Skip to content


Subversion checkout URL

You can clone with
Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

162 lines (151 sloc) 6.351 kB
/* queryoptimizer.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
* 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 <>.
#pragma once
#include "cursor.h"
#include "jsobj.h"
#include "queryutil.h"
namespace mongo {
class IndexDetails;
class QueryPlan : boost::noncopyable {
QueryPlan(NamespaceDetails *_d,
int _idxNo, // -1 = no index
const FieldRangeSet &fbs,
const BSONObj &order,
const BSONObj &startKey = BSONObj(),
const BSONObj &endKey = BSONObj() );
/* If true, no other index can do better. */
bool optimal() const { return optimal_; }
/* ScanAndOrder processing will be required if true */
bool scanAndOrderRequired() const { return scanAndOrderRequired_; }
/* When true, the index we are using has keys such that it can completely resolve the
query expression to match by itself without ever checking the main object.
bool exactKeyMatch() const { return exactKeyMatch_; }
/* If true, the startKey and endKey are unhelpful and the index order doesn't match the
requested sort order */
bool unhelpful() const { return unhelpful_; }
int direction() const { return direction_; }
auto_ptr< Cursor > newCursor( const DiskLoc &startLoc = DiskLoc() ) const;
auto_ptr< Cursor > newReverseCursor() const;
BSONObj indexKey() const;
const char *ns() const { return fbs_.ns(); }
BSONObj query() const { return fbs_.query(); }
BSONObj simplifiedQuery( const BSONObj& fields = BSONObj() ) const { return fbs_.simplifiedQuery( fields ); }
const FieldRange &range( const char *fieldName ) const { return fbs_.range( fieldName ); }
void registerSelf( long long nScanned ) const;
// just for testing
BoundList indexBounds() const { return indexBounds_; }
NamespaceDetails *d;
int idxNo;
const FieldRangeSet &fbs_;
const BSONObj &order_;
const IndexDetails *index_;
bool optimal_;
bool scanAndOrderRequired_;
bool exactKeyMatch_;
int direction_;
BoundList indexBounds_;
bool endKeyInclusive_;
bool unhelpful_;
// Inherit from this interface to implement a new query operation.
// The query optimizer will clone the QueryOp that is provided, giving
// each clone its own query plan.
class QueryOp {
QueryOp() : complete_(), qp_(), error_() {}
virtual ~QueryOp() {}
virtual void init() = 0;
virtual void next() = 0;
virtual bool mayRecordPlan() const = 0;
// Return a copy of the inheriting class, which will be run with its own
// query plan.
virtual QueryOp *clone() const = 0;
bool complete() const { return complete_; }
bool error() const { return error_; }
string exceptionMessage() const { return exceptionMessage_; }
const QueryPlan &qp() const { return *qp_; }
// To be called by QueryPlanSet::Runner only.
void setQueryPlan( const QueryPlan *qp ) { qp_ = qp; }
void setExceptionMessage( const string &exceptionMessage ) {
error_ = true;
exceptionMessage_ = exceptionMessage;
void setComplete() { complete_ = true; }
bool complete_;
string exceptionMessage_;
const QueryPlan *qp_;
bool error_;
// Set of candidate query plans for a particular query. Used for running
// a QueryOp on these plans.
class QueryPlanSet {
QueryPlanSet( const char *ns,
const BSONObj &query,
const BSONObj &order,
const BSONElement *hint = 0,
bool honorRecordedPlan = true,
const BSONObj &min = BSONObj(),
const BSONObj &max = BSONObj() );
int nPlans() const { return plans_.size(); }
shared_ptr< QueryOp > runOp( QueryOp &op );
template< class T >
shared_ptr< T > runOp( T &op ) {
return dynamic_pointer_cast< T >( runOp( static_cast< QueryOp& >( op ) ) );
const FieldRangeSet &fbs() const { return fbs_; }
BSONObj explain() const;
bool usingPrerecordedPlan() const { return usingPrerecordedPlan_; }
void addOtherPlans( bool checkFirst );
typedef boost::shared_ptr< QueryPlan > PlanPtr;
typedef vector< PlanPtr > PlanSet;
void addPlan( PlanPtr plan, bool checkFirst ) {
if ( checkFirst && plan->indexKey().woCompare( plans_[ 0 ]->indexKey() ) == 0 )
plans_.push_back( plan );
void init();
void addHint( IndexDetails &id );
struct Runner {
Runner( QueryPlanSet &plans, QueryOp &op );
shared_ptr< QueryOp > run();
QueryOp &op_;
QueryPlanSet &plans_;
static void initOp( QueryOp &op );
static void nextOp( QueryOp &op );
const char *ns;
FieldRangeSet fbs_;
PlanSet plans_;
bool mayRecordPlan_;
bool usingPrerecordedPlan_;
BSONObj hint_;
BSONObj order_;
long long oldNScanned_;
bool honorRecordedPlan_;
BSONObj min_;
BSONObj max_;
// NOTE min, max, and keyPattern will be updated to be consistent with the selected index.
IndexDetails *indexDetailsForRange( const char *ns, string &errmsg, BSONObj &min, BSONObj &max, BSONObj &keyPattern );
} // namespace mongo
Jump to Line
Something went wrong with that request. Please try again.