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/**
* Copyright (C) 2012-2014 MongoDB 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
#include "mongo/platform/basic.h"
#include "mongo/db/commands/find_and_modify.h"
#include <memory>
#include <boost/optional.hpp>
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/exec/working_set_common.h"
#include "mongo/db/lasterror.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/ops/delete_request.h"
#include "mongo/db/ops/insert.h"
#include "mongo/db/ops/parsed_delete.h"
#include "mongo/db/ops/parsed_update.h"
#include "mongo/db/ops/update_lifecycle_impl.h"
#include "mongo/db/ops/update_request.h"
#include "mongo/db/query/explain.h"
#include "mongo/db/query/find_and_modify_request.h"
#include "mongo/db/query/get_executor.h"
#include "mongo/db/query/plan_executor.h"
#include "mongo/db/repl/repl_client_info.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/db/write_concern.h"
#include "mongo/s/d_state.h"
#include "mongo/util/log.h"
namespace mongo {
namespace {
const UpdateStats* getUpdateStats(const PlanStageStats* stats) {
// The stats may refer to an update stage, or a projection stage wrapping an update stage.
if (StageType::STAGE_PROJECTION == stats->stageType) {
invariant(stats->children.size() == 1);
stats = stats->children[0];
}
invariant(StageType::STAGE_UPDATE == stats->stageType);
return static_cast<UpdateStats*>(stats->specific.get());
}
const DeleteStats* getDeleteStats(const PlanStageStats* stats) {
// The stats may refer to a delete stage, or a projection stage wrapping a delete stage.
if (StageType::STAGE_PROJECTION == stats->stageType) {
invariant(stats->children.size() == 1);
stats = stats->children[0];
}
invariant(StageType::STAGE_DELETE == stats->stageType);
return static_cast<DeleteStats*>(stats->specific.get());
}
/**
* If the operation succeeded, then Status::OK() is returned, possibly with a document value
* to return to the client. If no matching document to update or remove was found, then none
* is returned. Otherwise, the updated or deleted document is returned.
*
* If the operation failed, then an error Status is returned.
*/
StatusWith<boost::optional<BSONObj>> advanceExecutor(PlanExecutor* exec, bool isRemove) {
BSONObj value;
PlanExecutor::ExecState state = exec->getNext(&value, nullptr);
if (PlanExecutor::ADVANCED == state) {
return boost::optional<BSONObj>(std::move(value));
}
if (PlanExecutor::FAILURE == state || PlanExecutor::DEAD == state) {
const std::unique_ptr<PlanStageStats> stats(exec->getStats());
error() << "Plan executor error during findAndModify: "
<< PlanExecutor::statestr(state)
<< ", stats: " << Explain::statsToBSON(*stats);
if (WorkingSetCommon::isValidStatusMemberObject(value)) {
const Status errorStatus =
WorkingSetCommon::getMemberObjectStatus(value);
invariant(!errorStatus.isOK());
return {errorStatus.code(), errorStatus.reason()};
}
const std::string opstr = isRemove ? "delete" : "update";
return {ErrorCodes::OperationFailed, str::stream()
<< "executor returned " << PlanExecutor::statestr(state)
<< " while executing " << opstr};
}
invariant(state == PlanExecutor::IS_EOF);
return boost::optional<BSONObj>(boost::none);
}
void makeUpdateRequest(const FindAndModifyRequest& args,
bool explain,
UpdateLifecycleImpl* updateLifecycle,
UpdateRequest* requestOut) {
requestOut->setQuery(args.getQuery());
requestOut->setProj(args.getFields());
requestOut->setUpdates(args.getUpdateObj());
requestOut->setSort(args.getSort());
requestOut->setUpsert(args.isUpsert());
requestOut->setReturnDocs(args.shouldReturnNew()
? UpdateRequest::RETURN_NEW
: UpdateRequest::RETURN_OLD);
requestOut->setMulti(false);
requestOut->setYieldPolicy(PlanExecutor::YIELD_AUTO);
requestOut->setExplain(explain);
requestOut->setLifecycle(updateLifecycle);
}
void makeDeleteRequest(const FindAndModifyRequest& args,
bool explain,
DeleteRequest* requestOut) {
requestOut->setQuery(args.getQuery());
requestOut->setProj(args.getFields());
requestOut->setSort(args.getSort());
requestOut->setMulti(false);
requestOut->setYieldPolicy(PlanExecutor::YIELD_AUTO);
requestOut->setReturnDeleted(true); // Always return the old value.
