UpdateResult update(const UpdateRequest& request, OpDebug* opDebug) { // Should the modifiers validate their embedded docs via okForStorage // Only user updates should be checked. Any system or replication stuff should pass through. // Config db docs shouldn't get checked for valid field names since the shard key can have // a dot (".") in it. bool shouldValidate = !(request.isFromReplication() || request.getNamespaceString().isConfigDB()); // TODO: Consider some sort of unification between the UpdateDriver, ModifierInterface // and UpdateRequest structures. UpdateDriver::Options opts; opts.multi = request.isMulti(); opts.upsert = request.isUpsert(); opts.logOp = request.shouldUpdateOpLog(); opts.modOptions = ModifierInterface::Options( request.isFromReplication(), shouldValidate ); UpdateDriver driver( opts ); Status status = driver.parse( request.getUpdates() ); if ( !status.isOK() ) { uasserted( 16840, status.reason() ); } return update(request, opDebug, &driver); }
UpdateResult update(const UpdateRequest& request, OpDebug* opDebug, UpdateDriver* driver) { LOG(3) << "processing update : " << request; const NamespaceString& nsString = request.getNamespaceString(); validateUpdate( nsString.ns().c_str(), request.getUpdates(), request.getQuery() ); NamespaceDetails* nsDetails = nsdetails( nsString.ns() ); NamespaceDetailsTransient* nsDetailsTransient = &NamespaceDetailsTransient::get( nsString.ns().c_str() ); // TODO: This seems a bit circuitious. opDebug->updateobj = request.getUpdates(); driver->refreshIndexKeys( nsDetailsTransient->indexKeys() ); shared_ptr<Cursor> cursor = getOptimizedCursor( nsString.ns(), request.getQuery(), BSONObj(), request.getQueryPlanSelectionPolicy() ); // If the update was marked with '$isolated' (a.k.a '$atomic'), we are not allowed to // yield while evaluating the update loop below. // // TODO: Old code checks this repeatedly within the update loop. Is that necessary? It seems // that once atomic should be always atomic. const bool isolated = cursor->ok() && cursor->matcher() && cursor->matcher()->docMatcher().atomic(); // The 'cursor' the optimizer gave us may contain query plans that generate duplicate // diskloc's. We set up here the mechanims that will prevent us from processing those // twice if we see them. We also set up a 'ClientCursor' so that we can support // yielding. // // TODO: Is it valid to call this on a non-ok cursor? const bool dedupHere = cursor->autoDedup(); // // We'll start assuming we have one or more documents for this update. (Othwerwise, // we'll fallback to upserting.) // // We record that this will not be an upsert, in case a mod doesn't want to be applied // when in strict update mode. driver->setContext( ModifierInterface::ExecInfo::UPDATE_CONTEXT ); // Let's fetch each of them and pipe them through the update expression, making sure to // keep track of the necessary stats. Recall that we'll be pulling documents out of // cursors and some of them do not deduplicate the entries they generate. We have // deduping logic in here, too -- for now. unordered_set<DiskLoc, DiskLoc::Hasher> seenLocs; int numMatched = 0; // Reset these counters on each call. We might re-enter this function to retry this // update if we throw a page fault exception below, and we rely on these counters // reflecting only the actions taken locally. In particlar, we must have the no-op // counter reset so that we can meaningfully comapre it with numMatched above. opDebug->nscanned = 0; opDebug->nupdateNoops = 0; Client& client = cc(); mutablebson::Document doc; mutablebson::DamageVector damages; // If we are going to be yielding, we will need a ClientCursor scoped to this loop. We // only loop as long as the underlying cursor is OK. for ( auto_ptr<ClientCursor> clientCursor; cursor->ok(); ) { // If we haven't constructed a ClientCursor, and if the client allows us to throw // page faults, and if we are referring to a location that is likely not in // physical memory, then throw a PageFaultException. The entire operation will be // restarted. if ( clientCursor.get() == NULL && client.allowedToThrowPageFaultException() && !cursor->currLoc().isNull() && !cursor->currLoc().rec()->likelyInPhysicalMemory() ) { // We should never throw a PFE if we have already updated items. The numMatched // variable includes no-ops, which do not prevent us from raising a PFE, so if // numMatched is non-zero, we are still OK to throw as long all matched items // resulted in a no-op. dassert((numMatched == 