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Diffstat (limited to 'src/mongo/db/s/resharding/resharding_donor_oplog_iterator.cpp')
| -rw-r--r-- | src/mongo/db/s/resharding/resharding_donor_oplog_iterator.cpp | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/src/mongo/db/s/resharding/resharding_donor_oplog_iterator.cpp b/src/mongo/db/s/resharding/resharding_donor_oplog_iterator.cpp new file mode 100644 index 00000000000..ab3b96a3688 --- /dev/null +++ b/src/mongo/db/s/resharding/resharding_donor_oplog_iterator.cpp @@ -0,0 +1,159 @@ +/** + * 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. + */ + +#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kSharding + +#include "mongo/platform/basic.h" + +#include "mongo/db/s/resharding/resharding_donor_oplog_iterator.h" + +#include <fmt/format.h> + +#include "mongo/db/pipeline/pipeline_d.h" +#include "mongo/db/s/resharding_util.h" +#include "mongo/logv2/log.h" +#include "mongo/util/scopeguard.h" + +namespace mongo { + +using namespace fmt::literals; + +namespace { + +/** + * Extracts the oplog id from the oplog. + */ +ReshardingDonorOplogId getId(const repl::OplogEntry& oplog) { + return ReshardingDonorOplogId::parse( + IDLParserErrorContext("ReshardingDonorOplogIterator::getOplogId"), + oplog.get_id()->getDocument().toBson()); +} + +} // anonymous namespace + +/** + * Sentinel oplog format: + * { + * op: "n", + * ns: "<database>.<collection>", + * ui: <existingUUID>, + * destinedRecipient: <recipientShardId>, + * o: {msg: "Writes to <database>.<collection> is temporarily blocked for resharding"}, + * o2: {type: "reshardFinalOp", reshardingUUID: <reshardingUUID>}, + * fromMigrate: true, + * } + */ +bool isFinalOplog(const repl::OplogEntry& oplog) { + if (oplog.getOpType() != repl::OpTypeEnum::kNoop) { + return false; + } + + auto o2Field = oplog.getObject2(); + if (!o2Field) { + return false; + } + + return o2Field->getField("type").valueStringDataSafe() == "reshardFinalOp"_sd; +} + +ReshardingDonorOplogIterator::ReshardingDonorOplogIterator( + NamespaceString donorOplogBufferNs, boost::optional<ReshardingDonorOplogId> resumeToken) + : _oplogBufferNs(std::move(donorOplogBufferNs)), _resumeToken(std::move(resumeToken)) {} + +Future<boost::optional<repl::OplogEntry>> ReshardingDonorOplogIterator::getNext( + OperationContext* opCtx) { + boost::optional<repl::OplogEntry> oplogToReturn; + + if (_hasSeenFinalOplogEntry) { + return Future<boost::optional<repl::OplogEntry>>::makeReady(oplogToReturn); + } + + if (!_pipeline) { + auto expCtx = _makeExpressionContext(opCtx); + _pipeline = createAggForReshardingOplogBuffer(std::move(expCtx), _resumeToken, true); + _pipeline->detachFromOperationContext(); + } + + _pipeline->reattachToOperationContext(opCtx); + ON_BLOCK_EXIT([this] { + if (_pipeline) { + _pipeline->detachFromOperationContext(); + } + }); + + auto next = _pipeline->getNext(); + + if (!next) { + _pipeline.reset(); + return _waitForNewOplog().then([this, opCtx] { return getNext(opCtx); }); + } + + auto nextOplog = uassertStatusOK(repl::OplogEntry::parse(next->toBson())); + if (isFinalOplog(nextOplog)) { + _hasSeenFinalOplogEntry = true; + _pipeline.reset(); + return Future<boost::optional<repl::OplogEntry>>::makeReady(oplogToReturn); + } + + _resumeToken = getId(nextOplog); + + oplogToReturn = std::move(nextOplog); + return Future<boost::optional<repl::OplogEntry>>::makeReady(std::move(oplogToReturn)); +} + +bool ReshardingDonorOplogIterator::hasMore() const { + return !_hasSeenFinalOplogEntry; +} + +Future<void> ReshardingDonorOplogIterator::_waitForNewOplog() { + return Future<void>::makeReady(); +} + +boost::intrusive_ptr<ExpressionContext> ReshardingDonorOplogIterator::_makeExpressionContext( + OperationContext* opCtx) { + StringMap<ExpressionContext::ResolvedNamespace> resolvedNamespaces; + resolvedNamespaces.emplace(_oplogBufferNs.coll(), + ExpressionContext::ResolvedNamespace{_oplogBufferNs, {}}); + + return make_intrusive<ExpressionContext>(opCtx, + boost::none /* explain */, + false /* fromMongos */, + false /* needsMerge */, + false /* allowDiskUse */, + false /* bypassDocumentValidation */, + false /* isMapReduceCommand */, + _oplogBufferNs, + boost::none /* runtimeConstants */, + nullptr /* collator */, + MongoProcessInterface::create(opCtx), + std::move(resolvedNamespaces), + boost::none /* collUUID */); +} + +} // namespace mongo |