requestOut->setExplain(explain);
}
void appendCommandResponse(PlanExecutor* exec,
bool isRemove,
const boost::optional<BSONObj>& value,
BSONObjBuilder& result) {
const std::unique_ptr<PlanStageStats> stats(exec->getStats());
BSONObjBuilder lastErrorObjBuilder(result.subobjStart("lastErrorObject"));
if (isRemove) {
lastErrorObjBuilder.appendNumber("n", getDeleteStats(stats.get())->docsDeleted);
}
else {
const UpdateStats* updateStats = getUpdateStats(stats.get());
lastErrorObjBuilder.appendBool("updatedExisting", updateStats->nMatched > 0);
lastErrorObjBuilder.appendNumber("n", updateStats->inserted ? 1
: updateStats->nMatched);
// Note we have to use the objInserted from the stats here, rather than 'value'
// because the _id field could have been excluded by a projection.
if (!updateStats->objInserted.isEmpty()) {
lastErrorObjBuilder.appendAs(updateStats->objInserted["_id"], kUpsertedFieldName);
}
}
lastErrorObjBuilder.done();
if (value) {
result.append("value", *value);
}
else {
result.appendNull("value");
}
}
Status checkCanAcceptWritesForDatabase(const NamespaceString& nsString) {
if (!repl::getGlobalReplicationCoordinator()->canAcceptWritesFor(nsString)) {
return Status(ErrorCodes::NotMaster, str::stream()
<< "Not primary while running findAndModify command on collection "
<< nsString.ns());
}
return Status::OK();
}
} // namespace
/* Find and Modify an object returning either the old (default) or new value*/
class CmdFindAndModify : public Command {
public:
void help(std::stringstream& help) const override {
help <<
"{ findAndModify: \"collection\", query: {processed:false}, update: {$set: {processed:true}}, new: true}\n"
"{ findAndModify: \"collection\", query: {processed:false}, remove: true, sort: {priority:-1}}\n"
"Either update or remove is required, all other fields have default values.\n"
"Output is in the \"value\" field\n";
}
CmdFindAndModify() : Command("findAndModify", false, "findandmodify") { }
bool slaveOk() const override { return false; }
bool isWriteCommandForConfigServer() const override { return true; }
void addRequiredPrivileges(const std::string& dbname,
const BSONObj& cmdObj,
std::vector<Privilege>* out) override {
find_and_modify::addPrivilegesRequiredForFindAndModify(this, dbname, cmdObj, out);
}
Status explain(OperationContext* txn,
const std::string& dbName,
const BSONObj& cmdObj,
ExplainCommon::Verbosity verbosity,
BSONObjBuilder* out) const override {
const std::string fullNs = parseNsCollectionRequired(dbName, cmdObj);
Status allowedWriteStatus = userAllowedWriteNS(fullNs);
if (!allowedWriteStatus.isOK()) {
return allowedWriteStatus;
}
StatusWith<FindAndModifyRequest> parseStatus =
FindAndModifyRequest::parseFromBSON(NamespaceString(fullNs), cmdObj);
if (!parseStatus.isOK()) {
return parseStatus.getStatus();
}
const FindAndModifyRequest& args = parseStatus.getValue();
const NamespaceString& nsString = args.getNamespaceString();
auto client = txn->getClient();
if (args.isRemove()) {
DeleteRequest request(nsString);
const bool isExplain = true;
makeDeleteRequest(args, isExplain, &request);
ParsedDelete parsedDelete(txn, &request);
Status parsedDeleteStatus = parsedDelete.parseRequest();
if (!parsedDeleteStatus.isOK()) {
return parsedDeleteStatus;
}
// Explain calls of the findAndModify command are read-only, but we take write
// locks so that the timing information is more accurate.