0) || (numMatched == opDebug->nupdateNoops)); throw PageFaultException( cursor->currLoc().rec() ); } if ( !isolated && opDebug->nscanned != 0 ) { // We are permitted to yield. To do so we need a ClientCursor, so create one // now if we have not yet done so. if ( !clientCursor.get() ) clientCursor.reset( new ClientCursor( QueryOption_NoCursorTimeout, cursor, nsString.ns() ) ); // Ask the client cursor to yield. We get two bits of state back: whether or not // we yielded, and whether or not we correctly recovered from yielding. bool yielded = false; const bool recovered = clientCursor->yieldSometimes( ClientCursor::WillNeed, &yielded ); if ( !recovered ) { // If we failed to recover from the yield, then the ClientCursor is already // gone. Release it so we don't destroy it a second time. clientCursor.release(); break; } if ( !cursor->ok() ) { // If the cursor died while we were yielded, just get out of the update loop. break; } if ( yielded ) { // We yielded and recovered OK, and our cursor is still good. Details about // our namespace may have changed while we were yielded, so we re-acquire // them here. If we can't do so, escape the update loop. Otherwise, refresh // the driver so that it knows about what is currently indexed. nsDetails = nsdetails( nsString.ns() ); if ( !nsDetails ) break; nsDetailsTransient = &NamespaceDetailsTransient::get( nsString.ns().c_str() ); // TODO: This copies the index keys, but it may not need to do so. driver->refreshIndexKeys( nsDetailsTransient->indexKeys() ); } } // Let's fetch the next candidate object for this update. Record* record = cursor->_current(); DiskLoc loc = cursor->currLoc(); const BSONObj oldObj = loc.obj(); // We count how many documents we scanned even though we may skip those that are // deemed duplicated. The final 'numUpdated' and 'nscanned' numbers may differ for // that reason. opDebug->nscanned++; // Skips this document if it: // a) doesn't match the query portion of the update // b) was deemed duplicate by the underlying cursor machinery // // Now, if we are going to update the document, // c) we don't want to do so while the cursor is at it, as that may invalidate // the cursor. So, we advance to next document, before issuing the update. MatchDetails matchDetails; matchDetails.requestElemMatchKey(); if ( !cursor->currentMatches( &matchDetails ) ) { // a) cursor->advance(); continue; } else if ( cursor->getsetdup( loc ) && dedupHere ) { // b) cursor->advance(); continue; } else if (!driver->isDocReplacement() && request.isMulti()) { // c) cursor->advance(); if ( dedupHere ) { if ( seenLocs.count( loc ) ) { continue; } } // There are certain kind of cursors that hold multiple pointers to data // underneath. $or cursors is one example. In a $or cursor, it may be the case // that when we did the last advance(), we finished consuming documents from // one of $or child and started consuming the next one. In that case, it is // possible that the last document of the previous child is the same as the // first document of the next (see SERVER-5198 and jstests/orp.js). // // So we advance the cursor here until we see a new diskloc. // // Note that we won't be yielding, and we may not do so for a while if we find // a particularly duplicated sequence of loc's. That is highly unlikely, // though. (See SERVER-5725, if curious, but "stage" based $or will make that // ticket moot). while( cursor->ok() && loc == cursor->currLoc() ) { cursor->advance(); } } // For some (unfortunate) historical reasons, not all cursors would be valid after // a write simply because we advanced them to a document not affected by the write. // To protect in those cases, not only we engaged in the advance() logic above, but // we also tell the cursor we're about to write a document that we've just seen. // prepareToTouchEarlierIterate() requires calling later // recoverFromTouchingEarlierIterate(), so we make a note here to do so. bool touchPreviousDoc = request.isMulti() && cursor->ok(); if ( touchPreviousDoc ) { if ( clientCursor.get() ) clientCursor->setDoingDeletes( true ); cursor->prepareToTouchEarlierIterate(); } // Found a matching document numMatched++; // Ask the driver to apply the mods. It may be that the driver can apply those "in // place", that is, some values of the old document just get adjusted without any // change to the binary layout on the bson layer. It may be that a whole new // document is needed to accomodate the new bson layout of the resulting