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queryoptimizer.cpp
928 lines (842 loc) · 33.9 KB
/
queryoptimizer.cpp
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/* queryoptimizer.cpp */
/**
* 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/>.
*/
#include "pch.h"
#include "db.h"
#include "btree.h"
#include "pdfile.h"
#include "queryoptimizer.h"
#include "cmdline.h"
#include "clientcursor.h"
#include <queue>
//#define DEBUGQO(x) cout << x << endl;
#define DEBUGQO(x)
namespace mongo {
void checkTableScanAllowed( const char * ns ) {
if ( ! cmdLine.noTableScan )
return;
if ( strstr( ns , ".system." ) ||
strstr( ns , "local." ) )
return;
if ( ! nsdetails( ns ) )
return;
uassert( 10111 , (string)"table scans not allowed:" + ns , ! cmdLine.noTableScan );
}
double elementDirection( const BSONElement &e ) {
if ( e.isNumber() )
return e.number();
return 1;
}
QueryPlan::QueryPlan(
NamespaceDetails *d, int idxNo,
const FieldRangeSet &fbs, const FieldRangeSet &originalFrs, const BSONObj &originalQuery, const BSONObj &order, const BSONObj &startKey, const BSONObj &endKey , string special ) :
_d(d), _idxNo(idxNo),
_fbs( fbs ),
_originalQuery( originalQuery ),
_order( order ),
_index( 0 ),
_optimal( false ),
_scanAndOrderRequired( true ),
_exactKeyMatch( false ),
_direction( 0 ),
_endKeyInclusive( endKey.isEmpty() ),
_unhelpful( false ),
_special( special ),
_type(0),
_startOrEndSpec( !startKey.isEmpty() || !endKey.isEmpty() ) {
if ( !_fbs.matchPossible() ) {
_unhelpful = true;
_scanAndOrderRequired = false;
return;
}
if( _idxNo >= 0 ) {
_index = &d->idx(_idxNo);
}
else {
// full table scan case
if ( _order.isEmpty() || !strcmp( _order.firstElement().fieldName(), "$natural" ) )
_scanAndOrderRequired = false;
return;
}
if ( _special.size() ) {
_optimal = true;
_type = _index->getSpec().getType();
massert( 13040 , (string)"no type for special: " + _special , _type );
// hopefully safe to use original query in these contexts - don't think we can mix special with $or clause separation yet
_scanAndOrderRequired = _type->scanAndOrderRequired( _originalQuery , order );
return;
}
BSONObj idxKey = _index->keyPattern();
BSONObjIterator o( order );
BSONObjIterator k( idxKey );
if ( !o.moreWithEOO() )
_scanAndOrderRequired = false;
while( o.moreWithEOO() ) {
BSONElement oe = o.next();
if ( oe.eoo() ) {
_scanAndOrderRequired = false;
break;
}
if ( !k.moreWithEOO() )
break;
BSONElement ke;
while( 1 ) {
ke = k.next();
if ( ke.eoo() )
goto doneCheckOrder;
if ( strcmp( oe.fieldName(), ke.fieldName() ) == 0 )
break;
if ( !fbs.range( ke.fieldName() ).equality() )
goto doneCheckOrder;
}
int d = elementDirection( oe ) == elementDirection( ke ) ? 1 : -1;
if ( _direction == 0 )
_direction = d;
else if ( _direction != d )
break;
}
doneCheckOrder:
if ( _scanAndOrderRequired )
_direction = 0;
BSONObjIterator i( idxKey );
int exactIndexedQueryCount = 0;
int optimalIndexedQueryCount = 0;
bool stillOptimalIndexedQueryCount = true;
set< string > orderFieldsUnindexed;
order.getFieldNames( orderFieldsUnindexed );
while( i.moreWithEOO() ) {
