createIndex blocks for duration of checkpoint while holding locks

Thread 3 (Thread 0x7fe1682e1700 (LWP 22695)):

#0  __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135

#1  0x00007fe16e399cfd in __GI___pthread_mutex_lock (mutex=0x32d6440) at ../nptl/pthread_mutex_lock.c:80

#2  0x00000000019fe649 in __wt_curfile_open ()

#3  0x0000000001a63a05 in __session_open_cursor_int ()

#4  0x0000000001a14d33 in __wt_curtable_open ()

#5  0x0000000001a63889 in __session_open_cursor_int ()

#6  0x0000000001a63e19 in __session_open_cursor ()

#7  0x0000000001066119 in mongo::WiredTigerIndex::BulkBuilder::openBulkCursor(mongo::WiredTigerIndex*) ()

#8  0x000000000106137e in mongo::WiredTigerIndexStandard::getBulkBuilder(mongo::OperationContext*, bool) ()

#9  0x0000000000c79fa9 in mongo::IndexAccessMethod::commitBulk(mongo::OperationContext*, std::unique_ptr<mongo::IndexAccessMethod::BulkBuilder, std::default_delete<mongo::IndexAccessMethod::BulkBuilder> >, bool, bool, std::set<mongo::RecordId, std::less<mongo::RecordId>, std::allocator<mongo::RecordId> >*) ()

#10 0x0000000000ac29b0 in mongo::MultiIndexBlock::doneInserting(std::set<mongo::RecordId, std::less<mongo::RecordId>, std::allocator<mongo::RecordId> >*) ()

#11 0x0000000000ac2f00 in mongo::MultiIndexBlock::insertAllDocumentsInCollection(std::set<mongo::RecordId, std::less<mongo::RecordId>, std::allocator<mongo::RecordId> >*) ()

#12 0x0000000000aedf86 in mongo::CmdCreateIndex::run(mongo::OperationContext*, std::string const&, mongo::BSONObj&, int, std::string&, mongo::BSONObjBuilder&) ()

#13 0x0000000000b816e3 in mongo::Command::run(mongo::OperationContext*, mongo::rpc::RequestInterface const&, mongo::rpc::ReplyBuilderInterface*) ()

#14 0x0000000000b82554 in mongo::Command::execCommand(mongo::OperationContext*, mongo::Command*, mongo::rpc::RequestInterface const&, mongo::rpc::ReplyBuilderInterface*) ()

#15 0x0000000000ad98c0 in mongo::runCommands(mongo::OperationContext*, mongo::rpc::RequestInterface const&, mongo::rpc::ReplyBuilderInterface*) ()

#16 0x0000000000c9b095 in mongo::assembleResponse(mongo::OperationContext*, mongo::Message&, mongo::DbResponse&, mongo::HostAndPort const&) ()

#17 0x0000000000961c2c in mongo::MyMessageHandler::process(mongo::Message&, mongo::AbstractMessagingPort*) ()

#18 0x00000000012b508d in mongo::PortMessageServer::handleIncomingMsg(void*) ()

#19 0x00007fe16e3976aa in start_thread (arg=0x7fe1682e1700) at pthread_create.c:333

#20 0x00007fe16e0cd13d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

function insert(threads) {

    x = ''

    for (var i=0; i<1000; i++)

        x += 'x'

    docs = []

    for (var i=0; i<1000; i++)

        docs.push({x:x})

    ops = [{

        op: "insert",

        ns: "test.c",

        doc: docs,

    }]

    res = benchRun({

        ops: ops,

        seconds: 10000,

        parallel: threads

    })

    printjson(res)

}

function create() {

    for (var i=0; i<150; i++) {

        c = db['c'+i]

        t0 = new Date()

        print('createIndex at', t0)

        db['c'+i].createIndex({x:1})

        print('took', new Date() - t0, 'ms')

        sleep(1000)

    }

}