jstests/sharding/hash_shard_num_chunks.js


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// Hash sharding with initial chunk count set.
// @tags : [ hashed ]

var s = new ShardingTest({ shards : 3, mongos : 1, verbose : 1 });
var dbname = "test";
var coll = "foo";
var db = s.getDB(dbname);
db.adminCommand({ enablesharding : dbname });

//for simplicity turn off balancer
s.stopBalancer();

var res = db.adminCommand({ shardcollection : dbname + "." + coll,
                             key : { a : "hashed" },
                             numInitialChunks : 500 });
assert.eq(res.ok, 1, "shardcollection didn't work");
db.printShardingStatus();
var numChunks = s.config.chunks.count();
assert.eq(numChunks, 500 , "should be exactly 500 chunks");

var shards = s.config.shards.find();
shards.forEach(
    // check that each shard has one third the numInitialChunks
    function (shard){
        var numChunksOnShard = s.config.chunks.find({"shard" : shard._id}).count();
        assert.gte(numChunksOnShard, Math.floor(500/3));
    }
);

// Check that the collection gets dropped correctly (which doesn't happen if pre-splitting
// fails to create the collection on all shards).
res = db.runCommand({ "drop" : coll });
assert.eq(res.ok, 1, "couldn't drop empty, pre-split collection");

s.stop();