BSONElement e = i.next();
if ( e.eoo() )
break;
const FieldRange &fb = fbs.range( e.fieldName() );
if ( stillOptimalIndexedQueryCount ) {
if ( fb.nontrivial() )
++optimalIndexedQueryCount;
if ( !fb.equality() )
stillOptimalIndexedQueryCount = false;
}
else {
if ( fb.nontrivial() )
optimalIndexedQueryCount = -1;
}
if ( fb.equality() ) {
BSONElement e = fb.max();
if ( !e.isNumber() && !e.mayEncapsulate() && e.type() != RegEx )
++exactIndexedQueryCount;
}
orderFieldsUnindexed.erase( e.fieldName() );
}
if ( !_scanAndOrderRequired &&
( optimalIndexedQueryCount == fbs.nNontrivialRanges() ) )
_optimal = true;
if ( exactIndexedQueryCount == fbs.nNontrivialRanges() &&
orderFieldsUnindexed.size() == 0 &&
exactIndexedQueryCount == _index->keyPattern().nFields() &&
exactIndexedQueryCount == _originalQuery.nFields() ) {
_exactKeyMatch = true;
}
_frv.reset( new FieldRangeVector( fbs, idxKey, _direction ) );
_originalFrv.reset( new FieldRangeVector( originalFrs, idxKey, _direction ) );
if ( _startOrEndSpec ) {
BSONObj newStart, newEnd;
if ( !startKey.isEmpty() )
_startKey = startKey;
else
_startKey = _frv->startKey();
if ( !endKey.isEmpty() )
_endKey = endKey;
else
_endKey = _frv->endKey();
}
if ( ( _scanAndOrderRequired || _order.isEmpty() ) &&
!fbs.range( idxKey.firstElement().fieldName() ).nontrivial() ) {
_unhelpful = true;
}
}
shared_ptr<Cursor> QueryPlan::newCursor( const DiskLoc &startLoc , int numWanted ) const {
if ( _type ) {
// hopefully safe to use original query in these contexts - don't think we can mix type with $or clause separation yet
return _type->newCursor( _originalQuery , _order , numWanted );
}
if ( !_fbs.matchPossible() ) {
if ( _fbs.nNontrivialRanges() )
checkTableScanAllowed( _fbs.ns() );
return shared_ptr<Cursor>( new BasicCursor( DiskLoc() ) );
}
if ( !_index ) {
if ( _fbs.nNontrivialRanges() )
checkTableScanAllowed( _fbs.ns() );
return findTableScan( _fbs.ns(), _order, startLoc );
}
massert( 10363 , "newCursor() with start location not implemented for indexed plans", startLoc.isNull() );
if ( _startOrEndSpec ) {
// we are sure to spec _endKeyInclusive
return shared_ptr<Cursor>( new BtreeCursor( _d, _idxNo, *_index, _startKey, _endKey, _endKeyInclusive, _direction >= 0 ? 1 : -1 ) );
}
else if ( _index->getSpec().getType() ) {
return shared_ptr<Cursor>( new BtreeCursor( _d, _idxNo, *_index, _frv->startKey(), _frv->endKey(), true, _direction >= 0 ? 1 : -1 ) );
}
else {
return shared_ptr<Cursor>( new BtreeCursor( _d, _idxNo, *_index, _frv, _direction >= 0 ? 1 : -1 ) );
}
}
shared_ptr<Cursor> QueryPlan::newReverseCursor() const {
if ( !_fbs.matchPossible() )
return shared_ptr<Cursor>( new BasicCursor( DiskLoc() ) );
if ( !_index ) {
int orderSpec = _order.getIntField( "$natural" );
if ( orderSpec == INT_MIN )
orderSpec = 1;
return findTableScan( _fbs.ns(), BSON( "$natural" << -orderSpec ) );
}
massert( 10364 , "newReverseCursor() not implemented for indexed plans", false );
return shared_ptr<Cursor>();
}
BSONObj QueryPlan::indexKey() const {
if ( !_index )
return BSON( "$natural" << 1 );
return _index->keyPattern();
