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/**
* Copyright (C) 2019-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/commands.h"
#include "mongo/db/s/balancer/balancer_chunk_selection_policy_impl.h"
#include "mongo/db/s/balancer/cluster_statistics_impl.h"
#include "mongo/db/s/balancer/migration_test_fixture.h"
#include "mongo/platform/random.h"
namespace mongo {
namespace {
const std::string kDbName = "TestDb";
const NamespaceString kNamespace(kDbName, "TestColl");
const int kSizeOnDisk = 1;
class BalancerChunkSelectionTest : public MigrationTestFixture {
protected:
BalancerChunkSelectionTest()
: _random(std::random_device{}()),
_clusterStats(std::make_unique<ClusterStatisticsImpl>(_random)),
_chunkSelectionPolicy(
std::make_unique<BalancerChunkSelectionPolicyImpl>(_clusterStats.get(), _random)) {}
/**
* Sets up mock network to expect a listDatabases command and returns a BSON response with
* a dummy sizeOnDisk.
*/
void expectListDatabasesCommand() {
BSONObjBuilder resultBuilder;
CommandHelpers::appendCommandStatusNoThrow(resultBuilder, Status::OK());
onCommand([&resultBuilder](const RemoteCommandRequest& request) {
ASSERT(request.cmdObj["listDatabases"]);
vector<BSONObj> dbInfos;
BSONObjBuilder b;
b.append("name", kDbName);
b.append("sizeOnDisk", kSizeOnDisk);
b.append("empty", kSizeOnDisk > 0);
resultBuilder.append("databases", dbInfos);
resultBuilder.append("totalSize", kSizeOnDisk);
return resultBuilder.obj();
});
}
/**
* Sets up mock network to expect a serverStatus command and returns a BSON response with
* a dummy version.
*/
void expectServerStatusCommand() {
BSONObjBuilder resultBuilder;
CommandHelpers::appendCommandStatusNoThrow(resultBuilder, Status::OK());
onCommand([&resultBuilder](const RemoteCommandRequest& request) {
ASSERT(request.cmdObj["serverStatus"]);
resultBuilder.append("version", "MONGO_VERSION");
return resultBuilder.obj();
});
}
/**
* Sets up mock network for all the shards to expect the commands executed for computing cluster
* stats, which include listDatabase and serverStatus.
*/
void expectGetStatsCommands(int numShards) {
for (int i = 0; i < numShards; i++) {
expectListDatabasesCommand();
expectServerStatusCommand();
}
}
/**
* Returns a new BSON object with the tags appended.
*/
BSONObj appendTags(const BSONObj shardBSON, std::vector<std::string> tags) {
BSONObjBuilder appendedShardBSON(shardBSON);
BSONArrayBuilder tagsBuilder;
for (auto& tag : tags) {
tagsBuilder.append(tag);
}
tagsBuilder.done();
appendedShardBSON.append("tags", tagsBuilder.arr());
return appendedShardBSON.obj();
}
BalancerRandomSource _random;
std::unique_ptr<ClusterStatistics> _clusterStats;
std::unique_ptr<BalancerChunkSelectionPolicy> _chunkSelectionPolicy;
};
TEST_F(BalancerChunkSelectionTest, TagRangesOverlap) {
// Set up two shards in the metadata.
ASSERT_OK(catalogClient()->insertConfigDocument(
operationContext(), ShardType::ConfigNS, kShard0, kMajorityWriteConcern));
ASSERT_OK(catalogClient()->insertConfigDocument(
operationContext(), ShardType::ConfigNS, kShard1, kMajorityWriteConcern));
// Set up a database and a sharded collection in the metadata.
ChunkVersion version(2, 0, OID::gen());
setUpDatabase(kDbName, kShardId0);
setUpCollection(kNamespace, version);
// Set up one chunk for the collection in the metadata.
