SERVER-8187 Usability issues with splitting + hashed shard keys

Added new option for splitting keys on a cluster using hashed shard keys.

1 files changed, 84 insertions, 0 deletions

diff --git a/jstests/sharding/hash_basic.js b/jstests/sharding/hash_basic.js
new file mode 100644
index 00000000000..fd3c9bc42a1
--- /dev/null
+++ b/jstests/sharding/hash_basic.js
@@ -0,0 +1,84 @@
+var st = new ShardingTest({ shards: 2, chunkSize: 1, other: { shardOptions: { verbose: 1 }} });
+st.stopBalancer();
+
+var testDB = st.s.getDB('test');
+testDB.adminCommand({ enableSharding: 'test' });
+testDB.adminCommand({ shardCollection: 'test.user', key: { x: 'hashed' }});
+
+var configDB = st.s.getDB('config');
+var chunkCountBefore = configDB.chunks.count();
+assert.gt(chunkCountBefore, 1);
+
+for (var x = 0; x < 1000; x++) {
+    testDB.user.insert({ x: x });
+}
+
+// For debugging
+(function() {
+    var chunkList = configDB.chunks.find().sort({ min: -1 }).toArray();
+    chunkList.forEach(function(chunk) { chunk.count = 0; });
+
+    for (var x = 0; x < 1000; x++) {
+        var hashVal = testDB.adminCommand({ _hashBSONElement: x }).out;
+        var countSet = false;
+
+        for (var y = 0; y < chunkList.length - 2; y++) {
+            var chunkDoc = chunkList[y];
+            if (chunkDoc.min.x <= hashVal) {
+                countSet = true;
+                chunkDoc.count++;
+
+                print('doc in chunk: x [' + x + '], h[' + hashVal +
+                      '], min[' + chunkDoc.min.x +
+                      '], max[' + chunkDoc.max.x + ']');
+                break;
+            }
+        }
+
+        if (!countSet) {
+            chunkDoc = chunkList[chunkList.length - 1];
+            print('doc in chunk: x [' + x + '], h[' + hashVal +
+                  '], min[' + chunkDoc.min.x +
+                  '], max[' + chunkDoc.max.x + ']');
+            chunkDoc.count++;
+        }
+    }
+
+    chunkList.forEach(function(chunkDoc) {
+        print('chunk details: ' + tojson(chunkDoc));
+    });
+});
+
+var chunkDoc = configDB.chunks.find().sort({ min: 1 }).next();
+var min = chunkDoc.min;
+var max = chunkDoc.max;
+
+// Assumption: There are documents in the MinKey chunk, otherwise, splitVector will
+// fail. Note: This chunk will have 267 documents if collection was presplit to 4.
+var cmdRes = testDB.adminCommand({ split: 'test.user', bounds: [ min, max ]});
+assert(cmdRes.ok, 'split on bounds failed on chunk[' + tojson(chunkDoc) +
+    ']: ' + tojson(cmdRes));
+
+chunkDoc = configDB.chunks.find().sort({ min: 1 }).skip(1).next();
+var middle = chunkDoc.min + 1000000;
+
+cmdRes = testDB.adminCommand({ split: 'test.user', middle: { x: middle }});
+assert(cmdRes.ok, 'split failed with middle [' + middle + ']: ' + tojson(cmdRes));
+
+cmdRes = testDB.adminCommand({ split: 'test.user', find: { x: 7 }});
+assert(cmdRes.ok, 'split failed with find: ' + tojson(cmdRes));
+
+var chunkList = configDB.chunks.find().sort({ min: 1 }).toArray();
+assert.eq(chunkCountBefore + 3, chunkList.length);
+
+chunkList.forEach(function(chunkToMove) {
+    var toShard = configDB.shards.findOne({ _id: { $ne: chunkToMove.shard }})._id;
+
+    var cmdRes = testDB.adminCommand({ moveChunk: 'test.user',
+        bounds: [ chunkToMove.min, chunkToMove.max ],
+        to: toShard, _waitForDelete: true });
+    assert(cmdRes.ok, 'Cmd failed: ' + tojson(cmdRes));
+});
+
+st.stop();
+