}
void QueryPlan::registerSelf( long long nScanned ) const {
if ( _fbs.matchPossible() ) {
scoped_lock lk(NamespaceDetailsTransient::_qcMutex);
NamespaceDetailsTransient::get_inlock( ns() ).registerIndexForPattern( _fbs.pattern( _order ), indexKey(), nScanned );
}
}
bool QueryPlan::isMultiKey() const {
if ( _idxNo < 0 )
return false;
return _d->isMultikey( _idxNo );
}
QueryPlanSet::QueryPlanSet( const char *ns, auto_ptr< FieldRangeSet > frs, auto_ptr< FieldRangeSet > originalFrs, const BSONObj &originalQuery, const BSONObj &order, const BSONElement *hint, bool honorRecordedPlan, const BSONObj &min, const BSONObj &max, bool bestGuessOnly, bool mayYield ) :
_ns(ns),
_originalQuery( originalQuery ),
_fbs( frs ),
_originalFrs( originalFrs ),
_mayRecordPlan( true ),
_usingPrerecordedPlan( false ),
_hint( BSONObj() ),
_order( order.getOwned() ),
_oldNScanned( 0 ),
_honorRecordedPlan( honorRecordedPlan ),
_min( min.getOwned() ),
_max( max.getOwned() ),
_bestGuessOnly( bestGuessOnly ),
_mayYield( mayYield ),
_yieldSometimesTracker( 256, 20 ) {
if ( hint && !hint->eoo() ) {
_hint = hint->wrap();
}
init();
}
bool QueryPlanSet::modifiedKeys() const {
for( PlanSet::const_iterator i = _plans.begin(); i != _plans.end(); ++i )
if ( (*i)->isMultiKey() )
return true;
return false;
}
bool QueryPlanSet::hasMultiKey() const {
for( PlanSet::const_iterator i = _plans.begin(); i != _plans.end(); ++i )
if ( (*i)->isMultiKey() )
return true;
return false;
}
void QueryPlanSet::addHint( IndexDetails &id ) {
if ( !_min.isEmpty() || !_max.isEmpty() ) {
string errmsg;
BSONObj keyPattern = id.keyPattern();
// This reformats _min and _max to be used for index lookup.
massert( 10365 , errmsg, indexDetailsForRange( _fbs->ns(), errmsg, _min, _max, keyPattern ) );
}
NamespaceDetails *d = nsdetails(_ns);
_plans.push_back( QueryPlanPtr( new QueryPlan( d, d->idxNo(id), *_fbs, *_originalFrs, _originalQuery, _order, _min, _max ) ) );
}
// returns an IndexDetails * for a hint, 0 if hint is $natural.
// hint must not be eoo()
IndexDetails *parseHint( const BSONElement &hint, NamespaceDetails *d ) {
massert( 13292, "hint eoo", !hint.eoo() );
if( hint.type() == String ) {
string hintstr = hint.valuestr();
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
IndexDetails& ii = i.next();
if ( ii.indexName() == hintstr ) {
return ⅈ
}
}
}
else if( hint.type() == Object ) {
BSONObj hintobj = hint.embeddedObject();
uassert( 10112 , "bad hint", !hintobj.isEmpty() );
if ( !strcmp( hintobj.firstElement().fieldName(), "$natural" ) ) {
return 0;
}
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
IndexDetails& ii = i.next();
if( ii.keyPattern().woCompare(hintobj) == 0 ) {
return ⅈ
}
}
}
uassert( 10113 , "bad hint", false );
return 0;
}
void QueryPlanSet::init() {
DEBUGQO( "QueryPlanSet::init " << ns << "\t" << _originalQuery );
_plans.clear();
_mayRecordPlan = true;
_usingPrerecordedPlan = false;
const char *ns = _fbs->ns();
NamespaceDetails *d = nsdetails( ns );
if ( !d || !_fbs->matchPossible() ) {
// Table scan plan, when no matches are possible
