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/**
* Copyright (C) 2018-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/platform/basic.h"
#include <boost/optional.hpp>
#include <memory>
#include "mongo/db/exec/queued_data_stage.h"
#include "mongo/db/exec/trial_stage.h"
#include "mongo/db/exec/working_set.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/query/plan_yield_policy.h"
#include "mongo/db/service_context_d_test_fixture.h"
#include "mongo/unittest/unittest.h"
namespace mongo {
namespace {
class TrialStageTest : public unittest::Test {
public:
TrialStageTest() : _opCtx(cc().makeOperationContext()) {}
protected:
// Pushes BSONObjs from the given vector into the given QueuedDataStage. Each empty BSONObj in
// the vector causes a NEED_TIME to be queued up at that point instead of a result.
void queueData(const std::vector<BSONObj>& results, QueuedDataStage* queuedData) {
for (auto result : results) {
if (result.isEmpty()) {
queuedData->pushBack(PlanStage::NEED_TIME);
continue;
}
const auto id = _ws.allocate();
auto* member = _ws.get(id);
member->obj.setValue(result.getOwned());
_ws.transitionToOwnedObj(id);
queuedData->pushBack(id);
}
}
// Returns the next result from the TrialStage, or boost::none if there are no more results.
boost::optional<BSONObj> nextResult(TrialStage* trialStage) {
PlanStage::StageState state;
WorkingSetID id;
do {
state = trialStage->work(&id);
if (state == PlanStage::ADVANCED) {
auto* member = _ws.get(id);
return member->obj.value();
}
} while (state == PlanStage::NEED_TIME);
// There are not more results to return.
ASSERT_TRUE(trialStage->isEOF());
return boost::none;
}
std::unique_ptr<PlanYieldPolicy> yieldPolicy() {
return std::make_unique<PlanYieldPolicy>(
PlanExecutor::NO_YIELD, opCtx()->getServiceContext()->getFastClockSource());
}
OperationContext* opCtx() {
return _opCtx.get();
}
WorkingSet* ws() {
return &_ws;
}
private:
ServiceContext::UniqueOperationContext _opCtx;
WorkingSet _ws;
};
TEST_F(TrialStageTest, AdoptsTrialPlanIfTrialSucceeds) {
auto trialPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
auto backupPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
// Seed the trial plan with 20 results and no NEED_TIMEs.
std::vector<BSONObj> trialResults;
for (auto i = 0; i < 20; ++i) {
trialResults.push_back(BSON("_id" << i));
}
queueData(trialResults, trialPlan.get());
// Set the minimum advanced-to-works ratio to 0.75. Because every work() will result in an
// ADVANCE, the trial plan will succeed.
auto trialStage = std::make_unique<TrialStage>(
opCtx(), ws(), std::move(trialPlan), std::move(backupPlan), 10, 0.75);
ASSERT_OK(trialStage->pickBestPlan(yieldPolicy().get()));
// The trial phase completed and we picked the trial plan, not the backup plan.
ASSERT_TRUE(trialStage->isTrialPhaseComplete());
ASSERT_FALSE(trialStage->pickedBackupPlan());
// Confirm that we see the full trialPlan results when we iterate the trialStage.
for (auto result : trialResults) {
ASSERT_BSONOBJ_EQ(result, *nextResult(trialStage.get()));
}
ASSERT_FALSE(nextResult(trialStage.get()));
ASSERT_TRUE(trialStage->isEOF());
}
TEST_F(TrialStageTest, AdoptsTrialPlanIfTrialPlanHitsEOF) {
auto trialPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
auto backupPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
// Seed the trial plan with 5 results and no NEED_TIMEs.
std::vector<BSONObj> trialResults;
for (auto i = 0; i < 5; ++i) {
trialResults.push_back(BSON("_id" << i));
}
queueData(trialResults, trialPlan.get());
// We schedule the trial to run for 10 works. Because we hit EOF after 5 results, we will end
// the trial phase early and adopt the successful trial plan.
auto trialStage = std::make_unique<TrialStage>(
opCtx(), ws(), std::move(trialPlan), std::move(backupPlan), 10, 0.75);
ASSERT_OK(trialStage->pickBestPlan(yieldPolicy().get()));
// The trial phase completed and we picked the trial plan, not the backup plan.
