mongo/jstests/core/txns/multi_statement_transaction.js

// Test basic multi-statement transaction.
// @tags: [uses_transactions]
(function() {
    "use strict";

    const dbName = "test";
    const collName = "multi_statement_transaction";
    const testDB = db.getSiblingDB(dbName);
    const testColl = testDB[collName];

    testDB.runCommand({drop: collName, writeConcern: {w: "majority"}});

    assert.commandWorked(
        testDB.createCollection(testColl.getName(), {writeConcern: {w: "majority"}}));

    const sessionOptions = {causalConsistency: false};
    const session = db.getMongo().startSession(sessionOptions);
    const sessionDb = session.getDatabase(dbName);
    const sessionColl = sessionDb[collName];

    /***********************************************************************************************
     * Insert two documents in a transaction.
     **********************************************************************************************/

    assert.commandWorked(testColl.remove({}, {writeConcern: {w: "majority"}}));

    jsTest.log("Insert two documents in a transaction");

    session.startTransaction();

    // Insert a doc within the transaction.
    assert.commandWorked(sessionColl.insert({_id: "insert-1"}));

    // Cannot read with default read concern.
    assert.eq(null, testColl.findOne({_id: "insert-1"}));
    // But read in the same transaction returns the doc.
    assert.docEq({_id: "insert-1"}, sessionColl.findOne());

    // Read with aggregation also returns the document.
    let docs = sessionColl.aggregate([{$match: {_id: "insert-1"}}]).toArray();
    assert.sameMembers([{_id: "insert-1"}], docs);

    // Insert a doc within a transaction.
    assert.commandWorked(sessionColl.insert({_id: "insert-2"}));

    // Cannot read with default read concern.
    assert.eq(null, testColl.findOne({_id: "insert-1"}));
    // Cannot read with default read concern.
    assert.eq(null, testColl.findOne({_id: "insert-2"}));

    // Commit the transaction.
    session.commitTransaction();

    // Read with default read concern sees the committed transaction.
    assert.eq({_id: "insert-1"}, testColl.findOne({_id: "insert-1"}));
    assert.eq({_id: "insert-2"}, testColl.findOne({_id: "insert-2"}));

    /***********************************************************************************************
     * Update documents in a transaction.
     **********************************************************************************************/

    assert.commandWorked(testColl.remove({}, {writeConcern: {w: "majority"}}));

    jsTest.log("Update documents in a transaction");

    // Insert the docs to be updated.
    assert.commandWorked(sessionColl.insert([{_id: "update-1", a: 0}, {_id: "update-2", a: 0}],
                                            {writeConcern: {w: "majority"}}));

    // Update the docs in a new transaction.
    session.startTransaction();

    assert.commandWorked(sessionColl.update({_id: "update-1"}, {$inc: {a: 1}}));

    // Batch update in transaction.
    let bulk = sessionColl.initializeUnorderedBulkOp();
    bulk.find({_id: "update-1"}).updateOne({$inc: {a: 1}});
    bulk.find({_id: "update-2"}).updateOne({$inc: {a: 1}});
    assert.commandWorked(bulk.execute());

    // Cannot read with default read concern.
    assert.eq({_id: "update-1", a: 0}, testColl.findOne({_id: "update-1"}));
    assert.eq({_id: "update-2", a: 0}, testColl.findOne({_id: "update-2"}));

    // Commit the transaction.
    session.commitTransaction();

    // Read with default read concern sees the committed transaction.
    assert.eq({_id: "update-1", a: 2}, testColl.findOne({_id: "update-1"}));
    assert.eq({_id: "update-2", a: 1}, testColl.findOne({_id: "update-2"}));

    /***********************************************************************************************
     * Insert, update and read documents in a transaction.
     **********************************************************************************************/

    assert.commandWorked(testColl.remove({}, {writeConcern: {w: "majority"}}));

    jsTest.log("Insert, update and read documents in a transaction");

    session.startTransaction();
    assert.commandWorked(sessionColl.insert([{_id: "doc-1"}, {_id: "doc-2"}]));

    // Update the two docs in transaction.
    assert.commandWorked(sessionColl.update({_id: "doc-1"}, {$inc: {a: 1}}));
    assert.commandWorked(sessionColl.update({_id: "doc-2"}, {$inc: {a: 1}}));

    // Cannot read with default read concern.
    assert.eq(null, testColl.findOne({_id: "doc-1"}));
    assert.eq(null, testColl.findOne({_id: "doc-2"}));

    // But read in the same transaction returns the docs.
    docs = sessionColl.find({$or: [{_id: "doc-1"}, {_id: "doc-2"}]}).toArray();
    assert.sameMembers([{_id: "doc-1", a: 1}, {_id: "doc-2", a: 1}], docs);

    // Commit the transaction.
    session.commitTransaction();

    // Read with default read concern sees the committed transaction.
    assert.eq({_id: "doc-1", a: 1}, testColl.findOne({_id: "doc-1"}));
    assert.eq({_id: "doc-2", a: 1}, testColl.findOne({_id: "doc-2"}));

    jsTest.log("Insert and delete documents in a transaction");

    assert.commandWorked(testColl.remove({}, {writeConcern: {w: "majority"}}));

    assert.commandWorked(
        testColl.insert([{_id: "doc-1"}, {_id: "doc-2"}], {writeConcern: {w: "majority"}}));

    session.startTransaction();
    assert.commandWorked(sessionColl.insert({_id: "doc-3"}));

    // Remove three docs in transaction.
    assert.commandWorked(sessionColl.remove({_id: "doc-1"}));

    // Batch delete.
    bulk = sessionColl.initializeUnorderedBulkOp();
    bulk.find({_id: "doc-2"}).removeOne();
    bulk.find({_id: "doc-3"}).removeOne();
    assert.commandWorked(bulk.execute());

    // Cannot read the new doc and still see the to-be removed docs with default read concern.
    assert.eq({_id: "doc-1"}, testColl.findOne({_id: "doc-1"}));
    assert.eq({_id: "doc-2"}, testColl.findOne({_id: "doc-2"}));
    assert.eq(null, testColl.findOne({_id: "doc-3"}));

    // But read in the same transaction sees the docs get deleted.
    docs = sessionColl.find({$or: [{_id: "doc-1"}, {_id: "doc-2"}, {_id: "doc-3"}]}).toArray();
    assert.sameMembers([], docs);

    // Commit the transaction.
    session.commitTransaction();

    // Read with default read concern sees the commmitted transaction.
    assert.eq(null, testColl.findOne({_id: "doc-1"}));
    assert.eq(null, testColl.findOne({_id: "doc-2"}));
    assert.eq(null, testColl.findOne({_id: "doc-3"}));

    session.endSession();
}());