_plans.push_back( QueryPlanPtr( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) ) );
return;
}
BSONElement hint = _hint.firstElement();
if ( !hint.eoo() ) {
_mayRecordPlan = false;
IndexDetails *id = parseHint( hint, d );
if ( id ) {
addHint( *id );
}
else {
massert( 10366 , "natural order cannot be specified with $min/$max", _min.isEmpty() && _max.isEmpty() );
// Table scan plan
_plans.push_back( QueryPlanPtr( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) ) );
}
return;
}
if ( !_min.isEmpty() || !_max.isEmpty() ) {
string errmsg;
BSONObj keyPattern;
IndexDetails *idx = indexDetailsForRange( ns, errmsg, _min, _max, keyPattern );
massert( 10367 , errmsg, idx );
_plans.push_back( QueryPlanPtr( new QueryPlan( d, d->idxNo(*idx), *_fbs, *_originalFrs, _originalQuery, _order, _min, _max ) ) );
return;
}
if ( isSimpleIdQuery( _originalQuery ) ) {
int idx = d->findIdIndex();
if ( idx >= 0 ) {
_usingPrerecordedPlan = true;
_mayRecordPlan = false;
_plans.push_back( QueryPlanPtr( new QueryPlan( d , idx , *_fbs , *_fbs , _originalQuery, _order ) ) );
return;
}
}
if ( _originalQuery.isEmpty() && _order.isEmpty() ) {
_plans.push_back( QueryPlanPtr( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) ) );
return;
}
DEBUGQO( "\t special : " << _fbs->getSpecial() );
if ( _fbs->getSpecial().size() ) {
_special = _fbs->getSpecial();
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
int j = i.pos();
IndexDetails& ii = i.next();
const IndexSpec& spec = ii.getSpec();
if ( spec.getTypeName() == _special && spec.suitability( _originalQuery , _order ) ) {
_usingPrerecordedPlan = true;
_mayRecordPlan = false;
_plans.push_back( QueryPlanPtr( new QueryPlan( d , j , *_fbs , *_fbs , _originalQuery, _order ,
BSONObj() , BSONObj() , _special ) ) );
return;
}
}
uassert( 13038 , (string)"can't find special index: " + _special + " for: " + _originalQuery.toString() , 0 );
}
if ( _honorRecordedPlan ) {
scoped_lock lk(NamespaceDetailsTransient::_qcMutex);
NamespaceDetailsTransient& nsd = NamespaceDetailsTransient::get_inlock( ns );
BSONObj bestIndex = nsd.indexForPattern( _fbs->pattern( _order ) );
if ( !bestIndex.isEmpty() ) {
QueryPlanPtr p;
_oldNScanned = nsd.nScannedForPattern( _fbs->pattern( _order ) );
if ( !strcmp( bestIndex.firstElement().fieldName(), "$natural" ) ) {
// Table scan plan
p.reset( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) );
}
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
int j = i.pos();
IndexDetails& ii = i.next();
if( ii.keyPattern().woCompare(bestIndex) == 0 ) {
p.reset( new QueryPlan( d, j, *_fbs, *_originalFrs, _originalQuery, _order ) );
}
}
massert( 10368 , "Unable to locate previously recorded index", p.get() );
if ( !( _bestGuessOnly && p->scanAndOrderRequired() ) ) {
_usingPrerecordedPlan = true;
_mayRecordPlan = false;
_plans.push_back( p );
return;
}
}
}
addOtherPlans( false );
}
void QueryPlanSet::addOtherPlans( bool checkFirst ) {
const char *ns = _fbs->ns();
NamespaceDetails *d = nsdetails( ns );
if ( !d )
return;
// If table scan is optimal or natural order requested or tailable cursor requested
