NewTransactionAt requires managed mode: %v", r)
        }
    }()
    txn = db.NewTransactionAt(readTs, update)
    return
}

When it happens

Trigger: Calling db.NewTransactionAt(readTs, update) on a DB opened with managedTxns disabled (the default). Callers seen in practice: compareTwo, fullScanDB, showKeysStats, numKeysManaged, produceKVs — any tool code that assumes managed mode but opened the DB with plain options.

Common situations: A developer copies code from Dgraph or a managed-mode example without switching to WithManagedTxns(true) when opening the DB; a utility written for managed DBs is pointed at a normal application DB; options are refactored and the managed flag is dropped.

Related errors

• cannot use NewWriteBatchAt with managedDB=false. Use NewWrit
• cannot use NewManagedWriteBatch with managedDB=false. Use Ne
• Cannot use CommitAt with managedDB=false. Use Commit instead
• Cannot use SetDiscardTs with managedDB=false.
• This API can not be called in managed mode.

AI-assisted analysis of dgraph-io/badger@2a001d466f (2026-09-05). Data as JSON: /api/errors/28cbf05cd8e3d19f. Report an issue: GitHub.