Skip to main content
Journey Uncommon Logo
JourneyUncommon
mediumMongoDBmulti-document transactionsSingle-choice MCQ

What does the snippet most likely print, given that transactions in MongoDB use snapshot read concern by default within the transaction?

// account starts with balance: 100 const session = client.startSession(); session.startTransaction(); const coll = client.db('bank').collection('accounts'); await coll.findOne({ _id: 1 }, { session }); // establishes snapshot // meanwhile, a SEPARATE connection (no session) commits: // coll.updateOne({ _id: 1 }, { $set: { balance: 150 } }) const doc = await coll.findOne({ _id: 1 }, { session }); console.log(doc.balance); await session.commitTransaction();