mongo/jstests/replsets/rollback2.js

/*
 * Basic test of a succesful replica set rollback for CRUD operations.
 *
 * This tests sets up a 3 node set, data-bearing nodes A and B and an arbiter.
 * 
 * 1. A is elected PRIMARY and receives several writes, which are propagated to B.
 * 2. A is isolated from the rest of the set and B is elected PRIMARY.
 * 3. B receives several operations, which will later be undone during rollback.
 * 4. B is then isolated and A regains its connection to the arbiter.
 * 5. A receives many new operations, which B will replicate after rollback.
 * 6. B rejoins the set and goes through the rollback process.
 * 7. The contents of A and B are compare to ensure the rollback results in consistent nodes.
 */
load("jstests/replsets/rslib.js");

(function () {
    "use strict";
    // helper function for verifying contents at the end of the test
    var checkFinalResults = function(db) {
        assert.eq(0, db.bar.count({q: 70}));
        assert.eq(2, db.bar.count({q: 40}));
        assert.eq(3, db.bar.count({a: "foo"}));
        assert.eq(6, db.bar.count({q: {$gt: -1}}));
        assert.eq(1, db.bar.count({txt: "foo"}));
        assert.eq(33, db.bar.findOne({q: 0})["y"]);
        assert.eq(1, db.kap.count());
        assert.eq(0, db.kap2.count());
    }

    var name = "rollback2js";
    var replTest = new ReplSetTest({ name: name, nodes: 3, useBridge: true });
    var nodes = replTest.nodeList();

    var conns = replTest.startSet();
    replTest.initiate({ "_id": name,
                        "members": [
                            { "_id": 0, "host": nodes[0], priority: 3 },
                            { "_id": 1, "host": nodes[1] },
                            { "_id": 2, "host": nodes[2], arbiterOnly: true}
    ]});

    // Make sure we have a master and that that master is node A
    replTest.waitForState(replTest.nodes[0], ReplSetTest.State.PRIMARY, 60 * 1000);
    var master = replTest.getPrimary();
    var a_conn = conns[0];
    a_conn.setSlaveOk();
    var A = a_conn.getDB("admin");
    var b_conn = conns[1];
    b_conn.setSlaveOk();
    var B = b_conn.getDB("admin");
    assert.eq(master, conns[0], "conns[0] assumed to be master");
    assert.eq(a_conn, master);

    // Wait for initial replication
    var a = a_conn.getDB("foo");
    var b = b_conn.getDB("foo");

    // initial data for both nodes
    assert.writeOK(a.bar.insert({ q:0}));
    assert.writeOK(a.bar.insert({ q: 1, a: "foo" }));
    assert.writeOK(a.bar.insert({ q: 2, a: "foo", x: 1 }));
    assert.writeOK(a.bar.insert({ q: 3, bb: 9, a: "foo" }));
    assert.writeOK(a.bar.insert({ q: 40, a: 1 }));
    assert.writeOK(a.bar.insert({ q: 40, a: 2 }));
    assert.writeOK(a.bar.insert({ q: 70, txt: 'willremove' }));
    a.createCollection("kap", { capped: true, size: 5000 });
    assert.writeOK(a.kap.insert({ foo: 1 }));
    // going back to empty on capped is a special case and must be tested
    a.createCollection("kap2", { capped: true, size: 5501 });
    replTest.awaitReplication();

    var timeout;
    if (replTest.getConfigFromPrimary().protocolVersion == 1) {
        timeout = 30 * 1000;
    } else {
        timeout = 60 * 1000;
    }
    // isolate A and wait for B to become master
    conns[0].disconnect(conns[1]);
    conns[0].disconnect(conns[2]);
    assert.soon(function () {
        try {
            return B.isMaster().ismaster;
        } catch(e) {
            return false;
        }
    }, "node B did not become master as expected", timeout);

    // do operations on B and B alone, these will be rolled back
    assert.writeOK(b.bar.insert({ q: 4 }));
    assert.writeOK(b.bar.update({ q: 3 }, { q: 3, rb: true }));
    assert.writeOK(b.bar.remove({ q: 40 })); // multi remove test
    assert.writeOK(b.bar.update({ q: 2 }, { q: 39, rb: true }));
    // rolling back a delete will involve reinserting the item(s)
    assert.writeOK(b.bar.remove({ q: 1 }));
    assert.writeOK(b.bar.update({ q: 0 }, { $inc: { y: 1} }));
    assert.writeOK(b.kap.insert({ foo: 2 }));
    assert.writeOK(b.kap2.insert({ foo: 2 }));
    // create a collection (need to roll back the whole thing)
    assert.writeOK(b.newcoll.insert({ a: true }));
    // create a new empty collection (need to roll back the whole thing)
    b.createCollection("abc");

    // isolate B, bring A back into contact with the arbiter, then wait for A to become master
    // insert new data into A so that B will need to rollback when it reconnects to A
    conns[1].disconnect(conns[2]);
    assert.soon(function () { try { return !B.isMaster().ismaster; } catch(e) { return false; } });

    conns[0].reconnect(conns[2]);
    assert.soon(function () { try { return A.isMaster().ismaster; } catch(e) { return false; } });
    assert(a.bar.count() >= 1, "count check");
    assert.writeOK(a.bar.insert({ txt: 'foo' }));
    assert.writeOK(a.bar.remove({ q: 70 }));
    assert.writeOK(a.bar.update({ q: 0 }, { $inc: { y: 33} }));

    // A is 1 2 3 7 8
    // B is 1 2 3 4 5 6
    // put B back in contact with A and arbiter, as A is primary, B will rollback and then catch up
    conns[1].reconnect(conns[2]);
    conns[0].reconnect(conns[1]);

    awaitOpTime(b.getMongo(), getLatestOp(a_conn).ts);

    // await steady state and ensure the two nodes have the same contents
    replTest.awaitSecondaryNodes();
    replTest.awaitReplication();
    checkFinalResults(a);
    checkFinalResults(b);

    replTest.stopSet(15);
}());