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/**
* This test confirms that after sharding a collection with some pre-existing data,
* the resulting chunks aren't auto-split too aggressively.
*
* @tags: [requires_persistence]
*/
(function() {
'use strict';
load('jstests/sharding/autosplit_include.js');
var s = new ShardingTest({
name: "shard_existing_coll_chunk_count",
shards: 1,
mongos: 1,
other: {enableAutoSplit: true},
});
assert.commandWorked(s.s.adminCommand({enablesharding: "test"}));
var collNum = 0;
var overhead = Object.bsonsize({_id: ObjectId(), i: 1, pad: ""});
var getNumberChunks = function(ns) {
return s.getDB("config").getCollection("chunks").count({ns});
};
var runCase = function(opts) {
// Expected options.
assert.gte(opts.docSize, 0);
assert.gte(opts.stages.length, 2);
// Compute padding.
if (opts.docSize < overhead) {
var pad = "";
} else {
var pad = (new Array(opts.docSize - overhead + 1)).join(' ');
}
collNum++;
var db = s.getDB("test");
var collName = "coll" + collNum;
var coll = db.getCollection(collName);
var i = 0;
var limit = 0;
var stageNum = 0;
var stage = opts.stages[stageNum];
// Insert initial docs.
var bulk = coll.initializeUnorderedBulkOp();
limit += stage.numDocsToInsert;
for (; i < limit; i++) {
bulk.insert({i, pad});
}
assert.commandWorked(bulk.execute());
// Create shard key index.
assert.commandWorked(coll.createIndex({i: 1}));
// Shard collection.
assert.commandWorked(s.s.adminCommand({shardcollection: coll.getFullName(), key: {i: 1}}));
// Confirm initial number of chunks.
var numChunks = getNumberChunks(coll.getFullName());
assert.eq(numChunks,
stage.expectedNumChunks,
'in ' + coll.getFullName() + ' expected ' + stage.expectedNumChunks +
' initial chunks, but found ' + numChunks + '\nopts: ' + tojson(opts) +
'\nchunks:\n' + s.getChunksString(coll.getFullName()));
// Do the rest of the stages.
for (stageNum = 1; stageNum < opts.stages.length; stageNum++) {
stage = opts.stages[stageNum];
// Insert the later docs (one at a time, to maximise the autosplit effects).
limit += stage.numDocsToInsert;
for (; i < limit; i++) {
coll.insert({i, pad});
waitForOngoingChunkSplits(s);
}
// Confirm number of chunks for this stage.
var numChunks = getNumberChunks(coll.getFullName());
assert.gte(numChunks,
stage.expectedNumChunks,
'in ' + coll.getFullName() + ' expected ' + stage.expectedNumChunks +
' chunks for stage ' + stageNum + ', but found ' + numChunks + '\nopts: ' +
tojson(opts) + '\nchunks:\n' + s.getChunksString(coll.getFullName()));
}
};
// Original problematic case.
runCase({
docSize: 0,
stages: [
{numDocsToInsert: 20000, expectedNumChunks: 1},
{numDocsToInsert: 7, expectedNumChunks: 1},
{numDocsToInsert: 1000, expectedNumChunks: 1},
],
});
// Original problematic case (worse).
runCase({
docSize: 0,
stages: [
{numDocsToInsert: 90000, expectedNumChunks: 1},
{numDocsToInsert: 7, expectedNumChunks: 1},
{numDocsToInsert: 1000, expectedNumChunks: 1},
],
});
// Pathological case #1.
runCase({
docSize: 522,
stages: [
{numDocsToInsert: 8191, expectedNumChunks: 1},
{numDocsToInsert: 2, expectedNumChunks: 1},
{numDocsToInsert: 1000, expectedNumChunks: 1},
],
});
// Pathological case #2.
runCase({
docSize: 522,
stages: [
{numDocsToInsert: 8192, expectedNumChunks: 1},
{numDocsToInsert: 8192, expectedNumChunks: 1},
],
});
// Lower chunksize to 1MB, and restart the mongod for it to take. We also
// need to restart mongos for the case of the last-lts suite where the
// shard is also last-lts.
assert.commandWorked(
s.getDB("config").getCollection("settings").update({_id: "chunksize"}, {$set: {value: 1}}, {
upsert: true
}));
s.restartMongos(0);
s.restartShardRS(0);
// Original problematic case, scaled down to smaller chunksize.
runCase({
docSize: 0,
stages: [
{numDocsToInsert: 10000, expectedNumChunks: 1},
{numDocsToInsert: 10, expectedNumChunks: 1},
{numDocsToInsert: 20, expectedNumChunks: 1},
{numDocsToInsert: 40, expectedNumChunks: 1},
{numDocsToInsert: 1000, expectedNumChunks: 1},
],
});
// Docs just smaller than half chunk size.
runCase({
docSize: 510 * 1024,
stages: [
{numDocsToInsert: 10, expectedNumChunks: 6},
{numDocsToInsert: 10, expectedNumChunks: 10},
],
});
// Docs just larger than half chunk size.
runCase({
docSize: 514 * 1024,
stages: [
{numDocsToInsert: 10, expectedNumChunks: 10},
{numDocsToInsert: 10, expectedNumChunks: 18},
],
});
s.stop();
})();
|
