SERVER-16262: Add test case for Map/Reduce WriteConflict

1 files changed, 71 insertions, 0 deletions

diff --git a/jstests/noPassthroughWithMongod/mr_writeconflict.js b/jstests/noPassthroughWithMongod/mr_writeconflict.js
new file mode 100644
index 00000000000..e3963e80c98
--- /dev/null
+++ b/jstests/noPassthroughWithMongod/mr_writeconflict.js
@@ -0,0 +1,71 @@
+// SERVER-16262: Write-conflict during map-reduce operations
+(function() {
+    "use strict";
+
+    load('jstests/libs/parallelTester.js');
+
+    var makeDoc = function(keyLimit, valueLimit) {
+	return {
+	    _id: ObjectId(),
+	    key: Random.randInt(keyLimit),
+	    value: Random.randInt(valueLimit)
+	};
+    };
+
+    var main = function() {
+
+	function mapper() {
+	    var obj = {};
+	    obj[this.value] = 1;
+	    emit(this.key, obj);
+	}
+
+	function reducer(key, values) {
+	    var res = {};
+
+	    values.forEach(function(obj) {
+		Object.keys(obj).forEach(function(value) {
+		    if (!res.hasOwnProperty(value)) {
+			res[value] = 0;
+		    }
+		    res[value] += obj[value];
+		});
+	    });
+
+	    return res;
+	}
+
+	for (var i = 0; i < 10; i++) {
+	    // Have all threads combine their results into the same collection
+	    var res = db.source.mapReduce(mapper, reducer, { out: { reduce: 'dest' } });
+	    assert.commandWorked(res);
+	}
+    };
+
+    var numDocs = 200;
+    var bulk = db.source.initializeUnorderedBulkOp();
+    var i;
+    for (i = 0; i < numDocs; ++i) {
+	var doc = makeDoc(numDocs / 100, numDocs / 10);
+	bulk.insert(doc);
+    }
+
+    var res = bulk.execute();
+    assert.writeOK(res);
+    assert.eq(numDocs, res.nInserted);
+
+    db.dest.drop();
+    assert.commandWorked(db.createCollection('dest'));
+
+    var numThreads = 6;
+    var t = [];
+    for (i = 0; i < numThreads - 1; ++i) {
+	t[i] = new ScopedThread(main);
+	t[i].start();
+    }
+
+    main();
+    for (i = 0; i < numThreads - 1; ++i) {
+	t[i].join();
+    }
+}());