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/**
* Copyright (C) 2022-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 "mongo/bson/bsonobj.h"
#include "mongo/db/catalog/clustered_collection_options_gen.h"
#include "mongo/db/catalog/index_catalog.h"
namespace mongo {
class Collection;
class CollectionPtr;
class IndexDescriptor;
class ShardKeyIndex {
public:
/**
* Wraps information pertaining to the 'index' used as the shard key.
*
* A clustered index is not tied to an IndexDescriptor whereas all other types of indexes
* are. Either the 'index' is a clustered index and '_clusteredIndexKeyPattern' is
* non-empty, or '_indexDescriptor' is non-null and a standard index exists.
*/
ShardKeyIndex(const IndexDescriptor* indexDescriptor);
ShardKeyIndex(const ClusteredIndexSpec& clusteredIndexSpec);
const BSONObj& keyPattern() const;
const IndexDescriptor* descriptor() const {
return _indexDescriptor;
}
private:
const IndexDescriptor* _indexDescriptor;
// Stores the keyPattern when the index is a clustered index and there is no
// IndexDescriptor. Empty otherwise.
BSONObj _clusteredIndexKeyPattern;
};
/**
* Returns true if the given index is compatible with the shard key pattern.
*
* If return value is false and errMsg is non-null, the reasons that the existing index is
* incompatible will be appended to errMsg.
*/
bool isCompatibleWithShardKey(OperationContext* opCtx,
const CollectionPtr& collection,
const IndexCatalogEntry* indexEntry,
const BSONObj& shardKey,
bool requireSingleKey,
std::string* errMsg = nullptr);
/**
* Returns an index suitable for shard key range scans if it exists.
*
* This index:
* - must be prefixed by 'shardKey', and
* - must not be a partial index.
* - must have the simple collation.
*
* If the parameter 'requireSingleKey' is true, then this index additionally must not be
* multi-key.
*/
boost::optional<ShardKeyIndex> findShardKeyPrefixedIndex(OperationContext* opCtx,
const CollectionPtr& collection,
const IndexCatalog* indexCatalog,
const BSONObj& shardKey,
bool requireSingleKey,
std::string* errMsg = nullptr);
/**
* Returns true if the given index name is the last remaining index that is compatible with the
* shard key index.
*/
bool isLastShardKeyIndex(OperationContext* opCtx,
const CollectionPtr& collection,
const IndexCatalog* indexCatalog,
const std::string& indexName,
const BSONObj& shardKey);
} // namespace mongo
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