document. doc.reset( oldObj, mutablebson::Document::kInPlaceEnabled ); BSONObj logObj; // If there was a matched field, obtain it. string matchedField; if (matchDetails.hasElemMatchKey()) matchedField = matchDetails.elemMatchKey(); Status status = driver->update( matchedField, &doc, &logObj ); if ( !status.isOK() ) { uasserted( 16837, status.reason() ); } // If the driver applied the mods in place, we can ask the mutable for what // changed. We call those changes "damages". :) We use the damages to inform the // journal what was changed, and then apply them to the original document // ourselves. If, however, the driver applied the mods out of place, we ask it to // generate a new, modified document for us. In that case, the file manager will // take care of the journaling details for us. // // This code flow is admittedly odd. But, right now, journaling is baked in the file // manager. And if we aren't using the file manager, we have to do jounaling // ourselves. bool objectWasChanged = false; BSONObj newObj; const char* source = NULL; bool inPlace = doc.getInPlaceUpdates(&damages, &source); if ( inPlace && !driver->modsAffectIndices() ) { // If a set of modifiers were all no-ops, we are still 'in place', but there is // no work to do, in which case we want to consider the object unchanged. if (!damages.empty() ) { nsDetails->paddingFits(); // All updates were in place. Apply them via durability and writing pointer. mutablebson::DamageVector::const_iterator where = damages.begin(); const mutablebson::DamageVector::const_iterator end = damages.end(); for( ; where != end; ++where ) { const char* sourcePtr = source + where->sourceOffset; void* targetPtr = getDur().writingPtr( const_cast<char*>(oldObj.objdata()) + where->targetOffset, where->size); std::memcpy(targetPtr, sourcePtr, where->size); } objectWasChanged = true; opDebug->fastmod = true; } newObj = oldObj; } else { // The updates were not in place. Apply them through the file manager. newObj = doc.getObject(); DiskLoc newLoc = theDataFileMgr.updateRecord(nsString.ns().c_str(), nsDetails, nsDetailsTransient, record, loc, newObj.objdata(), newObj.objsize(), *opDebug); // If we've moved this object to a new location, make sure we don't apply // that update again if our traversal picks the objecta again. // // We also take note that the diskloc if the updates are affecting indices. // Chances are that we're traversing one of them and they may be multi key and // therefore duplicate disklocs. if ( newLoc != loc || driver->modsAffectIndices() ) { seenLocs.insert( newLoc ); } objectWasChanged = true; } // Log Obj if ( request.shouldUpdateOpLog() ) { if ( driver->isDocReplacement() || !logObj.isEmpty() ) { BSONObj idQuery = driver->makeOplogEntryQuery(newObj, request.isMulti()); logOp("u", nsString.ns().c_str(), logObj , &idQuery, NULL, request.isFromMigration(), &newObj); } } // If it was noop since the document didn't change, record that. if (!objectWasChanged) opDebug->nupdateNoops++; if (!request.isMulti()) { break; } // If we used the cursor mechanism that prepares an earlier seen document for a // write we need to tell such mechanisms that the write is over. if ( touchPreviousDoc ) { cursor->recoverFromTouchingEarlierIterate(); } getDur().commitIfNeeded(); } // TODO: Can this be simplified? if ((numMatched > 0) || (numMatched == 0 && !request.isUpsert()) ) { opDebug->nupdated = numMatched; return UpdateResult( numMatched > 0 /* updated existing object(s) */, !driver->isDocReplacement() /* $mod or obj replacement */, numMatched /* # of docments update, even no-ops */, BSONObj() ); } // // We haven't found any existing document so an insert is done // (upsert is true). // opDebug->upsert = true; // Since this is an insert (no docs found and upsert:true), we will be logging it // as an insert in the oplog. We don't need the driver's help to build the // oplog record, then. We also set the context of the update driver to the INSERT_CONTEXT. // Some mods may only work in that context (e.g. $setOnInsert). driver->setLogOp( false ); driver->setContext( ModifierInterface::ExecInfo::INSERT_CONTEXT ); BSONObj baseObj; // Reset the document we will be writing to doc.reset( baseObj, mutablebson::Document::kInPlaceDisabled ); if ( request.getQuery().hasElement("_id") ) { uassertStatusOK(doc.root().appendElement(request.getQuery().getField("_id"))); } // If this is a $mod base update, we need to generate a document by examining the // query and the mods. Otherwise, we can use the object replacement sent