// wiredtiger_kv_engine.cpp

/**
 *    Copyright (C) 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::kStorage

#include "mongo/platform/basic.h"

#ifdef _WIN32
#define NVALGRIND
#endif

#include <memory>

#include "mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h"

#include <boost/filesystem.hpp>
#include <boost/filesystem/operations.hpp>
#include <valgrind/valgrind.h>

#include "mongo/base/error_codes.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/bson/dotted_path_support.h"
#include "mongo/db/catalog/collection_catalog_entry.h"
#include "mongo/db/client.h"
#include "mongo/db/commands/server_status_metric.h"
#include "mongo/db/concurrency/locker.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/server_parameters.h"
#include "mongo/db/service_context.h"
#include "mongo/db/storage/journal_listener.h"
#include "mongo/db/storage/storage_options.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_customization_hooks.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_extensions.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_global_options.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_index.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_record_store.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_session_cache.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_size_storer.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_util.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/background.h"
#include "mongo/util/concurrency/idle_thread_block.h"
#include "mongo/util/concurrency/ticketholder.h"
#include "mongo/util/exit.h"
#include "mongo/util/log.h"
#include "mongo/util/processinfo.h"
#include "mongo/util/scopeguard.h"
#include "mongo/util/time_support.h"

#if !defined(__has_feature)
#define __has_feature(x) 0
#endif

namespace mongo {

using std::set;
using std::string;

namespace dps = ::mongo::dotted_path_support;

class WiredTigerKVEngine::WiredTigerJournalFlusher : public BackgroundJob {
public:
    explicit WiredTigerJournalFlusher(WiredTigerSessionCache* sessionCache)
        : BackgroundJob(false /* deleteSelf */), _sessionCache(sessionCache) {}

    virtual string name() const {
        return "WTJournalFlusher";
    }

    virtual void run() {
        Client::initThread(name().c_str());

        LOG(1) << "starting " << name() << " thread";

        while (!_shuttingDown.load()) {
            try {
                _sessionCache->waitUntilDurable(false);
            } catch (const UserException& e) {
                invariant(e.getCode() == ErrorCodes::ShutdownInProgress);
            }

            int ms = storageGlobalParams.journalCommitIntervalMs;
            if (!ms) {
                ms = 100;
            }

            MONGO_IDLE_THREAD_BLOCK;
            sleepmillis(ms);
        }
        LOG(1) << "stopping " << name() << " thread";
    }

    void shutdown() {
        _shuttingDown.store(true);
        wait();
    }

private:
    WiredTigerSessionCache* _sessionCache;
    std::atomic<bool> _shuttingDown{false};  // NOLINT
};

namespace {

class TicketServerParameter : public ServerParameter {
    MONGO_DISALLOW_COPYING(TicketServerParameter);

public:
    TicketServerParameter(TicketHolder* holder, const std::string& name)
        : ServerParameter(ServerParameterSet::getGlobal(), name, true, true), _holder(holder) {}

    virtual void append(OperationContext* txn, BSONObjBuilder& b, const std::string& name) {
        b.append(name, _holder->outof());
    }

    virtual Status set(const BSONElement& newValueElement) {
        if (!newValueElement.isNumber())
            return Status(ErrorCodes::BadValue, str::stream() << name() << " has to be a number");
        return _set(newValueElement.numberInt());
    }

    virtual Status setFromString(const std::string& str) {
        int num = 0;
        Status status = parseNumberFromString(str, &num);
        if (!status.isOK())
            return status;
        return _set(num);
    }

    Status _set(int newNum) {
        if (newNum <= 0) {
            return Status(ErrorCodes::BadValue, str::stream() << name() << " has to be > 0");
        }

        return _holder->resize(newNum);
    }

private:
    TicketHolder* _holder;
};

TicketHolder openWriteTransaction(128);
TicketServerParameter openWriteTransactionParam(&openWriteTransaction,
                                                "wiredTigerConcurrentWriteTransactions");

TicketHolder openReadTransaction(128);
TicketServerParameter openReadTransactionParam(&openReadTransaction,
                                               "wiredTigerConcurrentReadTransactions");

