diff --git a/lib/Alchemy/Phrasea/Model/Repositories/WorkerRunningJobRepository.php b/lib/Alchemy/Phrasea/Model/Repositories/WorkerRunningJobRepository.php
index be89a3589a..193f5d42be 100644
--- a/lib/Alchemy/Phrasea/Model/Repositories/WorkerRunningJobRepository.php
+++ b/lib/Alchemy/Phrasea/Model/Repositories/WorkerRunningJobRepository.php
@@ -5,9 +5,10 @@ namespace Alchemy\Phrasea\Model\Repositories;
 use Alchemy\Phrasea\Model\Entities\WorkerRunningJob;
 use Alchemy\Phrasea\WorkerManager\Queue\MessagePublisher;
 use DateTime;
+use Doctrine\DBAL\Driver\Connection;
 use Doctrine\ORM\EntityRepository;
-use Doctrine\ORM\OptimisticLockException;
 use Exception;
+use PDO;
 
 class WorkerRunningJobRepository extends EntityRepository
 {
@@ -15,7 +16,7 @@ class WorkerRunningJobRepository extends EntityRepository
     /**
      * Check and declare that we want to create a subdef from a document
      *
-     * - if it's possible : return WorkerRunningJob entity (created or updated) for the job
+     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
      * - if not (needed resource(s) already in use by other job(s)) : return null
      *
      * rules :
@@ -23,89 +24,68 @@ class WorkerRunningJobRepository extends EntityRepository
      * - if someone else is already writing this subdef, we can't re-create it
      *
      * @param array $payload
-     * @return WorkerRunningJob | null
-     * @throws OptimisticLockException
+     * @return int | null           workerRunningJobId
      */
     public function canCreateSubdef(array $payload)
     {
-        $databoxId      = $payload['databoxId'];
-        $recordId       = $payload['recordId'];
-        $subdefName     = $payload['subdefName'];
+        $this->reconnect();
+        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
 
-        file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf('canCreateSubdef for %s.%s.%s ?', $databoxId, $recordId, $subdefName)
-        ), FILE_APPEND | LOCK_EX);
+        $sqlclause = "(`work_on` = " . $cnx->quote('document') . " OR `work_on` = " . $cnx->quote($payload['subdefName']) . ")";
 
-        // first protect sql by a critical section
-        if( !( $recordMutex = $this->getRecordMutex($databoxId, $recordId)) ) {
-            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                'getRecordMutex() failed'
-            ), FILE_APPEND | LOCK_EX);
-
-            return null;
-        }
-
-        // here we can do sql atomically
-        $workerRunningJob = null;
-
-        // check the rules
-        /** @var WorkerRunningJob[] $r */
-        $r = $this->createQueryBuilder('w')
-            ->select('w')
-            ->where('w.status = :status')->setParameter('status', WorkerRunningJob::RUNNING)
-            ->andWhere('w.databoxId = :databox_id')->setParameter('databox_id', $databoxId)
-            ->andWhere('w.recordId = :record_id')->setParameter('record_id', $recordId)
-            ->andWhere('w.workOn = \'document\' OR w.workOn = :work_on')->setParameter(':work_on', $subdefName)
-            ->andWhere('w.work = :work_1 OR w.work = :work_2')
-            ->setParameter('work_1', MessagePublisher::WRITE_METADATAS_TYPE)
-            ->setParameter('work_2', MessagePublisher::SUBDEF_CREATION_TYPE)
-            ->setMaxResults(1)
-            ->getQuery()
-            ->getResult()
-        ;
-
-        if(count($r) == 0) {
-            // no conflict, create (or update) the job
-            $workerRunningJob = $this->creteOrUpdateJob($payload, MessagePublisher::SUBDEF_CREATION_TYPE);
-        }
-        else {
-            $r = $r[0];
-            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                sprintf("job %s already running on %s.%s.%s", $r->getId(), $r->getDataboxId(), $r->getRecordId(), $r->getWorkOn())
-            ), FILE_APPEND | LOCK_EX);
-        }
-
-        // end of critical section
-        $this->releaseRecordMutex($databoxId, $recordId);
-
-        return $workerRunningJob;
+        return $this->canDoJob($payload, MessagePublisher::SUBDEF_CREATION_TYPE, $sqlclause);
     }
 