ASSERT_TRUE(trialStage->isTrialPhaseComplete());
ASSERT_FALSE(trialStage->pickedBackupPlan());
// Get the specific stats for the stage and confirm that the trial completed early.
auto* stats = static_cast<const TrialStats*>(trialStage->getSpecificStats());
ASSERT_EQ(stats->trialPeriodMaxWorks, 10U);
ASSERT_EQ(stats->trialWorks, 5U);
// Confirm that we see the full trialPlan results when we iterate the trialStage.
for (auto result : trialResults) {
ASSERT_BSONOBJ_EQ(result, *nextResult(trialStage.get()));
}
ASSERT_FALSE(nextResult(trialStage.get()));
ASSERT_TRUE(trialStage->isEOF());
}
TEST_F(TrialStageTest, AdoptsBackupPlanIfTrialDoesNotSucceed) {
auto trialPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
auto backupPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
// Seed the trial plan with 20 results. Every second result will produce a NEED_TIME.
std::vector<BSONObj> trialResults;
for (auto i = 0; i < 20; ++i) {
trialResults.push_back((i % 2) ? BSON("_id" << i) : BSONObj());
}
queueData(std::move(trialResults), trialPlan.get());
// Seed the backup plan with 20 different results, so that we can validate that we see the
// correct dataset once the trial phase is complete.
std::vector<BSONObj> backupResults;
for (auto i = 0; i < 20; ++i) {
backupResults.push_back(BSON("_id" << (-i)));
}
queueData(backupResults, backupPlan.get());
// Set the minimum advanced-to-works ratio to 0.75. Because every second work() will result in a
// NEED_TIME and the actual ratio is thus 0.5, the trial plan will fail.
auto trialStage = std::make_unique<TrialStage>(
opCtx(), ws(), std::move(trialPlan), std::move(backupPlan), 10, 0.75);
ASSERT_OK(trialStage->pickBestPlan(yieldPolicy().get()));
// The trial phase completed and we picked the backup plan.
ASSERT_TRUE(trialStage->isTrialPhaseComplete());
ASSERT_TRUE(trialStage->pickedBackupPlan());
// Confirm that we see the full backupPlan results when we iterate the trialStage.
for (auto result : backupResults) {
ASSERT_BSONOBJ_EQ(result, *nextResult(trialStage.get()));
}
ASSERT_FALSE(nextResult(trialStage.get()));
ASSERT_TRUE(trialStage->isEOF());
}
TEST_F(TrialStageTest, AdoptsBackupPlanIfTrialPlanDies) {
auto trialPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
auto backupPlan = std::make_unique<QueuedDataStage>(opCtx(), ws());
// Seed the trial plan with 2 results followed by a PlanStage::FAILURE.
queueData({BSON("_id" << 0), BSON("_id" << 1)}, trialPlan.get());
trialPlan->pushBack(PlanStage::FAILURE);
// Seed the backup plan with 20 different results, so that we can validate that we see the
// correct dataset once the trial phase is complete.
std::vector<BSONObj> backupResults;
for (auto i = 0; i < 20; ++i) {
backupResults.push_back(BSON("_id" << (-i)));
}
queueData(backupResults, backupPlan.get());
// We schedule the trial to run for 10 works. Because we will encounter a PlanStage::FAILURE
// before this point, the trial will complete early and the backup plan will be adopted.
auto trialStage = std::make_unique<TrialStage>(
opCtx(), ws(), std::move(trialPlan), std::move(backupPlan), 10, 0.75);
ASSERT_OK(trialStage->pickBestPlan(yieldPolicy().get()));
// The trial phase completed and we picked the backup plan.
ASSERT_TRUE(trialStage->isTrialPhaseComplete());
ASSERT_TRUE(trialStage->pickedBackupPlan());
// Get the specific stats for the stage and confirm that the trial completed early.
auto* stats = static_cast<const TrialStats*>(trialStage->getSpecificStats());
ASSERT_EQ(stats->trialPeriodMaxWorks, 10U);
ASSERT_EQ(stats->trialWorks, 2U);
// Confirm that we see the full backupPlan results when we iterate the trialStage.
for (auto result : backupResults) {
ASSERT_BSONOBJ_EQ(result, *nextResult(trialStage.get()));
}
ASSERT_FALSE(nextResult(trialStage.get()));
ASSERT_TRUE(trialStage->isEOF());
}
} // namespace
} // namespace mongo
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