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// shard.h
/*
A "shard" is a database (replica pair typically) which represents
one partition of the overall database.
*/
/**
* Copyright (C) 2008 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/>.
*/
#pragma once
#include "../stdafx.h"
#include "../client/dbclient.h"
#include "../client/model.h"
#include "shardkey.h"
#include <boost/utility.hpp>
#undef assert
#define assert xassert
namespace mongo {
class DBConfig;
class ChunkManager;
class ChunkObjUnitTest;
typedef unsigned long long ShardChunkVersion;
/**
config.chunks
{ ns : "alleyinsider.fs.chunks" , min : {} , max : {} , server : "localhost:30001" }
x is in a shard iff
min <= x < max
*/
class Chunk : public Model , boost::noncopyable {
public:
Chunk( ChunkManager * info );
const BSONObj& getMin() const { return _min; }
const BSONObj& getMax() const { return _max; }
void setMin(const BSONObj& o){
_min = o;
}
void setMax(const BSONObj& o){
_max = o;
}
string getShard(){
return _shard;
}
void setShard( string shard );
bool contains( const BSONObj& obj );
string toString() const;
operator string() const { return toString(); }
bool operator==(const Chunk& s);
bool operator!=(const Chunk& s){
return ! ( *this == s );
}
void getFilter( BSONObjBuilder& b );
BSONObj getFilter(){ BSONObjBuilder b; getFilter( b ); return b.obj(); }
BSONObj pickSplitPoint();
Chunk * split();
Chunk * split( const BSONObj& middle );
/**
* @return size of shard in bytes
* talks to mongod to do this
*/
long getPhysicalSize();
long countObjects( const BSONObj& filter = BSONObj() );
/**
* if the amount of data written nears the max size of a shard
* then we check the real size, and if its too big, we split
*/
bool splitIfShould( long dataWritten );
/*
* moves either this shard or newShard if it makes sense too
* @return whether or not a shard was moved
*/
bool moveIfShould( Chunk * newShard = 0 );
bool moveAndCommit( const string& to , string& errmsg );
virtual const char * getNS(){ return "config.chunks"; }
virtual void serialize(BSONObjBuilder& to);
virtual void unserialize(const BSONObj& from);
virtual string modelServer();
virtual void save( bool check=false );
void ensureIndex();
void _markModified();
static long MaxChunkSize;
private:
// main shard info
ChunkManager * _manager;
ShardKeyPattern skey();
string _ns;
BSONObj _min;
BSONObj _max;
string _shard;
ShardChunkVersion _lastmod;
bool _modified;
// transient stuff
long _dataWritten;
// methods, etc..
void _split( BSONObj& middle );
friend class ChunkManager;
friend class ShardObjUnitTest;
};
/* config.sharding
{ ns: 'alleyinsider.fs.chunks' ,
key: { ts : 1 } ,
shards: [ { min: 1, max: 100, server: a } , { min: 101, max: 200 , server : b } ]
}
*/
class ChunkManager {
public:
ChunkManager( DBConfig * config , string ns , ShardKeyPattern pattern , bool unique );
virtual ~ChunkManager();
string getns(){
return _ns;
}
int numChunks(){ return _chunks.size(); }
Chunk* getChunk( int i ){ return _chunks[i]; }
bool hasShardKey( const BSONObj& obj );
Chunk& findChunk( const BSONObj& obj );
Chunk* findChunkOnServer( const string& server ) const;
ShardKeyPattern& getShardKey(){ return _key; }
bool isUnique(){ return _unique; }
/**
* makes sure the shard index is on all servers
*/
void ensureIndex();
/**
* @return number of Chunk added to the vector
*/
int getChunksForQuery( vector<Chunk*>& chunks , const BSONObj& query );
void getAllServers( set<string>& allServers );
void save();
string toString() const;
operator string() const { return toString(); }
ShardChunkVersion getVersion( const string& server ) const;
ShardChunkVersion getVersion() const;
/**
* this is just an increasing number of how many ChunkManagers we have so we know if something has been updated
*/
unsigned long long getSequenceNumber(){
return _sequenceNumber;
}
void drop();
private:
DBConfig * _config;
string _ns;
ShardKeyPattern _key;
bool _unique;
vector<Chunk*> _chunks;
map<string,unsigned long long> _maxMarkers;
unsigned long long _sequenceNumber;
friend class Chunk;
static unsigned long long NextSequenceNumber;
};
} // namespace mongo
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