1 files changed, 56 insertions, 0 deletions
diff --git a/jstests/sharding/server6179.js b/jstests/sharding/server6179.js
new file mode 100644
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+++ b/jstests/sharding/server6179.js
@@ -0,0 +1,56 @@
+// SERVER-6179: support for two $groups in sharded agg
+// @tags: [
+//   requires_sharding,
+//   requires_spawning_own_processes,
+// ]
+(function() {
+'use strict';
+
+var s = new ShardingTest({shards: 2});
+
+assert.commandWorked(s.s0.adminCommand({enablesharding: "test"}));
+s.ensurePrimaryShard('test', s.shard1.shardName);
+assert.commandWorked(s.s0.adminCommand({shardcollection: "test.data", key: {_id: 1}}));
+
+var d = s.getDB("test");
+
+// Insert _id values 0 - 99
+var N = 100;
+
+var bulkOp = d.data.initializeOrderedBulkOp();
+for (var i = 0; i < N; ++i) {
+    bulkOp.insert({_id: i, i: i % 10});
+}
+bulkOp.execute();
+
+// Split the data into 3 chunks
+assert.commandWorked(s.s0.adminCommand({split: "test.data", middle: {_id: 33}}));
+assert.commandWorked(s.s0.adminCommand({split: "test.data", middle: {_id: 66}}));
+
+// Migrate the middle chunk to another shard
+assert.commandWorked(s.s0.adminCommand(
+    {movechunk: "test.data", find: {_id: 50}, to: s.getOther(s.getPrimaryShard("test")).name}));
+
+// Check that we get results rather than an error
+var result = d.data
+                 .aggregate({$group: {_id: '$_id', i: {$first: '$i'}}},
+                            {$group: {_id: '$i', avg_id: {$avg: '$_id'}}},
+                            {$sort: {_id: 1}})
+                 .toArray();
+var expected = [
+    {"_id": 0, "avg_id": 45},
+    {"_id": 1, "avg_id": 46},
+    {"_id": 2, "avg_id": 47},
+    {"_id": 3, "avg_id": 48},
+    {"_id": 4, "avg_id": 49},
+    {"_id": 5, "avg_id": 50},
+    {"_id": 6, "avg_id": 51},
+    {"_id": 7, "avg_id": 52},
+    {"_id": 8, "avg_id": 53},
+    {"_id": 9, "avg_id": 54}
+];
+
+assert.eq(result, expected);
+
+s.stop();
+})();