+
     /**
      * Check and declare that we want to write meta into a subdef
      *
-     * - if it's possible : return WorkerRunningJob entity (created or updated) for the job
+     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
      * - if not (needed resource(s) already in use by other job(s)) : return null
      *
      * rule :
      * - if someone is already working on the file, we can't write
      *
      * @param array $payload
-     * @return WorkerRunningJob | null
-     * @throws OptimisticLockException
+     * @return int | null       workerRunningJobId
      */
     public function canWriteMetadata(array $payload)
     {
+        $this->reconnect();
+        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
+
+        $sqlclause = "(`work_on` = " . $cnx->quote($payload['subdefName']) . ")";
+
+        return $this->canDoJob($payload, MessagePublisher::WRITE_METADATAS_TYPE, $sqlclause);
+    }
+
+    /**
+     * Check and declare that we want to do jon for a subdef
+     *
+     * - if it's possible : return WorkerRunningJobId (created or updated) for the job
+     * - if not (needed resource(s) already in use by other job(s)) : return null
+     *
+     * The rule depends on caller / jobType (canCreateSubdef or canWriteMetadata)
+     *
+     * @param array $payload
+     * @param string $jobType           // MessagePublisher::WRITE_METADATAS_TYPE | MessagePublisher::SUBDEF_CREATION_TYPE
+     * @param string $sqlClause
+     * @return int | null       workerRunningJobId
+     */
+    private function canDoJob(array $payload, string $jobType, string $sqlClause)
+    {
+        $workerRunningJobId = null;     // returned
+
         $databoxId      = $payload['databoxId'];
         $recordId       = $payload['recordId'];
         $subdefName     = $payload['subdefName'];
 
         file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf('canWriteMetadata for %s.%s.%s ?', $databoxId, $recordId, $subdefName)
+            sprintf('canDoJob("%s") for %s.%s.%s ?', $jobType, $databoxId, $recordId, $subdefName)
         ), FILE_APPEND | LOCK_EX);
 
         // first protect sql by a critical section
-        if( !( $recordMutex = $this->getRecordMutex($databoxId, $recordId)) ) {
+        if( !( $recordMutexId = $this->getRecordMutex($databoxId, $recordId)) ) {
             file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                 'getRecordMutex() failed'
             ), FILE_APPEND | LOCK_EX);
@@ -114,127 +94,143 @@ class WorkerRunningJobRepository extends EntityRepository
         }
 
         // here we can do sql atomically
-        $workerRunningJob = null;
 
-        // check the rule
-        /** @var WorkerRunningJob[] $r */
-        $r = $this->createQueryBuilder('w')
-            ->select('w')
-            ->where('w.status = :status')->setParameter('status', WorkerRunningJob::RUNNING)
-            ->andWhere('w.databoxId = :databox_id')->setParameter('databox_id', $databoxId)
-            ->andWhere('w.recordId = :record_id')->setParameter('record_id', $recordId)
-            ->andWhere('w.workOn = :work_on')->setParameter(':work_on', $subdefName)
-            ->andWhere('w.work = :work_1 OR w.work = :work_2')
-            ->setParameter('work_1', MessagePublisher::WRITE_METADATAS_TYPE)
-            ->setParameter('work_2', MessagePublisher::SUBDEF_CREATION_TYPE)
-            ->setMaxResults(1)
-            ->getQuery()
-            ->getResult()
-        ;
+        $this->reconnect();
+        $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
 
