diff --git a/utilities/maintenance/databasetask.cpp b/utilities/maintenance/databasetask.cpp
index 840b165863..0da60532cf 100644
--- a/utilities/maintenance/databasetask.cpp
+++ b/utilities/maintenance/databasetask.cpp
@@ -1,452 +1,448 @@
 /* ============================================================
  *
  * This file is a part of digiKam project
  * http://www.digikam.org
  *
  * Date        : 2017-01-29
  * Description : Thread actions task for database cleanup.
  *
  * Copyright (C) 2017 by Mario Frank <mario dot frank at uni minus potsdam dot de>
  *
  * This program is free software; you can redistribute it
  * and/or modify it under the terms of the GNU General
  * Public License as published by the Free Software Foundation;
  * either version 2, or (at your option)
  * any later version.
  *
  * 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 General Public License for more details.
  *
  * ============================================================ */
 
 #include "databasetask.h"
 
 // Qt includes
 
 #include <QUrlQuery>
 
 // Local includes
 
 #include "digikam_debug.h"
 #include "imageinfo.h"
 #include "thumbsdb.h"
 #include "thumbsdbaccess.h"
 #include "coredb.h"
 #include "coredbaccess.h"
 #include "recognitiondatabase.h"
 #include "facetagseditor.h"
 #include "maintenancedata.h"
 
 namespace Digikam
 {
 
 class DatabaseTask::Private
 {
 public:
 
     Private()
         : scanThumbsDb(false),
           scanRecognitionDb(false),
           mode(Mode::Unknown),
           data(0)
     {
     }
 
     QString          objectIdentification;
 
     bool             scanThumbsDb;
     bool             scanRecognitionDb;
 
     Mode             mode;
     MaintenanceData* data;
 };
 
 // -------------------------------------------------------
 
 DatabaseTask::DatabaseTask()
     : ActionJob(),
       d(new Private)
 {
 }
 
 DatabaseTask::~DatabaseTask()
 {
     cancel();
     delete d;
 }
 
 void DatabaseTask::computeDatabaseJunk(bool thumbsDb, bool facesDb)
 {
     d->scanThumbsDb      = thumbsDb;
     d->scanRecognitionDb = facesDb;
 }
 
 void DatabaseTask::setMode(Mode mode)
 {
     d->mode = mode;
 }
 
 void DatabaseTask::setMaintenanceData(MaintenanceData* const data)
 {
     d->data = data;
 }
 
-void DatabaseTask::slotCancel()
-{
-}
-
 void DatabaseTask::run()
 {
     if (m_cancel)
     {
         return;
     }
 
     emit signalStarted();
 
     QThread::sleep(1);
 
     if (d->mode == Mode::ShrinkDatabases)
     {
         qCDebug(DIGIKAM_GENERAL_LOG) << "Shrinking databases";
         if (CoreDbAccess().db()->integrityCheck())
         {
             CoreDbAccess().db()->vacuum();
 
             if (!CoreDbAccess().db()->integrityCheck())
             {
                 qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for core DB failed after vacuum. Something went wrong.";
                 // Signal that the database was vacuumed but failed the integrity check afterwards.
                 emit signalFinished(true,false);
             }
             else
             {
                 qCDebug(DIGIKAM_DATABASE_LOG) << "Finished vacuuming of core DB. Integrity check after vacuuming was positive.";
                 emit signalFinished(true,true);
             }
         }
         else
         {
             qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for core DB failed. Will not vacuum.";
             // Signal that the integrity check failed and thus the vacuum was skipped
             emit signalFinished(false,false);
         }
 
