mongodb/jstests/noPassthrough/disable_majority_reads_restart.js

/**
 * Tests restarting mongod with 'enableMajorityReadConcern' varying between true and false.
 *
 * @tags: [requires_persistence, requires_replication, requires_majority_read_concern,
 * requires_wiredtiger]
 */
(function() {
    "use strict";

    const dbName = "test";
    const collName = "coll";

    const rst = new ReplSetTest({nodes: 1});
    rst.startSet();
    rst.initiate();

    // Insert a document and ensure it is in the stable checkpoint by restarting.
    let coll = rst.getPrimary().getDB(dbName)[collName];
    assert.commandWorked(coll.insert({_id: 0}, {writeConcern: {w: "majority"}}));
    rst.stopSet(undefined, true);
    rst.startSet(undefined, true);

    // Disable snapshotting on all members of the replica set so that further operations do not
    // enter the majority snapshot.
    assert.commandWorked(rst.getPrimary().adminCommand(
        {configureFailPoint: "disableSnapshotting", mode: "alwaysOn"}));

    // Insert a document that will not be in a stable checkpoint.
    coll = rst.getPrimary().getDB(dbName)[collName];
    assert.commandWorked(coll.insert({_id: 1}));

    // Restart the node with enableMajorityReadConcern:false.
    rst.stopSet(undefined, true);
    rst.startSet({noCleanData: true, enableMajorityReadConcern: "false"});

    // Both inserts should be reflected in the data and the oplog.
    coll = rst.getPrimary().getDB(dbName)[collName];
    assert.eq([{_id: 0}, {_id: 1}], coll.find().sort({_id: 1}).toArray());
    let oplog = rst.getPrimary().getDB("local").oplog.rs;
    assert.eq(1, oplog.find({o: {_id: 0}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 1}}).itcount());

    // Restart the node with enableMajorityReadConcern:false without adding any documents.
    rst.stopSet(undefined, true);
    rst.startSet({noCleanData: true, enableMajorityReadConcern: "false"});

    // Both inserts should still be reflected in the data and the oplog.
    coll = rst.getPrimary().getDB(dbName)[collName];
    assert.eq([{_id: 0}, {_id: 1}], coll.find().sort({_id: 1}).toArray());
    oplog = rst.getPrimary().getDB("local").oplog.rs;
    assert.eq(1, oplog.find({o: {_id: 0}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 1}}).itcount());

    // Insert another document.
    assert.commandWorked(coll.insert({_id: 2}, {writeConcern: {w: "majority"}}));

    // Restart the node with enableMajorityReadConcern:false.
    rst.stopSet(undefined, true);
    rst.startSet({noCleanData: true, enableMajorityReadConcern: "false"});

    // All three inserts should be reflected in the data and the oplog.
    coll = rst.getPrimary().getDB(dbName)[collName];
    assert.eq([{_id: 0}, {_id: 1}, {_id: 2}], coll.find().sort({_id: 1}).toArray());
    oplog = rst.getPrimary().getDB("local").oplog.rs;
    assert.eq(1, oplog.find({o: {_id: 0}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 1}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 2}}).itcount());

    // Restart the node with enableMajorityReadConcern:true.
    rst.stopSet(undefined, true);
    rst.startSet({noCleanData: true, enableMajorityReadConcern: "false"});

    // All three inserts should still be reflected in the data and the oplog.
    coll = rst.getPrimary().getDB(dbName)[collName];
    assert.eq([{_id: 0}, {_id: 1}, {_id: 2}], coll.find().sort({_id: 1}).toArray());
    oplog = rst.getPrimary().getDB("local").oplog.rs;
    assert.eq(1, oplog.find({o: {_id: 0}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 1}}).itcount());
    assert.eq(1, oplog.find({o: {_id: 2}}).itcount());

    rst.stopSet();
})();