diff options
Diffstat (limited to 'src/mongo/s/chunk.cpp')
| -rw-r--r-- | src/mongo/s/chunk.cpp | 1184 |
1 files changed, 576 insertions, 608 deletions
diff --git a/src/mongo/s/chunk.cpp b/src/mongo/s/chunk.cpp index 5e475771c07..ede622930f5 100644 --- a/src/mongo/s/chunk.cpp +++ b/src/mongo/s/chunk.cpp @@ -54,721 +54,689 @@ namespace mongo { - using std::shared_ptr; - using std::unique_ptr; - using std::map; - using std::ostringstream; - using std::set; - using std::string; - using std::stringstream; - using std::vector; +using std::shared_ptr; +using std::unique_ptr; +using std::map; +using std::ostringstream; +using std::set; +using std::string; +using std::stringstream; +using std::vector; namespace { - const int kTooManySplitPoints = 4; +const int kTooManySplitPoints = 4; - /** - * Attempts to move the given chunk to another shard. - * - * Returns true if the chunk was actually moved. - */ - bool tryMoveToOtherShard(const ChunkManager& manager, const ChunkType& chunk) { - // reload sharding metadata before starting migration - ChunkManagerPtr chunkMgr = manager.reload(false /* just reloaded in mulitsplit */); +/** + * Attempts to move the given chunk to another shard. + * + * Returns true if the chunk was actually moved. + */ +bool tryMoveToOtherShard(const ChunkManager& manager, const ChunkType& chunk) { + // reload sharding metadata before starting migration + ChunkManagerPtr chunkMgr = manager.reload(false /* just reloaded in mulitsplit */); - ShardInfoMap shardInfo; - Status loadStatus = DistributionStatus::populateShardInfoMap(&shardInfo); + ShardInfoMap shardInfo; + Status loadStatus = DistributionStatus::populateShardInfoMap(&shardInfo); - if (!loadStatus.isOK()) { - warning() << "failed to load shard metadata while trying to moveChunk after " - << "auto-splitting" << causedBy(loadStatus); - return false; - } + if (!loadStatus.isOK()) { + warning() << "failed to load shard metadata while trying to moveChunk after " + << "auto-splitting" << causedBy(loadStatus); + return false; + } - if (shardInfo.size() < 2) { - LOG(0) << "no need to move top chunk since there's only 1 shard"; - return false; - } + if (shardInfo.size() < 2) { + LOG(0) << "no need to move top chunk since there's only 1 shard"; + return false; + } - map<string, vector<ChunkType>> shardToChunkMap; - DistributionStatus::populateShardToChunksMap(shardInfo, *chunkMgr, &shardToChunkMap); + map<string, vector<ChunkType>> shardToChunkMap; + DistributionStatus::populateShardToChunksMap(shardInfo, *chunkMgr, &shardToChunkMap); - StatusWith<string> tagStatus = grid.catalogManager()->getTagForChunk(manager.getns(), - chunk); - if (!tagStatus.isOK()) { - warning() << "Not auto-moving chunk because of an error encountered while " - << "checking tag for chunk: " << tagStatus.getStatus(); - return false; - } + StatusWith<string> tagStatus = grid.catalogManager()->getTagForChunk(manager.getns(), chunk); + if (!tagStatus.isOK()) { + warning() << "Not auto-moving chunk because of an error encountered while " + << "checking tag for chunk: " << tagStatus.getStatus(); + return false; + } - DistributionStatus chunkDistribution(shardInfo, shardToChunkMap); - const string newLocation( - chunkDistribution.getBestReceieverShard(tagStatus.getValue())); + DistributionStatus chunkDistribution(shardInfo, shardToChunkMap); + const string newLocation(chunkDistribution.getBestReceieverShard(tagStatus.getValue())); - if (newLocation.empty()) { - LOG(1) << "recently split chunk: " << chunk - << " but no suitable shard to move to"; - return false; - } + if (newLocation.empty()) { + LOG(1) << "recently split chunk: " << chunk << " but no suitable shard to move to"; + return false; + } - if (chunk.getShard() == newLocation) { - // if this is the best shard, then we shouldn't do anything. - LOG(1) << "recently split chunk: " << chunk - << " already in the best shard"; - return false; - } + if (chunk.getShard() == newLocation) { + // if this is the best shard, then we shouldn't do anything. + LOG(1) << "recently split chunk: " << chunk << " already in the best shard"; + return false; + } - ChunkPtr toMove = chunkMgr->findIntersectingChunk(chunk.getMin()); + ChunkPtr toMove = chunkMgr->findIntersectingChunk(chunk.getMin()); - if (!(toMove->getMin() == chunk.getMin() && toMove->getMax() == chunk.getMax())) { - LOG(1) << "recently split chunk: " << chunk - << " modified before we could migrate " << toMove->toString(); - return false; - } + if (!(toMove->getMin() == chunk.getMin() && toMove->getMax() == chunk.getMax())) { + LOG(1) << "recently split chunk: " << chunk << " modified before we could migrate " + << toMove->toString(); + return false; + } - log() << "moving chunk (auto): " << toMove->toString() << " to: " << newLocation; + log() << "moving chunk (auto): " << toMove->toString() << " to: " << newLocation; - shared_ptr<Shard> newShard = grid.shardRegistry()->getShard(newLocation); - if (!newShard) { - warning() << "Newly selected shard " << newLocation << " could not be found."; - return false; - } + shared_ptr<Shard> newShard = grid.shardRegistry()->getShard(newLocation); + if (!newShard) { + warning() << "Newly selected shard " << newLocation << " could not be found."; + return false; + } - BSONObj res; - WriteConcernOptions noThrottle; - if (!toMove->moveAndCommit(newShard->getId(), - Chunk::MaxChunkSize, - &noThrottle, /* secondaryThrottle */ - false, /* waitForDelete - small chunk, no need */ - 0, /* maxTimeMS - don't time out */ - res)) { - msgassertedNoTrace(10412, str::stream() << "moveAndCommit