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/**
* Copyright (C) 2008 10gen 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.
*/
#pragma once
#include <boost/optional.hpp>
#include <deque>
#include "mongo/base/status.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/db/repl/minvalid.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/db/storage/mmap_v1/dur.h"
#include "mongo/stdx/functional.h"
#include "mongo/util/concurrency/old_thread_pool.h"
namespace mongo {
class Database;
class OperationContext;
namespace repl {
class BackgroundSyncInterface;
class ReplicationCoordinator;
class OpTime;
/**
* "Normal" replica set syncing
*/
class SyncTail {
public:
using MultiSyncApplyFunc = stdx::function<void(const std::vector<BSONObj>& ops, SyncTail* st)>;
/**
* Type of function that takes a non-command op and applies it locally.
* Used for applying from an oplog.
* Last boolean argument 'inSteadyStateReplication' converts some updates to upserts for
* idempotency reasons.
* Returns failure status if the op was an update that could not be applied.
*/
using ApplyOperationInLockFn =
stdx::function<Status(OperationContext*, Database*, const BSONObj&, bool)>;
/**
* Type of function that takes a command op and applies it locally.
* Used for applying from an oplog.
* Returns failure status if the op that could not be applied.
*/
using ApplyCommandInLockFn = stdx::function<Status(OperationContext*, const BSONObj&, bool)>;
/**
* Type of function to increment "repl.apply.ops" server status metric.
*/
using IncrementOpsAppliedStatsFn = stdx::function<void()>;
SyncTail(BackgroundSyncInterface* q, MultiSyncApplyFunc func);
virtual ~SyncTail();
/**
* Applies the operation that is in param o.
* Functions for applying operations/commands and increment server status counters may
* be overridden for testing.
*/
static Status syncApply(OperationContext* txn,
const BSONObj& o,
bool inSteadyStateReplication,
ApplyOperationInLockFn applyOperationInLock,
ApplyCommandInLockFn applyCommandInLock,
IncrementOpsAppliedStatsFn incrementOpsAppliedStats);
static Status syncApply(OperationContext* txn, const BSONObj& o, bool inSteadyStateReplication);
void oplogApplication(StorageInterface* storageInterface);
bool peek(BSONObj* obj);
/**
* A parsed oplog entry.
*
* This only includes the fields used by the code using this object at the time this was
* written. As more code uses this, more fields should be added.
*
* All unowned members (such as StringDatas and BSONElements) point into the raw BSON.
* All StringData members are guaranteed to be NUL terminated.
*/
struct OplogEntry {
explicit OplogEntry(const BSONObj& raw);
BSONObj raw; // Owned.
StringData ns = "";
StringData opType = "";
BSONElement version;
BSONElement o;
BSONElement o2;
BSONElement ts;
};
class OpQueue {
public:
OpQueue() : _size(0) {}
size_t getSize() const {
return _size;
}
const std::deque<OplogEntry>& getDeque() const {
return _deque;
}
void push_back(OplogEntry&& op) {
_size += op.raw.objsize();
_deque.push_back(std::move(op));
}
bool empty() const {
return _deque.empty();
}
const OplogEntry& back() const {
invariant(!_deque.empty());
return _deque.back();
}
const OplogEntry& front() const {
invariant(!_deque.empty());
return _deque.front();
}
private:
std::deque<OplogEntry> _deque;
size_t _size;
};
struct BatchLimits {
size_t bytes = replBatchLimitBytes;
size_t ops = replBatchLimitOperations;
// If provided, the batch will not include any operations with timestamps after this point.
// This is intended for implementing slaveDelay, so it should be some number of seconds
// before now.
boost::optional<Date_t> slaveDelayLatestTimestamp = {};
};
/**
* Attempts to pop an OplogEntry off the BGSync queue and add it to ops.
*
* Returns true if the (possibly empty) batch in ops should be ended and a new one started.
* If ops is empty on entry and nothing can be added yet, will wait up to a second before
* returning true.
*/
bool tryPopAndWaitForMore(OperationContext* txn, OpQueue* ops, const BatchLimits& limits);
/**
* Fetch a single document referenced in the operation from the sync source.
*/
virtual BSONObj getMissingDoc(OperationContext* txn, Database* db, const BSONObj& o);
/**
* If applyOperation_inlock should be called again after an update fails.
*/
virtual bool shouldRetry(OperationContext* txn, const BSONObj& o);
void setHostname(const std::string& hostname);
/**
* This variable determines the number of writer threads SyncTail will have. It has a default
* value, which varies based on architecture and can be overridden using the
* "replWriterThreadCount" server parameter.
*/
static int replWriterThreadCount;
protected:
// Cap the batches using the limit on journal commits.
// This works out to be 100 MB (64 bit) or 50 MB (32 bit)
static const unsigned int replBatchLimitBytes = dur::UncommittedBytesLimit;
static const unsigned int replBatchLimitOperations = 5000;
// Apply a batch of operations, using multiple threads.
// If boundries is supplied, will update minValid document at begin and end of batch.
// Returns the last OpTime applied during the apply batch, ops.end["ts"] basically.
OpTime multiApply(OperationContext* txn, const OpQueue& ops);
private:
class OpQueueBatcher;
std::string _hostname;
BackgroundSyncInterface* _networkQueue;
// Function to use during applyOps
MultiSyncApplyFunc _applyFunc;
// persistent pool of worker threads for writing ops to the databases
OldThreadPool _writerPool;
// persistent pool of worker threads for prefetching
OldThreadPool _prefetcherPool;
};
// These free functions are used by the thread pool workers to write ops to the db.
void multiSyncApply(const std::vector<BSONObj>& ops, SyncTail* st);
void multiInitialSyncApply(const std::vector<BSONObj>& ops, SyncTail* st);
Status multiInitialSyncApply_noAbort(OperationContext* txn,
const std::vector<BSONObj>& ops,
SyncTail* st);
} // namespace repl
} // namespace mongo
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