         QThread::sleep(1);
 
         if (m_cancel)
         {
             return;
         }
 
         if (ThumbsDbAccess::isInitialized())
         {
             if (ThumbsDbAccess().db()->integrityCheck())
             {
                 ThumbsDbAccess().db()->vacuum();
 
                 if (!ThumbsDbAccess().db()->integrityCheck())
                 {
                     qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for thumbnails DB failed after vacuum. Something went wrong.";
                     // Signal that the database was vacuumed but failed the integrity check afterwards.
                     emit signalFinished(true,false);
                 }
                 else
                 {
                     qCDebug(DIGIKAM_DATABASE_LOG) << "Finished vacuuming of thumbnails DB. Integrity check after vacuuming was positive.";
                     emit signalFinished(true,true);
                 }
             }
             else
             {
                 qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for thumbnails DB failed. Will not vacuum.";
                 // Signal that the integrity check failed and thus the vacuum was skipped
                 emit signalFinished(false,false);
             }
         }
         else
         {
             qCWarning(DIGIKAM_DATABASE_LOG) << "Thumbnails DB is not initialised. Will not vacuum.";
             emit signalFinished(false,false);
         }
 
         QThread::sleep(1);
 
         if (m_cancel)
         {
             return;
         }
 
         if (RecognitionDatabase().integrityCheck())
         {
             RecognitionDatabase().vacuum();
 
             if (!RecognitionDatabase().integrityCheck())
             {
                 qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for recognition DB failed after vacuum. Something went wrong.";
                 // Signal that the database was vacuumed but failed the integrity check afterwards.
                 emit signalFinished(true,false);
             }
             else
             {
                 qCDebug(DIGIKAM_DATABASE_LOG) << "Finished vacuuming of recognition DB. Integrity check after vacuuming was positive.";
                 emit signalFinished(true,true);
             }
         }
         else
         {
             qCWarning(DIGIKAM_DATABASE_LOG) << "Integrity check for recognition DB failed. Will not vacuum.";
             // Signal that the integrity check failed and thus the vacuum was skipped
             emit signalFinished(false,false);
         }
 
         QThread::sleep(1);
     }
     else if (d->mode == Mode::ComputeDatabaseJunk)
     {
         QList<qlonglong>              staleImageIds;
         QList<int>                    staleThumbIds;
         QList<Identity>  staleIdentities;
         int additionalItemsToProcess = 0;
 
         // Get the count of image entries in DB to delete.
         staleImageIds   = CoreDbAccess().db()->getImageIds(DatabaseItem::Status::Obsolete);
 
         // get the count of items to process for thumbnails cleanup it enabled.
         if (d->scanThumbsDb && ThumbsDbAccess::isInitialized())
         {
             additionalItemsToProcess += CoreDbAccess().db()->getAllItems().size();
         }
 
         // get the count of items to process for identities cleanup it enabled.
         if (d->scanRecognitionDb)
         {
             additionalItemsToProcess += RecognitionDatabase().allIdentities().size();
         }
 
         if (additionalItemsToProcess > 0)
         {
             emit signalAddItemsToProcess(additionalItemsToProcess);
         }
 
         emit signalFinished();
 
         // Get the stale thumbnail paths.
 
         if (d->scanThumbsDb && ThumbsDbAccess::isInitialized())
         {
             // Thumbnails should be deleted, if the following conditions hold:
             // 1) The file path to which the thumb is assigned does not lead to an item
             // 2) The unique hash and file size are not used in core db for an item.
             // 3) The custom identifier does not exist in core db for an item.
             // OR
             // The thumbnail is stale, i.e. no thumbs db table references it.
 
             QSet<int> thumbIds     = ThumbsDbAccess().db()->findAll().toSet();
 
             // Get all items, i.e. images, videos, ...
             QList<qlonglong> items = CoreDbAccess().db()->getAllItems();
 
             FaceTagsEditor editor;
 
             foreach(qlonglong item, items)
             {
                 if (m_cancel)
                 {
                     return;
                 }
 
                 ImageInfo info(item);
 
                 if (!info.isNull())
                 {
                     QString hash       = CoreDbAccess().db()->getImagesFields(item,DatabaseFields::ImagesField::UniqueHash).first().toString();
                     qlonglong fileSize = info.fileSize();
                     bool removed       = false;
 
