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/**
* Copyright (C) 2023-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/db/change_stream_pre_images_truncate_markers.h"
#include "mongo/db/change_stream_pre_image_util.h"
#include "mongo/db/change_stream_serverless_helpers.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/repl/storage_interface.h"
#include "mongo/logv2/log.h"
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kDefault
namespace mongo {
namespace {
// Returns true if the pre-image with highestRecordId and highestWallTime is expired.
bool isExpired(OperationContext* opCtx,
const boost::optional<TenantId>& tenantId,
const RecordId& highestRecordId,
Date_t highestWallTime) {
auto currentTimeForTimeBasedExpiration =
change_stream_pre_image_util::getCurrentTimeForPreImageRemoval();
if (tenantId) {
// In a serverless environment, the 'expireAfterSeconds' is set per tenant and is the only
// criteria considered when determining whether a marker is expired.
//
// The oldest marker is expired if:
// 'wallTime' of the oldest marker <= current node time - 'expireAfterSeconds'
auto expireAfterSeconds =
Seconds{change_stream_serverless_helpers::getExpireAfterSeconds(tenantId.get())};
auto preImageExpirationTime = currentTimeForTimeBasedExpiration - expireAfterSeconds;
return highestWallTime <= preImageExpirationTime;
}
// In a non-serverless enviornment, a marker is expired if either:
// (1) 'highestWallTime' of the (partial) marker <= current node time -
// 'expireAfterSeconds' OR
// (2) Timestamp of the 'highestRecordId' in the oldest marker <
// Timestamp of earliest oplog entry
// The 'expireAfterSeconds' may or may not be set in a non-serverless enviornment.
const auto preImageExpirationTime = change_stream_pre_image_util::getPreImageExpirationTime(
opCtx, currentTimeForTimeBasedExpiration);
bool expiredByTimeBasedExpiration =
preImageExpirationTime ? highestWallTime <= preImageExpirationTime : false;
const auto currentEarliestOplogEntryTs =
repl::StorageInterface::get(opCtx->getServiceContext())->getEarliestOplogTimestamp(opCtx);
auto highestRecordTimestamp =
change_stream_pre_image_util::getPreImageTimestamp(highestRecordId);
return expiredByTimeBasedExpiration || highestRecordTimestamp < currentEarliestOplogEntryTs;
}
} // namespace
PreImagesTruncateMarkersPerCollection::PreImagesTruncateMarkersPerCollection(
boost::optional<TenantId> tenantId,
std::deque<Marker> markers,
int64_t leftoverRecordsCount,
int64_t leftoverRecordsBytes,
int64_t minBytesPerMarker)
: CollectionTruncateMarkersWithPartialExpiration(
std::move(markers), leftoverRecordsCount, leftoverRecordsBytes, minBytesPerMarker),
_tenantId(std::move(tenantId)) {}
// TODO SERVER-76586: Finalize initialisation methods of truncate markers for pre-images.
CollectionTruncateMarkers::InitialSetOfMarkers
PreImagesTruncateMarkersPerCollection::createTruncateMarkersByScanning(
OperationContext* opCtx,
RecordStore* rs,
const UUID& nsUUID,
RecordId& highestSeenRecordId,
Date_t& highestSeenWallTime) {
Timer scanningTimer;
RecordIdBound minRecordIdBound =
change_stream_pre_image_util::getAbsoluteMinPreImageRecordIdBoundForNs(nsUUID);
RecordId minRecordId = minRecordIdBound.recordId();
RecordIdBound maxRecordIdBound =
change_stream_pre_image_util::getAbsoluteMaxPreImageRecordIdBoundForNs(nsUUID);
RecordId maxRecordId = maxRecordIdBound.recordId();
auto cursor = rs->getCursor(opCtx, true);
auto record = cursor->seekNear(minRecordId);
// A forward seekNear will return the previous entry if one does not match exactly. In most
// cases, we will need to call next() to get our correct UUID.
while (record && record->id < minRecordId) {
record = cursor->next();
}
if (!record || (record && record->id > maxRecordId)) {
// There appear to be no pre-images for 'nsUUID'.
//
// TODO SERVER-76586: Determine the appropriate course of action to ensure truncate markers
// for an empty pre-images collection don't stay around indefinitely.
//
// For now, leave 'highestSeenRecordId' and 'highestSeenWallTime' their default values.
return CollectionTruncateMarkers::InitialSetOfMarkers{
{}, 0, 0, Microseconds{0}, MarkersCreationMethod::EmptyCollection};
}
auto getRecordIdAndWallTime =
[](const Record& record) -> CollectionTruncateMarkers::RecordIdAndWallTime {
BSONObj preImageObj = record.data.toBson();
return CollectionTruncateMarkers::RecordIdAndWallTime(
record.id, preImageObj[ChangeStreamPreImage::kOperationTimeFieldName].date());
};
auto minBytesPerMarker = gPreImagesCollectionTruncateMarkersMinBytes;
int64_t currentRecords = 0;
int64_t currentBytes = 0;
std::deque<CollectionTruncateMarkers::Marker> markers;
while (record && record->id < maxRecordId) {
currentRecords++;
currentBytes += record->data.size();
auto [rId, wallTime] = getRecordIdAndWallTime(*record);
highestSeenRecordId = rId;
highestSeenWallTime = wallTime;
if (currentBytes >= minBytesPerMarker) {
LOGV2_DEBUG(7500500,
1,
"Marking entry as a potential future truncation point for collection with "
"pre-images enabled",
"wallTime"_attr = wallTime,
"nsUuid"_attr = nsUUID);
markers.emplace_back(
std::exchange(currentRecords, 0), std::exchange(currentBytes, 0), rId, wallTime);
}
record = cursor->next();
}
return CollectionTruncateMarkers::InitialSetOfMarkers{
std::move(markers),
currentRecords,
currentBytes,
scanningTimer.elapsed(),
CollectionTruncateMarkers::MarkersCreationMethod::Scanning};
}
bool PreImagesTruncateMarkersPerCollection::_hasExcessMarkers(OperationContext* opCtx) const {
const auto& markers = getMarkers();
if (markers.empty()) {
// If there's nothing in the markers queue then we don't have excess markers by definition.
return false;
}
const Marker& oldestMarker = markers.front();
return isExpired(opCtx, _tenantId, oldestMarker.lastRecord, oldestMarker.wallTime);
}
bool PreImagesTruncateMarkersPerCollection::_hasPartialMarkerExpired(
OperationContext* opCtx) const {
const auto& [highestSeenRecordId, highestSeenWallTime] = getPartialMarker();
return isExpired(opCtx, _tenantId, highestSeenRecordId, highestSeenWallTime);
}
} // namespace mongo
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