AutoGetDb autoDb(txn, dbName, MODE_IX);
Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
ensureShardVersionOKOrThrow(client, nsString.ns());
Collection* collection = nullptr;
if (autoDb.getDb()) {
collection = autoDb.getDb()->getCollection(nsString.ns());
}
else {
return {ErrorCodes::DatabaseNotFound,
str::stream() << "database " << dbName << " does not exist."};
}
PlanExecutor* rawExec;
Status execStatus = getExecutorDelete(txn, collection, &parsedDelete, &rawExec);
if (!execStatus.isOK()) {
return execStatus;
}
const std::unique_ptr<PlanExecutor> exec(rawExec);
Explain::explainStages(exec.get(), verbosity, out);
}
else {
UpdateRequest request(nsString);
const bool ignoreVersion = false;
UpdateLifecycleImpl updateLifecycle(ignoreVersion, nsString);
const bool isExplain = true;
makeUpdateRequest(args, isExplain, &updateLifecycle, &request);
ParsedUpdate parsedUpdate(txn, &request);
Status parsedUpdateStatus = parsedUpdate.parseRequest();
if (!parsedUpdateStatus.isOK()) {
return parsedUpdateStatus;
}
OpDebug* opDebug = &CurOp::get(txn)->debug();
// Explain calls of the findAndModify command are read-only, but we take write
// locks so that the timing information is more accurate.
AutoGetDb autoDb(txn, dbName, MODE_IX);
Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
ensureShardVersionOKOrThrow(client, nsString.ns());
Collection* collection = nullptr;
if (autoDb.getDb()) {
collection = autoDb.getDb()->getCollection(nsString.ns());
}
else {
return {ErrorCodes::DatabaseNotFound,
str::stream() << "database " << dbName << " does not exist."};
}
PlanExecutor* rawExec;
Status execStatus = getExecutorUpdate(txn, collection, &parsedUpdate, opDebug,
&rawExec);
if (!execStatus.isOK()) {
return execStatus;
}
const std::unique_ptr<PlanExecutor> exec(rawExec);
Explain::explainStages(exec.get(), verbosity, out);
}
return Status::OK();
}
bool run(OperationContext* txn,
const std::string& dbName,
BSONObj& cmdObj,
int options,
std::string& errmsg,
BSONObjBuilder& result) override {
// findAndModify command is not replicated directly.
invariant(txn->writesAreReplicated());
const std::string fullNs = parseNsCollectionRequired(dbName, cmdObj);
Status allowedWriteStatus = userAllowedWriteNS(fullNs);
if (!allowedWriteStatus.isOK()) {
return appendCommandStatus(result, allowedWriteStatus);
}
StatusWith<FindAndModifyRequest> parseStatus =
FindAndModifyRequest::parseFromBSON(NamespaceString(fullNs), cmdObj);
if (!parseStatus.isOK()) {
return appendCommandStatus(result, parseStatus.getStatus());
}
const FindAndModifyRequest& args = parseStatus.getValue();
const NamespaceString& nsString = args.getNamespaceString();
StatusWith<WriteConcernOptions> wcResult = extractWriteConcern(cmdObj);
if (!wcResult.isOK()) {
return appendCommandStatus(result, wcResult.getStatus());
}
txn->setWriteConcern(wcResult.getValue());
setupSynchronousCommit(txn);
boost::optional<DisableDocumentValidation> maybeDisableValidation;
if (shouldBypassDocumentValidationForCommand(cmdObj))
maybeDisableValidation.emplace(txn);
auto client = txn->getClient();
// We may encounter a WriteConflictException when creating a collection during an
// upsert, even when holding the exclusive lock on the database (due to other load on
// the system). The query framework should handle all other WriteConflictExceptions,
// but we defensively wrap the operation in the retry loop anyway.
//
// SERVER-17579 getExecutorUpdate() and getExecutorDelete() can throw a
// WriteConflictException when checking whether an index is ready or not.