failed: " << res); - } + BSONObj res; + WriteConcernOptions noThrottle; + if (!toMove->moveAndCommit(newShard->getId(), + Chunk::MaxChunkSize, + &noThrottle, /* secondaryThrottle */ + false, /* waitForDelete - small chunk, no need */ + 0, /* maxTimeMS - don't time out */ + res)) { + msgassertedNoTrace(10412, str::stream() << "moveAndCommit failed: " << res); + } - // update our config - manager.reload(); + // update our config + manager.reload(); - return true; - } + return true; +} -} // namespace +} // namespace - long long Chunk::MaxChunkSize = 1024 * 1024 * 64; - int Chunk::MaxObjectPerChunk = 250000; +long long Chunk::MaxChunkSize = 1024 * 1024 * 64; +int Chunk::MaxObjectPerChunk = 250000; - // Can be overridden from command line - bool Chunk::ShouldAutoSplit = true; +// Can be overridden from command line +bool Chunk::ShouldAutoSplit = true; - Chunk::Chunk(const ChunkManager * manager, BSONObj from) - : _manager(manager), _lastmod(0, 0, OID()), _dataWritten(mkDataWritten()) - { - string ns = from.getStringField(ChunkType::ns().c_str()); - _shardId = from.getStringField(ChunkType::shard().c_str()); +Chunk::Chunk(const ChunkManager* manager, BSONObj from) + : _manager(manager), _lastmod(0, 0, OID()), _dataWritten(mkDataWritten()) { + string ns = from.getStringField(ChunkType::ns().c_str()); + _shardId = from.getStringField(ChunkType::shard().c_str()); - _lastmod = ChunkVersion::fromBSON(from[ChunkType::DEPRECATED_lastmod()]); - verify( _lastmod.isSet() ); + _lastmod = ChunkVersion::fromBSON(from[ChunkType::DEPRECATED_lastmod()]); + verify(_lastmod.isSet()); - _min = from.getObjectField(ChunkType::min().c_str()).getOwned(); - _max = from.getObjectField(ChunkType::max().c_str()).getOwned(); - - _jumbo = from[ChunkType::jumbo()].trueValue(); + _min = from.getObjectField(ChunkType::min().c_str()).getOwned(); + _max = from.getObjectField(ChunkType::max().c_str()).getOwned(); - uassert( 10170 , "Chunk needs a ns" , ! ns.empty() ); - uassert( 13327 , "Chunk ns must match server ns" , ns == _manager->getns() ); + _jumbo = from[ChunkType::jumbo()].trueValue(); - { - const auto shard = grid.shardRegistry()->getShard(_shardId); - uassert(10171, "Chunk needs a server", shard); - } + uassert(10170, "Chunk needs a ns", !ns.empty()); + uassert(13327, "Chunk ns must match server ns", ns == _manager->getns()); - uassert( 10172 , "Chunk needs a min" , ! _min.isEmpty() ); - uassert( 10173 , "Chunk needs a max" , ! _max.isEmpty() ); + { + const auto shard = grid.shardRegistry()->getShard(_shardId); + uassert(10171, "Chunk needs a server", shard); } - Chunk::Chunk(const ChunkManager * info, - const BSONObj& min, - const BSONObj& max, - const ShardId& shardId, - ChunkVersion lastmod) - : _manager(info), - _min(min), - _max(max), - _shardId(shardId), - _lastmod(lastmod), - _jumbo(false), - _dataWritten(mkDataWritten()) - {} + uassert(10172, "Chunk needs a min", !_min.isEmpty()); + uassert(10173, "Chunk needs a max", !_max.isEmpty()); +} + +Chunk::Chunk(const ChunkManager* info, + const BSONObj& min, + const BSONObj& max, + const ShardId& shardId, + ChunkVersion lastmod) + : _manager(info), + _min(min), + _max(max), + _shardId(shardId), + _lastmod(lastmod), + _jumbo(false), + _dataWritten(mkDataWritten()) {} + +int Chunk::mkDataWritten() { + PseudoRandom r(static_cast<int64_t>(time(0))); + return r.nextInt32(MaxChunkSize / ChunkManager::SplitHeuristics::splitTestFactor); +} + +bool Chunk::containsKey(const BSONObj& shardKey) const { + return getMin().woCompare(shardKey) <= 0 && shardKey.woCompare(getMax()) < 0; +} + +bool ChunkRange::containsKey(const BSONObj& shardKey) const { + // same as Chunk method + return getMin().woCompare(shardKey) <= 0 && shardKey.woCompare(getMax()) < 0; +} + +bool Chunk::_minIsInf() const { + return 0 == _manager->getShardKeyPattern().getKeyPattern().globalMin().woCompare(getMin()); +} + +bool Chunk::_maxIsInf() const { + return 0 == _manager->getShardKeyPattern().getKeyPattern().globalMax().woCompare(getMax()); +} + +BSONObj Chunk::_getExtremeKey(bool doSplitAtLower) const { + Query q; + if (doSplitAtLower) { + q.sort(_manager->getShardKeyPattern().toBSON()); + } else { + // need to invert shard key pattern to sort backwards + // TODO: make a helper in ShardKeyPattern? + + BSONObj k = _manager->getShardKeyPattern().toBSON(); + BSONObjBuilder r; + + BSONObjIterator i(k); + while (i.more()) { + BSONElement e = i.next(); + uassert(10163, "can only handle numbers here - which i think is correct", e.isNumber()); + r.append(e.fieldName(), -1 * e.number()); + } - int Chunk::mkDataWritten() { - PseudoRandom r(static_cast<int64_t>(time(0))); - return r.nextInt32( MaxChunkSize / ChunkManager::SplitHeuristics::splitTestFactor ); + q.sort(r.obj()); } - bool Chunk::containsKey( const BSONObj& shardKey ) const { - return getMin().woCompare( shardKey ) <= 0 && shardKey.woCompare( getMax() ) < 0; - } + // find the extreme key + ScopedDbConnection conn(_getShardConnectionString()); + BSONObj end; + + if (doSplitAtLower) { + // Splitting close to the lower bound means that the split point will be the + // upper bound. Chunk range upper bounds are exclusive so skip a document to + // make the lower half of the split end up with a single document. + unique_ptr<DBClientCursor> cursor = conn->query(_manager->getns(), + q, + 1, /* nToReturn */ + 1 /* nToSkip */); - bool ChunkRange::containsKey( const BSONObj& shardKey ) const { - // same as Chunk method - return getMin().woCompare( shardKey ) <= 0 && shardKey.woCompare( getMax() ) < 