-        if(count($r) == 0) {
-            // no conflict, create (or update) the job
-            $workerRunningJob = $this->creteOrUpdateJob($payload, MessagePublisher::WRITE_METADATAS_TYPE);
+        if($cnx->beginTransaction() === true) {
+
+            try {
+                $row = null;
+                $sql = "SELECT * FROM `WorkerRunningJob` WHERE\n"
+                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING) . " AND\n"
+                    . " `databox_id` = " . $cnx->quote($databoxId, PDO::PARAM_INT) . " AND\n"
+                    . " `record_id` = " . $cnx->quote($recordId, PDO::PARAM_INT) . " AND\n"
+                    . " " . $sqlClause . " AND\n"
+                    . " (`work` = " . $cnx->quote(MessagePublisher::WRITE_METADATAS_TYPE) . " OR `work` = " . $cnx->quote(MessagePublisher::SUBDEF_CREATION_TYPE) . ")\n"
+                    . " LIMIT 1";
+
+                $stmt = $cnx->prepare($sql);
+                if ($stmt->execute() === true) {
+                    $row = $stmt->fetch(PDO::FETCH_ASSOC);
+                }
+                else {
+                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("!!! FAILED select on %s.%s.%s because (%s)", $databoxId, $recordId, $subdefName, $stmt->errorCode())
+                    ), FILE_APPEND | LOCK_EX);
+                }
+                $stmt->closeCursor();
+
+                if(!$row) {
+                    // no job running : create or update (may return false) if error
+                    $workerRunningJobId = $this->creteOrUpdateJob($cnx, $payload, $jobType);
+                }
+                else {
+                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("job %s (id=%s) already running on %s.%s.%s", $row['work'], $row['id'], $databoxId, $recordId, $subdefName)
+                    ), FILE_APPEND | LOCK_EX);
+                }
+
+                $cnx->commit();
+            }
+            catch (Exception $e) {
+                $cnx->rollBack();
+
+                file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                    sprintf("!!! FAILED in transaction to select/create on %s.%s.%s because (%s)", $databoxId, $recordId, $subdefName, $e->getMessage())
+                ), FILE_APPEND | LOCK_EX);
+            }
         }
         else {
-            $r = $r[0];
-            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                sprintf("job %s already running on %s.%s.%s", $r->getId(), $r->getDataboxId(), $r->getRecordId(), $r->getWorkOn())
+            file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                sprintf("!!! FAILED to create transaction to select/create on %s.%s.%s", $databoxId, $recordId, $subdefName)
             ), FILE_APPEND | LOCK_EX);
-
         }
 
         // end of critical section
-        $this->releaseRecordMutex($databoxId, $recordId);
+        $this->releaseMutex($recordMutexId);
 
-        return $workerRunningJob;
+        return $workerRunningJobId;
     }
 
     /**
+     * @param Connection $cnx
      * @param array $payload
      * @param string $type
-     * @return WorkerRunningJob|null
-     * @throws OptimisticLockException
+     * @return int|null     // workerJobId
      */
-    private function creteOrUpdateJob(array $payload, string $type)
+    private function creteOrUpdateJob(Connection $cnx, array $payload, string $type)
     {
         // for unpredicted sql errors we can still ignore and return null (lock failed),
         // because anyway the worker/rabbit retry system will stop itself after n failures.
 
-        if (!isset($payload['workerJobId'])) {
+        $workerJobId = null;
 
-            // new job
+        try {
+            if (!isset($payload['workerJobId'])) {
 
-            $this->getEntityManager()->beginTransaction();
-            try {
-                $date = new DateTime();
-                $workerRunningJob = new WorkerRunningJob();
-                $workerRunningJob
-                    ->setDataboxId($payload['databoxId'])
-                    ->setRecordId($payload['recordId'])
-                    ->setWork($type)
-                    ->setWorkOn($payload['subdefName'])
-                    ->setPayload([
-                        'message_type'  => $type,
-                        'payload'       => $payload
-                    ])
-                    ->setPublished($date->setTimestamp($payload['published']))
-                    ->setStatus(WorkerRunningJob::RUNNING)
-                ;
+                // new job
 
-                $this->getEntityManager()->persist($workerRunningJob);
-                $this->getEntityManager()->flush();
-                $this->getEntityManager()->commit();
+                $datePublished = new DateTime();
+                $datePublished->setTimestamp($payload['published']);
+                $datePublished->format('Y-m-d H:i:s');
 
-                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("created job %s for %s.%s.%s", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
-                ), FILE_APPEND | LOCK_EX);
+                $pl = json_encode([
+                    'message_type' => $type,
+                    'payload'      => $payload
+                ]);
 