                     // Remove the id that is found by the file path. Finding the id -1 does no harm
                     removed            = thumbIds.remove(ThumbsDbAccess().db()->findByFilePath(info.filePath()).id);
 
                     if (!removed)
                     {
                         // Remove the id that is found by the hash and file size. Finding the id -1 does no harm
                         thumbIds.remove(ThumbsDbAccess().db()->findByHash(hash,fileSize).id);
                     }
 
                     // Add the custom identifier.
                     // get all faces for the image and generate the custom identifiers
                     QUrl url;
                     url.setScheme(QLatin1String("detail"));
                     url.setPath(info.filePath());
                     QList<FaceTagsIface> faces = editor.databaseFaces(item);
 
                     foreach(FaceTagsIface face, faces)
                     {
                         QRect rect = face.region().toRect();
                         QString r  = QString::fromLatin1("%1,%2-%3x%4").arg(rect.x()).arg(rect.y()).arg(rect.width()).arg(rect.height());
                         QUrlQuery q(url);
 
                         // Remove the previous query if existent.
                         q.removeQueryItem(QLatin1String("rect"));
                         q.addQueryItem(QLatin1String("rect"), r);
                         url.setQuery(q);
 
                         //qCDebug(DIGIKAM_GENERAL_LOG) << "URL: " << url.toString(); 
 
                         // Remove the id that is found by the custom identifyer. Finding the id -1 does no harm
                         thumbIds.remove(ThumbsDbAccess().db()->findByCustomIdentifier(url.toString()).id);
                     }
                 }
 
                 // Signal that this item was processed.
                 emit signalFinished();
             }
 
             // The remaining thumbnail ids should be used to remove them since they are stale.
             staleThumbIds = thumbIds.toList();
 
             // Signal that the database was processed.
             emit signalFinished();
         }
 
         if (m_cancel)
         {
             return;
         }
 
         // Get the stale face identities.
         if (d->scanRecognitionDb)
         {
             QList<TagProperty> properties = CoreDbAccess().db()->getTagProperties(TagPropertyName::faceEngineUuid());
             QSet<QString> uuidSet;
 
             foreach(TagProperty prop, properties)
             {
                 uuidSet << prop.value;
             }
 
             QList<Identity> identities = RecognitionDatabase().allIdentities();
 
             // Get all identitites to remove. Don't remove now in order to make sure no side effects occur.
 
             foreach(Identity identity, identities)
             {
                 QString value = identity.attribute(QLatin1String("uuid"));
 
                 if (!value.isEmpty() && !uuidSet.contains(value))
                 {
                     staleIdentities << identity;
                 }
 
                 // Signal that this identity was processed.
                 emit signalFinished();
             }
 
             // Signal that the database was processed.
             emit signalFinished();
         }
 
         emit signalData(staleImageIds,staleThumbIds,staleIdentities);
     }
     else if (d->mode == Mode::CleanCoreDb)
     {
         // While we have data (using this as check for non-null)
         while (d->data)
         {
             if (m_cancel)
             {
                 return;
             }
 
             qlonglong imageId = d->data->getImageId();
             if (imageId == -1)
             {
                 break;
             }
 
             CoreDbAccess().db()->deleteItem(imageId);
             CoreDbAccess().db()->removeImagePropertyByName(QLatin1String("similarityTo_")+QString::number(imageId));
 
             emit signalFinished();
         }
     }
     else if (d->mode == Mode::CleanThumbsDb)
     {
         BdEngineBackend::QueryState lastQueryState = BdEngineBackend::ConnectionError;
 
         // Connect to the database
         lastQueryState                             = ThumbsDbAccess().backend()->beginTransaction();
 
         if (BdEngineBackend::NoErrors == lastQueryState)
         {
             // Start removing.
 
