load( "jstests/libs/slow_weekly_util.js" )
test = new SlowWeeklyMongod( "conc_update" )
db = test.getDB("concurrency")
db.dropDatabase();

NRECORDS=3*1024*1024

print("loading "+NRECORDS+" documents (progress msg every 1024*1024 documents)")
var bulk = db.conc.initializeUnorderedBulkOp();
for (var i = 0; i < NRECORDS; i++) {
    bulk.insert({ x: i });
}
assert.writeOK(bulk.execute());

print("making an index (this will take a while)")
db.conc.ensureIndex({x:1})

var c1=db.conc.count({x:{$lt:NRECORDS}})

updater = startParallelShell("db = db.getSisterDB('concurrency');\
                              db.concflag.insert({ inprog: true });\
                              sleep(20);\
                              assert.writeOK(db.conc.update({}, \
                                             { $inc: { x: " + NRECORDS + "}}, false, true)); \
                              assert.writeOK(db.concflag.update({}, { inprog: false }));");

assert.soon( function(){ var x = db.concflag.findOne(); return x && x.inprog; } ,
             "wait for fork" , 30000 , 1 );

querycount=0;
decrements=0;
misses=0

assert.soon(function(){
    c2=db.conc.count({x:{$lt:NRECORDS}})
    print(c2)
    querycount++;
    if (c2<c1)
        decrements++;
    else
        misses++;
    c1 = c2;
    return ! db.concflag.findOne().inprog;
}, "update never finished" , 2 * 60 * 60 * 1000 , 10 );

print(querycount + " queries, " + decrements + " decrements, " + misses + " misses");

assert.eq( NRECORDS , db.conc.count() , "AT END 1" )

updater() // wait()

test.stop();