mongodb/node-mongodb-native · error · MongoCompatibilityError

Snapshot reads require MongoDB 5.0 or later

Error message

Snapshot reads require MongoDB 5.0 or later

What it means

executeOperation (src/operations/execute_operation.ts:93) throws a MongoCompatibilityError when a session with snapshot reads enabled (startSession({ snapshot: true })) is used against a server whose wire version is below MIN_SUPPORTED_SNAPSHOT_READS_WIRE_VERSION, i.e. a server older than MongoDB 5.0. Snapshot sessions are a server feature introduced in 5.0 and cannot be emulated by the driver.

Source

Thrown at src/operations/execute_operation.ts:93

    client.topology == null
      ? await abortable(autoConnect(client), operation.options)
      : client.topology;

  // The driver sessions spec mandates that we implicitly create sessions for operations
  // that are not explicitly provided with a session.
  let session = operation.session;
  let owner: symbol | undefined;

  if (session == null) {
    owner = Symbol();
    session = client.startSession({ owner, explicit: false });
  } else if (session.hasEnded) {
    throw new MongoExpiredSessionError('Use of expired sessions is not permitted');
  } else if (
    session.snapshotEnabled &&
    maxWireVersion(topology) < MIN_SUPPORTED_SNAPSHOT_READS_WIRE_VERSION
  ) {
    throw new MongoCompatibilityError('Snapshot reads require MongoDB 5.0 or later');
  } else if (session.client !== client) {
    throw new MongoInvalidArgumentError('ClientSession must be from the same MongoClient');
  }

  operation.session ??= session;

  const readPreference = operation.readPreference ?? ReadPreference.primary;
  const inTransaction = !!session?.inTransaction();

  const hasReadAspect = operation.hasAspect(Aspect.READ_OPERATION);

  if (
    inTransaction &&
    !readPreference.equals(ReadPreference.primary) &&
    (hasReadAspect || operation.commandName === 'runCommand')
  ) {
    throw new MongoTransactionError(
      `Read preference in a transaction must be primary, not: ${readPreference.mode}`

View on GitHub (pinned to 3366c21a63)

Solutions

1. Upgrade the MongoDB deployment to 5.0 or later — snapshot reads require it.
2. If upgrade is not possible, remove the snapshot:true option from startSession.
3. Verify the deployment version with a hello/buildInfo command to confirm compatibility before enabling the feature.

Example fix

// before
const session = client.startSession({ snapshot: true }); // on MongoDB 4.4

// after (upgrade server, or remove snapshot)
const session = client.startSession(); // no snapshot on < 5.0
// or upgrade the deployment to >= 5.0 and keep snapshot:true

// Check server version before enabling snapshot reads
const admin = client.db().admin();
const buildInfo = await admin.command({ buildInfo: 1 });
const major = parseInt(buildInfo.versionArray[0], 10);
const snapshotOk = major >= 5;
const session = client.startSession(snapshotOk ? { snapshot: true } : {});

When it happens

Trigger: Calling client.startSession({ snapshot: true }) and using it against a standalone, replica set, or sharded cluster running MongoDB 4.4 or earlier.

Common situations: Upgrading the driver to use snapshot reads while the deployment has not been upgraded to 5.0+, or pointing a snapshot-enabled app at a legacy test/dev instance.

Related errors

• Transactions are not supported in snapshot sessions
• Driver attempted to initialize in load balancing mode, but t
• Current topology does not support sessions
• Unexpected null session. A cursor creating command should ha
• Unexpected null session. A cursor creating command should ha

AI-assisted analysis of mongodb/node-mongodb-native@3366c21a63 (2026-08-04). Data as JSON: /data/errors/2c7c66dfb0d451ff.json. Report an issue: GitHub.