-            }
-            catch (Exception $e) {
-                // bad case : we return false anyway
-                $this->getEntityManager()->rollback();
-                // $this->logger->error("Error persisting WorkerRunningJob !");
-                $workerRunningJob = null;
-
-                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("!!! error creating job %s for %s.%s.%s", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
-                ), FILE_APPEND | LOCK_EX);
-
-            }
-        }
-        else {
-
-            // retry from delayed
-
-            /** @var WorkerRunningJob $workerRunningJob */
-            if(!is_null($workerRunningJob = $this->find($payload['workerJobId']))) {
-                // update retry count (value is already incremented in payload)
-                $workerRunningJob
-                    ->setInfo(WorkerRunningJob::ATTEMPT . $payload['count'])
-                    ->setStatus(WorkerRunningJob::RUNNING);
-
-                $this->getEntityManager()->persist($workerRunningJob);
-                $this->getEntityManager()->flush();
-
-                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("incremented job %s for %s.%s.%s (count=%s)", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'], $payload['count'])
-                ), FILE_APPEND | LOCK_EX);
+                $sql = "INSERT INTO `WorkerRunningJob` SET \n"
+                    . " `databox_id` = " . $cnx->quote($payload['databoxId'], PDO::PARAM_INT) . ",\n"
+                    . " `record_id` = " . $cnx->quote($payload['recordId'], PDO::PARAM_INT) . ",\n"
+                    . " `work` = " . $cnx->quote($type) . ",\n"
+                    . " `work_on` = " . $cnx->quote($payload['subdefName']) . ",\n"
+                    . " `payload` = " . $cnx->quote($pl) . ",\n"
+                    . " `published` = " . $cnx->quote($datePublished->format('Y-m-d H:i:s')) . ",\n"
+                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING);
 
+                if ($cnx->exec($sql) === 1) {
+                    // went well, the row is inserted
+                    $workerJobId = $cnx->lastInsertId();
+                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("created job %s (id=%s) for %s.%s.%s", $type, $workerJobId, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
+                    ), FILE_APPEND | LOCK_EX);
+                }
+                else {
+                    // row not inserted ?
+                    throw new Exception("Failed to insert into WorkerRunningJob");
+                }
             }
             else {
-                // the row has been deleted by purge ?
-                // bad case : we return false anyway
+                // retry from delayed : update retry count (value is already incremented in payload)
+                $sql = "UPDATE `WorkerRunningJob` SET \n"
+                    . " `info` = " . $cnx->quote(WorkerRunningJob::ATTEMPT . $payload['count']) . ",\n"
+                    . " `status` = " . $cnx->quote(WorkerRunningJob::RUNNING)
+                    . " WHERE `id` = " . $cnx->quote($payload['workerJobId'], PDO::PARAM_INT);
 
-                // $this->logger->error("Given workerJobId not found !");
-                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("!!! error incrementing job %s for %s.%s.%s (count=%s)", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'], $payload['count'])
-                ), FILE_APPEND | LOCK_EX);
+                if ($cnx->exec($sql) === 1) {
+                    // went well, the row is updated
+                    $workerJobId = $payload['workerJobId'];
 
+                    file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("updated job %s (id=%s) for %s.%s.%s", $type, $workerJobId, $payload['databoxId'], $payload['recordId'], $payload['subdefName'])
+                    ), FILE_APPEND | LOCK_EX);
+                }
+                else {
+                    // row not inserted ?
+                    throw new Exception(sprintf("Failed to update WorkerRunningJob with id=%s", $payload['workerJobId']));
+                }
             }
         }
+        catch (Exception $e) {
+            // bad case : we return null anyway
 
-        return $workerRunningJob;
+            file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                sprintf("!!! FAILED creating/updating job %s for %s.%s.%s because (%s)", $type, $payload['databoxId'], $payload['recordId'], $payload['subdefName'], $e->getMessage())
+            ), FILE_APPEND | LOCK_EX);
+        }
+
+        return $workerJobId;
     }
 
