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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.
*/
#pragma once
#include <map>
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobj_comparator_interface.h"
#include "mongo/bson/simple_bsonobj_comparator.h"
#include "mongo/db/namespace_string.h"
#include "mongo/s/chunk_manager.h"
#include "mongo/s/ns_targeter.h"
namespace mongo {
struct TargeterStats {
// Map of chunk shard minKey -> approximate delta. This is used for deciding whether a chunk
// might need splitting or not.
BSONObjIndexedMap<int> chunkSizeDelta{
SimpleBSONObjComparator::kInstance.makeBSONObjIndexedMap<int>()};
};
using StaleShardVersionMap = std::map<ShardId, ChunkVersion>;
/**
* NSTargeter based on a ChunkManager implementation. Wraps all exception codepaths and returns
* NamespaceNotFound status on applicable failures.
*
* Must be initialized before use, and initialization may fail.
*/
class ChunkManagerTargeter : public NSTargeter {
public:
enum class LastErrorType { kCouldNotTarget, kStaleShardVersion, kStaleDbVersion };
/**
* Initializes the targeter with the latest routing information for the namespace, which means
* it may have to block and load information from the config server.
*
* If 'nss' is a sharded time-series collection, replaces this value with namespace string of a
* time-series buckets collection.
*
* If 'expectedEpoch' is specified, the targeter will throws 'StaleEpoch' exception if the epoch
* for 'nss' ever becomes different from 'expectedEpoch'. Otherwise, the targeter will continue
* targeting even if the collection gets dropped and recreated.
*/
ChunkManagerTargeter(OperationContext* opCtx,
const NamespaceString& nss,
boost::optional<OID> expectedEpoch = boost::none);
const NamespaceString& getNS() const override;
ShardEndpoint targetInsert(OperationContext* opCtx, const BSONObj& doc) const override;
std::vector<ShardEndpoint> targetUpdate(OperationContext* opCtx,
const BatchItemRef& itemRef) const override;
std::vector<ShardEndpoint> targetDelete(OperationContext* opCtx,
const BatchItemRef& itemRef) const override;
std::vector<ShardEndpoint> targetAllShards(OperationContext* opCtx) const override;
void noteCouldNotTarget() override;
void noteStaleShardResponse(OperationContext* opCtx,
const ShardEndpoint& endpoint,
const StaleConfigInfo& staleInfo) override;
void noteStaleDbResponse(OperationContext* opCtx,
const ShardEndpoint& endpoint,
const StaleDbRoutingVersion& staleInfo) override;
/**
* Replaces the targeting information with the latest information from the cache. If this
* information is stale WRT the noted stale responses or a remote refresh is needed due
* to a targeting failure, will contact the config servers to reload the metadata.
*
* Return true if the metadata was different after this reload.
*
* Also see NSTargeter::refreshIfNeeded().
*/
bool refreshIfNeeded(OperationContext* opCtx) override;
int getNShardsOwningChunks() const override;
bool isShardedTimeSeriesBucketsNamespace() const override;
bool timeseriesNamespaceNeedsRewrite(const NamespaceString& nss) const;
const ChunkManager& getRoutingInfo() const;
static BSONObj extractBucketsShardKeyFromTimeseriesDoc(
const BSONObj& doc,
const ShardKeyPattern& pattern,
const TimeseriesOptions& timeseriesOptions);
private:
ChunkManager _init(OperationContext* opCtx, bool refresh);
/**
* Returns a vector of ShardEndpoints for a potentially multi-shard query.
*
* Returns !OK with message if query could not be targeted.
*
* If 'collation' is empty, we use the collection default collation for targeting.
*/
StatusWith<std::vector<ShardEndpoint>> _targetQuery(
boost::intrusive_ptr<ExpressionContext> expCtx,
const BSONObj& query,
const BSONObj& collation) const;
/**
* Returns a ShardEndpoint for an exact shard key query.
*
* Also has the side effect of updating the chunks stats with an estimate of the amount of
* data targeted at this shard key.
*
* If 'collation' is empty, we use the collection default collation for targeting.
*/
StatusWith<ShardEndpoint> _targetShardKey(const BSONObj& shardKey,
const BSONObj& collation) const;
// Full namespace of the collection for this targeter
NamespaceString _nss;
// Used to identify the original namespace that the user has requested. Note: this will only be
// true if the buckets namespace is sharded.
bool _isRequestOnTimeseriesViewNamespace = false;
// Stores last error occurred
boost::optional<LastErrorType> _lastError;
// Set to the epoch of the namespace we are targeting. If we ever refresh the catalog cache and
// find a new epoch, we immediately throw a StaleEpoch exception.
boost::optional<OID> _targetEpoch;
// The latest loaded routing cache entry
ChunkManager _cm;
};
} // namespace mongo
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