// Doles out all the work to the writer pool threads and waits for them to complete
void SyncTail::multiApply( std::deque<BSONObj>& ops, MultiSyncApplyFunc applyFunc ) {
// Use a ThreadPool to prefetch all the operations in a batch.
prefetchOps(ops);
std::vector< std::vector<BSONObj> > writerVectors(theReplSet->replWriterThreadCount);
fillWriterVectors(ops, &writerVectors);
LOG(2) << "replication batch size is " << ops.size() << endl;
// We must grab this because we're going to grab write locks later.
// We hold this mutex the entire time we're writing; it doesn't matter
// because all readers are blocked anyway.
SimpleMutex::scoped_lock fsynclk(filesLockedFsync);
// stop all readers until we're done
Lock::ParallelBatchWriterMode pbwm;
applyOps(writerVectors, applyFunc);
}
// Applies a batch of oplog entries, by using a set of threads to apply the operations and then
// writes the oplog entries to the local oplog.
OpTime SyncTail::multiApply(OperationContext* txn, const OpQueue& ops) {
invariant(_applyFunc);
if (getGlobalServiceContext()->getGlobalStorageEngine()->isMmapV1()) {
// Use a ThreadPool to prefetch all the operations in a batch.
prefetchOps(ops.getDeque(), &_prefetcherPool);
}
std::vector<std::vector<BSONObj>> writerVectors(replWriterThreadCount);
fillWriterVectors(txn, ops.getDeque(), &writerVectors);
LOG(2) << "replication batch size is " << ops.getDeque().size() << endl;
// We must grab this because we're going to grab write locks later.
// We hold this mutex the entire time we're writing; it doesn't matter
// because all readers are blocked anyway.
stdx::lock_guard<SimpleMutex> fsynclk(filesLockedFsync);
// stop all readers until we're done
Lock::ParallelBatchWriterMode pbwm(txn->lockState());
ReplicationCoordinator* replCoord = getGlobalReplicationCoordinator();
if (replCoord->getMemberState().primary() && !replCoord->isWaitingForApplierToDrain()) {
severe() << "attempting to replicate ops while primary";
fassertFailed(28527);
}
applyOps(writerVectors, &_writerPool, _applyFunc, this);
OpTime lastOpTime;
{
ON_BLOCK_EXIT([&] { _writerPool.join(); });
std::vector<BSONObj> raws;
raws.reserve(ops.getDeque().size());
for (auto&& op : ops.getDeque()) {
raws.emplace_back(op.raw);
}
lastOpTime = writeOpsToOplog(txn, raws);
if (inShutdown()) {
return OpTime();
}
}
// We have now written all database writes and updated the oplog to match.
return lastOpTime;
}