by the user // update command that was parsed by the driver before. // In the following block we handle the query part, and then do the regular mods after. if ( *request.getUpdates().firstElementFieldName() == '$' ) { uassertStatusOK(UpdateDriver::createFromQuery(request.getQuery(), doc)); opDebug->fastmodinsert = true; } // Apply the update modifications and then log the update as an insert manually. Status status = driver->update( StringData(), &doc, NULL /* no oplog record */); if ( !status.isOK() ) { uasserted( 16836, status.reason() ); } BSONObj newObj = doc.getObject(); theDataFileMgr.insertWithObjMod( nsString.ns().c_str(), newObj, false, request.isGod() ); if ( request.shouldUpdateOpLog() ) { logOp( "i", nsString.ns().c_str(), newObj, NULL, NULL, request.isFromMigration(), &newObj ); } opDebug->nupdated = 1; return UpdateResult( false /* updated a non existing document */, !driver->isDocReplacement() /* $mod or obj replacement? */, 1 /* count of updated documents */, newObj /* object that was upserted */ ); }
UpdateResult update( OperationContext* txn, Database* db, const UpdateRequest& request, OpDebug* opDebug, UpdateDriver* driver, CanonicalQuery* cq) { LOG(3) << "processing update : " << request; std::auto_ptr<CanonicalQuery> cqHolder(cq); const NamespaceString& nsString = request.getNamespaceString(); UpdateLifecycle* lifecycle = request.getLifecycle(); Collection* collection = db->getCollection(txn, nsString.ns()); validateUpdate(nsString.ns().c_str(), request.getUpdates(), request.getQuery()); // TODO: This seems a bit circuitious. opDebug->updateobj = request.getUpdates(); if (lifecycle) { lifecycle->setCollection(collection); driver->refreshIndexKeys(lifecycle->getIndexKeys()); } Runner* rawRunner; Status status = cq ? getRunner(collection, cqHolder.release(), &rawRunner) : getRunner(collection, nsString.ns(), request.getQuery(), &rawRunner, &cq); uassert(17243, "could not get runner " + request.getQuery().toString() + "; " + causedBy(status), status.isOK()); // Create the runner and setup all deps. auto_ptr<Runner> runner(rawRunner); // Register Runner with ClientCursor const ScopedRunnerRegistration safety(runner.get()); // // We'll start assuming we have one or more documents for this update. (Otherwise, // we'll fall-back to insert case (if upsert is true).) // // We are an update until we fall into the insert case below. driver->setContext(ModifierInterface::ExecInfo::UPDATE_CONTEXT); int numMatched = 0; // If the update was in-place, we may see it again. This only matters if we're doing // a multi-update; if we're not doing a multi-update we stop after one update and we // won't see any more docs. // // For example: If we're scanning an index {x:1} and performing {$inc:{x:5}}, we'll keep // moving the document forward and it will continue to reappear in our index scan. // Unless the index is multikey, the underlying query machinery won't de-dup. // // If the update wasn't in-place we may see it again. Our query may return the new // document and we wouldn't want to update that. // // So, no matter what, we keep track of where the doc wound up. typedef unordered_set<DiskLoc, DiskLoc::Hasher> DiskLocSet; const scoped_ptr<DiskLocSet> updatedLocs(request.isMulti() ? new DiskLocSet : NULL); // Reset these counters on each call. We might re-enter this function to retry this // update if we throw a page fault exception below, and we rely on these counters // reflecting only the actions taken locally. In particlar, we must have the no-op // counter reset so that we can meaningfully comapre it with numMatched above. opDebug->nscanned = 0; opDebug->nscannedObjects = 0; opDebug->nModified = 0; // Get the cached document from the update driver. mutablebson::Document& doc = driver->getDocument(); mutablebson::DamageVector damages; // Used during iteration of docs BSONObj oldObj; // Get first doc, and location Runner::RunnerState state = Runner::RUNNER_ADVANCED; uassert(ErrorCodes::NotMaster, mongoutils::str::stream() << "Not primary while updating " << nsString.ns(), !request.shouldCallLogOp() || repl::getGlobalReplicationCoordinator()->canAcceptWritesForDatabase( nsString.db())); while (true) { // Get next doc, and location DiskLoc loc; state = runner->getNext(&oldObj, &loc); if (state != Runner::RUNNER_ADVANCED) { if (state == Runner::RUNNER_EOF) { // We have reached the logical end of the loop, so do yielding recovery break; } else { uassertStatusOK(Status(ErrorCodes::InternalError, str::stream() << " Update