/**
* Copyright (C) 2014 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/run_aggregate.h"
#include "mongo/db/curop.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/exec/count.h"
#include "mongo/db/query/explain.h"
#include "mongo/db/query/get_executor.h"
#include "mongo/db/query/plan_summary_stats.h"
#include "mongo/db/query/view_response_formatter.h"
#include "mongo/db/views/resolved_view.h"
#include "mongo/util/log.h"
namespace mongo {
namespace {
using std::unique_ptr;
using std::string;
using std::stringstream;
/**
* Implements the MongoD side of the count command.
*/
class CmdCount : public BasicCommand {
public:
CmdCount() : BasicCommand("count") {}
std::string help() const override {
return "count objects in collection";
}
bool supportsWriteConcern(const BSONObj& cmd) const override {
return false;
}
AllowedOnSecondary secondaryAllowed(ServiceContext* serviceContext) const override {
return Command::AllowedOnSecondary::kOptIn;
}
bool maintenanceOk() const override {
return false;
}
bool adminOnly() const override {
return false;
}
bool supportsReadConcern(const std::string& dbName,
const BSONObj& cmdObj,
repl::ReadConcernLevel level) const override {
return level != repl::ReadConcernLevel::kSnapshotReadConcern;
}
ReadWriteType getReadWriteType() const override {
return ReadWriteType::kRead;
}
Status checkAuthForOperation(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj) const override {
AuthorizationSession* authSession = AuthorizationSession::get(opCtx->getClient());
if (!authSession->isAuthorizedToParseNamespaceElement(cmdObj.firstElement())) {
return Status(ErrorCodes::Unauthorized, "Unauthorized");
}
const auto hasTerm = false;
return authSession->checkAuthForFind(
AutoGetCollection::resolveNamespaceStringOrUUID(
opCtx, CommandHelpers::parseNsOrUUID(dbname, cmdObj)),
hasTerm);
}
Status explain(OperationContext* opCtx,
const OpMsgRequest& opMsgRequest,
ExplainOptions::Verbosity verbosity,
BSONObjBuilder* out) const override {
std::string dbname = opMsgRequest.getDatabase().toString();
const BSONObj& cmdObj = opMsgRequest.body;
// Acquire locks and resolve possible UUID. The RAII object is optional, because in the case
// of a view, the locks need to be released.
boost::optional ctx;
ctx.emplace(opCtx,
CommandHelpers::parseNsOrUUID(dbname, cmdObj),
AutoGetCollection::ViewMode::kViewsPermitted);
const auto nss = ctx->getNss();
const bool isExplain = true;
auto request = CountRequest::parseFromBSON(nss, cmdObj, isExplain);
if (!request.isOK()) {
return request.getStatus();
}
if (ctx->getView()) {
// Relinquish locks. The aggregation command will re-acquire them.
ctx.reset();
auto viewAggregation = request.getValue().asAggregationCommand();
if (!viewAggregation.isOK()) {
return viewAggregation.getStatus();
}
auto viewAggRequest = AggregationRequest::parseFromBSON(
request.getValue().getNs(), viewAggregation.getValue(), verbosity);
if (!viewAggRequest.isOK()) {
return viewAggRequest.getStatus();
}
return runAggregate(opCtx,
viewAggRequest.getValue().getNamespaceString(),
viewAggRequest.getValue(),
viewAggregation.getValue(),
*out);
}
Collection* const collection = ctx->getCollection();
// Prevent chunks from being cleaned up during yields - this allows us to only check the
// version on initial entry into count.
auto rangePreserver = CollectionShardingState::get(opCtx, nss)->getMetadata(opCtx);
auto statusWithPlanExecutor =
getExecutorCount(opCtx, collection, request.getValue(), true /*explain*/);
if (!statusWithPlanExecutor.isOK()) {
return statusWithPlanExecutor.getStatus();
}
auto exec = std::move(statusWithPlanExecutor.getValue());
Explain::explainStages(exec.get(), collection, verbosity, out);
return Status::OK();
}
bool run(OperationContext* opCtx,
const string& dbname,
const BSONObj& cmdObj,
BSONObjBuilder& result) override {
// Acquire locks and resolve possible UUID. The RAII object is optional, because in the case
// of a view, the locks need to be released.
boost::optional ctx;
ctx.emplace(opCtx,
CommandHelpers::parseNsOrUUID(dbname, cmdObj),
AutoGetCollection::ViewMode::kViewsPermitted);
const auto nss = ctx->getNss();
const bool isExplain = false;
auto request = CountRequest::parseFromBSON(nss, cmdObj, isExplain);
uassertStatusOK(request.getStatus());
// Check whether we are allowed to read from this node after acquiring our locks.
auto replCoord = repl::ReplicationCoordinator::get(opCtx);
uassertStatusOK(replCoord->checkCanServeReadsFor(
opCtx, nss, ReadPreferenceSetting::get(opCtx).canRunOnSecondary()));
if (ctx->getView()) {
// Relinquish locks. The aggregation command will re-acquire them.
ctx.reset();
auto viewAggregation = request.getValue().asAggregationCommand();
uassertStatusOK(viewAggregation.getStatus());
BSONObj aggResult = CommandHelpers::runCommandDirectly(
opCtx, OpMsgRequest::fromDBAndBody(dbname, std::move(viewAggregation.getValue())));
uassertStatusOK(ViewResponseFormatter(aggResult).appendAsCountResponse(&result));
return true;
}
Collection* const collection = ctx->getCollection();
// Prevent chunks from being cleaned up during yields - this allows us to only check the
// version on initial entry into count.
auto rangePreserver = CollectionShardingState::get(opCtx, nss)->getMetadata(opCtx);
auto statusWithPlanExecutor =
getExecutorCount(opCtx, collection, request.getValue(), false /*explain*/);
uassertStatusOK(statusWithPlanExecutor.getStatus());
auto exec = std::move(statusWithPlanExecutor.getValue());
// Store the plan summary string in CurOp.
auto curOp = CurOp::get(opCtx);
{
stdx::lock_guard lk(*opCtx->getClient());
curOp->setPlanSummary_inlock(Explain::getPlanSummary(exec.get()));
}
Status execPlanStatus = exec->executePlan();
uassertStatusOK(execPlanStatus);
PlanSummaryStats summaryStats;
Explain::getSummaryStats(*exec, &summaryStats);
if (collection) {
collection->infoCache()->notifyOfQuery(opCtx, summaryStats.indexesUsed);
}
curOp->debug().setPlanSummaryMetrics(summaryStats);
if (curOp->shouldDBProfile()) {
BSONObjBuilder execStatsBob;
Explain::getWinningPlanStats(exec.get(), &execStatsBob);
curOp->debug().execStats = execStatsBob.obj();
}
// Plan is done executing. We just need to pull the count out of the root stage.
invariant(STAGE_COUNT == exec->getRootStage()->stageType());
CountStage* countStage = static_cast(exec->getRootStage());
const CountStats* countStats =
static_cast(countStage->getSpecificStats());
result.appendNumber("n", countStats->nCounted);
return true;
}
} cmdCount;
} // namespace
} // namespace mongo