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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 "mongo/db/query/canonical_query.h"
#include "mongo/db/query/index_bounds.h"
#include "mongo/s/chunk_manager.h"
#include "mongo/s/shard_key_pattern.h"
namespace mongo {
/**
* Given a simple BSON query, extracts the shard key corresponding to the key pattern from equality
* matches in the query. The query expression *must not* be a complex query with sorts or other
* attributes.
*
* Logically, the equalities in the BSON query can be serialized into a BSON document and then a
* shard key is extracted from this equality document.
*
* NOTE: BSON queries and BSON documents look similar but are different languages. Use the correct
* shard key extraction function.
*
* Returns !OK status if the query cannot be parsed.
* Returns an empty BSONObj() if there is no shard key found in the query equalities.
*
* Examples:
* If the key pattern is { a : 1 }
* { a : "hi", b : 4 } --> returns { a : "hi" }
* { a : { $eq : "hi" }, b : 4 } --> returns { a : "hi" }
* { $and : [{a : { $eq : "hi" }}, { b : 4 }] } --> returns { a : "hi" }
* If the key pattern is { 'a.b' : 1 }
* { a : { b : "hi" } } --> returns { 'a.b' : "hi" }
* { 'a.b' : "hi" } --> returns { 'a.b' : "hi" }
* { a : { b : { $eq : "hi" } } } --> returns {} because the query language treats this as
* a : { $eq : { b : ... } }
*/
StatusWith<BSONObj> extractShardKeyFromBasicQuery(OperationContext* opCtx,
const NamespaceString& nss,
const ShardKeyPattern& shardKeyPattern,
const BSONObj& basicQuery);
/**
* Variant of the above, which is used to parse queries that contain let parameters and runtime
* constants.
*/
StatusWith<BSONObj> extractShardKeyFromBasicQueryWithContext(
boost::intrusive_ptr<ExpressionContext> expCtx,
const ShardKeyPattern& shardKeyPattern,
const BSONObj& basicQuery);
BSONObj extractShardKeyFromQuery(const ShardKeyPattern& shardKeyPattern,
const CanonicalQuery& query);
/**
* Return an ordered list of bounds generated using a ShardKeyPattern and the bounds from the
* IndexBounds. This function is used in sharding to determine where to route queries according to
* the shard key pattern.
*
* Examples:
*
* Key { a: 1 }, Bounds a: [0] => { a: 0 } -> { a: 0 }
* Key { a: 1 }, Bounds a: [2, 3) => { a: 2 } -> { a: 3 } // bound inclusion ignored.
*
* The bounds returned by this function may be a superset of those defined by the constraints. For
* instance, if this KeyPattern is {a : 1, b: 1} Bounds: { a : {$in : [1,2]} , b : {$in : [3,4,5]} }
* => {a : 1 , b : 3} -> {a : 1 , b : 5}, {a : 2 , b : 3} -> {a : 2 , b : 5}
*
* If the IndexBounds are not defined for all the fields in this keypattern, which means some fields
* are unsatisfied, an empty BoundList could return.
*
*/
BoundList flattenBounds(const ShardKeyPattern& shardKeyPattern, const IndexBounds& indexBounds);
/**
* Transforms query into bounds for each field in the shard key.
* For example :
* Key { a: 1, b: 1 },
* Query { a : { $gte : 1, $lt : 2 },
* b : { $gte : 3, $lt : 4 } }
* => Bounds { a : [1, 2), b : [3, 4) }
*/
IndexBounds getIndexBoundsForQuery(const BSONObj& key, const CanonicalQuery& canonicalQuery);
namespace shard_key_pattern_query_util {
struct QueryTargetingInfo {
enum Description { kSingleKey, kMultipleKeys, kMinKeyToMaxKey };
Description desc;
std::set<ChunkRange> chunkRanges;
};
} // namespace shard_key_pattern_query_util
/**
* Populates 'shardIds' with the shard ids for a query with given filter and collation. If the
* collation is empty, it uses the collection default collation for targeting. If 'info' is not
* null, populates it with the ChunkRanges that the query targets and a description about whether
* the query targets a single shard key value, multiple but not all shard key values or all shard
* key values.
*/
void getShardIdsForQuery(boost::intrusive_ptr<ExpressionContext> expCtx,
const BSONObj& query,
const BSONObj& collation,
const ChunkManager& cm,
std::set<ShardId>* shardIds,
shard_key_pattern_query_util::QueryTargetingInfo* info = nullptr);
} // namespace mongo
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