if ( !_fbs->matchPossible() || ( _fbs->nNontrivialRanges() == 0 && _order.isEmpty() ) ||
( !_order.isEmpty() && !strcmp( _order.firstElement().fieldName(), "$natural" ) ) ) {
// Table scan plan
addPlan( QueryPlanPtr( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) ), checkFirst );
return;
}
bool normalQuery = _hint.isEmpty() && _min.isEmpty() && _max.isEmpty();
PlanSet plans;
for( int i = 0; i < d->nIndexes; ++i ) {
IndexDetails& id = d->idx(i);
const IndexSpec& spec = id.getSpec();
IndexSuitability suitability = HELPFUL;
if ( normalQuery ) {
suitability = spec.suitability( _fbs->simplifiedQuery() , _order );
if ( suitability == USELESS )
continue;
}
QueryPlanPtr p( new QueryPlan( d, i, *_fbs, *_originalFrs, _originalQuery, _order ) );
if ( p->optimal() ) {
addPlan( p, checkFirst );
return;
}
else if ( !p->unhelpful() ) {
plans.push_back( p );
}
}
for( PlanSet::iterator i = plans.begin(); i != plans.end(); ++i )
addPlan( *i, checkFirst );
// Table scan plan
addPlan( QueryPlanPtr( new QueryPlan( d, -1, *_fbs, *_originalFrs, _originalQuery, _order ) ), checkFirst );
}
shared_ptr< QueryOp > QueryPlanSet::runOp( QueryOp &op ) {
if ( _usingPrerecordedPlan ) {
Runner r( *this, op );
shared_ptr< QueryOp > res = r.run();
// _plans.size() > 1 if addOtherPlans was called in Runner::run().
if ( _bestGuessOnly || res->complete() || _plans.size() > 1 )
return res;
{
scoped_lock lk(NamespaceDetailsTransient::_qcMutex);
NamespaceDetailsTransient::get_inlock( _fbs->ns() ).registerIndexForPattern( _fbs->pattern( _order ), BSONObj(), 0 );
}
init();
}
Runner r( *this, op );
return r.run();
}
BSONObj QueryPlanSet::explain() const {
vector< BSONObj > arr;
for( PlanSet::const_iterator i = _plans.begin(); i != _plans.end(); ++i ) {
shared_ptr<Cursor> c = (*i)->newCursor();
BSONObjBuilder explain;
explain.append( "cursor", c->toString() );
explain.append( "indexBounds", c->prettyIndexBounds() );
arr.push_back( explain.obj() );
}
BSONObjBuilder b;
b.append( "allPlans", arr );
return b.obj();
}
QueryPlanSet::QueryPlanPtr QueryPlanSet::getBestGuess() const {
assert( _plans.size() );
if ( _plans[ 0 ]->scanAndOrderRequired() ) {
for ( unsigned i=1; i<_plans.size(); i++ ) {
if ( ! _plans[i]->scanAndOrderRequired() )
return _plans[i];
}
stringstream ss;
ss << "best guess plan requested, but scan and order required:";
ss << " query: " << _fbs->simplifiedQuery();
ss << " order: " << _order;
ss << " choices: ";
for ( unsigned i=0; i<_plans.size(); i++ ) {
ss << _plans[i]->indexKey() << " ";
}
string s = ss.str();
msgassertedNoTrace( 13284, s.c_str() );
}
return _plans[0];
}
QueryPlanSet::Runner::Runner( QueryPlanSet &plans, QueryOp &op ) :
_op( op ),
_plans( plans ) {
}
void QueryPlanSet::Runner::mayYield( const vector< shared_ptr< QueryOp > > &ops ) {
if ( _plans._mayYield ) {
if ( _plans._yieldSometimesTracker.ping() ) {
int micros = ClientCursor::yieldSuggest();
if ( micros > 0 ) {
for( vector< shared_ptr< QueryOp > >::const_iterator i = ops.begin(); i != ops.end(); ++i ) {
if ( !prepareToYield( **i ) ) {
return;
}
}
