mongo/jstests/replsets/read_majority_two_arbs.js

/**
 * Tests that writeConcern 'majority' writes succeed and are visible in a replica set that has one
 * data-bearing node and two arbiters.
 *
 * @tags: [requires_majority_read_concern, requires_fcv_53]
 */
import {ReplSetTest} from "jstests/libs/replsettest.js";

function log(arg) {
    jsTest.log(tojson(arg));
}

// Set up a set and grab things for later.
let name = "read_majority_two_arbs";
let replTest = new ReplSetTest({name: name, nodes: 3});

replTest.startSet({setParameter: {allowMultipleArbiters: true}});
let nodes = replTest.nodeList();
let config = {
    "_id": name,
    "members": [
        {"_id": 0, "host": nodes[0]},
        {"_id": 1, "host": nodes[1], arbiterOnly: true},
        {"_id": 2, "host": nodes[2], arbiterOnly: true},
    ],
};

replTest.initiate(config);

let primary = replTest.getPrimary();
var db = primary.getDB(name);
let t = db[name];

function doRead(readConcern) {
    readConcern.maxTimeMS = 3000;
    let res = assert.commandWorked(t.runCommand("find", readConcern));
    let docs = new DBCommandCursor(db, res).toArray();
    assert.gt(docs.length, 0, "no docs returned!");
    return docs[0].state;
}

function doDirtyRead() {
    log("doing dirty read");
    let ret = doRead({"readConcern": {"level": "local"}});
    log("done doing dirty read.");
    return ret;
}

function doCommittedRead() {
    log("doing committed read");
    let ret = doRead({"readConcern": {"level": "majority"}});
    log("done doing committed read.");
    return ret;
}

jsTest.log("doing write");
assert.commandWorked(t.save({_id: 1, state: 0}, {writeConcern: {w: "majority", wtimeout: 10 * 1000}}));
jsTest.log("doing read");
assert.eq(doDirtyRead(), 0);
jsTest.log("doing committed read");
assert.eq(doCommittedRead(), 0);
jsTest.log("stopping replTest; test completed successfully");
replTest.stopSet();