// (on debug builds only)
MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
if (args.isRemove()) {
DeleteRequest request(nsString);
const bool isExplain = false;
makeDeleteRequest(args, isExplain, &request);
ParsedDelete parsedDelete(txn, &request);
Status parsedDeleteStatus = parsedDelete.parseRequest();
if (!parsedDeleteStatus.isOK()) {
return appendCommandStatus(result, parsedDeleteStatus);
}
AutoGetOrCreateDb autoDb(txn, dbName, MODE_IX);
Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
Collection* collection = autoDb.getDb()->getCollection(nsString.ns());
ensureShardVersionOKOrThrow(client, nsString.ns());
Status isPrimary = checkCanAcceptWritesForDatabase(nsString);
if (!isPrimary.isOK()) {
return appendCommandStatus(result, isPrimary);
}
PlanExecutor* rawExec;
Status execStatus = getExecutorDelete(txn, collection, &parsedDelete, &rawExec);
if (!execStatus.isOK()) {
return appendCommandStatus(result, execStatus);
}
const std::unique_ptr<PlanExecutor> exec(rawExec);
StatusWith<boost::optional<BSONObj>> advanceStatus =
advanceExecutor(exec.get(), args.isRemove());
if (!advanceStatus.isOK()) {
return appendCommandStatus(result, advanceStatus.getStatus());
}
boost::optional<BSONObj> value = advanceStatus.getValue();
appendCommandResponse(exec.get(), args.isRemove(), value, result);
}
else {
UpdateRequest request(nsString);
const bool ignoreVersion = false;
UpdateLifecycleImpl updateLifecycle(ignoreVersion, nsString);
const bool isExplain = false;
makeUpdateRequest(args, isExplain, &updateLifecycle, &request);
ParsedUpdate parsedUpdate(txn, &request);
Status parsedUpdateStatus = parsedUpdate.parseRequest();
if (!parsedUpdateStatus.isOK()) {
return appendCommandStatus(result, parsedUpdateStatus);
}
OpDebug* opDebug = &CurOp::get(txn)->debug();
AutoGetOrCreateDb autoDb(txn, dbName, MODE_IX);
Lock::CollectionLock collLock(txn->lockState(), nsString.ns(), MODE_IX);
Collection* collection = autoDb.getDb()->getCollection(nsString.ns());
ensureShardVersionOKOrThrow(client, nsString.ns());
Status isPrimary = checkCanAcceptWritesForDatabase(nsString);
if (!isPrimary.isOK()) {
return appendCommandStatus(result, isPrimary);
}
// Create the collection if it does not exist when performing an upsert
// because the update stage does not create its own collection.
if (!collection && args.isUpsert()) {
// Release the collection lock and reacquire a lock on the database
// in exclusive mode in order to create the collection.
collLock.relockAsDatabaseExclusive(autoDb.lock());
collection = autoDb.getDb()->getCollection(nsString.ns());
Status isPrimaryAfterRelock = checkCanAcceptWritesForDatabase(nsString);
if (!isPrimaryAfterRelock.isOK()) {
return appendCommandStatus(result, isPrimaryAfterRelock);
}
if (collection) {
// Someone else beat us to creating the collection, do nothing.
}
else {
WriteUnitOfWork wuow(txn);
Status createCollStatus = userCreateNS(txn, autoDb.getDb(),
nsString.ns(), BSONObj());
if (!createCollStatus.isOK()) {
return appendCommandStatus(result, createCollStatus);
}
wuow.commit();
collection = autoDb.getDb()->getCollection(nsString.ns());
invariant(collection);
}
}
PlanExecutor* rawExec;
Status execStatus = getExecutorUpdate(txn, collection, &parsedUpdate, opDebug,
&rawExec);
if (!execStatus.isOK()) {
return appendCommandStatus(result, execStatus);
}
const std::unique_ptr<PlanExecutor> exec(rawExec);
StatusWith<boost::optional<BSONObj>> advanceStatus =
advanceExecutor(exec.get(), args.isRemove());
if (!advanceStatus.isOK()) {
return appendCommandStatus(result, advanceStatus.getStatus());
}
boost::optional<BSONObj> value = advanceStatus.getValue();
appendCommandResponse(exec.get(), args.isRemove(), value, result);
}
} MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "findAndModify", nsString.ns());
WriteConcernResult res;
auto waitForWCStatus = waitForWriteConcern(
txn,
repl::ReplClientInfo::forClient(txn->getClient()).getLastOp(),
&res
);
appendCommandWCStatus(result, waitForWCStatus);
return true;
}
} cmdFindAndModify;
} // namespace mongo
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