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/**
* Copyright (C) 2008-2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kSharding
#include "mongo/platform/basic.h"
#include "mongo/s/chunk.h"
#include "mongo/platform/random.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
namespace {
// Test whether we should split once data * kSplitCheckInterval > chunkSize (approximately)
PseudoRandom prng(static_cast<int64_t>(time(0)));
// Assume user has 64MB chunkSize setting. It is ok if this assumption is wrong since it is only
// a heuristic.
const int64_t kMaxDataWritten = 64 / Chunk::kSplitTestFactor;
/**
* Generates a random value for _dataWritten so that a mongos restart wouldn't cause delay in
* splitting.
*/
int64_t mkDataWritten() {
return prng.nextInt64(kMaxDataWritten);
}
} // namespace
ChunkInfo::ChunkInfo(const ChunkType& from)
: _range(from.getMin(), from.getMax()),
_shardId(from.getShard()),
_lastmod(from.getVersion()),
_history(from.getHistory()),
_jumbo(from.getJumbo()),
_dataWritten(mkDataWritten()) {
invariant(from.validate());
if (!_history.empty()) {
invariant(_shardId == _history.front().getShard());
}
}
const ShardId& ChunkInfo::getShardIdAt(const boost::optional<Timestamp>& ts) const {
// This chunk was refreshed from FCV 3.6 config server so it doesn't have history
if (_history.empty()) {
// TODO: SERVER-34619 - add uassert
return _shardId;
}
// If the tiemstamp is not provided than we return the latest shardid
if (!ts) {
invariant(_shardId == _history.front().getShard());
return _history.front().getShard();
}
for (const auto& h : _history) {
if (h.getValidAfter() <= ts) {
return h.getShard();
}
}
uasserted(ErrorCodes::StaleChunkHistory,
str::stream() << "Cant find shardId the chunk belonged to at cluster time "
<< ts.get().toString());
}
bool ChunkInfo::containsKey(const BSONObj& shardKey) const {
return getMin().woCompare(shardKey) <= 0 && shardKey.woCompare(getMax()) < 0;
}
uint64_t ChunkInfo::getBytesWritten() const {
return _dataWritten;
}
uint64_t ChunkInfo::addBytesWritten(uint64_t bytesWrittenIncrement) {
_dataWritten += bytesWrittenIncrement;
return _dataWritten;
}
void ChunkInfo::clearBytesWritten() {
_dataWritten = 0;
}
bool ChunkInfo::shouldSplit(uint64_t desiredChunkSize, bool minIsInf, bool maxIsInf) const {
// If this chunk is at either end of the range, trigger auto-split at 10% less data written in
// order to trigger the top-chunk optimization.
const uint64_t splitThreshold = (minIsInf || maxIsInf)
? static_cast<uint64_t>((double)desiredChunkSize * 0.9)
: desiredChunkSize;
// Check if there are enough estimated bytes written to warrant a split
return _dataWritten >= splitThreshold / Chunk::kSplitTestFactor;
}
std::string ChunkInfo::toString() const {
return str::stream() << ChunkType::shard() << ": " << _shardId << ", " << ChunkType::lastmod()
<< ": " << _lastmod.toString() << ", " << _range.toString();
}
void ChunkInfo::markAsJumbo() {
_jumbo = true;
}
} // namespace mongo
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