ClientCursor::staticYield( micros , _plans._ns );
for( vector< shared_ptr< QueryOp > >::const_iterator i = ops.begin(); i != ops.end(); ++i ) {
recoverFromYield( **i );
}
}
}
}
}
struct OpHolder {
OpHolder( const shared_ptr< QueryOp > &op ) : _op( op ), _offset() {}
shared_ptr< QueryOp > _op;
long long _offset;
bool operator<( const OpHolder &other ) const {
return _op->nscanned() + _offset > other._op->nscanned() + other._offset;
}
};
shared_ptr< QueryOp > QueryPlanSet::Runner::run() {
massert( 10369 , "no plans", _plans._plans.size() > 0 );
vector< shared_ptr< QueryOp > > ops;
if ( _plans._bestGuessOnly ) {
shared_ptr< QueryOp > op( _op.createChild() );
op->setQueryPlan( _plans.getBestGuess().get() );
ops.push_back( op );
}
else {
if ( _plans._plans.size() > 1 )
log(1) << " running multiple plans" << endl;
for( PlanSet::iterator i = _plans._plans.begin(); i != _plans._plans.end(); ++i ) {
shared_ptr< QueryOp > op( _op.createChild() );
op->setQueryPlan( i->get() );
ops.push_back( op );
}
}
for( vector< shared_ptr< QueryOp > >::iterator i = ops.begin(); i != ops.end(); ++i ) {
initOp( **i );
if ( (*i)->complete() )
return *i;
}
std::priority_queue< OpHolder > queue;
for( vector< shared_ptr< QueryOp > >::iterator i = ops.begin(); i != ops.end(); ++i ) {
if ( !(*i)->error() ) {
queue.push( *i );
}
}
while( !queue.empty() ) {
mayYield( ops );
OpHolder holder = queue.top();
queue.pop();
QueryOp &op = *holder._op;
nextOp( op );
if ( op.complete() ) {
if ( _plans._mayRecordPlan && op.mayRecordPlan() ) {
op.qp().registerSelf( op.nscanned() );
}
return holder._op;
}
if ( op.error() ) {
continue;
}
queue.push( holder );
if ( !_plans._bestGuessOnly && _plans._usingPrerecordedPlan && op.nscanned() > _plans._oldNScanned * 10 && _plans._special.empty() ) {
holder._offset = -op.nscanned();
_plans.addOtherPlans( true );
PlanSet::iterator i = _plans._plans.begin();
++i;
for( ; i != _plans._plans.end(); ++i ) {
shared_ptr< QueryOp > op( _op.createChild() );
op->setQueryPlan( i->get() );
ops.push_back( op );
initOp( *op );
if ( op->complete() )
return op;
queue.push( op );
}
_plans._mayRecordPlan = true;
_plans._usingPrerecordedPlan = false;
}
}
return ops[ 0 ];
}
#define GUARD_OP_EXCEPTION( op, expression ) \
try { \
expression; \
} \
catch ( DBException& e ) { \
op.setException( e.getInfo() ); \
} \
catch ( const std::exception &e ) { \
op.setException( ExceptionInfo( e.what() , 0 ) ); \
} \
catch ( ... ) { \
op.setException( ExceptionInfo( "Caught unknown exception" , 0 ) ); \
}
void QueryPlanSet::Runner::initOp( QueryOp &op ) {
GUARD_OP_EXCEPTION( op, op.init() );
}
void QueryPlanSet::Runner::nextOp( QueryOp &op ) {
GUARD_OP_EXCEPTION( op, if ( !op.error() ) { op.next(); } );
}
bool QueryPlanSet::Runner::prepareToYield( QueryOp &op ) {
GUARD_OP_EXCEPTION( op,
if ( op.error() ) {
return true;
}
else {
return op.prepareToYield();
} );
return true;
}
void QueryPlanSet::Runner::recoverFromYield( QueryOp &op ) {
GUARD_OP_EXCEPTION( op, if ( !op.error() ) { op.recoverFromYield(); } );
}
MultiPlanScanner::MultiPlanScanner( const char *ns,
const BSONObj &query,