}  // namespace

WiredTigerKVEngine::WiredTigerKVEngine(const std::string& canonicalName,
                                       const std::string& path,
                                       ClockSource* cs,
                                       const std::string& extraOpenOptions,
                                       size_t cacheSizeMB,
                                       bool durable,
                                       bool ephemeral,
                                       bool repair,
                                       bool readOnly)
    : _eventHandler(WiredTigerUtil::defaultEventHandlers()),
      _canonicalName(canonicalName),
      _path(path),
      _sizeStorerSyncTracker(cs, 100000, Seconds(60)),
      _durable(durable),
      _ephemeral(ephemeral),
      _readOnly(readOnly) {
    boost::filesystem::path journalPath = path;
    journalPath /= "journal";
    if (_durable) {
        if (!boost::filesystem::exists(journalPath)) {
            try {
                boost::filesystem::create_directory(journalPath);
            } catch (std::exception& e) {
                log() << "error creating journal dir " << journalPath.string() << ' ' << e.what();
                throw;
            }
        }
    }

    _previousCheckedDropsQueued = Date_t::now();

    std::stringstream ss;
    ss << "create,";
    ss << "cache_size=" << cacheSizeMB << "M,";
    ss << "session_max=20000,";
    ss << "eviction=(threads_min=4,threads_max=4),";
    ss << "config_base=false,";
    ss << "statistics=(fast),";
    // The setting may have a later setting override it if not using the journal.  We make it
    // unconditional here because even nojournal may need this setting if it is a transition
    // from using the journal.
    if (!_readOnly) {
        // If we're readOnly skip all WAL-related settings.
        ss << "log=(enabled=true,archive=true,path=journal,compressor=";
        ss << wiredTigerGlobalOptions.journalCompressor << "),";
        ss << "file_manager=(close_idle_time=100000),";  //~28 hours, will put better fix in 3.1.x
        ss << "checkpoint=(wait=" << wiredTigerGlobalOptions.checkpointDelaySecs;
        ss << ",log_size=2GB),";
        ss << "statistics_log=(wait=" << wiredTigerGlobalOptions.statisticsLogDelaySecs << "),";
    }
    ss << WiredTigerCustomizationHooks::get(getGlobalServiceContext())
              ->getTableCreateConfig("system");
    ss << WiredTigerExtensions::get(getGlobalServiceContext())->getOpenExtensionsConfig();
    ss << extraOpenOptions;
    if (_readOnly) {
        invariant(!_durable);
        ss << "readonly=true,";
    }
    if (!_durable && !_readOnly) {
        // If we started without the journal, but previously used the journal then open with the
        // WT log enabled to perform any unclean shutdown recovery and then close and reopen in
        // the normal path without the journal.
        if (boost::filesystem::exists(journalPath)) {
            string config = ss.str();
            log() << "Detected WT journal files.  Running recovery from last checkpoint.";
            log() << "journal to nojournal transition config: " << config;
            int ret = wiredtiger_open(path.c_str(), &_eventHandler, config.c_str(), &_conn);
            if (ret == EINVAL) {
                fassertFailedNoTrace(28717);
            } else if (ret != 0) {
                Status s(wtRCToStatus(ret));
                msgassertedNoTrace(28718, s.reason());
            }
            invariantWTOK(_conn->close(_conn, NULL));
        }
        // This setting overrides the earlier setting because it is later in the config string.
        ss << ",log=(enabled=false),";
    }
    string config = ss.str();
    log() << "wiredtiger_open config: " << config;
    int ret = wiredtiger_open(path.c_str(), &_eventHandler, config.c_str(), &_conn);
    // Invalid argument (EINVAL) is usually caused by invalid configuration string.
    // We still fassert() but without a stack trace.
    if (ret == EINVAL) {
        fassertFailedNoTrace(28561);
    } else if (ret != 0) {
        Status s(wtRCToStatus(ret));
        msgassertedNoTrace(28595, s.reason());
    }