0; + if (cursor->more()) { + end = cursor->next().getOwned(); + } + } else { + end = conn->findOne(_manager->getns(), q); } - bool Chunk::_minIsInf() const { - return 0 == - _manager->getShardKeyPattern().getKeyPattern().globalMin().woCompare(getMin()); + conn.done(); + if (end.isEmpty()) + return BSONObj(); + return _manager->getShardKeyPattern().extractShardKeyFromDoc(end); +} + +void Chunk::pickMedianKey(BSONObj& medianKey) const { + // Ask the mongod holding this chunk to figure out the split points. + ScopedDbConnection conn(_getShardConnectionString()); + BSONObj result; + BSONObjBuilder cmd; + cmd.append("splitVector", _manager->getns()); + cmd.append("keyPattern", _manager->getShardKeyPattern().toBSON()); + cmd.append("min", getMin()); + cmd.append("max", getMax()); + cmd.appendBool("force", true); + BSONObj cmdObj = cmd.obj(); + + if (!conn->runCommand("admin", cmdObj, result)) { + conn.done(); + ostringstream os; + os << "splitVector command (median key) failed: " << result; + uassert(13503, os.str(), 0); } - bool Chunk::_maxIsInf() const { - return 0 == - _manager->getShardKeyPattern().getKeyPattern().globalMax().woCompare(getMax()); + BSONObjIterator it(result.getObjectField("splitKeys")); + if (it.more()) { + medianKey = it.next().Obj().getOwned(); } - BSONObj Chunk::_getExtremeKey(bool doSplitAtLower) const { - Query q; - if (doSplitAtLower) { - q.sort( _manager->getShardKeyPattern().toBSON() ); - } - else { - // need to invert shard key pattern to sort backwards - // TODO: make a helper in ShardKeyPattern? - - BSONObj k = _manager->getShardKeyPattern().toBSON(); - BSONObjBuilder r; - - BSONObjIterator i(k); - while( i.more() ) { - BSONElement e = i.next(); - uassert( 10163 , "can only handle numbers here - which i think is correct" , e.isNumber() ); - r.append( e.fieldName() , -1 * e.number() ); - } + conn.done(); +} + +void Chunk::pickSplitVector(vector<BSONObj>& splitPoints, + long long chunkSize /* bytes */, + int maxPoints, + int maxObjs) const { + // Ask the mongod holding this chunk to figure out the split points. + ScopedDbConnection conn(_getShardConnectionString()); + BSONObj result; + BSONObjBuilder cmd; + cmd.append("splitVector", _manager->getns()); + cmd.append("keyPattern", _manager->getShardKeyPattern().toBSON()); + cmd.append("min", getMin()); + cmd.append("max", getMax()); + cmd.append("maxChunkSizeBytes", chunkSize); + cmd.append("maxSplitPoints", maxPoints); + cmd.append("maxChunkObjects", maxObjs); + BSONObj cmdObj = cmd.obj(); + + if (!conn->runCommand("admin", cmdObj, result)) { + conn.done(); + ostringstream os; + os << "splitVector command failed: " << result; + uassert(13345, os.str(), 0); + } - q.sort( r.obj() ); + BSONObjIterator it(result.getObjectField("splitKeys")); + while (it.more()) { + splitPoints.push_back(it.next().Obj().getOwned()); + } + conn.done(); +} + +void Chunk::determineSplitPoints(bool atMedian, vector<BSONObj>* splitPoints) const { + // if splitting is not obligatory we may return early if there are not enough data + // we cap the number of objects that would fall in the first half (before the split point) + // the rationale is we'll find a split point without traversing all the data + if (atMedian) { + BSONObj medianKey; + pickMedianKey(medianKey); + if (!medianKey.isEmpty()) + splitPoints->push_back(medianKey); + } else { + long long chunkSize = _manager->getCurrentDesiredChunkSize(); + + // Note: One split point for every 1/2 chunk size. + const int estNumSplitPoints = _dataWritten / chunkSize * 2; + if (estNumSplitPoints >= kTooManySplitPoints) { + // The current desired chunk size will split the chunk into lots of small chunks + // (At the worst case, this can result into thousands of chunks); so check and + // see if a bigger value can be used. + + chunkSize = std::min(_dataWritten, Chunk::MaxChunkSize); + } + + pickSplitVector(*splitPoints, chunkSize, 0, MaxObjectPerChunk); + + if (splitPoints->size() <= 1) { + // no split points means there isn't enough data to split on + // 1 split point means we have between half the chunk size to full chunk size + // so we shouldn't split + splitPoints->clear(); } + } +} - // find the extreme key - ScopedDbConnection conn(_getShardConnectionString()); - BSONObj end; - - if (doSplitAtLower) { - // Splitting close to the lower bound means that the split point will be the - // upper bound. Chunk range upper bounds are exclusive so skip a document to - // make the lower half of the split end up with a single document. - unique_ptr<DBClientCursor> cursor = conn->query(_manager->getns(), - q, - 1, /* nToReturn */ - 1 /* nToSkip */); - - if (cursor->more()) { - end = cursor->next().getOwned(); - } - } - else { - end = conn->findOne(_manager->getns(), q); - } +Status Chunk::split(SplitPointMode mode, size_t* resultingSplits, BSONObj* res) const { + size_t dummy; + if (resultingSplits == NULL) { + resultingSplits = &dummy; + } - conn.done(); - if ( end.isEmpty() ) - return BSONObj(); - return _manager->getShardKeyPattern().extractShardKeyFromDoc(end); - } - - void Chunk::pickMedianKey( BSONObj& medianKey ) const { - // Ask the mongod holding this chunk to figure out the split points. - ScopedDbConnection conn(_getShardConnectionString()); - BSONObj result; - BSONObjBuilder cmd; - cmd.append( "splitVector" , _manager->getns() ); - cmd.append( "keyPattern" , _manager->getShardKeyPattern().toBSON() ); - cmd.append( "min" , getMin() ); - cmd.append( "max" , getMax() ); - cmd.appendBool( "force" , true ); - BSONObj cmdObj = cmd.obj(); - - if ( ! conn->runCommand( "admin" , cmdObj , result )) { - conn.done(); - ostringstream os; - os << "splitVector command (median key) failed: " << result; - uassert( 13503 , os.str() , 0 ); - } + bool atMedian = mode == Chunk::atMedian; + vector<BSONObj> splitPoints; - BSONObjIterator it( result.getObjectField( "splitKeys" ) ); - if ( it.more() ) { - medianKey = it.next().Obj().getOwned(); + determineSplitPoints(atMedian, &splitPoints); + if (splitPoints.empty()) { + string msg; + if (atMedian) { + msg = "cannot find median in chunk, possibly empty"; + } else { + msg = "chunk not full enough to trigger auto-split"; } - conn.done(); + LOG(1) << msg; + return Status(ErrorCodes::CannotSplit, msg); } - void Chunk::pickSplitVector(vector<BSONObj>& splitPoints, - long long chunkSize /* bytes */, - int maxPoints, - int maxObjs) const { - // Ask the mongod holding this chunk to figure out the split points. - ScopedDbConnection conn(_getShardConnectionString()); - BSONObj result; - BSONObjBuilder cmd; - cmd.append( "splitVector" , _manager->getns() ); - cmd.append( "keyPattern" , _manager->getShardKeyPattern().toBSON() ); - cmd.append( "min" , getMin() ); - cmd.append( "max" , getMax() ); - cmd.append( "maxChunkSizeBytes" , chunkSize ); - cmd.append( "maxSplitPoints" , maxPoints ); - cmd.append( "maxChunkObjects" , maxObjs ); - BSONObj cmdObj = cmd.obj(); - - if ( ! conn->runCommand( "admin" , cmdObj , result )) { - conn.done(); - ostringstream os; - os << "splitVector command failed: " << result; - uassert( 13345 , os.str() , 0 ); - } - - BSONObjIterator it( result.getObjectField( "splitKeys" ) ); - while ( it.more() ) { - splitPoints.push_back( it.next().Obj().getOwned() ); + // We assume that if the chunk being split is the first (or last) one on the collection, + // this chunk is likely to see more insertions. Instead of splitting mid-chunk, we use + // the very first (or last) key as a split point. + // This heuristic is skipped for "special" shard key patterns that are not likely to + // produce monotonically increasing or decreasing values (e.g. hashed shard keys). + if (mode == Chunk::autoSplitInternal && + KeyPattern::isOrderedKeyPattern(_manager->getShardKeyPattern().toBSON())) { + if (_minIsInf()) { + BSONObj key = _getExtremeKey(true); + if (!key.isEmpty()) { + splitPoints[0] = key.getOwned(); + } + } else if (_maxIsInf()) { + BSONObj key = _getExtremeKey(false); + if (!key.isEmpty()) { + splitPoints.pop_back(); + splitPoints.push_back(key); + } } - conn.done(); } - void Chunk::determineSplitPoints(bool atMedian, vector<BSONObj>* splitPoints) const { - // if splitting is not obligatory we may return early if there are not enough data - // we cap the number of objects that would fall in the first half (before the split point) - // the rationale is we'll find a split point without traversing all the data - if ( atMedian ) { - BSONObj medianKey; - pickMedianKey( medianKey ); - if ( ! medianKey.isEmpty() ) - splitPoints->push_back( medianKey ); - } - else { - long long chunkSize = _manager->getCurrentDesiredChunkSize(); + // Normally, we'd have a sound split point here if the chunk is not empty. + // It's also a good place to sanity check. + if (_min == splitPoints.front()) { + string msg(str::stream() << "not splitting chunk " << toString() << ", split point " + << splitPoints.front() << " is exactly on chunk bounds"); + log() << msg; + return Status(ErrorCodes::CannotSplit, msg); + } - // Note: One split point for every 1/2 chunk size. - const int estNumSplitPoints = _dataWritten / chunkSize * 2; - if (estNumSplitPoints >= kTooManySplitPoints) { - // The current desired chunk size will split the chunk into lots of small chunks - // (At the worst case, this can result into thousands of chunks); so check and - // see if a bigger value can be used. + if (_max == splitPoints.back()) { + string msg(str::stream() << "not splitting chunk " << toString() << ", split point " + << splitPoints.back() << " is exactly on chunk bounds"); + log() << msg; + return Status(ErrorCodes::CannotSplit, msg); + } - chunkSize = std::min(_dataWritten, Chunk::MaxChunkSize); - } + Status status = multiSplit(splitPoints, res); + *resultingSplits = splitPoints.size(); + return status; +} + +Status Chunk::multiSplit(const vector<BSONObj>& m, BSONObj* res) const { + const size_t maxSplitPoints = 8192; + + uassert(10165, "can't split as shard doesn't have a manager", _manager); + uassert(13332, "need a split key to split chunk", !m.empty()); + uassert(13333, "can't split a chunk in that many parts", m.size() < maxSplitPoints); + uassert(13003, "can't split a chunk with only one distinct value", _min.woCompare(_max)); + + ScopedDbConnection conn(_getShardConnectionString()); + + BSONObjBuilder cmd; + cmd.append("splitChunk", _manager->getns()); + cmd.append("keyPattern", _manager->getShardKeyPattern().toBSON()); + cmd.append("min", getMin()); + cmd.append("max", getMax()); + cmd.append("from", getShardId()); + cmd.append("splitKeys", m); + cmd.append("configdb", grid.catalogManager()->connectionString().toString()); + cmd.append("epoch", _manager->getVersion().epoch()); + BSONObj cmdObj = cmd.obj(); + + BSONObj dummy; + if (res == NULL) { + res = &dummy; + } - pickSplitVector(*splitPoints, chunkSize, 0, MaxObjectPerChunk); + if (!conn->runCommand("admin", cmdObj, *res)) { + string msg(str::stream() << "splitChunk failed - cmd: " << cmdObj << " result: " << *res); + warning() << msg; + conn.done(); - if ( splitPoints->size() <= 1 ) { - // no split points means there