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mongodb/db/index.h
2010-02-25 23:34:01 -05:00

289 lines
9.4 KiB
C++

// index.h
/**
* 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 "diskloc.h"
#include "jsobj.h"
#include <map>
namespace mongo {
class IndexSpec;
class IndexType; // TODO: this name sucks
class IndexPlugin;
class IndexDetails;
/**
* this represents an instance of a index plugin
* done this way so parsing, etc... can be cached
* so if there is a FTS IndexPlugin, for each index using FTS
* there will be 1 of these, and it can have things pre-parsed, etc...
*/
class IndexType : boost::noncopyable {
public:
IndexType( const IndexPlugin * plugin );
virtual ~IndexType();
virtual void getKeys( const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const = 0;
virtual int compare( const IndexSpec& spec , const BSONObj& l , const BSONObj& r ) const;
const IndexPlugin * getPlugin() const { return _plugin; }
virtual auto_ptr<Cursor> newCursor( const BSONObj& query , const BSONObj& order , int numWanted ) const = 0;
virtual BSONObj fixKey( const BSONObj& in ) { return in; }
protected:
const IndexPlugin * _plugin;
};
/**
* this represents a plugin
* a plugin could be something like full text search, sparse index, etc...
* 1 of these exists per type of index per server
* 1 IndexType is created per index using this plugin
*/
class IndexPlugin : boost::noncopyable {
public:
IndexPlugin( const string& name );
virtual ~IndexPlugin(){}
virtual IndexType* generate( const IndexSpec * spec ) const = 0;
static IndexPlugin* get( const string& name ){
if ( ! _plugins )
return 0;
map<string,IndexPlugin*>::iterator i = _plugins->find( name );
if ( i == _plugins->end() )
return 0;
return i->second;
}
string getName() const { return _name; }
private:
string _name;
static map<string,IndexPlugin*> * _plugins;
};
/* precomputed details about an index, used for inserting keys on updates
stored/cached in NamespaceDetailsTransient, or can be used standalone
*/
class IndexSpec {
public:
BSONObj keyPattern; // e.g., { name : 1 }
BSONObj info; // this is the same as IndexDetails::info.obj()
IndexSpec()
: _details(0) , _finishedInit(false){
}
IndexSpec( const BSONObj& k , const BSONObj& m = BSONObj() )
: keyPattern(k) , info(m) , _details(0) , _finishedInit(false){
_init();
}
/**
this is a DiscLoc of an IndexDetails info
should have a key field
*/
IndexSpec( const DiskLoc& loc ){
reset( loc );
}
void reset( const DiskLoc& loc );
void reset( const IndexDetails * details );
void getKeys( const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const;
BSONElement missingField() const { return _nullElt; }
string getTypeName() const {
if ( _indexType.get() )
return _indexType->getPlugin()->getName();
return "";
}
IndexType* getType() const {
return _indexType.get();
}
const IndexDetails * getDetails() const {
return _details;
}
protected:
void _getKeys( vector<const char*> fieldNames , vector<BSONElement> fixed , const BSONObj &obj, BSONObjSetDefaultOrder &keys ) const;
BSONSizeTracker _sizeTracker;
vector<const char*> _fieldNames;
vector<BSONElement> _fixed;
BSONObj _nullKey;
BSONObj _nullObj;
BSONElement _nullElt;
shared_ptr<IndexType> _indexType;
const IndexDetails * _details;
void _init();
public:
bool _finishedInit;
friend class IndexType;
};
/* Details about a particular index. There is one of these effectively for each object in
system.namespaces (although this also includes the head pointer, which is not in that
collection).
** MemoryMapped Record ** (i.e., this is on disk data)
*/
class IndexDetails {
public:
DiskLoc head; /* btree head disk location */
/* Location of index info object. Format:
{ name:"nameofindex", ns:"parentnsname", key: {keypattobject}
[, unique: <bool>, background: <bool>]
}
This object is in the system.indexes collection. Note that since we
have a pointer to the object here, the object in system.indexes MUST NEVER MOVE.
*/
DiskLoc info;
/* extract key value from the query object
e.g., if key() == { x : 1 },
{ x : 70, y : 3 } -> { x : 70 }
*/
BSONObj getKeyFromQuery(const BSONObj& query) const {
BSONObj k = keyPattern();
BSONObj res = query.extractFieldsUnDotted(k);
return res;
}
/* pull out the relevant key objects from obj, so we
can index them. Note that the set is multiple elements
only when it's a "multikey" array.
keys will be left empty if key not found in the object.
*/
void getKeysFromObject( const BSONObj& obj, BSONObjSetDefaultOrder& keys) const;
/* get the key pattern for this object.
e.g., { lastname:1, firstname:1 }
*/
BSONObj keyPattern() const {
return info.obj().getObjectField("key");
}
/* true if the specified key is in the index */
bool hasKey(const BSONObj& key);
bool wouldCreateDup(const BSONObj& key, DiskLoc self);
// returns name of this index's storage area
// database.table.$index
string indexNamespace() const {
BSONObj io = info.obj();
string s;
s.reserve(Namespace::MaxNsLen);
s = io.getStringField("ns");
assert( !s.empty() );
s += ".$";
s += io.getStringField("name");
return s;
}
string indexName() const { // e.g. "ts_1"
BSONObj io = info.obj();
return io.getStringField("name");
}
static bool isIdIndexPattern( const BSONObj &pattern ) {
BSONObjIterator i(pattern);
BSONElement e = i.next();
if( strcmp(e.fieldName(), "_id") != 0 ) return false;
return i.next().eoo();
}
/* returns true if this is the _id index. */
bool isIdIndex() const {
return isIdIndexPattern( keyPattern() );
}
/* gets not our namespace name (indexNamespace for that),
but the collection we index, its name.
*/
string parentNS() const {
BSONObj io = info.obj();
return io.getStringField("ns");
}
bool unique() const {
BSONObj io = info.obj();
return io["unique"].trueValue() ||
/* temp: can we juse make unique:true always be there for _id and get rid of this? */
isIdIndex();
}
/* if set, when building index, if any duplicates, drop the duplicating object */
bool dropDups() const {
return info.obj().getBoolField( "dropDups" );
}
/* delete this index. does NOT clean up the system catalog
(system.indexes or system.namespaces) -- only NamespaceIndex.
*/
void kill_idx();
const IndexSpec& getSpec() const;
operator string() const {
return info.obj().toString();
}
};
struct IndexChanges/*on an update*/ {
BSONObjSetDefaultOrder oldkeys;
BSONObjSetDefaultOrder newkeys;
vector<BSONObj*> removed; // these keys were removed as part of the change
vector<BSONObj*> added; // these keys were added as part of the change
/** @curObjLoc - the object we want to add's location. if it is already in the
index, that is allowed here (for bg indexing case).
*/
void dupCheck(IndexDetails& idx, DiskLoc curObjLoc) {
if( added.empty() || !idx.unique() )
return;
for( vector<BSONObj*>::iterator i = added.begin(); i != added.end(); i++ ) {
bool dup = idx.wouldCreateDup(**i, curObjLoc);
uassert( 11001 , "E11001 duplicate key on update", !dup);
}
}
};
class NamespaceDetails;
void getIndexChanges(vector<IndexChanges>& v, NamespaceDetails& d, BSONObj newObj, BSONObj oldObj);
void dupCheck(vector<IndexChanges>& v, NamespaceDetails& d, DiskLoc curObjLoc);
} // namespace mongo