    _sessionCache.reset(new WiredTigerSessionCache(this));

    if (_durable && !_ephemeral) {
        _journalFlusher = stdx::make_unique<WiredTigerJournalFlusher>(_sessionCache.get());
        _journalFlusher->go();
    }

    _sizeStorerUri = "table:sizeStorer";
    WiredTigerSession session(_conn);
    if (!_readOnly && repair && _hasUri(session.getSession(), _sizeStorerUri)) {
        log() << "Repairing size cache";
        fassertNoTrace(28577, _salvageIfNeeded(_sizeStorerUri.c_str()));
    }
    _sizeStorer.reset(new WiredTigerSizeStorer(_conn, _sizeStorerUri));
    _sizeStorer->fillCache();

    Locker::setGlobalThrottling(&openReadTransaction, &openWriteTransaction);
}


WiredTigerKVEngine::~WiredTigerKVEngine() {
    if (_conn) {
        cleanShutdown();
    }

    _sessionCache.reset(NULL);
}

void WiredTigerKVEngine::appendGlobalStats(BSONObjBuilder& b) {
    BSONObjBuilder bb(b.subobjStart("concurrentTransactions"));
    {
        BSONObjBuilder bbb(bb.subobjStart("write"));
        bbb.append("out", openWriteTransaction.used());
        bbb.append("available", openWriteTransaction.available());
        bbb.append("totalTickets", openWriteTransaction.outof());
        bbb.done();
    }
    {
        BSONObjBuilder bbb(bb.subobjStart("read"));
        bbb.append("out", openReadTransaction.used());
        bbb.append("available", openReadTransaction.available());
        bbb.append("totalTickets", openReadTransaction.outof());
        bbb.done();
    }
    bb.done();
}

void WiredTigerKVEngine::cleanShutdown() {
    log() << "WiredTigerKVEngine shutting down";
    if (!_readOnly)
        syncSizeInfo(true);
    if (_conn) {
        // these must be the last things we do before _conn->close();
        if (_journalFlusher)
            _journalFlusher->shutdown();
        _sizeStorer.reset();
        _sessionCache->shuttingDown();

// We want WiredTiger to leak memory for faster shutdown except when we are running tools to
// look for memory leaks.
#if !__has_feature(address_sanitizer)
        bool leak_memory = true;
#else
        bool leak_memory = false;
#endif
        const char* config = nullptr;

        if (RUNNING_ON_VALGRIND) {
            leak_memory = false;
        }

        if (leak_memory) {
            config = "leak_memory=true";
        }

        invariantWTOK(_conn->close(_conn, config));
        _conn = NULL;
    }
}

Status WiredTigerKVEngine::okToRename(OperationContext* opCtx,
                                      StringData fromNS,
                                      StringData toNS,
                                      StringData ident,
                                      const RecordStore* originalRecordStore) const {
    _sizeStorer->storeToCache(
        _uri(ident), originalRecordStore->numRecords(opCtx), originalRecordStore->dataSize(opCtx));
    syncSizeInfo(true);
    return Status::OK();
}

int64_t WiredTigerKVEngine::getIdentSize(OperationContext* opCtx, StringData ident) {
    WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx);
    return WiredTigerUtil::getIdentSize(session->getSession(), _uri(ident));
}

Status WiredTigerKVEngine::repairIdent(OperationContext* opCtx, StringData ident) {
    WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx);
    string uri = _uri(ident);
    session->closeAllCursors(uri);
    _sessionCache->closeAllCursors(uri);
    if (isEphemeral()) {
        return Status::OK();
    }
    return _salvageIfNeeded(uri.c_str());
}

Status WiredTigerKVEngine::_salvageIfNeeded(const char* uri) {
    // Using a side session to avoid transactional issues
    WiredTigerSession sessionWrapper(_conn);
    WT_SESSION* session = sessionWrapper.getSession();

    int rc = (session->verify)(session, uri, NULL);
    if (rc == 0) {
        log() << "Verify succeeded on uri " << uri << ". Not salvaging.";
        return Status::OK();
    }

    if (rc == EBUSY) {
        // SERVER-16457: verify and salvage are occasionally failing with EBUSY. For now we
        // lie and return OK to avoid breaking tests. This block should go away when that ticket
        // is resolved.
        error() << "Verify on " << uri << " failed with EBUSY. Assuming no salvage is needed.";
        return Status::OK();
    }

