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Diffstat (limited to 'src/mongo/db/snapshot_window_util.cpp')
| -rw-r--r-- | src/mongo/db/snapshot_window_util.cpp | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/src/mongo/db/snapshot_window_util.cpp b/src/mongo/db/snapshot_window_util.cpp deleted file mode 100644 index 9490ceedf8c..00000000000 --- a/src/mongo/db/snapshot_window_util.cpp +++ /dev/null @@ -1,173 +0,0 @@ -/** - * 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. - */ - -#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kStorage - -#include "mongo/platform/basic.h" - -#include "mongo/db/snapshot_window_util.h" - -#include "mongo/db/commands/test_commands_enabled.h" -#include "mongo/db/operation_context.h" -#include "mongo/db/service_context.h" -#include "mongo/db/snapshot_window_options.h" -#include "mongo/db/storage/storage_engine.h" -#include "mongo/logv2/log.h" -#include "mongo/platform/mutex.h" -#include "mongo/util/concurrency/with_lock.h" -#include "mongo/util/fail_point.h" - -namespace mongo { - -// This failpoint is used for performance testing. -MONGO_FAIL_POINT_DEFINE(preventDynamicSnapshotHistoryWindowTargetAdjustments); - -namespace SnapshotWindowUtil { - -// Adds concurrency control to increaseTargetSnapshotWindowSize() and -// decreaseTargetSnapshotWindowSize(). They should not run concurrently with themselves or one -// another, since they act on and modify the same storage parameters. Further guards the static -// variables "_snapshotWindowLastDecreasedAt" and "_snapshotWindowLastIncreasedAt" used in -// increaseTargetSnapshotWindowSize() and decreaseSnapshowWindow(). -Mutex snapshotWindowMutex; - -namespace { - -void _decreaseTargetSnapshotWindowSize(WithLock lock, OperationContext* opCtx) { - // Tracks the last time that the snapshot window was decreased so that it does not go down so - // fast that the system does not have time to react and reduce snapshot availability. - static Date_t _snapshotWindowLastDecreasedAt{Date_t::min()}; - - if (_snapshotWindowLastDecreasedAt > - (Date_t::now() - - Milliseconds(snapshotWindowParams.minMillisBetweenSnapshotWindowDec.load()))) { - // We have already decreased the window size in the last minMillisBetweenSnapshotWindowDec - // milliseconds. - return; - } - - snapshotWindowParams.targetSnapshotHistoryWindowInSeconds.store( - snapshotWindowParams.targetSnapshotHistoryWindowInSeconds.load() * - snapshotWindowParams.snapshotWindowMultiplicativeDecrease.load()); - - // Try to set the oldest_timestamp immediately without waiting for a write to adjust the - // window. May or may not work depending on the state of the system. - StorageEngine* engine = opCtx->getServiceContext()->getStorageEngine(); - invariant(engine); - engine->setOldestTimestampFromStable(); - - _snapshotWindowLastDecreasedAt = Date_t::now(); -} - -} // namespace - -void increaseTargetSnapshotWindowSize(OperationContext* opCtx) { - if (MONGO_unlikely(preventDynamicSnapshotHistoryWindowTargetAdjustments.shouldFail())) { - return; - } - - stdx::unique_lock<Latch> lock(snapshotWindowMutex); - - // Tracks the last time that the snapshot window was increased so that it does not go up so fast - // that the storage engine does not have time to improve snapshot availability. - static Date_t _snapshotWindowLastIncreasedAt{Date_t::min()}; - - if (_snapshotWindowLastIncreasedAt > - (Date_t::now() - - Milliseconds(snapshotWindowParams.minMillisBetweenSnapshotWindowInc.load()))) { - // We have already increased the window size in the last minMillisBetweenSnapshotWindowInc - // milliseconds. - return; - } - - // If the cache pressure is already too high, we will not put more pressure on it by increasing - // the window size. - StorageEngine* engine = opCtx->getServiceContext()->getStorageEngine(); - if (engine && engine->isCacheUnderPressure(opCtx)) { - invariant(!engine->isEphemeral() || getTestCommandsEnabled()); - LOGV2_WARNING( - 23788, - "Attempted to increase the time window of available snapshots for " - "point-in-time operations (readConcern level 'snapshot' or transactions), but " - "the storage engine cache pressure, per the cachePressureThreshold setting of " - "'{snapshotWindowParams_cachePressureThreshold_load}', is too high to allow it to " - "increase. If this happens frequently, consider " - "either increasing the cache pressure threshold or increasing the memory " - "available to the storage engine cache, in order to improve the success rate " - "or speed of point-in-time requests.", - "snapshotWindowParams_cachePressureThreshold_load"_attr = - snapshotWindowParams.cachePressureThreshold.load()); - _decreaseTargetSnapshotWindowSize(lock, opCtx); - return; - } - - if (snapshotWindowParams.targetSnapshotHistoryWindowInSeconds.load() == - snapshotWindowParams.maxTargetSnapshotHistoryWindowInSeconds.load()) { - LOGV2_WARNING( - 23789, - "Attempted to increase the time window of available snapshots for " - "point-in-time operations (readConcern level 'snapshot' or transactions), but " - "maxTargetSnapshotHistoryWindowInSeconds has already been reached. If this " - "happens frequently, consider increasing the " - "maxTargetSnapshotHistoryWindowInSeconds setting value, which is currently " - "set to '{snapshotWindowParams_maxTargetSnapshotHistoryWindowInSeconds_load}'.", - "snapshotWindowParams_maxTargetSnapshotHistoryWindowInSeconds_load"_attr = - snapshotWindowParams.maxTargetSnapshotHistoryWindowInSeconds.load()); - return; - } - - int increasedSnapshotWindow = snapshotWindowParams.targetSnapshotHistoryWindowInSeconds.load() + - snapshotWindowParams.snapshotWindowAdditiveIncreaseSeconds.load(); - snapshotWindowParams.targetSnapshotHistoryWindowInSeconds.store( - std::min(increasedSnapshotWindow, - snapshotWindowParams.maxTargetSnapshotHistoryWindowInSeconds.load())); - - _snapshotWindowLastIncreasedAt = Date_t::now(); -} - -void decreaseTargetSnapshotWindowSize(OperationContext* opCtx) { - if (MONGO_unlikely(preventDynamicSnapshotHistoryWindowTargetAdjustments.shouldFail())) { - return; - } - - stdx::unique_lock<Latch> lock(snapshotWindowMutex); - - StorageEngine* engine = opCtx->getServiceContext()->getStorageEngine(); - if (engine && engine->isCacheUnderPressure(opCtx)) { - invariant(!engine->isEphemeral() || getTestCommandsEnabled()); - _decreaseTargetSnapshotWindowSize(lock, opCtx); - } -} - -void incrementSnapshotTooOldErrorCount() { - snapshotWindowParams.snapshotTooOldErrorCount.addAndFetch(1); -} - -} // namespace SnapshotWindowUtil -} // namespace mongo |