static void handleCursorCommand(CursorId id, BSONObj& cmdObj, BSONObjBuilder& result) {
BSONElement batchSizeElem = cmdObj.getFieldDotted("cursor.batchSize");
const long long batchSize = batchSizeElem.isNumber()
? batchSizeElem.numberLong()
: 101; // same as query
ClientCursorPin pin(id);
ClientCursor* cursor = pin.c();
massert(16958, "Cursor shouldn't have been deleted",
cursor);
verify(cursor->isAggCursor);
PipelineRunner* runner = dynamic_cast<PipelineRunner*>(cursor->getRunner());
verify(runner);
try {
const string cursorNs = cursor->ns(); // we need this after cursor may have been deleted
// can't use result BSONObjBuilder directly since it won't handle exceptions correctly.
BSONArrayBuilder resultsArray;
const int byteLimit = MaxBytesToReturnToClientAtOnce;
BSONObj next;
for (int objCount = 0; objCount < batchSize; objCount++) {
// The initial getNext() on a PipelineRunner may be very expensive so we don't do it
// when batchSize is 0 since that indicates a desire for a fast return.
if (runner->getNext(&next, NULL) != Runner::RUNNER_ADVANCED) {
pin.deleteUnderlying();
id = 0;
cursor = NULL; // make it an obvious error to use cursor after this point
break;
}
if (resultsArray.len() + next.objsize() > byteLimit) {
// too big. next will be the first doc in the second batch
runner->pushBack(next);
break;
}
resultsArray.append(next);
}
if (cursor) {
// If a time limit was set on the pipeline, remaining time is "rolled over" to the
// cursor (for use by future getmore ops).
cursor->setLeftoverMaxTimeMicros( cc().curop()->getRemainingMaxTimeMicros() );
}
BSONObjBuilder cursorObj(result.subobjStart("cursor"));
cursorObj.append("id", id);
cursorObj.append("ns", cursorNs);
cursorObj.append("firstBatch", resultsArray.arr());
cursorObj.done();
}
catch (...) {
// Clean up cursor on way out of scope.
pin.deleteUnderlying();
throw;
}
}
void Command::appendCursorResponseObject(long long cursorId,
StringData cursorNamespace,
BSONArray firstBatch,
BSONObjBuilder* builder) {
BSONObjBuilder cursorObj(builder->subobjStart("cursor"));
cursorObj.append("id", cursorId);
cursorObj.append("ns", cursorNamespace);
cursorObj.append("firstBatch", firstBatch);
cursorObj.done();
}
void appendGetMoreResponseObject(long long cursorId,
StringData cursorNamespace,
BSONArray nextBatch,
BSONObjBuilder* builder) {
BSONObjBuilder cursorObj(builder->subobjStart(kCursorField));
cursorObj.append(kIdField, cursorId);
cursorObj.append(kNsField, cursorNamespace);
cursorObj.append(kBatchField, nextBatch);
cursorObj.done();
}
static void handleCursorCommand(CursorId id, BSONObj& cmdObj, BSONObjBuilder& result) {
BSONElement batchSizeElem = cmdObj.getFieldDotted("cursor.batchSize");
const long long batchSize = batchSizeElem.isNumber()
? batchSizeElem.numberLong()
: 101; // same as query
// Using limited cursor API that ignores many edge cases. Should be sufficient for commands.
ClientCursor::Pin pin(id);
ClientCursor* cursor = pin.c();
massert(16958, "Cursor shouldn't have been deleted",
cursor);
// Make sure this cursor won't disappear on us
fassert(16959, !cursor->c()->shouldDestroyOnNSDeletion());
fassert(16960, !cursor->c()->requiresLock());
try {
// can't use result BSONObjBuilder directly since it won't handle exceptions correctly.