    // TODO need to cleanup the sizeStorer cache after salvaging.
    log() << "Verify failed on uri " << uri << ". Running a salvage operation.";
    return wtRCToStatus(session->salvage(session, uri, NULL), "Salvage failed:");
}

int WiredTigerKVEngine::flushAllFiles(bool sync) {
    LOG(1) << "WiredTigerKVEngine::flushAllFiles";
    if (_ephemeral) {
        return 0;
    }
    syncSizeInfo(true);
    _sessionCache->waitUntilDurable(true);

    return 1;
}

Status WiredTigerKVEngine::beginBackup(OperationContext* txn) {
    invariant(!_backupSession);

    // This cursor will be freed by the backupSession being closed as the session is uncached
    auto session = stdx::make_unique<WiredTigerSession>(_conn);
    WT_CURSOR* c = NULL;
    WT_SESSION* s = session->getSession();
    int ret = WT_OP_CHECK(s->open_cursor(s, "backup:", NULL, NULL, &c));
    if (ret != 0) {
        return wtRCToStatus(ret);
    }
    _backupSession = std::move(session);
    return Status::OK();
}

void WiredTigerKVEngine::endBackup(OperationContext* txn) {
    _backupSession.reset();
}

void WiredTigerKVEngine::syncSizeInfo(bool sync) const {
    if (!_sizeStorer)
        return;

    try {
        _sizeStorer->syncCache(sync);
    } catch (const WriteConflictException&) {
        // ignore, we'll try again later.
    }
}

RecoveryUnit* WiredTigerKVEngine::newRecoveryUnit() {
    return new WiredTigerRecoveryUnit(_sessionCache.get());
}

void WiredTigerKVEngine::setRecordStoreExtraOptions(const std::string& options) {
    _rsOptions = options;
}

void WiredTigerKVEngine::setSortedDataInterfaceExtraOptions(const std::string& options) {
    _indexOptions = options;
}

Status WiredTigerKVEngine::createRecordStore(OperationContext* opCtx,
                                             StringData ns,
                                             StringData ident,
                                             const CollectionOptions& options) {
    _checkIdentPath(ident);
    WiredTigerSession session(_conn);

    StatusWith<std::string> result =
        WiredTigerRecordStore::generateCreateString(_canonicalName, ns, options, _rsOptions);
    if (!result.isOK()) {
        return result.getStatus();
    }
    std::string config = result.getValue();

    string uri = _uri(ident);
    WT_SESSION* s = session.getSession();
    LOG(2) << "WiredTigerKVEngine::createRecordStore uri: " << uri << " config: " << config;
    return wtRCToStatus(s->create(s, uri.c_str(), config.c_str()));
}

std::unique_ptr<RecordStore> WiredTigerKVEngine::getRecordStore(OperationContext* opCtx,
                                                                StringData ns,
                                                                StringData ident,
                                                                const CollectionOptions& options) {
    if (options.capped) {
        return stdx::make_unique<WiredTigerRecordStore>(
            opCtx,
            ns,
            _uri(ident),
            _canonicalName,
            options.capped,
            _ephemeral,
            options.cappedSize ? options.cappedSize : 4096,
            options.cappedMaxDocs ? options.cappedMaxDocs : -1,
            nullptr,
            _sizeStorer.get());
    } else {
        return stdx::make_unique<WiredTigerRecordStore>(opCtx,
                                                        ns,
                                                        _uri(ident),
                                                        _canonicalName,
                                                        false,
                                                        _ephemeral,
                                                        -1,
                                                        -1,
                                                        nullptr,
                                                        _sizeStorer.get());
    }
}

string WiredTigerKVEngine::_uri(StringData ident) const {
    return string("table:") + ident.toString();
}

