diff --git a/API_documentation/v3/api.yaml b/API_documentation/v3/api.yaml
index b5eb563fba..dfc4a8e5ae 100644
--- a/API_documentation/v3/api.yaml
+++ b/API_documentation/v3/api.yaml
@@ -118,3 +118,46 @@ paths:
                     description: Record not found
                 default:
                     $ref: 'responses.yaml#/error_response'
+    '/stories/{sbas_id}/{record_id}/children':
+        get:
+            tags:
+                - story
+            summary: Returns uri of each record (child) contained in the story ; Optional pagination
+            description: Returns children of a story
+            operationId: getRecordById
+            parameters:
+                - name: sbas_id
+                  in: path
+                  description: ID of the databox
+                  required: true
+                  schema:
+                      $ref: schemas.yaml#/ID
+                - name: record_id
+                  in: path
+                  description: ID of the story record
+                  required: true
+                  schema:
+                      $ref: schemas.yaml#/ID
+                - name: page
+                  in: query
+                  description: page number (default 1)
+                  required: false
+                  schema:
+                      type: integer
+                - name: per_page
+                  in: query
+                  description: number of children (records uri) per page (default 10)
+                  required: false
+                  schema:
+                      type: integer
+            responses:
+                200:
+                    description: ok
+                    content:
+                        application/json:
+                            schema:
+                                $ref: schemas.yaml#/ApiResponse_RecordsUriArray
+                404:
+                    description: Story (record) not found
+                default:
+                    $ref: 'responses.yaml#/error_response'
diff --git a/API_documentation/v3/responses.yaml b/API_documentation/v3/responses.yaml
index 5cf544e8f0..1ac2155f3e 100644
--- a/API_documentation/v3/responses.yaml
+++ b/API_documentation/v3/responses.yaml
@@ -1,2 +1,15 @@
+record_response:
+    type: object
+    properties:
+        200:
+            description: successful operation
+            content:
+                application/json:
+                    schema:
+                        $ref: schemas.yaml#/ApiResponse_record
+        400:
+            description: Any other error
+        404:
+            description: Record not found
 error_response:
         description: Any (other) error
diff --git a/API_documentation/v3/schemas.yaml b/API_documentation/v3/schemas.yaml
index 77c30061e1..108e6f7580 100644
--- a/API_documentation/v3/schemas.yaml
+++ b/API_documentation/v3/schemas.yaml
@@ -169,4 +169,19 @@ Record:
                 - video
         uuid:
             type: string
+RecordUri:
+    type: string
+    example:
+        '/api/v3/records/1/48'
+RecordsUriArray:
+    type: array
+    items:
+        $ref: '#/RecordUri'
 
+ApiResponse_RecordsUriArray:
+    type: object
+    properties:
+        meta:
+            $ref: '#/ApiResponse_meta'
+        response:
+            $ref: '#/RecordsUriArray'
diff --git a/lib/Alchemy/Phrasea/Databox/Record/LegacyRecordRepository.php b/lib/Alchemy/Phrasea/Databox/Record/LegacyRecordRepository.php
index 30feada346..f52cbac467 100644
--- a/lib/Alchemy/Phrasea/Databox/Record/LegacyRecordRepository.php
+++ b/lib/Alchemy/Phrasea/Databox/Record/LegacyRecordRepository.php
@@ -12,8 +12,11 @@ namespace Alchemy\Phrasea\Databox\Record;
 use Alchemy\Phrasea\Application;
 use Alchemy\Phrasea\Cache\Exception;
 use Alchemy\Phrasea\Model\Entities\User;
+use databox;
 use Doctrine\DBAL\Connection;
 use Doctrine\DBAL\Query\QueryBuilder;
+use record_adapter;
+use set_selection;
 
 class LegacyRecordRepository implements RecordRepository
 {
@@ -23,7 +26,7 @@ class LegacyRecordRepository implements RecordRepository
     private $app;
 
     /**
-     * @var \databox
+     * @var databox
      */
     private $databox;
 
@@ -32,7 +35,7 @@ class LegacyRecordRepository implements RecordRepository
      */
     private $site;
 
-    public function __construct(Application $app, \databox $databox, $site)
+    public function __construct(Application $app, databox $databox, $site)
     {
         $this->app = $app;
         $this->databox = $databox;
@@ -41,7 +44,7 @@ class LegacyRecordRepository implements RecordRepository
 
     public function find($record_id, $number = null)
     {
-        $record = new \record_adapter($this->app, $this->databox->get_sbas_id(), $record_id, $number, false);
+        $record = new record_adapter($this->app, $this->databox->get_sbas_id(), $record_id, $number, false);
         try {
             $data = $record->get_data_from_cache();
         } catch (Exception $exception) {
@@ -67,7 +70,7 @@ class LegacyRecordRepository implements RecordRepository
 