query failed -- " << Runner::statestr(state))); } } // We fill this with the new locs of moved doc so we don't double-update. if (updatedLocs && updatedLocs->count(loc) > 0) { continue; } // We count how many documents we scanned even though we may skip those that are // deemed duplicated. The final 'numMatched' and 'nscanned' numbers may differ for // that reason. // TODO: Do we want to pull this out of the underlying query plan? opDebug->nscanned++; // Found a matching document opDebug->nscannedObjects++; numMatched++; // Ask the driver to apply the mods. It may be that the driver can apply those "in // place", that is, some values of the old document just get adjusted without any // change to the binary layout on the bson layer. It may be that a whole new // document is needed to accomodate the new bson layout of the resulting document. doc.reset(oldObj, mutablebson::Document::kInPlaceEnabled); BSONObj logObj; FieldRefSet updatedFields; Status status = Status::OK(); if (!driver->needMatchDetails()) { // If we don't need match details, avoid doing the rematch status = driver->update(StringData(), &doc, &logObj, &updatedFields); } else { // If there was a matched field, obtain it. MatchDetails matchDetails; matchDetails.requestElemMatchKey(); dassert(cq); verify(cq->root()->matchesBSON(oldObj, &matchDetails)); string matchedField; if (matchDetails.hasElemMatchKey()) matchedField = matchDetails.elemMatchKey(); // TODO: Right now, each mod checks in 'prepare' that if it needs positional // data, that a non-empty StringData() was provided. In principle, we could do // that check here in an else clause to the above conditional and remove the // checks from the mods. status = driver->update(matchedField, &doc, &logObj, &updatedFields); } if (!status.isOK()) { uasserted(16837, status.reason()); } // Ensure _id exists and is first uassertStatusOK(ensureIdAndFirst(doc)); // If the driver applied the mods in place, we can ask the mutable for what // changed. We call those changes "damages". :) We use the damages to inform the // journal what was changed, and then apply them to the original document // ourselves. If, however, the driver applied the mods out of place, we ask it to // generate a new, modified document for us. In that case, the file manager will // take care of the journaling details for us. // // This code flow is admittedly odd. But, right now, journaling is baked in the file // manager. And if we aren't using the file manager, we have to do jounaling // ourselves. bool docWasModified = false; BSONObj newObj; const char* source = NULL; bool inPlace = doc.getInPlaceUpdates(&damages, &source); // If something changed in the document, verify that no immutable fields were changed // and data is valid for storage. if ((!inPlace || !damages.empty()) ) { if (!(request.isFromReplication() || request.isFromMigration())) { const std::vector<FieldRef*>* immutableFields = NULL; if (lifecycle) immutableFields = lifecycle->getImmutableFields(); uassertStatusOK(validate(oldObj, updatedFields, doc, immutableFields, driver->modOptions()) ); } } // Save state before making changes runner->saveState(); if (inPlace && !driver->modsAffectIndices()) { // If a set of modifiers were all no-ops, we are still 'in place', but there is // no work to do, in which case we want to consider the object unchanged. if (!damages.empty() ) { collection->updateDocumentWithDamages( txn, loc, source, damages ); docWasModified = true; opDebug->fastmod = true; } newObj = oldObj; } else { // The updates were not in place. Apply them through the file manager. // XXX: With experimental document-level locking, we do not hold the sufficient // locks, so this would cause corruption. fassert(18516, !useExperimentalDocLocking); newObj = doc.getObject(); uassert(17419, str::stream() << "Resulting document after update is larger than " << BSONObjMaxUserSize, newObj.objsize() <= BSONObjMaxUserSize); StatusWith<DiskLoc> res = collection->updateDocument(txn, loc, newObj, true, opDebug); uassertStatusOK(res.getStatus()); DiskLoc newLoc = res.getValue(); docWasModified = true; // If the document moved, we might see it again in a collection scan (maybe it's // a document after our current document). // // If the document is indexed and the mod changes an indexed value, we might see it // again. For an example, see the comment above near declaration of updatedLocs. if (updatedLocs && (newLoc != loc || driver->modsAffectIndices())) { updatedLocs->insert(newLoc); } } // Restore