diff options
Diffstat (limited to 'src/mongo/db/exec/count.cpp')
| -rw-r--r-- | src/mongo/db/exec/count.cpp | 301 |
1 files changed, 148 insertions, 153 deletions
diff --git a/src/mongo/db/exec/count.cpp b/src/mongo/db/exec/count.cpp index 7534f7e1e44..092c36dfc03 100644 --- a/src/mongo/db/exec/count.cpp +++ b/src/mongo/db/exec/count.cpp @@ -36,185 +36,180 @@ namespace mongo { - using std::unique_ptr; - using std::vector; - - // static - const char* CountStage::kStageType = "COUNT"; - - CountStage::CountStage(OperationContext* txn, - Collection* collection, - const CountRequest& request, - WorkingSet* ws, - PlanStage* child) - : _txn(txn), - _collection(collection), - _request(request), - _leftToSkip(request.getSkip()), - _ws(ws), - _child(child), - _commonStats(kStageType) { } - - CountStage::~CountStage() { } - - bool CountStage::isEOF() { - if (_specificStats.trivialCount) { - return true; - } - - if (_request.getLimit() > 0 && _specificStats.nCounted >= _request.getLimit()) { - return true; - } - - return NULL != _child.get() && _child->isEOF(); +using std::unique_ptr; +using std::vector; + +// static +const char* CountStage::kStageType = "COUNT"; + +CountStage::CountStage(OperationContext* txn, + Collection* collection, + const CountRequest& request, + WorkingSet* ws, + PlanStage* child) + : _txn(txn), + _collection(collection), + _request(request), + _leftToSkip(request.getSkip()), + _ws(ws), + _child(child), + _commonStats(kStageType) {} + +CountStage::~CountStage() {} + +bool CountStage::isEOF() { + if (_specificStats.trivialCount) { + return true; } - void CountStage::trivialCount() { - invariant(_collection); - long long nCounted = _collection->numRecords(_txn); + if (_request.getLimit() > 0 && _specificStats.nCounted >= _request.getLimit()) { + return true; + } - if (0 != _request.getSkip()) { - nCounted -= _request.getSkip(); - if (nCounted < 0) { - nCounted = 0; - } - } + return NULL != _child.get() && _child->isEOF(); +} - long long limit = _request.getLimit(); - if (limit < 0) { - limit = -limit; - } +void CountStage::trivialCount() { + invariant(_collection); + long long nCounted = _collection->numRecords(_txn); - if (limit < nCounted && 0 != limit) { - nCounted = limit; + if (0 != _request.getSkip()) { + nCounted -= _request.getSkip(); + if (nCounted < 0) { + nCounted = 0; } + } - _specificStats.nCounted = nCounted; - _specificStats.nSkipped = _request.getSkip(); - _specificStats.trivialCount = true; + long long limit = _request.getLimit(); + if (limit < 0) { + limit = -limit; } - PlanStage::StageState CountStage::work(WorkingSetID* out) { - ++_commonStats.works; + if (limit < nCounted && 0 != limit) { + nCounted = limit; + } - // Adds the amount of time taken by work() to executionTimeMillis. - ScopedTimer timer(&_commonStats.executionTimeMillis); + _specificStats.nCounted = nCounted; + _specificStats.nSkipped = _request.getSkip(); + _specificStats.trivialCount = true; +} - // This stage never returns a working set member. - *out = WorkingSet::INVALID_ID; +PlanStage::StageState CountStage::work(WorkingSetID* out) { + ++_commonStats.works; - // If we don't have a query and we have a non-NULL collection, then we can execute this - // as a trivial count (just ask the collection for how many records it has). - if (_request.getQuery().isEmpty() && NULL != _collection) { - trivialCount(); - return PlanStage::IS_EOF; - } + // Adds the amount of time taken by work() to executionTimeMillis. + ScopedTimer timer(&_commonStats.executionTimeMillis); - if (isEOF()) { - _commonStats.isEOF = true; - return PlanStage::IS_EOF; - } - - // For non-trivial counts, we should always have a child stage from which we can retrieve - // results. - invariant(_child.get()); - WorkingSetID id = WorkingSet::INVALID_ID; - PlanStage::StageState state = _child->work(&id); - - if (PlanStage::IS_EOF == state) { - _commonStats.isEOF = true; - return PlanStage::IS_EOF; - } - else if (PlanStage::DEAD == state) { - return state; - } - else if (PlanStage::FAILURE == state || PlanStage::DEAD == state) { - *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) { - const std::string errmsg = "count stage failed to read result from child"; - Status status = Status(ErrorCodes::InternalError, errmsg); - *out = WorkingSetCommon::allocateStatusMember(_ws, status); - } - return state; - } - else if (PlanStage::ADVANCED == state) { - // We got a result. If we're still skipping, then decrement the number left to skip. - // Otherwise increment the count until we hit the limit. - if (_leftToSkip > 0) { - _leftToSkip--; - _specificStats.nSkipped++; - } - else { - _specificStats.nCounted++; - } - - // Count