     /**
@@ -244,24 +240,58 @@ class WorkerRunningJobRepository extends EntityRepository
      * when many q-messages are consumed at the same time, many process may ask the same mutex immediatly, many fails.
      * so we retry after a short random delay which gives a good chance to ok, and avoids unnecessary "delayed" q-messages.
      *
+     *
+     * !!! IMPORTANT !!!
+     * we CAN'T use the entity manager to insert, because if this fails with exception (possible case),
+     * the EM will be closed and we will have no other chance for anothe tryout.
+     * So we play plain sql everywhere here.
+     *
      * @param int $databoxId
      * @param int $recordId
      * @return bool
      */
     private function getRecordMutex(int $databoxId, int $recordId)
     {
-        $e = null;  // exception if failed
+        // First we delete old unreleased mutex (which should never happen).
+        // A mutex is supposed to last only for a very short time (select + insert-or-update).
+        // 60s is considered as a dead mutex
+        //
+        try {
+            $this->reconnect();
+            $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
+
+            $sql = "DELETE FROM `WorkerRunningJob` WHERE\n"
+                . " `databox_id` = " . $cnx->quote($databoxId) . " AND\n"
+                . " `record_id` = " . $cnx->quote($recordId) . " AND\n"
+                . " `flock` = " . $cnx->quote('_mutex_') . " AND\n"
+                . " TIMESTAMPDIFF(SECOND, `published`, NOW()) > 60";
+
+            if ($cnx->exec($sql) > 0) {
+                // affected rows is 1 since by definition this key is unique
+                file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                    sprintf("!!! old mutex for %s.%s deleted (!!! SHOULD NOT HAPPEN !!!)", $databoxId, $recordId)
+                ), FILE_APPEND | LOCK_EX);
+            }
+        }
+        catch(Exception $e) {
+            // here something went very wrong, like sql death
+            file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                sprintf("!!! FAILED while trying to delete old mutex for %s.%s (!!! SHOULD NOT HAPPEN !!!)", $databoxId, $recordId)
+            ), FILE_APPEND | LOCK_EX);
+
+            return false; // we could choose to continue, but if we end up here... better to stop
+        }
+
+        // here we create a mutex, which CAN fail if another process did the same right before us
+        //
+        $e = null;  // last exception if failed
+
         for($tryout=1; $tryout<=3; $tryout++) {
             try {
                 $this->reconnect();
 
-                /**
-                 * !!! IMPORTANT !!!
-                 * we CAN'T use the entity manager to insert, because if this fails with exception (possible case),
-                 * the EM will be closed and we will have no other chance for anothe tryout.
-                 * So we do plain sql here.
-                 */
-                $cnx = $this->getEntityManager()->getConnection();
+                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
+
                 $sql = "INSERT INTO WorkerRunningJob (`databox_id`, `record_id`, `published`, `status`, `flock`) VALUES (\n"
                     . $cnx->quote($databoxId) . ",\n"
                     . $cnx->quote($recordId) . ",\n"
@@ -270,59 +300,88 @@ class WorkerRunningJobRepository extends EntityRepository
                     . $cnx->quote('_mutex_') . "\n"
                     . ")";
 
-                $cnx->exec($sql);
+                if(($a = $cnx->exec($sql)) === 1) {
 
-                file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("getMutex tryout %s for %s.%s OK", $tryout, $databoxId, $recordId)
-                ), FILE_APPEND | LOCK_EX);
+                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("getMutex tryout %s for %s.%s OK", $tryout, $databoxId, $recordId)
+                    ), FILE_APPEND | LOCK_EX);
 
-                return true;
+                    return $cnx->lastInsertId();
+                }
+
+                throw new Exception(sprintf("inserting mutex should return 1 row affected, got %s", $a));
             }
             catch (Exception $e) {
                 /**
                  * with plain sql, EM should still be opened here
                  */
 
-                // duplicate key ?
+                // duplicate key is possible, we retry on any kind of error
                 if($tryout < 3) {
-                    //sleep(1);
-                    $rnd = rand(10, 50) * 10;
+                    $rnd = rand(10, 50) * 10;   // 100 ms ... 500 ms with 10 ms steps
 
                     file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
                         sprintf("getMutex retry in %d msec", $rnd)
                     ), FILE_APPEND | LOCK_EX);
 
-                    usleep($rnd * 1000);   // 100 ms ... 500 ms with 10 ms steps
+                    usleep($rnd * 1000);
                 }
             }
         }
 
         file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf("getMutex tryout %s for %s.%s FAILED because (%s)", $tryout, $databoxId, $recordId, $e->getMessage())
+            sprintf("!!! FAILED getMutex for %s.%s because (%s)", $databoxId, $recordId, $e->getMessage())
         ), FILE_APPEND | LOCK_EX);
 
