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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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/s/hedge_options_util.h"
#include "mongo/client/read_preference.h"
#include "mongo/db/query/query_request.h"
#include "mongo/s/mongos_server_parameters_gen.h"
namespace mongo {
boost::optional<executor::RemoteCommandRequestOnAny::HedgeOptions> extractHedgeOptions(
OperationContext* opCtx, const BSONObj& cmdObj) {
const auto hedgingMode = ReadPreferenceSetting::get(opCtx).hedgingMode;
if (gReadHedgingMode.load() == ReadHedgingMode::kOn && hedgingMode &&
hedgingMode->getEnabled()) {
boost::optional<int> maxTimeMS;
if (auto cmdOptionMaxTimeMSField = cmdObj[QueryRequest::cmdOptionMaxTimeMS]) {
maxTimeMS = uassertStatusOK(QueryRequest::parseMaxTimeMS(cmdOptionMaxTimeMSField));
}
// Check if the operation is worth hedging.
if (maxTimeMS && maxTimeMS > gMaxTimeMSThresholdForHedging.load()) {
return boost::none;
}
// Compute the delay.
auto delay = Milliseconds{0};
bool shouldDelayHedging = hedgingMode->getDelay();
if (shouldDelayHedging) {
delay = maxTimeMS ? Milliseconds{gHedgingDelayPercentage.load() * maxTimeMS.get() / 100}
: Milliseconds{gDefaultHedgingDelayMS.load()};
}
return executor::RemoteCommandRequestOnAny::HedgeOptions{1, delay};
}
return boost::none;
}
} // namespace mongo
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