Status WiredTigerKVEngine::createSortedDataInterface(OperationContext* opCtx,
                                                     StringData ident,
                                                     const IndexDescriptor* desc) {
    _checkIdentPath(ident);

    std::string collIndexOptions;
    const Collection* collection = desc->getCollection();

    // Treat 'collIndexOptions' as an empty string when the collection member of 'desc' is NULL in
    // order to allow for unit testing WiredTigerKVEngine::createSortedDataInterface().
    if (collection) {
        const CollectionCatalogEntry* cce = collection->getCatalogEntry();
        const CollectionOptions collOptions = cce->getCollectionOptions(opCtx);

        if (!collOptions.indexOptionDefaults["storageEngine"].eoo()) {
            BSONObj storageEngineOptions = collOptions.indexOptionDefaults["storageEngine"].Obj();
            collIndexOptions =
                dps::extractElementAtPath(storageEngineOptions, _canonicalName + ".configString")
                    .valuestrsafe();
        }
    }

    StatusWith<std::string> result = WiredTigerIndex::generateCreateString(
        _canonicalName, _indexOptions, collIndexOptions, *desc);
    if (!result.isOK()) {
        return result.getStatus();
    }

    std::string config = result.getValue();

    LOG(2) << "WiredTigerKVEngine::createSortedDataInterface ident: " << ident
           << " config: " << config;
    return wtRCToStatus(WiredTigerIndex::Create(opCtx, _uri(ident), config));
}

SortedDataInterface* WiredTigerKVEngine::getSortedDataInterface(OperationContext* opCtx,
                                                                StringData ident,
                                                                const IndexDescriptor* desc) {
    if (desc->unique())
        return new WiredTigerIndexUnique(opCtx, _uri(ident), desc);
    return new WiredTigerIndexStandard(opCtx, _uri(ident), desc);
}

Status WiredTigerKVEngine::dropIdent(OperationContext* opCtx, StringData ident) {
    _drop(ident);
    return Status::OK();
}

bool WiredTigerKVEngine::_drop(StringData ident) {
    string uri = _uri(ident);

    _sessionCache->closeAllCursors(uri);

    WiredTigerSession session(_conn);

    int ret = session.getSession()->drop(
        session.getSession(), uri.c_str(), "force,checkpoint_wait=false");
    LOG(1) << "WT drop of  " << uri << " res " << ret;

    if (ret == 0) {
        // yay, it worked
        return true;
    }

    if (ret == EBUSY) {
        // this is expected, queue it up
        {
            stdx::lock_guard<stdx::mutex> lk(_identToDropMutex);
            _identToDrop.push_front(uri);
        }
        _sessionCache->closeCursorsForQueuedDrops();
        return false;
    }

    invariantWTOK(ret);
    return false;
}

std::list<WiredTigerCachedCursor> WiredTigerKVEngine::filterCursorsWithQueuedDrops(
    std::list<WiredTigerCachedCursor>* cache) {
    std::list<WiredTigerCachedCursor> toDrop;

    stdx::lock_guard<stdx::mutex> lk(_identToDropMutex);
    if (_identToDrop.empty())
        return toDrop;

    for (auto i = cache->begin(); i != cache->end();) {
        if (!i->_cursor ||
            std::find(_identToDrop.begin(), _identToDrop.end(), std::string(i->_cursor->uri)) ==
                _identToDrop.end()) {
            ++i;
            continue;
        }
        toDrop.push_back(*i);
        i = cache->erase(i);
    }

    return toDrop;
}

bool WiredTigerKVEngine::haveDropsQueued() const {
    Date_t now = Date_t::now();
    Milliseconds delta = now - _previousCheckedDropsQueued;

    if (!_readOnly && _sizeStorerSyncTracker.intervalHasElapsed()) {
        _sizeStorerSyncTracker.resetLastTime();
        syncSizeInfo(false);
    }

    // We only want to check the queue max once per second or we'll thrash
    if (delta < Milliseconds(1000))
        return false;

    _previousCheckedDropsQueued = now;