const BSONObj &order,
const BSONElement *hint,
bool honorRecordedPlan,
const BSONObj &min,
const BSONObj &max,
bool bestGuessOnly,
bool mayYield ) :
_ns( ns ),
_or( !query.getField( "$or" ).eoo() ),
_query( query.getOwned() ),
_fros( ns, _query ),
_i(),
_honorRecordedPlan( honorRecordedPlan ),
_bestGuessOnly( bestGuessOnly ),
_hint( ( hint && !hint->eoo() ) ? hint->wrap() : BSONObj() ),
_mayYield( mayYield ),
_tableScanned() {
if ( !order.isEmpty() || !min.isEmpty() || !max.isEmpty() || !_fros.getSpecial().empty() ) {
_or = false;
}
if ( _or && uselessOr( _hint.firstElement() ) ) {
_or = false;
}
// if _or == false, don't use or clauses for index selection
if ( !_or ) {
auto_ptr< FieldRangeSet > frs( new FieldRangeSet( ns, _query ) );
auto_ptr< FieldRangeSet > oldFrs( new FieldRangeSet( *frs ) );
_currentQps.reset( new QueryPlanSet( ns, frs, oldFrs, _query, order, hint, honorRecordedPlan, min, max, _bestGuessOnly, _mayYield ) );
}
else {
BSONElement e = _query.getField( "$or" );
massert( 13268, "invalid $or spec", e.type() == Array && e.embeddedObject().nFields() > 0 );
}
}
shared_ptr< QueryOp > MultiPlanScanner::runOpOnce( QueryOp &op ) {
massert( 13271, "can't run more ops", mayRunMore() );
if ( !_or ) {
++_i;
return _currentQps->runOp( op );
}
++_i;
auto_ptr< FieldRangeSet > frs( _fros.topFrs() );
auto_ptr< FieldRangeSet > originalFrs( _fros.topFrsOriginal() );
BSONElement hintElt = _hint.firstElement();
_currentQps.reset( new QueryPlanSet( _ns, frs, originalFrs, _query, BSONObj(), &hintElt, _honorRecordedPlan, BSONObj(), BSONObj(), _bestGuessOnly, _mayYield ) );
shared_ptr< QueryOp > ret( _currentQps->runOp( op ) );
if ( ret->qp().willScanTable() ) {
_tableScanned = true;
}
_fros.popOrClause( ret->qp().indexed() ? ret->qp().indexKey() : BSONObj() );
return ret;
}
shared_ptr< QueryOp > MultiPlanScanner::runOp( QueryOp &op ) {
shared_ptr< QueryOp > ret = runOpOnce( op );
while( !ret->stopRequested() && mayRunMore() ) {
ret = runOpOnce( *ret );
}
return ret;
}
bool MultiPlanScanner::uselessOr( const BSONElement &hint ) const {
NamespaceDetails *nsd = nsdetails( _ns );
if ( !nsd ) {
return true;
}
IndexDetails *id = 0;
if ( !hint.eoo() ) {
IndexDetails *id = parseHint( hint, nsd );
if ( !id ) {
return true;
}
}
vector< BSONObj > ret;
_fros.allClausesSimplified( ret );
for( vector< BSONObj >::const_iterator i = ret.begin(); i != ret.end(); ++i ) {
if ( id ) {
if ( id->getSpec().suitability( *i, BSONObj() ) == USELESS ) {
return true;
}
}
else {
bool useful = false;
NamespaceDetails::IndexIterator j = nsd->ii();
while( j.more() ) {
IndexDetails &id = j.next();
if ( id.getSpec().suitability( *i, BSONObj() ) != USELESS ) {
useful = true;
break;
}
}
if ( !useful ) {
return true;
}
}
}
return false;
}
bool indexWorks( const BSONObj &idxPattern, const BSONObj &sampleKey, int direction, int firstSignificantField ) {
BSONObjIterator p( idxPattern );
BSONObjIterator k( sampleKey );
int i = 0;
while( 1 ) {
BSONElement pe = p.next();
BSONElement ke = k.next();
if ( pe.eoo() && ke.eoo() )
return true;
if ( pe.eoo() || ke.eoo() )
