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// This test runs map reduce from a sharded input collection and outputs it to a sharded
// collection. The test is done in 2 passes - the first pass runs the map reduce and
// outputs it to a non-existing collection. The second pass runs map reduce with the
// collection input twice the size of the first and outputs it to the new sharded
// collection created in the first pass.
var st = new ShardingTest({shards: 2, other: {chunkSize: 1, enableAutoSplit: true}});
var config = st.getDB("config");
st.adminCommand({enablesharding: "test"});
st.ensurePrimaryShard("test", "shard0001");
st.adminCommand({shardcollection: "test.foo", key: {"a": 1}});
var testDB = st.getDB("test");
function map2() {
emit(this.i, {count: 1, y: this.y});
}
function reduce2(key, values) {
return values[0];
}
var numDocs = 0;
var numBatch = 5000;
var str = new Array(1024).join('a');
// Pre split now so we don't have to balance the chunks later.
// M/R is strange in that it chooses the output shards based on currently sharded
// collections in the database. The upshot is that we need a sharded collection on
// both shards in order to ensure M/R will output to two shards.
st.adminCommand({split: 'test.foo', middle: {a: numDocs + numBatch / 2}});
st.adminCommand({moveChunk: 'test.foo', find: {a: numDocs}, to: 'shard0000'});
// Add some more data for input so that chunks will get split further
for (var splitPoint = 0; splitPoint < numBatch; splitPoint += 400) {
testDB.adminCommand({split: 'test.foo', middle: {a: splitPoint}});
}
var bulk = testDB.foo.initializeUnorderedBulkOp();
for (var i = 0; i < numBatch; ++i) {
bulk.insert({a: numDocs + i, y: str, i: numDocs + i});
}
assert.writeOK(bulk.execute());
numDocs += numBatch;
// Do the MapReduce step
jsTest.log("Setup OK: count matches (" + numDocs + ") -- Starting MapReduce");
var res = testDB.foo.mapReduce(map2, reduce2, {out: {replace: "mrShardedOut", sharded: true}});
jsTest.log("MapReduce results:" + tojson(res));
var reduceOutputCount = res.counts.output;
assert.eq(numDocs,
reduceOutputCount,
"MapReduce FAILED: res.counts.output = " + reduceOutputCount + ", should be " + numDocs);
jsTest.log("Checking that all MapReduce output documents are in output collection");
var outColl = testDB["mrShardedOut"];
var outCollCount = outColl.find().itcount();
assert.eq(numDocs,
outCollCount,
"MapReduce FAILED: outColl.find().itcount() = " + outCollCount + ", should be " +
numDocs + ": this may happen intermittently until resolution of SERVER-3627");
// Make sure it's sharded and split
var newNumChunks = config.chunks.count({ns: testDB.mrShardedOut._fullName});
assert.gt(newNumChunks,
1,
"Sharding FAILURE: " + testDB.mrShardedOut._fullName + " has only 1 chunk");
// Check that there are no "jumbo" chunks.
var objSize = Object.bsonsize(testDB.mrShardedOut.findOne());
var docsPerChunk = 1024 * 1024 / objSize * 1.1; // 1MB chunk size + allowance
printShardingStatus(config, true);
config.chunks.find({ns: testDB.mrShardedOut.getFullName()})
.forEach(function(chunkDoc) {
var count =
testDB.mrShardedOut.find({_id: {$gte: chunkDoc.min._id, $lt: chunkDoc.max._id}})
.itcount();
assert.lte(count, docsPerChunk, 'Chunk has too many docs: ' + tojson(chunkDoc));
});
// Check that chunks for the newly created sharded output collection are well distributed.
var shard0Chunks =
config.chunks.find({ns: testDB.mrShardedOut._fullName, shard: 'shard0000'}).count();
var shard1Chunks =
config.chunks.find({ns: testDB.mrShardedOut._fullName, shard: 'shard0001'}).count();
assert.lte(Math.abs(shard0Chunks - shard1Chunks), 1);
jsTest.log('Starting second pass');
st.adminCommand({split: 'test.foo', middle: {a: numDocs + numBatch / 2}});
st.adminCommand({moveChunk: 'test.foo', find: {a: numDocs}, to: 'shard0000'});
// Add some more data for input so that chunks will get split further
for (splitPoint = 0; splitPoint < numBatch; splitPoint += 400) {
testDB.adminCommand({split: 'test.foo', middle: {a: numDocs + splitPoint}});
}
bulk = testDB.foo.initializeUnorderedBulkOp();
for (var i = 0; i < numBatch; ++i) {
bulk.insert({a: numDocs + i, y: str, i: numDocs + i});
}
assert.writeOK(bulk.execute());
jsTest.log("No errors on insert batch.");
numDocs += numBatch;
// Do the MapReduce step
jsTest.log("Setup OK: count matches (" + numDocs + ") -- Starting MapReduce");
res = testDB.foo.mapReduce(map2, reduce2, {out: {replace: "mrShardedOut", sharded: true}});
jsTest.log("MapReduce results:" + tojson(res));
reduceOutputCount = res.counts.output;
assert.eq(numDocs,
reduceOutputCount,
"MapReduce FAILED: res.counts.output = " + reduceOutputCount + ", should be " + numDocs);
jsTest.log("Checking that all MapReduce output documents are in output collection");
outColl = testDB["mrShardedOut"];
outCollCount = outColl.find().itcount();
assert.eq(numDocs,
outCollCount,
"MapReduce FAILED: outColl.find().itcount() = " + outCollCount + ", should be " +
numDocs + ": this may happen intermittently until resolution of SERVER-3627");
// Make sure it's sharded and split
newNumChunks = config.chunks.count({ns: testDB.mrShardedOut._fullName});
assert.gt(newNumChunks,
1,
"Sharding FAILURE: " + testDB.mrShardedOut._fullName + " has only 1 chunk");
printShardingStatus(config, true);
// TODO: fix SERVER-12581
/*
config.chunks.find({ ns: testDB.mrShardedOut.getFullName() }).forEach(function(chunkDoc) {
var count = testDB.mrShardedOut.find({ _id: { $gte: chunkDoc.min._id,
$lt: chunkDoc.max._id }}).itcount();
assert.lte(count, docsPerChunk, 'Chunk has too many docs: ' + tojson(chunkDoc));
});
*/
// Note: No need to check if chunk is balanced. It is the job of the balancer
// to balance chunks.
st.stop();
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