             // While we have data (using this as check for non-null)
             while (d->data)
             {
                 if (m_cancel)
                 {
                     return;
                 }
 
                 int thumbId = d->data->getThumbnailId();
 
                 if (thumbId == -1)
                 {
                     break;
                 }
 
                 lastQueryState = ThumbsDbAccess().db()->remove(thumbId);
                 emit signalFinished();
             }
 
             // Check for errors.
 
             if (BdEngineBackend::NoErrors == lastQueryState)
             {
                 // Commit the removel if everything was fine.
                 lastQueryState = ThumbsDbAccess().backend()->commitTransaction();
 
                 if (BdEngineBackend::NoErrors != lastQueryState)
                 {
                     qCWarning(DIGIKAM_THUMBSDB_LOG) << "Could not commit the removal of " << d->objectIdentification << " due to error ";
                 }
             }
             else
             {
                 qCWarning(DIGIKAM_THUMBSDB_LOG) << "Could not start the removal of " << d->objectIdentification << " due to error ";
             }
         }
         else
         {
             qCWarning(DIGIKAM_THUMBSDB_LOG) << "Could not begin the transaction for the removal of " << d->objectIdentification << " due to error ";
         }
     }
     else if (d->mode == Mode::CleanRecognitionDb)
     {
         // While we have data (using this as check for non-null)
         while (d->data)
         {
             if (m_cancel)
             {
                 return;
             }
 
             Identity identity = d->data->getIdentity();
 
             if (identity.isNull())
             {
                 break;
             }
 
             RecognitionDatabase().deleteIdentity(identity);
             emit signalFinished();
         }
     }
 
     emit signalDone();
 }
 
 } // namespace Digikam
diff --git a/utilities/maintenance/databasetask.h b/utilities/maintenance/databasetask.h
index 45aae1d852..961270f326 100644
--- a/utilities/maintenance/databasetask.h
+++ b/utilities/maintenance/databasetask.h
@@ -1,98 +1,94 @@
 /* ============================================================
  *
  * This file is a part of digiKam project
  * http://www.digikam.org
  *
  * Date        : 2017-01-29
  * Description : Thread actions task for database cleanup.
  *
  * Copyright (C) 2017 by Mario Frank <mario dot frank at uni minus potsdam dot de>
  *
  * This program is free software; you can redistribute it
  * and/or modify it under the terms of the GNU General
  * Public License as published by the Free Software Foundation;
  * either version 2, or (at your option)
  * any later version.
  *
  * 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 General Public License for more details.
  *
  * ============================================================ */
 
 #ifndef DATABASE_TASK_H
 #define DATABASE_TASK_H
 
 // Local includes
 
 #include "actionthreadbase.h"
 
 namespace Digikam
 {
     class Identity;
 }
 
 namespace Digikam
 {
 
 class LoadingDescription;
 class MaintenanceData;
 
 class DatabaseTask : public ActionJob
 {
     Q_OBJECT
 
 public:
 
     enum Mode{
         Unknown,
         ComputeDatabaseJunk,
         CleanCoreDb,
         CleanThumbsDb,
         CleanRecognitionDb,
         ShrinkDatabases
     };
 
     explicit DatabaseTask();
     virtual ~DatabaseTask();
 
     void setMode(Mode mode);
     void setMaintenanceData(MaintenanceData* const data=0);
 
     void computeDatabaseJunk(bool thumbsDb=false, bool facesDb=false);
 
 
 Q_SIGNALS:
 
     void signalFinished();
     void signalFinished(bool done, bool errorFree);
 
     void signalData(const QList<qlonglong>& staleImageIds,
                     const QList<int>& staleThumbIds,
                     const QList<Identity>& staleIdentities);
 
     void signalStarted();
 
     /**
      * Signal to emit the count of additional items to process.
      */
     void signalAddItemsToProcess(int count);
 
-public Q_SLOTS:
-
-    void slotCancel();
-
 protected:
 
     void run();
 
 private:
 
     class Private;
     Private* const d;
 };
 
 }  // namespace Digikam
 
 #endif // DATABASE_TASK_H