    // Don't wait for the mutex: if we can't get it, report that no drops are queued.
    stdx::unique_lock<stdx::mutex> lk(_identToDropMutex, stdx::defer_lock);
    return lk.try_lock() && !_identToDrop.empty();
}

void WiredTigerKVEngine::dropSomeQueuedIdents() {
    int numInQueue;

    WiredTigerSession session(_conn);

    {
        stdx::lock_guard<stdx::mutex> lk(_identToDropMutex);
        numInQueue = _identToDrop.size();
    }

    int numToDelete = 10;
    int tenPercentQueue = numInQueue * 0.1;
    if (tenPercentQueue > 10)
        numToDelete = tenPercentQueue;

    LOG(1) << "WT Queue is: " << numInQueue << " attempting to drop: " << numToDelete << " tables";
    for (int i = 0; i < numToDelete; i++) {
        string uri;
        {
            stdx::lock_guard<stdx::mutex> lk(_identToDropMutex);
            if (_identToDrop.empty())
                break;
            uri = _identToDrop.front();
            _identToDrop.pop_front();
        }
        int ret = session.getSession()->drop(
            session.getSession(), uri.c_str(), "force,checkpoint_wait=false");
        LOG(1) << "WT queued drop of  " << uri << " res " << ret;

        if (ret == EBUSY) {
            stdx::lock_guard<stdx::mutex> lk(_identToDropMutex);
            _identToDrop.push_back(uri);
        } else {
            invariantWTOK(ret);
        }
    }
}

bool WiredTigerKVEngine::supportsDocLocking() const {
    return true;
}

bool WiredTigerKVEngine::supportsDirectoryPerDB() const {
    return true;
}

bool WiredTigerKVEngine::hasIdent(OperationContext* opCtx, StringData ident) const {
    return _hasUri(WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx)->getSession(),
                   _uri(ident));
}

bool WiredTigerKVEngine::_hasUri(WT_SESSION* session, const std::string& uri) const {
    // can't use WiredTigerCursor since this is called from constructor.
    WT_CURSOR* c = NULL;
    int ret = session->open_cursor(session, "metadata:", NULL, NULL, &c);
    if (ret == ENOENT)
        return false;
    invariantWTOK(ret);
    ON_BLOCK_EXIT(c->close, c);

    c->set_key(c, uri.c_str());
    return c->search(c) == 0;
}

std::vector<std::string> WiredTigerKVEngine::getAllIdents(OperationContext* opCtx) const {
    std::vector<std::string> all;
    WiredTigerCursor cursor("metadata:", WiredTigerSession::kMetadataTableId, false, opCtx);
    WT_CURSOR* c = cursor.get();
    if (!c)
        return all;

    while (c->next(c) == 0) {
        const char* raw;
        c->get_key(c, &raw);
        StringData key(raw);
        size_t idx = key.find(':');
        if (idx == string::npos)
            continue;
        StringData type = key.substr(0, idx);
        if (type != "table")
            continue;

        StringData ident = key.substr(idx + 1);
        if (ident == "sizeStorer")
            continue;

        all.push_back(ident.toString());
    }

    return all;
}

int WiredTigerKVEngine::reconfigure(const char* str) {
    return _conn->reconfigure(_conn, str);
}

void WiredTigerKVEngine::_checkIdentPath(StringData ident) {
    size_t start = 0;
    size_t idx;
    while ((idx = ident.find('/', start)) != string::npos) {
        StringData dir = ident.substr(0, idx);

        boost::filesystem::path subdir = _path;
        subdir /= dir.toString();
        if (!boost::filesystem::exists(subdir)) {
            LOG(1) << "creating subdirectory: " << dir;
            try {
                boost::filesystem::create_directory(subdir);
            } catch (const std::exception& e) {
                error() << "error creating path " << subdir.string() << ' ' << e.what();
                throw;
            }
        }

        start = idx + 1;
    }
}

void WiredTigerKVEngine::setJournalListener(JournalListener* jl) {
    return _sessionCache->setJournalListener(jl);
}
}