         return false;
     }
 
-    private function releaseRecordMutex(int $databoxId, int $recordId)
+    /**
+     * Release a mutex by deleting it.
+     * This should not fail, but -as for creation-, we will try N times
+     *
+     * @param int $recordMutexId
+     */
+    private function releaseMutex(int $recordMutexId)
     {
-        file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf("releaseMutex for %s.%s", $databoxId, $recordId)
+        $e = null;  // last exception if failed
+        for($tryout=1; $tryout<=3; $tryout++) {
+            try {
+                $this->reconnect();
+
+                /**
+                 * because we did not create an entity for mutex row,
+                 * we must use plain sql also to delete it
+                 */
+                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
+                $sql = "DELETE FROM WorkerRunningJob WHERE `id` = " . $cnx->quote($recordMutexId);
+
+                $cnx->exec($sql);
+
+                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                    sprintf("releaseMutex (id=%s) DONE", $recordMutexId)
+                ), FILE_APPEND | LOCK_EX);
+
+                return;
+            }
+            catch (Exception $e) {
+                if($tryout < 3) {
+                    $rnd = rand(10, 50) * 10;   // 100 ms ... 500 ms with 10 ms steps
+
+                    file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("releaseMutex (id=%s) retry in %d msec", $recordMutexId, $rnd)
+                    ), FILE_APPEND | LOCK_EX);
+
+                    usleep($rnd * 1000);
+                }
+            }
+        }
+
+        // Here we were not able to release a mutex (bad)
+        // The last chance will be later, when old mutex (60s) is deleted
+        file_put_contents(dirname(__FILE__) . '/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(true)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+            sprintf("!!! FAILED release mutex (id=%s) because (%s)", $recordMutexId, $e->getMessage())
         ), FILE_APPEND | LOCK_EX);
-
-        $this->reconnect();
-
-        /**
-         * because we did not create an entity for mutex row,
-         * we must use plain sql also to delete it
-         */
-        $cnx = $this->getEntityManager()->getConnection();
-        $sql = "DELETE FROM WorkerRunningJob\n"
-            . " WHERE `databox_id` = " . $cnx->quote($databoxId)
-            . "   AND `record_id` = " . $cnx->quote($recordId)
-            . "   AND `flock` = " . $cnx->quote("_mutex_");
-
-        $cnx->exec($sql);
     }
 
     /**
@@ -331,40 +390,46 @@ class WorkerRunningJobRepository extends EntityRepository
      *      But sometimes (?) a first commit fails (due to reconnect ?), while the second one is ok.
      *      So here we try 2 times, just in case...
      *
-     * @param WorkerRunningJob $workerRunningJob
+     * @param int $workerRunningJobId
      * @param null $info
      */
-    public function markFinished(WorkerRunningJob $workerRunningJob, $info = null)
+    public function markFinished(int $workerRunningJobId, $info = null)
     {
-        $this->reconnect();
-        for($try=1; $try<=2; $try++) {
+        for($tryout=1; $tryout<=2; $tryout++) {
             try {
-                $workerRunningJob->setStatus(WorkerRunningJob::FINISHED)
-                    ->setFinished(new DateTime('now'))
-                    ->setStatus(WorkerRunningJob::FINISHED);
-                if (!is_null($info)) {
-                    $workerRunningJob->setInfo($info);
+                $this->reconnect();
+                $cnx = $this->getEntityManager()->getConnection()->getWrappedConnection();
+                $sql = "UPDATE `WorkerRunningJob` SET \n"
+                    . " `finished` = NOW(),\n"
+                    . " `status` = " . $cnx->quote(WorkerRunningJob::FINISHED);
+                if(!is_null($info)) {
+                    $sql .= ",\n `info` = " . $cnx->quote(WorkerRunningJob::FINISHED);
                 }
+                $sql .= "\n WHERE `id` = " . $cnx->quote($workerRunningJobId, PDO::PARAM_INT);
 
-                $this->getEntityManager()->beginTransaction();
-                $this->getEntityManager()->persist($workerRunningJob);
-                $this->getEntityManager()->flush();
-                $this->getEntityManager()->commit();
+                if(($a = $cnx->exec($sql) )=== 1) {
+                    // ok
+                    file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+                        sprintf("job (id=%d) marked as finished", $workerRunningJobId)
+                    ), FILE_APPEND | LOCK_EX);
 