return false;
if ( strcmp( pe.fieldName(), ke.fieldName() ) != 0 )
return false;
if ( ( i == firstSignificantField ) && !( ( direction > 0 ) == ( pe.number() > 0 ) ) )
return false;
++i;
}
return false;
}
BSONObj extremeKeyForIndex( const BSONObj &idxPattern, int baseDirection ) {
BSONObjIterator i( idxPattern );
BSONObjBuilder b;
while( i.moreWithEOO() ) {
BSONElement e = i.next();
if ( e.eoo() )
break;
int idxDirection = e.number() >= 0 ? 1 : -1;
int direction = idxDirection * baseDirection;
switch( direction ) {
case 1:
b.appendMaxKey( e.fieldName() );
break;
case -1:
b.appendMinKey( e.fieldName() );
break;
default:
assert( false );
}
}
return b.obj();
}
pair< int, int > keyAudit( const BSONObj &min, const BSONObj &max ) {
int direction = 0;
int firstSignificantField = 0;
BSONObjIterator i( min );
BSONObjIterator a( max );
while( 1 ) {
BSONElement ie = i.next();
BSONElement ae = a.next();
if ( ie.eoo() && ae.eoo() )
break;
if ( ie.eoo() || ae.eoo() || strcmp( ie.fieldName(), ae.fieldName() ) != 0 ) {
return make_pair( -1, -1 );
}
int cmp = ie.woCompare( ae );
if ( cmp < 0 )
direction = 1;
if ( cmp > 0 )
direction = -1;
if ( direction != 0 )
break;
++firstSignificantField;
}
return make_pair( direction, firstSignificantField );
}
pair< int, int > flexibleKeyAudit( const BSONObj &min, const BSONObj &max ) {
if ( min.isEmpty() || max.isEmpty() ) {
return make_pair( 1, -1 );
}
else {
return keyAudit( min, 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 ) {
if ( min.isEmpty() && max.isEmpty() ) {
errmsg = "one of min or max must be specified";
return 0;
}
Client::Context ctx( ns );
IndexDetails *id = 0;
NamespaceDetails *d = nsdetails( ns );
if ( !d ) {
errmsg = "ns not found";
return 0;
}
pair< int, int > ret = flexibleKeyAudit( min, max );
if ( ret == make_pair( -1, -1 ) ) {
errmsg = "min and max keys do not share pattern";
return 0;
}
if ( keyPattern.isEmpty() ) {
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
IndexDetails& ii = i.next();
if ( indexWorks( ii.keyPattern(), min.isEmpty() ? max : min, ret.first, ret.second ) ) {
if ( ii.getSpec().getType() == 0 ) {
id = ⅈ
keyPattern = ii.keyPattern();
break;
}
}
}
}
else {
if ( !indexWorks( keyPattern, min.isEmpty() ? max : min, ret.first, ret.second ) ) {
errmsg = "requested keyPattern does not match specified keys";
return 0;
}
NamespaceDetails::IndexIterator i = d->ii();
while( i.more() ) {
IndexDetails& ii = i.next();
if( ii.keyPattern().woCompare(keyPattern) == 0 ) {
id = ⅈ
break;
}
if ( keyPattern.nFields() == 1 && ii.keyPattern().nFields() == 1 &&
IndexDetails::isIdIndexPattern( keyPattern ) &&
ii.isIdIndex() ) {
id = ⅈ
break;
}
}
}
if ( min.isEmpty() ) {
min = extremeKeyForIndex( keyPattern, -1 );
}
else if ( max.isEmpty() ) {
max = extremeKeyForIndex( keyPattern, 1 );
}
if ( !id ) {
errmsg = str::stream() << "no index found for specified keyPattern: " << keyPattern.toString()
<< " min: " << min << " max: " << max;
return 0;
}
min = min.extractFieldsUnDotted( keyPattern );
max = max.extractFieldsUnDotted( keyPattern );
return id;
}
} // namespace mongo