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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.
*/
#include "mongo/db/exec/fetch.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/exec/filter.h"
#include "mongo/db/exec/working_set_common.h"
#include "mongo/util/fail_point_service.h"
#include "mongo/util/mongoutils/str.h"
namespace mongo {
// static
const char* FetchStage::kStageType = "FETCH";
FetchStage::FetchStage(WorkingSet* ws,
PlanStage* child,
const MatchExpression* filter,
const Collection* collection)
: _collection(collection),
_ws(ws),
_child(child),
_filter(filter),
_commonStats(kStageType) { }
FetchStage::~FetchStage() { }
bool FetchStage::isEOF() {
return _child->isEOF();
}
PlanStage::StageState FetchStage::work(WorkingSetID* out) {
++_commonStats.works;
// Adds the amount of time taken by work() to executionTimeMillis.
ScopedTimer timer(&_commonStats.executionTimeMillis);
if (isEOF()) { return PlanStage::IS_EOF; }
// If we're here, we're not waiting for a DiskLoc to be fetched. Get another to-be-fetched
// result from our child.
WorkingSetID id = WorkingSet::INVALID_ID;
StageState status = _child->work(&id);
if (PlanStage::ADVANCED == status) {
WorkingSetMember* member = _ws->get(id);
// If there's an obj there, there is no fetching to perform.
if (member->hasObj()) {
++_specificStats.alreadyHasObj;
}
else {
// We need a valid loc to fetch from and this is the only state that has one.
verify(WorkingSetMember::LOC_AND_IDX == member->state);
verify(member->hasLoc());
// Don't need index data anymore as we have an obj.
member->keyData.clear();
member->obj = _collection->docFor(member->loc);
member->state = WorkingSetMember::LOC_AND_UNOWNED_OBJ;
}
++_specificStats.docsExamined;
return returnIfMatches(member, id, out);
}
else if (PlanStage::FAILURE == status) {
*out = id;
// If a stage fails, it may create a status WSM to indicate why it
// failed, in which case 'id' is valid. If ID is invalid, we
// create our own error message.
if (WorkingSet::INVALID_ID == id) {
mongoutils::str::stream ss;
ss << "fetch stage failed to read in results from child";
Status status(ErrorCodes::InternalError, ss);
*out = WorkingSetCommon::allocateStatusMember( _ws, status);
}
return status;
}
else {
if (PlanStage::NEED_TIME == status) {
++_commonStats.needTime;
}
return status;
}
}
void FetchStage::prepareToYield() {
++_commonStats.yields;
_child->prepareToYield();
}
void FetchStage::recoverFromYield(OperationContext* opCtx) {
++_commonStats.unyields;
_child->recoverFromYield(opCtx);
}
void FetchStage::invalidate(const DiskLoc& dl, InvalidationType type) {
++_commonStats.invalidates;
_child->invalidate(dl, type);
}
PlanStage::StageState FetchStage::returnIfMatches(WorkingSetMember* member,
WorkingSetID memberID,
WorkingSetID* out) {
if (Filter::passes(member, _filter)) {
if (NULL != _filter) {
++_specificStats.matchTested;
}
*out = memberID;
++_commonStats.advanced;
return PlanStage::ADVANCED;
}
else {
_ws->free(memberID);
++_commonStats.needTime;
return PlanStage::NEED_TIME;
}
}
vector<PlanStage*> FetchStage::getChildren() const {
vector<PlanStage*> children;
children.push_back(_child.get());
return children;
}
PlanStageStats* FetchStage::getStats() {
_commonStats.isEOF = isEOF();
// Add a BSON representation of the filter to the stats tree, if there is one.
if (NULL != _filter) {
BSONObjBuilder bob;
_filter->toBSON(&bob);
_commonStats.filter = bob.obj();
}
auto_ptr<PlanStageStats> ret(new PlanStageStats(_commonStats, STAGE_FETCH));
ret->specific.reset(new FetchStats(_specificStats));
ret->children.push_back(_child->getStats());
return ret.release();
}
const CommonStats* FetchStage::getCommonStats() {
return &_commonStats;
}
const SpecificStats* FetchStage::getSpecificStats() {
return &_specificStats;
}
} // namespace mongo
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