-                file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("job %s (%d) finished for %s.%s.%s", $workerRunningJob->getWork(), $workerRunningJob->getId(), $workerRunningJob->getDataboxId(), $workerRunningJob->getRecordId(), $workerRunningJob->getWorkOn())
-                ), FILE_APPEND | LOCK_EX);
-
-                break;
+                    return;
+                }
+                // not ok ? retry
+                throw new Exception(sprintf("updating WorkerRunningJob should return 1 row affected, got %s", $a));
             }
             catch (Exception $e) {
                 file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                    sprintf("!!! failed to mark job %s (%d) as finished (try %s/2) for %s.%s.%s", $workerRunningJob->getWork(), $workerRunningJob->getId(), $try, $workerRunningJob->getDataboxId(), $workerRunningJob->getRecordId(), $workerRunningJob->getWorkOn())
+                    sprintf("failed to mark job (id=%d) as finished (tryout %s, retry in 1 sec) because (%s)", $workerRunningJobId, $tryout, $e->getMessage())
                 ), FILE_APPEND | LOCK_EX);
-
-                $this->getEntityManager()->rollback();
+                if($tryout < 2) {
+                    sleep(1);   // retry in 1 sec
+                }
             }
         }
+        file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
+            sprintf("!!! FAILED to mark job (id=%d) as finished", $workerRunningJobId)
+        ), FILE_APPEND | LOCK_EX);
     }
 
     /**
diff --git a/lib/Alchemy/Phrasea/WorkerManager/Worker/SubdefCreationWorker.php b/lib/Alchemy/Phrasea/WorkerManager/Worker/SubdefCreationWorker.php
index dd9a16af6c..c6a18c3e64 100644
--- a/lib/Alchemy/Phrasea/WorkerManager/Worker/SubdefCreationWorker.php
+++ b/lib/Alchemy/Phrasea/WorkerManager/Worker/SubdefCreationWorker.php
@@ -79,9 +79,9 @@ class SubdefCreationWorker implements WorkerInterface
         $oldLogger = $this->subdefGenerator->getLogger();
 
         // try to "lock" the file, will return null if already locked
-        $workerRunningJob = $this->repoWorker->canCreateSubdef($payload);
+        $workerRunningJobId = $this->repoWorker->canCreateSubdef($payload);
 
-        if (is_null($workerRunningJob)) {
+        if (is_null($workerRunningJobId)) {
             // the file is written by another worker, delay to retry later
             $this->messagePublisher->publishDelayedMessage(
                 [
@@ -136,7 +136,7 @@ class SubdefCreationWorker implements WorkerInterface
                 $subdefName,
                 $workerMessage,
                 $count,
-                $workerRunningJob->getId()
+                $workerRunningJobId
             ));
 
             // the subscriber will "unlock" the row, no need to do it here
@@ -171,7 +171,7 @@ class SubdefCreationWorker implements WorkerInterface
                 $subdefName,
                 'Subdef generation failed !',
                 $count,
-                $workerRunningJob->getId()
+                $workerRunningJobId
             ));
 
             $this->subdefGenerator->setLogger($oldLogger);
@@ -219,7 +219,7 @@ class SubdefCreationWorker implements WorkerInterface
         $this->indexer->flushQueue();
 
         // tell that we have finished to work on this file (=unlock)
-        $this->repoWorker->markFinished($workerRunningJob);
+        $this->repoWorker->markFinished($workerRunningJobId);
 
     }
 
diff --git a/lib/Alchemy/Phrasea/WorkerManager/Worker/WriteMetadatasWorker.php b/lib/Alchemy/Phrasea/WorkerManager/Worker/WriteMetadatasWorker.php
index 7b8347cb18..e3fc7b2650 100644
--- a/lib/Alchemy/Phrasea/WorkerManager/Worker/WriteMetadatasWorker.php
+++ b/lib/Alchemy/Phrasea/WorkerManager/Worker/WriteMetadatasWorker.php
@@ -76,9 +76,9 @@ class WriteMetadatasWorker implements WorkerInterface
         $databox     = $this->findDataboxById($databoxId);
 
         // try to "lock" the file, will return null if already locked
-        $workerRunningJob = $this->repoWorker->canWriteMetadata($payload);
+        $workerRunningJobId = $this->repoWorker->canWriteMetadata($payload);
 
