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/**
* Copyright (C) 2013 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <boost/scoped_ptr.hpp>
#include <map>
#include "mongo/bson/bsonobj.h"
#include "mongo/db/namespace_string.h"
#include "mongo/s/chunk.h"
#include "mongo/s/shard.h"
#include "mongo/s/chunk_version.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.
std::map<BSONObj, int> chunkSizeDelta;
};
/**
* NSTargeter based on a ChunkManager implementation. Wraps all exception codepaths and
* returns DatabaseNotFound statuses on applicable failures.
*
* Must be initialized before use, and initialization may fail.
*/
class ChunkManagerTargeter : public NSTargeter {
public:
ChunkManagerTargeter(const NamespaceString& nss);
/**
* Initializes the ChunkManagerTargeter with the latest targeting information for the
* namespace. May need to block and load information from a remote config server.
*
* Returns !OK if the information could not be initialized.
*/
Status init();
const NamespaceString& getNS() const;
// Returns ShardKeyNotFound if document does not have a full shard key.
Status targetInsert( const BSONObj& doc, ShardEndpoint** endpoint ) const;
// Returns ShardKeyNotFound if the update can't be targeted without a shard key.
Status targetUpdate( const BatchedUpdateDocument& updateDoc,
std::vector<ShardEndpoint*>* endpoints ) const;
// Returns ShardKeyNotFound if the delete can't be targeted without a shard key.
Status targetDelete( const BatchedDeleteDocument& deleteDoc,
std::vector<ShardEndpoint*>* endpoints ) const;
Status targetCollection( std::vector<ShardEndpoint*>* endpoints ) const;
Status targetAllShards( std::vector<ShardEndpoint*>* endpoints ) const;
void noteStaleResponse( const ShardEndpoint& endpoint, const BSONObj& staleInfo );
void noteCouldNotTarget();
/**
* 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.
*
* Reports wasChanged = true if the metadata is different after this reload.
*
* Also see NSTargeter::refreshIfNeeded().
*/
Status refreshIfNeeded( bool* wasChanged );
/**
* Returns the stats. Note that the returned stats object is still owned by this targeter.
*/
const TargeterStats* getStats() const;
private:
// Different ways we can refresh metadata
enum RefreshType {
// No refresh is needed
RefreshType_None,
// The version has gone up, but the collection hasn't been dropped
RefreshType_RefreshChunkManager,
// The collection may have been dropped, so we need to reload the db
RefreshType_ReloadDatabase
};
typedef std::map<std::string, ChunkVersion> ShardVersionMap;
/**
* Performs an actual refresh from the config server.
*/
Status refreshNow( RefreshType refreshType );
/**
* Returns a vector of ShardEndpoints where a document might need to be placed.
*
* Returns !OK with message if replacement could not be targeted
*/
Status targetDoc(const BSONObj& doc, std::vector<ShardEndpoint*>* endpoints) const;
/**
* Returns a vector of ShardEndpoints for a potentially multi-shard query.
*
* Returns !OK with message if query could not be targeted.
*/
Status targetQuery( const BSONObj& query, std::vector<ShardEndpoint*>* endpoints ) 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.
*/
Status targetShardKey(const BSONObj& doc,
long long estDataSize,
ShardEndpoint** endpoint) const;
// Full namespace of the collection for this targeter
const NamespaceString _nss;
// Stores whether we need to check the remote server on refresh
bool _needsTargetingRefresh;
// Represents only the view and not really part of the targeter state.
mutable TargeterStats _stats;
// Zero or one of these are filled at all times
// If sharded, _manager, if unsharded, _primary, on error, neither
ChunkManagerPtr _manager;
ShardPtr _primary;
// Map of shard->remote shard version reported from stale errors
ShardVersionMap _remoteShardVersions;
};
} // namespace mongo
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