isn't enough data to split on - // 1 split point means we have between half the chunk size to full chunk size - // so we shouldn't split - splitPoints->clear(); - } - } + return Status(ErrorCodes::SplitFailed, msg); } - Status Chunk::split(SplitPointMode mode, size_t* resultingSplits, BSONObj* res) const { - size_t dummy; - if (resultingSplits == NULL) { - resultingSplits = &dummy; - } - - bool atMedian = mode == Chunk::atMedian; - vector<BSONObj> splitPoints; + conn.done(); - determineSplitPoints( atMedian, &splitPoints ); - if (splitPoints.empty()) { - string msg; - if (atMedian) { - msg = "cannot find median in chunk, possibly empty"; - } - else { - msg = "chunk not full enough to trigger auto-split"; - } + // force reload of config + _manager->reload(); - LOG(1) << msg; - return Status(ErrorCodes::CannotSplit, msg); - } + return Status::OK(); +} - // We assume that if the chunk being split is the first (or last) one on the collection, - // this chunk is likely to see more insertions. Instead of splitting mid-chunk, we use - // the very first (or last) key as a split point. - // This heuristic is skipped for "special" shard key patterns that are not likely to - // produce monotonically increasing or decreasing values (e.g. hashed shard keys). - if (mode == Chunk::autoSplitInternal && - KeyPattern::isOrderedKeyPattern(_manager->getShardKeyPattern().toBSON())) { - - if (_minIsInf()) { - BSONObj key = _getExtremeKey(true); - if (!key.isEmpty()) { - splitPoints[0] = key.getOwned(); - } - } - else if (_maxIsInf()) { - BSONObj key = _getExtremeKey(false); - if (!key.isEmpty()) { - splitPoints.pop_back(); - splitPoints.push_back(key); - } - } - } +bool Chunk::moveAndCommit(const ShardId& toShardId, + long long chunkSize /* bytes */, + const WriteConcernOptions* writeConcern, + bool waitForDelete, + int maxTimeMS, + BSONObj& res) const { + uassert(10167, "can't move shard to its current location!", getShardId() != toShardId); - // Normally, we'd have a sound split point here if the chunk is not empty. - // It's also a good place to sanity check. - if ( _min == splitPoints.front() ) { - string msg(str::stream() << "not splitting chunk " << toString() - << ", split point " << splitPoints.front() - << " is exactly on chunk bounds"); - log() << msg; - return Status(ErrorCodes::CannotSplit, msg); - } + log() << "moving chunk ns: " << _manager->getns() << " moving ( " << toString() << ") " + << getShardId() << " -> " << toShardId; - if ( _max == splitPoints.back() ) { - string msg(str::stream() << "not splitting chunk " << toString() - << ", split point " << splitPoints.back() - << " is exactly on chunk bounds"); - log() << msg; - return Status(ErrorCodes::CannotSplit, msg); - } + const auto from = grid.shardRegistry()->getShard(getShardId()); - Status status = multiSplit(splitPoints, res); - *resultingSplits = splitPoints.size(); - return status; + BSONObjBuilder builder; + builder.append("moveChunk", _manager->getns()); + builder.append("from", from->getConnString().toString()); + { + const auto toShard = grid.shardRegistry()->getShard(toShardId); + builder.append("to", toShard->getConnString().toString()); + } + // NEEDED FOR 2.0 COMPATIBILITY + builder.append("fromShard", from->getId()); + builder.append("toShard", toShardId); + /////////////////////////////// + builder.append("min", _min); + builder.append("max", _max); + builder.append("maxChunkSizeBytes", chunkSize); + builder.append("configdb", grid.catalogManager()->connectionString().toString()); + + // For legacy secondary throttle setting. + bool secondaryThrottle = true; + if (writeConcern && writeConcern->wNumNodes <= 1 && writeConcern->wMode.empty()) { + secondaryThrottle = false; } - Status Chunk::multiSplit(const vector<BSONObj>& m, BSONObj* res) const { - const size_t maxSplitPoints = 8192; - - uassert( 10165 , "can't split as shard doesn't have a manager" , _manager ); - uassert( 13332 , "need a split key to split chunk" , !m.empty() ); - uassert( 13333 , "can't split a chunk in that many parts", m.size() < maxSplitPoints ); - uassert( 13003 , "can't split a chunk with only one distinct value" , _min.woCompare(_max) ); + builder.append("secondaryThrottle", secondaryThrottle); - ScopedDbConnection conn(_getShardConnectionString()); + if (secondaryThrottle && writeConcern) { + builder.append("writeConcern", writeConcern->toBSON()); + } - BSONObjBuilder cmd; - cmd.append( "splitChunk" , _manager->getns() ); - cmd.append( "keyPattern" , _manager->getShardKeyPattern().toBSON() ); - cmd.append( "min" , getMin() ); - cmd.append( "max" , getMax() ); - cmd.append( "from" , getShardId()); - cmd.append( "splitKeys" , m ); - cmd.append("configdb", grid.catalogManager()->connectionString().toString()); - cmd.append("epoch", _manager->getVersion().epoch()); - BSONObj cmdObj = cmd.obj(); + builder.append("waitForDelete", waitForDelete); + builder.append(LiteParsedQuery::cmdOptionMaxTimeMS, maxTimeMS); + builder.append("epoch", _manager->getVersion().epoch()); - BSONObj dummy; - if (res == NULL) { - res = &dummy; - } + ScopedDbConnection fromconn(from->getConnString()); + bool worked = fromconn->runCommand("admin", builder.done(), res); + fromconn.done(); - if (!conn->runCommand("admin", cmdObj, *res)) { - string msg(str::stream() << "splitChunk failed - cmd: " - << cmdObj << " result: " << *res); - warning() << msg; - conn.done(); + LOG(worked ? 