-        if (is_null($workerRunningJob)) {
+        if (is_null($workerRunningJobId)) {
             // the file is written by another worker, delay to retry later
             $this->messagePublisher->publishDelayedMessage(
                 [
@@ -103,7 +103,7 @@ class WriteMetadatasWorker implements WorkerInterface
         $record  = $databox->get_record($recordId);
 
         file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf(" --!!!-- recordid = %s", $record->getRecordId())
+            sprintf(" - recordid = %s", $record->getRecordId())
         ), FILE_APPEND | LOCK_EX);
 
         if ($record->getMimeType() == 'image/svg+xml') {
@@ -111,7 +111,7 @@ class WriteMetadatasWorker implements WorkerInterface
             $this->logger->error("Can't write meta on svg file!");
 
             // tell that we have finished to work on this file ("unlock")
-            $this->repoWorker->markFinished($workerRunningJob, "Can't write meta on svg file!");
+            $this->repoWorker->markFinished($workerRunningJobId, "Can't write meta on svg file!");
 
             return;
         }
@@ -120,14 +120,14 @@ class WriteMetadatasWorker implements WorkerInterface
 
         try {
             file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                sprintf(" --!!!-- getsubdef %s", $subdefName)
+                sprintf(" - getsubdef %s", $subdefName)
             ), FILE_APPEND | LOCK_EX);
 
             $subdef = $record->get_subdef($subdefName);
         }
         catch (Exception $e) {
             file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                sprintf(" --!!!-- %s", $e->getMessage())
+                sprintf(" - %s", $e->getMessage())
             ), FILE_APPEND | LOCK_EX);
 
             $workerMessage = "Exception catched when try to get subdef " .$subdefName. " from DB for the recordID: " .$recordId;
@@ -142,7 +142,7 @@ class WriteMetadatasWorker implements WorkerInterface
                 SubdefinitionWritemetaEvent::FAILED,
                 $workerMessage,
                 $count,
-                $workerRunningJob->getId()
+                $workerRunningJobId
             ));
 
             // the subscriber will mark the job as errored, no need to do it here
@@ -151,7 +151,7 @@ class WriteMetadatasWorker implements WorkerInterface
 
         if (!$subdef->is_physically_present()) {
             file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-                sprintf(" --!!!-- not present")
+                sprintf(" - not present")
             ), FILE_APPEND | LOCK_EX);
 
             $count = isset($payload['count']) ? $payload['count'] + 1 : 2 ;
@@ -163,7 +163,7 @@ class WriteMetadatasWorker implements WorkerInterface
                 SubdefinitionWritemetaEvent::FAILED,
                 'Subdef is not physically present!',
                 $count,
-                $workerRunningJob->getId()
+                $workerRunningJobId
             ));
 
             // the subscriber will mark the job as errored, no need to do it here
@@ -266,7 +266,7 @@ class WriteMetadatasWorker implements WorkerInterface
         }
 
         file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf(" --!!!-- reset")
+            sprintf(" - reset")
         ), FILE_APPEND | LOCK_EX);
 
         $this->writer->reset();
@@ -278,7 +278,7 @@ class WriteMetadatasWorker implements WorkerInterface
         $this->writer->erase($subdef->get_name() != 'document' || $clearDoc, true);
 
         file_put_contents(dirname(__FILE__).'/../../../../../logs/trace.txt', sprintf("%s [%s] : %s (%s); %s\n", (\DateTime::createFromFormat('U.u', microtime(TRUE)))->format('Y-m-d\TH:i:s.u'), getmypid(), __FILE__, __LINE__,
-            sprintf(" --!!!-- erased")
+            sprintf(" - erased")
         ), FILE_APPEND | LOCK_EX);
 
         // write meta in file
@@ -309,7 +309,7 @@ class WriteMetadatasWorker implements WorkerInterface
                 SubdefinitionWritemetaEvent::FAILED,
                 $workerMessage,
                 $count,
-                $workerRunningJob->getId()
+                $workerRunningJobId
             ));
 
             // the subscriber will "unlock" the row, no need to do it here
@@ -320,7 +320,7 @@ class WriteMetadatasWorker implements WorkerInterface
         $this->updateJeton($record);
 
         // tell that we have finished to work on this file (=unlock)
-        $this->repoWorker->markFinished($workerRunningJob);
+        $this->repoWorker->markFinished($workerRunningJobId);
     }
 
     private function removeNulChar($value)