jstests/sharding/hash_shard_num_chunks.js


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// Hash sharding with initial chunk count set.
(function() {
    'use strict';

    var s = new ShardingTest({shards: 3});

    var dbname = "test";
    var coll = "foo";
    var db = s.getDB(dbname);

    assert.commandWorked(db.adminCommand({enablesharding: dbname}));
    s.ensurePrimaryShard(dbname, s.shard1.shardName);

    assert.commandWorked(db.adminCommand(
        {shardcollection: dbname + "." + coll, key: {a: "hashed"}, numInitialChunks: 500}));

    s.printShardingStatus();

    var numChunks = s.config.chunks.count({"ns": "test.foo"});
    assert.eq(numChunks, 500, "should be exactly 500 chunks");

    s.config.shards.find().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).
    assert.commandWorked(db.runCommand({"drop": coll}),
                         "couldn't drop empty, pre-split collection");

    s.stop();
})();