1 : 0) << "moveChunk result: " << res; - return Status(ErrorCodes::SplitFailed, msg); - } + // if succeeded, needs to reload to pick up the new location + // if failed, mongos may be stale + // reload is excessive here as the failure could be simply because collection metadata is taken + _manager->reload(); - conn.done(); - - // force reload of config - _manager->reload(); - - return Status::OK(); - } - - bool Chunk::moveAndCommit(const ShardId& toShardId, - long long chunkSize /* bytes */, - const WriteConcernOptions* writeConcern, - bool waitForDelete, - int maxTimeMS, - BSONObj& res) const { - uassert(10167, - "can't move shard to its current location!", - getShardId() != toShardId); - - log() << "moving chunk ns: " << _manager->getns() << " moving ( " << toString() << ") " - << getShardId() << " -> " << toShardId; - - const auto from = grid.shardRegistry()->getShard(getShardId()); - - BSONObjBuilder builder; - builder.append("moveChunk", _manager->getns()); - builder.append("from", from->getConnString().toString()); - { - const auto toShard = grid.shardRegistry()->getShard(toShardId); - builder.append("to", toShard->getConnString().toString()); - } - // NEEDED FOR 2.0 COMPATIBILITY - builder.append("fromShard", from->getId()); - builder.append("toShard", toShardId); - /////////////////////////////// - builder.append("min", _min); - builder.append("max", _max); - builder.append("maxChunkSizeBytes", chunkSize); - builder.append("configdb", grid.catalogManager()->connectionString().toString()); - - // For legacy secondary throttle setting. - bool secondaryThrottle = true; - if (writeConcern && - writeConcern->wNumNodes <= 1 && - writeConcern->wMode.empty()) { - secondaryThrottle = false; - } + return worked; +} - builder.append("secondaryThrottle", secondaryThrottle); +bool Chunk::splitIfShould(long dataWritten) const { + dassert(ShouldAutoSplit); + LastError::Disabled d(&LastError::get(cc())); - if (secondaryThrottle && writeConcern) { - builder.append("writeConcern", writeConcern->toBSON()); + try { + _dataWritten += dataWritten; + int splitThreshold = getManager()->getCurrentDesiredChunkSize(); + if (_minIsInf() || _maxIsInf()) { + splitThreshold = (int)((double)splitThreshold * .9); } - builder.append("waitForDelete", waitForDelete); - builder.append(LiteParsedQuery::cmdOptionMaxTimeMS, maxTimeMS); - builder.append("epoch", _manager->getVersion().epoch()); - - ScopedDbConnection fromconn(from->getConnString()); - bool worked = fromconn->runCommand("admin", builder.done(), res); - fromconn.done(); + if (_dataWritten < splitThreshold / ChunkManager::SplitHeuristics::splitTestFactor) + return false; - LOG( worked ? 1 : 0 ) << "moveChunk result: " << res; + if (!getManager()->_splitHeuristics._splitTickets.tryAcquire()) { + LOG(1) << "won't auto split because not enough tickets: " << getManager()->getns(); + return false; + } + TicketHolderReleaser releaser(&(getManager()->_splitHeuristics._splitTickets)); - // if succeeded, needs to reload to pick up the new location - // if failed, mongos may be stale - // reload is excessive here as the failure could be simply because collection metadata is taken - _manager->reload(); + // this is a bit ugly + // we need it so that mongos blocks for the writes to actually be committed + // this does mean mongos has more back pressure than mongod alone + // since it nots 100% tcp queue bound + // this was implicit before since we did a splitVector on the same socket + ShardConnection::sync(); - return worked; - } + LOG(1) << "about to initiate autosplit: " << *this << " dataWritten: " << _dataWritten + << " splitThreshold: " << splitThreshold; - bool Chunk::splitIfShould( long dataWritten ) const { - dassert( ShouldAutoSplit ); - LastError::Disabled d(&LastError::get(cc())); + BSONObj res; + size_t splitCount = 0; + Status status = split(Chunk::autoSplitInternal, &splitCount, &res); + if (!status.isOK()) { + // Split would have issued a message if we got here. This means there wasn't enough + // data to split, so don't want to try again until considerable more data + _dataWritten = 0; + return false; + } - try { - _dataWritten += dataWritten; - int splitThreshold = getManager()->getCurrentDesiredChunkSize(); - if (_minIsInf() || _maxIsInf()) { - splitThreshold = (int)((double)splitThreshold * .9); - } + if (_maxIsInf() || _minIsInf()) { + // we don't want to reset _dataWritten since we kind of want to check the other side right away + } else { + // we're splitting, so should wait a bit + _dataWritten = 0; + } - if ( _dataWritten < splitThreshold / ChunkManager::SplitHeuristics::splitTestFactor ) - return false; - - if ( ! getManager()->_splitHeuristics._splitTickets.tryAcquire() ) { - LOG(1) << "won't auto split because not enough tickets: " << getManager()->getns(); - return false; - } - TicketHolderReleaser releaser( &(getManager()->_splitHeuristics._splitTickets) ); - - // this is a bit ugly - // we need it so that mongos blocks for the writes to actually be committed - // this does mean mongos has more back pressure than mongod alone - // since it nots 100% tcp queue bound - // this was implicit before since we did a splitVector on the same socket - ShardConnection::sync(); - - LOG(1) << "about to initiate autosplit: " << *this << " dataWritten: " << _dataWritten << " splitThreshold: " << splitThreshold; - - BSONObj res; - size_t splitCount = 0; - Status status = split(Chunk::autoSplitInternal, - &splitCount, - &res); + bool shouldBalance = grid.getConfigShouldBalance(); + if (shouldBalance) { + auto status = grid.catalogManager()->getCollection(_manager->getns()); if (!status.isOK()) { - // Split would have issued a message if we got