1 files changed, 85 insertions, 0 deletions
diff --git a/jstests/sharding/autosplit_heuristics.js b/jstests/sharding/autosplit_heuristics.js
new file mode 100644
index 00000000000..6618dd329a5
--- /dev/null
+++ b/jstests/sharding/autosplit_heuristics.js
@@ -0,0 +1,85 @@
+//
+// Tests autosplitting heuristics, and that the heuristic counting of chunk sizes
+// works as expected even after splitting.
+//
+
+var st = new ShardingTest({ shards : 1, 
+                            mongos : 1, 
+                            other : { mongosOptions : { chunkSize : 1, verbose : 2 }}});
+
+// The balancer may interfere unpredictably with the chunk moves/splits depending on timing.
+st.stopBalancer();
+
+// Test is not valid for debug build, heuristics get all mangled by debug reload behavior
+var isDebugBuild = st.s0.getDB( "admin" ).serverBuildInfo().debug;
+
+if ( !isDebugBuild ) {
+
+var mongos = st.s0;
+var config = mongos.getDB("config");
+var admin = mongos.getDB("admin");
+var coll = mongos.getCollection("foo.hashBar");
+
+printjson(admin.runCommand({ enableSharding : coll.getDB() + "" }));
+printjson(admin.runCommand({ shardCollection : coll + "", key : { _id : 1 } }));
+
+var numChunks = 10;
+
+// Split off the low and high chunks, to get non-special-case behavior
+printjson( admin.runCommand({ split : coll + "", middle : { _id : 0 } }) );
+printjson( admin.runCommand({ split : coll + "", middle : { _id : numChunks + 1 } }) );
+
+// Split all the other chunks, and an extra chunk
+// We need the extra chunk to compensate for the fact that the chunk differ resets the highest
+// chunk's (i.e. the last-split-chunk's) data count on reload.
+for (var i = 1; i < numChunks + 1; i++) {
+    printjson( admin.runCommand({ split : coll + "", middle : { _id : i } }) );
+}
+
+jsTest.log("Setup collection...");
+st.printShardingStatus(true);
+
+var approxSize = Object.bsonsize({ _id : 0.0 });
+
+jsTest.log("Starting inserts of approx size: " + approxSize + "...");
+
+var chunkSizeBytes = 1024 * 1024;
+
+// We insert slightly more than the max number of docs per chunk, to test
+// if resetting the chunk size happens during reloads.  If the size is 
+// reset, we'd expect to split less, since the first split would then
+// disable further splits (statistically, since the decision is randomized).
+// We choose 1.4 since split attempts happen about once every 1/5 chunksize,
+// and we want to be sure we def get a split attempt at a full chunk.
+var insertsForSplit = Math.ceil((chunkSizeBytes * 1.4) / approxSize);
+var totalInserts = insertsForSplit * numChunks;
+
+printjson({ chunkSizeBytes : chunkSizeBytes,
+            insertsForSplit : insertsForSplit,
+            totalInserts : totalInserts });
+
+// Insert enough docs to trigger splits into all chunks
+var bulk = coll.initializeUnorderedBulkOp();
+for (var i = 0; i < totalInserts; i++) {
+    bulk.insert({ _id : i % numChunks + (i / totalInserts) });
+}
+assert.writeOK(bulk.execute());
+
+jsTest.log("Inserts completed...");
+
+st.printShardingStatus(true);
+printjson(coll.stats());
+
+// Check that all chunks (except the two extreme chunks)
+// have been split at least once + 1 extra chunk as reload buffer
+assert.gte(config.chunks.count(), numChunks * 2 + 3);
+
+jsTest.log("DONE!");
+
+}
+else {
+   jsTest.log( "Disabled test in debug builds." );
+}
+
+st.stop();
+