BSONArrayBuilder resultsArray;
const int byteLimit = MaxBytesToReturnToClientAtOnce;
for (int objs = 0;
objs < batchSize && cursor->ok() && resultsArray.len() <= byteLimit;
objs++) {
// TODO may need special logic if cursor->current() would cause results to be > 16MB
resultsArray.append(cursor->current());
cursor->advance();
}
// The initial ok() on a cursor may be very expensive so we don't do it when batchSize
// is 0 since that indicates a desire for a fast return.
if (batchSize != 0 && !cursor->ok()) {
// There is no more data. Kill the cursor.
pin.release();
ClientCursor::erase(id);
id = 0;
}
BSONObjBuilder cursorObj(result.subobjStart("cursor"));
cursorObj.append("id", id);
cursorObj.append("ns", cursor->ns());
cursorObj.append("firstBatch", resultsArray.arr());
cursorObj.done();
}
catch (...) {
// Clean up cursor on way out of scope.
pin.release();
ClientCursor::erase(id);
throw;
}
}
static void handleCursorCommand(OperationContext* txn,
const string& ns,
ClientCursorPin* pin,
PlanExecutor* exec,
const BSONObj& cmdObj,
BSONObjBuilder& result) {
ClientCursor* cursor = pin ? pin->c() : NULL;
if (pin) {
invariant(cursor);
invariant(cursor->getExecutor() == exec);
invariant(cursor->isAggCursor());
}
BSONElement batchSizeElem = cmdObj.getFieldDotted("cursor.batchSize");
const long long batchSize = batchSizeElem.isNumber()
? batchSizeElem.numberLong()
: 101; // same as query
// can't use result BSONObjBuilder directly since it won't handle exceptions correctly.
BSONArrayBuilder resultsArray;
const int byteLimit = MaxBytesToReturnToClientAtOnce;
BSONObj next;
for (int objCount = 0; objCount < batchSize; objCount++) {
// The initial getNext() on a PipelineProxyStage may be very expensive so we don't
// do it when batchSize is 0 since that indicates a desire for a fast return.
if (exec->getNext(&next, NULL) != PlanExecutor::ADVANCED) {
if (pin) pin->deleteUnderlying();
// make it an obvious error to use cursor or executor after this point
cursor = NULL;
exec = NULL;
break;
}
if (resultsArray.len() + next.objsize() > byteLimit) {
// Get the pipeline proxy stage wrapped by this PlanExecutor.
PipelineProxyStage* proxy = static_cast<PipelineProxyStage*>(exec->getRootStage());
// too big. next will be the first doc in the second batch
proxy->pushBack(next);
break;
}
resultsArray.append(next);
}
// NOTE: exec->isEOF() can have side effects such as writing by $out. However, it should
// be relatively quick since if there was no pin then the input is empty. Also, this
// violates the contract for batchSize==0. Sharding requires a cursor to be returned in that
// case. This is ok for now however, since you can't have a sharded collection that doesn't
// exist.
const bool canReturnMoreBatches = pin;
if (!canReturnMoreBatches && exec && !exec->isEOF()) {
// msgasserting since this shouldn't be possible to trigger from today's aggregation
// language. The wording assumes that the only reason pin would be null is if the
// collection doesn't exist.
msgasserted(17391, str::stream()
<< "Aggregation has more results than fit in initial batch, but can't "
<< "create cursor since collection " << ns << " doesn't exist");
}
if (cursor) {
// If a time limit was set on the pipeline, remaining time is "rolled over" to the
// cursor (for use by future getmore ops).
cursor->setLeftoverMaxTimeMicros( txn->getCurOp()->getRemainingMaxTimeMicros() );
// We stash away the RecoveryUnit in the ClientCursor. It's used for subsequent
// getMore requests. The calling OpCtx gets a fresh RecoveryUnit.
cursor->setOwnedRecoveryUnit(txn->releaseRecoveryUnit());
StorageEngine* storageEngine = getGlobalEnvironment()->getGlobalStorageEngine();
txn->setRecoveryUnit(storageEngine->newRecoveryUnit());
// Cursor needs to be in a saved state while we yield locks for getmore. State
// will be restored in getMore().
exec->saveState();
}
BSONObjBuilder cursorObj(result.subobjStart("cursor"));
cursorObj.append("id", cursor ? cursor->cursorid() : 0LL);
cursorObj.append("ns", ns);
cursorObj.append("firstBatch", resultsArray.arr());
cursorObj.done();
}
static void handleCursorCommand(CursorId id, BSONObj& cmdObj, BSONObjBuilder& result) {
BSONElement batchSizeElem = cmdObj.getFieldDotted("cursor.batchSize");
const long long batchSize = batchSizeElem.isNumber()
? batchSizeElem.numberLong()
: 101; // same as query
// Using limited cursor API that ignores many edge cases. Should be sufficient for commands.
