/**
* Copyright (C) 2014-2016 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 .
*
* 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.
*/
#include "mongo/platform/basic.h"
#include "mongo/base/checked_cast.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/database.h"
#include "mongo/db/commands.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/exec/multi_iterator.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/query/cursor_response.h"
#include "mongo/db/service_context.h"
#include "mongo/stdx/memory.h"
namespace mongo {
using std::unique_ptr;
using std::string;
using stdx::make_unique;
namespace {
class ParallelCollectionScanCmd : public Command {
public:
struct ExtentInfo {
ExtentInfo(RecordId dl, size_t s) : diskLoc(dl), size(s) {}
RecordId diskLoc;
size_t size;
};
ParallelCollectionScanCmd() : Command("parallelCollectionScan") {}
virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
return false;
}
virtual bool slaveOk() const {
return true;
}
bool supportsReadConcern() const final {
return true;
}
ReadWriteType getReadWriteType() const {
return ReadWriteType::kCommand;
}
virtual Status checkAuthForCommand(Client* client,
const std::string& dbname,
const BSONObj& cmdObj) {
ActionSet actions;
actions.addAction(ActionType::find);
Privilege p(parseResourcePattern(dbname, cmdObj), actions);
if (AuthorizationSession::get(client)->isAuthorizedForPrivilege(p))
return Status::OK();
return Status(ErrorCodes::Unauthorized, "Unauthorized");
}
virtual bool run(OperationContext* opCtx,
const string& dbname,
BSONObj& cmdObj,
int options,
string& errmsg,
BSONObjBuilder& result) {
const NamespaceString ns(parseNsCollectionRequired(dbname, cmdObj));
AutoGetCollectionForReadCommand ctx(opCtx, ns);
Collection* collection = ctx.getCollection();
if (!collection)
return appendCommandStatus(result,
Status(ErrorCodes::NamespaceNotFound,
str::stream() << "ns does not exist: " << ns.ns()));
size_t numCursors = static_cast(cmdObj["numCursors"].numberInt());
if (numCursors == 0 || numCursors > 10000)
return appendCommandStatus(result,
Status(ErrorCodes::BadValue,
str::stream()
<< "numCursors has to be between 1 and 10000"
<< " was: "
<< numCursors));
auto iterators = collection->getManyCursors(opCtx);
if (iterators.size() < numCursors) {
numCursors = iterators.size();
}
std::vector> execs;
for (size_t i = 0; i < numCursors; i++) {
unique_ptr ws = make_unique();
unique_ptr mis =
make_unique(opCtx, ws.get(), collection);
// Takes ownership of 'ws' and 'mis'.
auto statusWithPlanExecutor = PlanExecutor::make(
opCtx, std::move(ws), std::move(mis), collection, PlanExecutor::YIELD_AUTO);
invariant(statusWithPlanExecutor.isOK());
execs.push_back(std::move(statusWithPlanExecutor.getValue()));
}
// transfer iterators to executors using a round-robin distribution.
// TODO consider using a common work queue once invalidation issues go away.
for (size_t i = 0; i < iterators.size(); i++) {
auto& planExec = execs[i % execs.size()];
MultiIteratorStage* mis = checked_cast(planExec->getRootStage());
mis->addIterator(std::move(iterators[i]));
}
{
BSONArrayBuilder bucketsBuilder;
for (auto&& exec : execs) {
// The PlanExecutor was registered on construction due to the YIELD_AUTO policy.
// We have to deregister it, as it will be registered with ClientCursor.
exec->deregisterExec();
// Need to save state while yielding locks between now and getMore().
exec->saveState();
exec->detachFromOperationContext();
// Create and regiter a new ClientCursor.
auto pinnedCursor = collection->getCursorManager()->registerCursor(
{exec.release(),
ns.ns(),
opCtx->recoveryUnit()->isReadingFromMajorityCommittedSnapshot()});
pinnedCursor.getCursor()->setLeftoverMaxTimeMicros(
opCtx->getRemainingMaxTimeMicros());
BSONObjBuilder threadResult;
appendCursorResponseObject(
pinnedCursor.getCursor()->cursorid(), ns.ns(), BSONArray(), &threadResult);
threadResult.appendBool("ok", 1);
bucketsBuilder.append(threadResult.obj());
}
result.appendArray("cursors", bucketsBuilder.obj());
}
return true;
}
} parallelCollectionScanCmd;
} // namespace
} // namespace mongo