ChunkType chunk = setUpChunk(
kNamespace, kKeyPattern.globalMin(), kKeyPattern.globalMax(), kShardId0, version);
auto assertRangeOverlapConflictWhenMoveChunk = [this, &chunk](const StringMap<ChunkRange>&
tagChunkRanges) {
// Set up two zones whose ranges overlap.
setUpTags(kNamespace, tagChunkRanges);
auto future = launchAsync([this, &chunk] {
// Requesting chunks to be relocated requires running commands on each shard to get
// shard statistics. Set up dummy hosts for the source shards.
shardTargeterMock(operationContext(), kShardId0)->setFindHostReturnValue(kShardHost0);
shardTargeterMock(operationContext(), kShardId1)->setFindHostReturnValue(kShardHost1);
auto migrateInfoStatus =
_chunkSelectionPolicy.get()->selectSpecificChunkToMove(operationContext(), chunk);
ASSERT_EQUALS(ErrorCodes::RangeOverlapConflict, migrateInfoStatus.getStatus().code());
});
expectGetStatsCommands(2);
future.default_timed_get();
removeAllTags(kNamespace);
};
assertRangeOverlapConflictWhenMoveChunk(
{{"A", {kKeyPattern.globalMin(), BSON(kPattern << -10)}},
{"B", {BSON(kPattern << -15), kKeyPattern.globalMax()}}});
assertRangeOverlapConflictWhenMoveChunk(
{{"A", {kKeyPattern.globalMin(), BSON(kPattern << -5)}},
{"B", {BSON(kPattern << -10), kKeyPattern.globalMax()}}});
assertRangeOverlapConflictWhenMoveChunk(
{{"A", {kKeyPattern.globalMin(), kKeyPattern.globalMax()}},
{"B", {BSON(kPattern << -15), kKeyPattern.globalMax()}}});
}
TEST_F(BalancerChunkSelectionTest, TagRangeMaxNotAlignedWithChunkMax) {
// Set up two shards in the metadata.
ASSERT_OK(catalogClient()->insertConfigDocument(operationContext(),
ShardType::ConfigNS,
appendTags(kShard0, {"A"}),
kMajorityWriteConcern));
ASSERT_OK(catalogClient()->insertConfigDocument(operationContext(),
ShardType::ConfigNS,
appendTags(kShard1, {"A"}),
kMajorityWriteConcern));
// Set up a database and a sharded collection in the metadata.
ChunkVersion version(2, 0, OID::gen());
setUpDatabase(kDbName, kShardId0);
setUpCollection(kNamespace, version);
// Set up the zone.
setUpTags(kNamespace, {{"A", {kKeyPattern.globalMin(), BSON(kPattern << -10)}}});
auto assertErrorWhenMoveChunk = [this, &version](const std::vector<ChunkRange>& chunkRanges) {
// Give shard0 all the chunks so the cluster is imbalanced.
for (const auto& chunkRange : chunkRanges) {
setUpChunk(kNamespace, chunkRange.getMin(), chunkRange.getMax(), kShardId0, version);
version.incMinor();
}
auto future = launchAsync([this] {
// Requests chunks to be relocated requires running commands on each shard to
// get shard statistics. Set up dummy hosts for the source shards.
shardTargeterMock(operationContext(), kShardId0)->setFindHostReturnValue(kShardHost0);
shardTargeterMock(operationContext(), kShardId1)->setFindHostReturnValue(kShardHost1);
auto candidateChunksStatus =
_chunkSelectionPolicy.get()->selectChunksToMove(operationContext());
ASSERT_OK(candidateChunksStatus.getStatus());
// The balancer does not bubble up the IllegalOperation error, but it is expected
// to postpone the balancing work for the zones with the error until the chunks
// are split appropriately.
ASSERT_EQUALS(0U, candidateChunksStatus.getValue().size());
});
expectGetStatsCommands(2);
future.default_timed_get();
removeAllChunks(kNamespace);
};
assertErrorWhenMoveChunk({{kKeyPattern.globalMin(), BSON(kPattern << -5)},
{BSON(kPattern << -5), kKeyPattern.globalMax()}});
assertErrorWhenMoveChunk({{kKeyPattern.globalMin(), BSON(kPattern << -15)},
{BSON(kPattern << -15), kKeyPattern.globalMax()}});
}
} // namespace
} // namespace mongo
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