ClientCursorPin pin(id);
ClientCursor* cursor = pin.c();
massert(16958, "Cursor shouldn't have been deleted",
cursor);
// Make sure this cursor won't disappear on us
fassert(16959, !cursor->c()->shouldDestroyOnNSDeletion());
fassert(16960, !cursor->c()->requiresLock());
try {
const string cursorNs = cursor->ns(); // we need this after cursor may have been deleted
// can't use result BSONObjBuilder directly since it won't handle exceptions correctly.
BSONArrayBuilder resultsArray;
const int byteLimit = MaxBytesToReturnToClientAtOnce;
for (int objCount = 0; objCount < batchSize && cursor->ok(); objCount++) {
BSONObj current = cursor->current();
if (resultsArray.len() + current.objsize() > byteLimit)
break; // too big. current will be the first doc in the second batch
resultsArray.append(current);
cursor->advance();
}
// The initial ok() on a cursor may be very expensive so we don't do it when batchSize
// is 0 since that indicates a desire for a fast return.
if (batchSize != 0 && !cursor->ok()) {
// There is no more data. Kill the cursor.
pin.release();
ClientCursor::erase(id);
id = 0;
cursor = NULL; // make it an obvious error to use cursor after this point
}
if (cursor) {
// If a time limit was set on the pipeline, remaining time is "rolled over" to the
// cursor (for use by future getmore ops).
cursor->setLeftoverMaxTimeMicros( cc().curop()->getRemainingMaxTimeMicros() );
}
BSONObjBuilder cursorObj(result.subobjStart("cursor"));
cursorObj.append("id", id);
cursorObj.append("ns", cursorNs);
cursorObj.append("firstBatch", resultsArray.arr());
cursorObj.done();
}
catch (...) {
// Clean up cursor on way out of scope.
pin.release();
ClientCursor::erase(id);
throw;
}
}
static void handleCursorCommand(const string& ns,
ClientCursorPin* pin,
PipelineRunner* runner,
const BSONObj& cmdObj,
BSONObjBuilder& result) {
ClientCursor* cursor = pin ? pin->c() : NULL;
if (pin) {
invariant(cursor);
invariant(cursor->getRunner() == runner);
invariant(cursor->isAggCursor);
}
BSONElement batchSizeElem = cmdObj.getFieldDotted("cursor.batchSize");
const long long batchSize = batchSizeElem.isNumber()
? batchSizeElem.numberLong()
: 101; // same as query
// can't use result BSONObjBuilder directly since it won't handle exceptions correctly.
BSONArrayBuilder resultsArray;
const int byteLimit = MaxBytesToReturnToClientAtOnce;
BSONObj next;
for (int objCount = 0; objCount < batchSize; objCount++) {
// The initial getNext() on a PipelineRunner may be very expensive so we don't
// do it when batchSize is 0 since that indicates a desire for a fast return.
if (runner->getNext(&next, NULL) != Runner::RUNNER_ADVANCED) {
if (pin) pin->deleteUnderlying();
// make it an obvious error to use cursor or runner after this point
cursor = NULL;
runner = NULL;
break;
}
if (resultsArray.len() + next.objsize() > byteLimit) {
// too big. next will be the first doc in the second batch
runner->pushBack(next);
break;
}
resultsArray.append(next);
}
// NOTE: runner->isEOF() can have side effects such as writing by $out. However, it should
// be relatively quick since if there was no pin then the input is empty. Also, this
// violates the contract for batchSize==0. Sharding requires a cursor to be returned in that
// case. This is ok for now however, since you can't have a sharded collection that doesn't
// exist.
const bool canReturnMoreBatches = pin;
if (!canReturnMoreBatches && runner && !runner->isEOF()) {
// msgasserting since this shouldn't be possible to trigger from today's aggregation
// language. The wording assumes that the only reason pin would be null is if the
// collection doesn't exist.
msgasserted(17391, str::stream()
<< "Aggregation has more results than fit in initial batch, but can't "
<< "create cursor since collection " << ns << " doesn't exist");
}
if (cursor) {
// If a time limit was set on the pipeline, remaining time is "rolled over" to the
// cursor (for use by future getmore ops).
cursor->setLeftoverMaxTimeMicros( cc().curop()->getRemainingMaxTimeMicros() );
}
BSONObjBuilder cursorObj(result.subobjStart("cursor"));
cursorObj.append("id", cursor ? cursor->cursorid() : 0LL);
cursorObj.append("ns", ns);
cursorObj.append("firstBatch", resultsArray.arr());
cursorObj.done();
}