doesn't need the actual results, so we just discard any valid working - // set members that got returned from the child. - if (WorkingSet::INVALID_ID != id) { - _ws->free(id); - } - } - else if (PlanStage::NEED_YIELD == state) { - *out = id; - _commonStats.needYield++; - return PlanStage::NEED_YIELD; - } + // This stage never returns a working set member. + *out = WorkingSet::INVALID_ID; - _commonStats.needTime++; - return PlanStage::NEED_TIME; + // If we don't have a query and we have a non-NULL collection, then we can execute this + // as a trivial count (just ask the collection for how many records it has). + if (_request.getQuery().isEmpty() && NULL != _collection) { + trivialCount(); + return PlanStage::IS_EOF; } - void CountStage::saveState() { - _txn = NULL; - ++_commonStats.yields; - if (_child.get()) { - _child->saveState(); - } + if (isEOF()) { + _commonStats.isEOF = true; + return PlanStage::IS_EOF; } - void CountStage::restoreState(OperationContext* opCtx) { - invariant(_txn == NULL); - _txn = opCtx; - ++_commonStats.unyields; - if (_child.get()) { - _child->restoreState(opCtx); - } + // For non-trivial counts, we should always have a child stage from which we can retrieve + // results. + invariant(_child.get()); + WorkingSetID id = WorkingSet::INVALID_ID; + PlanStage::StageState state = _child->work(&id); + + if (PlanStage::IS_EOF == state) { + _commonStats.isEOF = true; + return PlanStage::IS_EOF; + } else if (PlanStage::DEAD == state) { + return state; + } else if (PlanStage::FAILURE == state || PlanStage::DEAD == state) { + *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) { + const std::string errmsg = "count stage failed to read result from child"; + Status status = Status(ErrorCodes::InternalError, errmsg); + *out = WorkingSetCommon::allocateStatusMember(_ws, status); + } + return state; + } else if (PlanStage::ADVANCED == state) { + // We got a result. If we're still skipping, then decrement the number left to skip. + // Otherwise increment the count until we hit the limit. + if (_leftToSkip > 0) { + _leftToSkip--; + _specificStats.nSkipped++; + } else { + _specificStats.nCounted++; + } + + // Count doesn't need the actual results, so we just discard any valid working + // set members that got returned from the child. + if (WorkingSet::INVALID_ID != id) { + _ws->free(id); + } + } else if (PlanStage::NEED_YIELD == state) { + *out = id; + _commonStats.needYield++; + return PlanStage::NEED_YIELD; } - void CountStage::invalidate(OperationContext* txn, const RecordId& dl, InvalidationType type) { - ++_commonStats.invalidates; - if (_child.get()) { - _child->invalidate(txn, dl, type); - } - } + _commonStats.needTime++; + return PlanStage::NEED_TIME; +} - vector<PlanStage*> CountStage::getChildren() const { - vector<PlanStage*> children; - if (_child.get()) { - children.push_back(_child.get()); - } - return children; +void CountStage::saveState() { + _txn = NULL; + ++_commonStats.yields; + if (_child.get()) { + _child->saveState(); } - - PlanStageStats* CountStage::getStats() { - _commonStats.isEOF = isEOF(); - unique_ptr<PlanStageStats> ret(new PlanStageStats(_commonStats, STAGE_COUNT)); - CountStats* countStats = new CountStats(_specificStats); - ret->specific.reset(countStats); - if (_child.get()) { - ret->children.push_back(_child->getStats()); - } - return ret.release(); +} + +void CountStage::restoreState(OperationContext* opCtx) { + invariant(_txn == NULL); + _txn = opCtx; + ++_commonStats.unyields; + if (_child.get()) { + _child->restoreState(opCtx); } +} - const CommonStats* CountStage::getCommonStats() const { - return &_commonStats; +void CountStage::invalidate(OperationContext* txn, const RecordId& dl, InvalidationType type) { + ++_commonStats.invalidates; + if (_child.get()) { + _child->invalidate(txn, dl, type); } +} - const SpecificStats* CountStage::getSpecificStats() const { - return &_specificStats; +vector<PlanStage*> CountStage::getChildren() const { + vector<PlanStage*> children; + if (_child.get()) { + children.push_back(_child.get()); } + return children; +} + +PlanStageStats* CountStage::getStats() { + _commonStats.isEOF = isEOF(); + unique_ptr<PlanStageStats> ret(new PlanStageStats(_commonStats, STAGE_COUNT)); + CountStats* countStats = new CountStats(_specificStats); + ret->specific.reset(countStats); + if (_child.get()) { + ret->children.push_back(_child->getStats()); + } + return ret.release(); +} + +const CommonStats* CountStage::getCommonStats() const { + return &_commonStats; +} + +const SpecificStats* CountStage::getSpecificStats() const { + return &_specificStats; +} } // namespace mongo |