state after modification uassert(17278, "Update could not restore runner state after updating a document.", runner->restoreState(txn)); // Call logOp if requested. if (request.shouldCallLogOp() && !logObj.isEmpty()) { BSONObj idQuery = driver->makeOplogEntryQuery(newObj, request.isMulti()); repl::logOp(txn, "u", nsString.ns().c_str(), logObj , &idQuery, NULL, request.isFromMigration()); } // Only record doc modifications if they wrote (exclude no-ops) if (docWasModified) opDebug->nModified++; if (!request.isMulti()) { break; } // Opportunity for journaling to write during the update. txn->recoveryUnit()->commitIfNeeded(); } // TODO: Can this be simplified? if ((numMatched > 0) || (numMatched == 0 && !request.isUpsert()) ) { opDebug->nMatched = numMatched; return UpdateResult(numMatched > 0 /* updated existing object(s) */, !driver->isDocReplacement() /* $mod or obj replacement */, opDebug->nModified /* number of modified docs, no no-ops */, numMatched /* # of docs matched/updated, even no-ops */, BSONObj()); } // // We haven't found any existing document so an insert is done // (upsert is true). // opDebug->upsert = true; // Since this is an insert (no docs found and upsert:true), we will be logging it // as an insert in the oplog. We don't need the driver's help to build the // oplog record, then. We also set the context of the update driver to the INSERT_CONTEXT. // Some mods may only work in that context (e.g. $setOnInsert). driver->setLogOp(false); driver->setContext(ModifierInterface::ExecInfo::INSERT_CONTEXT); // Reset the document we will be writing to doc.reset(); // This remains the empty object in the case of an object replacement, but in the case // of an upsert where we are creating a base object from the query and applying mods, // we capture the query as the original so that we can detect immutable field mutations. BSONObj original = BSONObj(); // Calling createFromQuery will populate the 'doc' with fields from the query which // creates the base of the update for the inserterd doc (because upsert was true) if (cq) { uassertStatusOK(driver->populateDocumentWithQueryFields(cq, doc)); // Validate the base doc, as taken from the query -- no fields means validate all. FieldRefSet noFields; uassertStatusOK(validate(BSONObj(), noFields, doc, NULL, driver->modOptions())); if (!driver->isDocReplacement()) { opDebug->fastmodinsert = true; // We need all the fields from the query to compare against for validation below. original = doc.getObject(); } else { original = request.getQuery(); } } else { fassert(17354, CanonicalQuery::isSimpleIdQuery(request.getQuery())); BSONElement idElt = request.getQuery()["_id"]; original = idElt.wrap(); fassert(17352, doc.root().appendElement(idElt)); } // Apply the update modifications and then log the update as an insert manually. FieldRefSet updatedFields; status = driver->update(StringData(), &doc, NULL, &updatedFields); if (!status.isOK()) { uasserted(16836, status.reason()); } // Ensure _id exists and is first uassertStatusOK(ensureIdAndFirst(doc)); // Validate that the object replacement or modifiers resulted in a document // that contains all the immutable keys and can be stored. if (!(request.isFromReplication() || request.isFromMigration())){ const std::vector<FieldRef*>* immutableFields = NULL; if (lifecycle) immutableFields = lifecycle->getImmutableFields(); // This will only validate the modified fields if not a replacement. uassertStatusOK(validate(original, updatedFields, doc, immutableFields, driver->modOptions()) ); } // Only create the collection if the doc will be inserted. if (!collection) { collection = db->getCollection(txn, request.getNamespaceString().ns()); if (!collection) { collection = db->createCollection(txn, request.getNamespaceString().ns()); } } // Insert the doc BSONObj newObj = doc.getObject(); uassert(17420, str::stream() << "Document to upsert is larger than " << BSONObjMaxUserSize, newObj.objsize() <= BSONObjMaxUserSize); StatusWith<DiskLoc> newLoc = collection->insertDocument(txn, newObj, !request.isGod() /*enforceQuota*/); uassertStatusOK(newLoc.getStatus()); if (request.shouldCallLogOp()) { repl::logOp(txn, "i", nsString.ns().c_str(), newObj, NULL, NULL, request.isFromMigration()); } opDebug->nMatched = 1; return UpdateResult(false /* updated a non existing document */, !driver->isDocReplacement() /* $mod or obj replacement? */, 1 /* docs written*/, 1 /* count of updated documents */, newObj /* object that was upserted */ ); }