here. This means there wasn't enough - // data to split, so don't want to try again until considerable more data - _dataWritten = 0; + log() << "Auto-split for " << _manager->getns() + << " failed to load collection metadata due to " << status.getStatus(); return false; } - - if (_maxIsInf() || _minIsInf()) { - // we don't want to reset _dataWritten since we kind of want to check the other side right away - } - else { - // we're splitting, so should wait a bit - _dataWritten = 0; - } - - bool shouldBalance = grid.getConfigShouldBalance(); - if (shouldBalance) { - auto status = grid.catalogManager()->getCollection(_manager->getns()); - if (!status.isOK()) { - log() << "Auto-split for " << _manager->getns() - << " failed to load collection metadata due to " << status.getStatus(); - return false; - } - shouldBalance = status.getValue().getAllowBalance(); - } + shouldBalance = status.getValue().getAllowBalance(); + } - log() << "autosplitted " << _manager->getns() - << " shard: " << toString() - << " into " << (splitCount + 1) - << " (splitThreshold " << splitThreshold << ")" + log() << "autosplitted " << _manager->getns() << " shard: " << toString() << " into " + << (splitCount + 1) << " (splitThreshold " << splitThreshold << ")" #ifdef MONGO_CONFIG_DEBUG_BUILD - << " size: " << getPhysicalSize() // slow - but can be useful when debugging + << " size: " << getPhysicalSize() // slow - but can be useful when debugging #endif - << ( res["shouldMigrate"].eoo() ? "" : (string)" (migrate suggested" + - ( shouldBalance ? ")" : ", but no migrations allowed)" ) ); - - // Top chunk optimization - try to move the top chunk out of this shard - // to prevent the hot spot from staying on a single shard. This is based on - // the assumption that succeeding inserts will fall on the top chunk. - BSONElement shouldMigrate = res["shouldMigrate"]; // not in mongod < 1.9.1 but that is ok - if ( ! shouldMigrate.eoo() && shouldBalance ){ - BSONObj range = shouldMigrate.embeddedObject(); - - ChunkType chunkToMove; - { - const auto shard = grid.shardRegistry()->getShard(getShardId()); - chunkToMove.setShard(shard->toString()); - } - chunkToMove.setMin(range["min"].embeddedObject()); - chunkToMove.setMax(range["max"].embeddedObject()); - - tryMoveToOtherShard(*_manager, chunkToMove); + << (res["shouldMigrate"].eoo() ? "" : (string) " (migrate suggested" + + (shouldBalance ? ")" : ", but no migrations allowed)")); + + // Top chunk optimization - try to move the top chunk out of this shard + // to prevent the hot spot from staying on a single shard. This is based on + // the assumption that succeeding inserts will fall on the top chunk. + BSONElement shouldMigrate = res["shouldMigrate"]; // not in mongod < 1.9.1 but that is ok + if (!shouldMigrate.eoo() && shouldBalance) { + BSONObj range = shouldMigrate.embeddedObject(); + + ChunkType chunkToMove; + { + const auto shard = grid.shardRegistry()->getShard(getShardId()); + chunkToMove.setShard(shard->toString()); } + chunkToMove.setMin(range["min"].embeddedObject()); + chunkToMove.setMax(range["max"].embeddedObject()); - return true; - + tryMoveToOtherShard(*_manager, chunkToMove); } - catch ( DBException& e ) { - // TODO: Make this better - there are lots of reasons a split could fail - // Random so that we don't sync up with other failed splits - _dataWritten = mkDataWritten(); - - // if the collection lock is taken (e.g. we're migrating), it is fine for the split to fail. - warning() << "could not autosplit collection " << _manager->getns() << causedBy( e ); - return false; - } - } - - const ConnectionString& Chunk::_getShardConnectionString() const { - const auto shard = grid.shardRegistry()->getShard(getShardId()); - return shard->getConnString(); - } - - long Chunk::getPhysicalSize() const { - ScopedDbConnection conn(_getShardConnectionString()); + return true; - BSONObj result; - uassert( 10169 , "datasize failed!" , conn->runCommand( "admin" , - BSON( "datasize" << _manager->getns() - << "keyPattern" << _manager->getShardKeyPattern().toBSON() - << "min" << getMin() - << "max" << getMax() - << "maxSize" << ( MaxChunkSize + 1 ) - << "estimate" << true - ) , result ) ); + } catch (DBException& e) { + // TODO: Make this better - there are lots of reasons a split could fail + // Random so that we don't sync up with other failed splits + _dataWritten = mkDataWritten(); - conn.done(); - return (long)result["size"].number(); + // if the collection lock is taken (e.g. we're migrating), it is fine for the split to fail. + warning() << "could not autosplit collection " << _manager->getns() << causedBy(e); + return false; } - - void Chunk::appendShortVersion( const char * name , BSONObjBuilder& b ) const { - BSONObjBuilder bb( b.subobjStart( name ) ); - bb.append(ChunkType::min(), _min); - bb.append(ChunkType::max(), _max); - bb.done(); +} + +const ConnectionString& Chunk::_getShardConnectionString() const { + const auto shard = grid.shardRegistry()->getShard(getShardId()); + return shard->getConnString(); +} + +long Chunk::getPhysicalSize() const { + ScopedDbConnection conn(_getShardConnectionString()); + + BSONObj result; + uassert(10169, + "datasize failed!", + conn->runCommand("admin", + BSON("datasize" << _manager->getns() << "keyPattern" + << _manager->getShardKeyPattern().toBSON() << "min" + << getMin() << "max" << getMax() << "maxSize" + << (MaxChunkSize + 1) << "estimate" << true), + result)); + + conn.done(); + return (long)result["size"].number(); +} + +void Chunk::appendShortVersion(const char* name, BSONObjBuilder& b) const { + BSONObjBuilder bb(b.subobjStart(name)); + bb.append(ChunkType::min(), _min); + bb.append(ChunkType::max(), _max); + bb.done(); +} + +bool Chunk::operator==(const Chunk& s) const { + return _min.woCompare(s._min) == 0 && _max.woCompare(s._max) == 0; +} + +void Chunk::serialize(BSONObjBuilder& to, ChunkVersion myLastMod) { + to.append("_id", genID(_manager->getns(), _min)); + + if (myLastMod.isSet()) { + myLastMod.addToBSON(to, ChunkType::DEPRECATED_lastmod()); + } else if (_lastmod.isSet()) { + _lastmod.addToBSON(to, ChunkType::DEPRECATED_lastmod()); + } else { + verify(0); } - bool Chunk::operator==( const Chunk& s ) const { - return _min.woCompare( s._min ) == 0 && _max.woCompare( s._max ) == 0; - } + to << ChunkType::ns(_manager->getns()); + to << ChunkType::min(_min); + to << ChunkType::max(_max); + to << ChunkType::shard(_shardId); +} - void Chunk::serialize(BSONObjBuilder& to,ChunkVersion myLastMod) { +string Chunk::genID() const { + return genID(_manager->getns(), _min); +} - to.append( "_id" , genID( _manager->getns() , _min ) ); +string Chunk::genID(const string& ns, const BSONObj& o) { + StringBuilder buf; + buf << ns << "-"; - if ( myLastMod.isSet() ) { - myLastMod.addToBSON(to, ChunkType::DEPRECATED_lastmod()); - } - else if ( _lastmod.isSet() ) { - _lastmod.addToBSON(to, ChunkType::DEPRECATED_lastmod()); - } - else { - verify(0); - } - - to << ChunkType::ns(_manager->getns()); - to << ChunkType::min(_min); - to << ChunkType::max(_max); - to << ChunkType::shard(_shardId); + BSONObjIterator i(o); + while (i.more()) { + BSONElement e = i.next(); + buf << e.fieldName() << "_" << e.toString(false, true); } - string Chunk::genID() const { - return genID(_manager->getns(), _min); + return buf.str(); +} + +string Chunk::toString() const { + stringstream ss; + ss << ChunkType::ns() << ": " << _manager->getns() << ", " << ChunkType::shard() << ": " + << _shardId << ", " << ChunkType::DEPRECATED_lastmod() << ": " << _lastmod.toString() << ", " + << ChunkType::min() << ": " << _min << ", " << ChunkType::max() << ": " << _max; + return ss.str(); +} + +void Chunk::markAsJumbo() const { + // set this first + // even if we can't set it in the db + // at least this mongos won't try and keep moving + _jumbo = true; + + Status result = grid.catalogManager()->update(ChunkType::ConfigNS, + BSON(ChunkType::name(genID())), + BSON("$set" << BSON(ChunkType::jumbo(true))), + false, // upsert + false, // multi + NULL); + if (!result.isOK()) { + warning() << "couldn't set jumbo for chunk: " << genID() << result.reason(); } - - string Chunk::genID( const string& ns , const BSONObj& o ) { - StringBuilder buf; - buf << ns << "-"; - - BSONObjIterator i(o); - while ( i.more() ) { - BSONElement e = i.next(); - buf << e.fieldName() << "_" << e.toString(false, true); - } - - return buf.str(); - } - - string Chunk::toString() const { - stringstream ss; - ss << ChunkType::ns() << ": " << _manager->getns() << ", " - << ChunkType::shard() << ": " << _shardId << ", " - << ChunkType::DEPRECATED_lastmod() << ": " << _lastmod.toString() << ", " - << ChunkType::min() << ": " << _min << ", " - << ChunkType::max() << ": " << _max; - return ss.str(); - } - - void Chunk::markAsJumbo() const { - // set this first - // even if we can't set it in the db - // at least this mongos won't try and keep moving - _jumbo = true; - - Status result = grid.catalogManager()->update(ChunkType::ConfigNS, - BSON(ChunkType::name(genID())), - BSON("$set" << BSON(ChunkType::jumbo(true))), - false, // upsert - false, // multi - NULL); - if (!result.isOK()) { - warning() << "couldn't set jumbo for chunk: " << genID() << result.reason(); - } +} + +void Chunk::refreshChunkSize() { + auto chunkSizeSettingsResult = + grid.catalogManager()->getGlobalSettings(SettingsType::ChunkSizeDocKey); + if (!chunkSizeSettingsResult.isOK()) { + log() << chunkSizeSettingsResult.getStatus(); + return; } + SettingsType chunkSizeSettings = chunkSizeSettingsResult.getValue(); + int csize = chunkSizeSettings.getChunkSizeMB(); - void Chunk::refreshChunkSize() { - auto chunkSizeSettingsResult = - grid.catalogManager()->getGlobalSettings(SettingsType::ChunkSizeDocKey); - if (!chunkSizeSettingsResult.isOK()) { - log() << chunkSizeSettingsResult.getStatus(); - return; - } - SettingsType chunkSizeSettings = chunkSizeSettingsResult.getValue(); - int csize = chunkSizeSettings.getChunkSizeMB(); - - LOG(1) << "Refreshing MaxChunkSize: " << csize << "MB"; - - if (csize != Chunk::MaxChunkSize/(1024*1024)) { - log() << "MaxChunkSize changing from " << Chunk::MaxChunkSize/(1024*1024) << "MB" - << " to " << csize << "MB"; - } + LOG(1) << "Refreshing MaxChunkSize: " << csize << "MB"; - if ( !setMaxChunkSizeSizeMB( csize ) ) { - warning() << "invalid MaxChunkSize: " << csize; - } + if (csize != Chunk::MaxChunkSize / (1024 * 1024)) { + log() << "MaxChunkSize changing from " << Chunk::MaxChunkSize / (1024 * 1024) << "MB" + << " to " << csize << "MB"; } - bool Chunk::setMaxChunkSizeSizeMB( int newMaxChunkSize ) { - if ( newMaxChunkSize < 1 ) - return false; - if ( newMaxChunkSize > 1024 ) - return false; - MaxChunkSize = newMaxChunkSize * 1024 * 1024; - return true; + if (!setMaxChunkSizeSizeMB(csize)) { + warning() << "invalid MaxChunkSize: " << csize; } - -} // namespace mongo +} + +bool Chunk::setMaxChunkSizeSizeMB(int newMaxChunkSize) { + if (newMaxChunkSize < 1) + return false; + if (newMaxChunkSize > 1024) + return false; + MaxChunkSize = newMaxChunkSize * 1024 * 1024; + return true; +} + +} // namespace mongo |