mongo/jstests/core/queryoptimizer3.js

// Validates cases where index scans are aborted due to the collection being dropped (SERVER-4400)
//
// Drop and other sharding commands can conflict with LockBusy errors in a sharding passthrough
// suite. This is because drop against a mongos takes distlocks, whereas drop against a mongod does
// not. Due to the huge number of parallel drops in this test, the other thead is very likely to be
// starved frequently.
// Note: this tag can be safely removed once PM-697 is complete and replaces distlocks with a
// LockManager that has a fairness policy, which distlocks lack.
// @tags: [
//   assumes_against_mongod_not_mongos,
//   requires_non_retryable_writes,
//   uses_multiple_connections,
// ]

(function() {
'use strict';

var coll = db.jstests_queryoptimizer3;

var shellWaitHandle = startParallelShell(function() {
    for (var i = 0; i < 400; ++i) {
        sleep(50);
        try {
            db.jstests_queryoptimizer3.drop();
        } catch (e) {
            if (e.code === ErrorCodes.BackgroundOperationInProgressForNamespace) {
                print("Background operation temporarily in progress while attempting to drop " +
                      "collection.");
                continue;
            }
            throw e;
        }
    }
});

for (var i = 0; i < 100; ++i) {
    coll.drop();
    assert.commandWorked(coll.ensureIndex({a: 1}));
    assert.commandWorked(coll.ensureIndex({b: 1}));

    var bulk = coll.initializeUnorderedBulkOp();
    for (var j = 0; j < 100; ++j) {
        bulk.insert({a: j, b: j});
    }
    assert.commandWorked(bulk.execute());

    try {
        var m = i % 5;
        if (m == 0) {
            coll.count({a: {$gte: 0}, b: {$gte: 0}});
        } else if (m == 1) {
            coll.find({a: {$gte: 0}, b: {$gte: 0}}).itcount();
        } else if (m == 2) {
            coll.remove({a: {$gte: 0}, b: {$gte: 0}});
        } else if (m == 3) {
            coll.update({a: {$gte: 0}, b: {$gte: 0}}, {});
        } else if (m == 4) {
            coll.distinct('x', {a: {$gte: 0}, b: {$gte: 0}});
        }
    } catch (e) {
        print("Op killed during yield: " + e.message);
    }
}

shellWaitHandle();

// Ensure that the server is still responding
assert.commandWorked(db.runCommand({isMaster: 1}));
})();