diff options
Diffstat (limited to 'src/mongo/db/pipeline/change_stream_split_event_helpers.cpp')
| -rw-r--r-- | src/mongo/db/pipeline/change_stream_split_event_helpers.cpp | 131 |
1 files changed, 0 insertions, 131 deletions
diff --git a/src/mongo/db/pipeline/change_stream_split_event_helpers.cpp b/src/mongo/db/pipeline/change_stream_split_event_helpers.cpp deleted file mode 100644 index 19fba5afea5..00000000000 --- a/src/mongo/db/pipeline/change_stream_split_event_helpers.cpp +++ /dev/null @@ -1,131 +0,0 @@ -/** - * 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/pipeline/change_stream_split_event_helpers.h" - -#include "mongo/db/pipeline/field_path.h" -#include "mongo/db/pipeline/resume_token.h" - -namespace mongo { -namespace change_stream_split_event { - -std::pair<Document, size_t> processChangeEventBeforeSplit(const Document& event, - bool withMetadata) { - if (withMetadata) { - auto eventBson = event.toBsonWithMetaData<BSONObj::LargeSizeTrait>(); - return {Document::fromBsonWithMetaData(eventBson), eventBson.objsize()}; - } else { - // Serialize just the user data, and add the metadata fields separately. - auto eventBson = event.toBson<BSONObj::LargeSizeTrait>(); - MutableDocument mutDoc(Document{eventBson}); - mutDoc.copyMetaDataFrom(event); - return {mutDoc.freeze(), eventBson.objsize()}; - } -} - -std::queue<Document> splitChangeEvent(const Document& event, - size_t maxFragmentBsonSize, - size_t skipFirstFragments) { - // Extract the underlying BSON. We expect the event to be trivially convertible either with - // or without metadata, so we attempt to optimize the serialization here. - auto eventBson = - (event.isTriviallyConvertible() ? event.toBson<BSONObj::LargeSizeTrait>() - : event.toBsonWithMetaData<BSONObj::LargeSizeTrait>()); - - // Construct a sorted map of fields ordered by size and key for a deterministic greedy strategy - // to minimize the total number of fragments (the first fragment contains as many fields as - // possible). Don't include the original '_id' field, since each fragment will have its own. - std::map<std::pair<size_t, std::string>, Value> sortedFieldMap; - for (auto it = event.fieldIterator(); it.more();) { - auto&& [key, value] = it.next(); - if (key != kIdField) { - sortedFieldMap.emplace(std::make_pair(eventBson[key].size(), key), value); - } - } - - uassert(7182502, - "Cannot split an empty event or an event containing solely '_id' field", - !sortedFieldMap.empty()); - - auto resumeTokenData = - ResumeToken::parse(event.metadata().getSortKey().getDocument()).getData(); - - std::list<MutableDocument> fragments; - for (auto it = sortedFieldMap.cbegin(); it != sortedFieldMap.cend();) { - // Update the resume token with the index of the fragment we're about to add. - resumeTokenData.fragmentNum = fragments.size(); - - // Add a new fragment at the end of the fragments list. - auto& fragment = fragments.emplace_back(); - - // Add fields required by all fragments. - ResumeToken token(resumeTokenData); - fragment.metadata().setSortKey(Value(token.toDocument()), true); - fragment.addField(kIdField, fragment.metadata().getSortKey()); - fragment.addField(kSplitEventField, - Value(Document{{kFragmentNumberField, static_cast<int>(fragments.size())}, - {kTotalFragmentsField, 0}})); - - auto fragmentBsonSize = static_cast<size_t>(fragment.peek().toBsonWithMetaData().objsize()); - - // Fill the fragment with as many fields as we can until we run out or exceed max size. - // Always make sure we add at least one new field on each iteration. - do { - fragment.addField(it->first.second /* field name */, it->second /* field value */); - fragmentBsonSize += it->first.first /* field size */; - } while (++it != sortedFieldMap.cend() && - fragmentBsonSize + it->first.first /* field size */ <= maxFragmentBsonSize); - - uassert(7182500, - str::stream() << "Splitting change event failed: fragment size " << fragmentBsonSize - << " is greater than maximum allowed fragment size " - << maxFragmentBsonSize, - fragmentBsonSize <= maxFragmentBsonSize); - } - - // Iterate over the fragments to populate the 'kTotalFragmentsField' field and freeze the final - // events. - const auto totalFragments = Value(static_cast<int>(fragments.size())); - const auto totalFragmentsFieldPath = - FieldPath::getFullyQualifiedPath(kSplitEventField, kTotalFragmentsField); - - std::queue<Document> outputFragments; - for (auto [it, i] = std::make_pair(fragments.begin(), 0ULL); it != fragments.end(); ++it, ++i) { - // Do not insert first 'skipFirstFragments' into the output. - if (i >= skipFirstFragments) { - it->setNestedField(totalFragmentsFieldPath, totalFragments); - outputFragments.push(it->freeze()); - } - } - - return outputFragments; -} - -} // namespace change_stream_split_event -} // namespace mongo |