     /**
      * @param string $sha256
-     * @return \record_adapter[]
+     * @return record_adapter[]
      */
     public function findBySha256($sha256)
     {
@@ -112,7 +115,7 @@ class LegacyRecordRepository implements RecordRepository
 
     /**
      * @param string $uuid
-     * @return \record_adapter[]
+     * @return record_adapter[]
      */
     public function findByUuid($uuid)
     {
@@ -130,7 +133,7 @@ class LegacyRecordRepository implements RecordRepository
     /**
      * @param string $uuid
      * @param array $excludedCollIds
-     * @return \record_adapter[]
+     * @return record_adapter[]
      */
     public function findByUuidWithExcludedCollIds($uuid, $excludedCollIds = [])
     {
@@ -190,85 +193,86 @@ class LegacyRecordRepository implements RecordRepository
 
         $connection = $this->databox->get_connection();
 
+        // the columns we want from the record
+        //
         $selects = $this->getRecordSelects();
+        array_unshift($selects, 'r.rid_parent AS story_id');    // add this to default
+
+        // sql parameters will be completed depending of (paginated / not paginated) and/or (user / no user)
+        //
+        $parmValues = [
+            ':storyIds' => $storyIds,
+        ];
+        $parmTypes  = [
+            ':storyIds' => Connection::PARAM_INT_ARRAY,
+        ];
+
+        // if there is a user, we must join collusr to filter results depending on coll/masks
+        //
+        $userFilter = "";
+        if(!is_null($user)) {
+            $userFilter = "         INNER JOIN collusr c ON c.site = :site AND c.usr_id = :userId AND c.coll_id=r.coll_id AND ((r.status ^ c.mask_xor) & c.mask_and) = 0\n";
+            $parmValues[':site'] = $this->site;
+            $parmValues[':userId'] = $user instanceof User ? $user->getId() : (int)$user;
+        }
 
         if ($max_items) {
-            array_unshift($selects, 'sr.rid_parent as story_id');
-
-            $subBuilder = $connection->createQueryBuilder();
-
-            $subBuilder
-                ->select('s.*,
-                    IF(@old_rid_parent != s.rid_parent, @cpt := 1, @cpt := @cpt+1) AS CPT')
-                ->addSelect("IF(@old_rid_parent != s.rid_parent, IF(@old_rid_parent:=s.rid_parent,'NEW PARENT',0), '----------') AS Y")
-                ->from('regroup', 's')
-                ->where('s.rid_parent IN (:storyIds)')
-                ->setParameter('storyIds', $storyIds, Connection::PARAM_INT_ARRAY)
-                ->orderBy('s.rid_parent, s.ord')
+            //
+            // we want paginated results AFTER applying all filters, we build a dynamic cptr
+            // WARNING : due to bugs (?) in mysql optimizer, do NOT try to optimize this sql (e.g. removing a sub-q, or moving cpt to anothe sub-q)
+            //
+            $sql = "SELECT " . join(', ', $selects) . "\n"
+                . "FROM (\n"
+                . "  SELECT t.*,\n"
+                . "         IF(@old_rid_parent != t.rid_parent, @cpt := 1, @cpt := @cpt+1) AS CPT,\n"
+                . "         IF(@old_rid_parent != t.rid_parent, IF(@old_rid_parent:=t.rid_parent,'NEW PARENT',0), '----------') AS Y\n"
+                . "  FROM (\n"
+                . "    SELECT g.ord, g.rid_parent, r.coll_id, r.record_id, r.credate, r.status, r.uuid, r.moddate, r.parent_record_id,r.type, r.originalname, r.sha256, r.mime\n"
+                . "    FROM regroup g\n"
+                . "         INNER JOIN record r ON r.record_id=g.rid_child\n"
+                . $userFilter
+                . "    WHERE g.rid_parent IN ( :storyIds )\n"
+                . "    ORDER BY g.rid_parent, g.ord ASC\n"
+                . "  ) t\n"
+                . ") r\n"
+                . "WHERE CPT BETWEEN :offset AND :maxresult"
             ;
 
-            $builder = $subBuilder->getConnection()->createQueryBuilder();
-
-            $builder->select($selects)
-                ->from(sprintf('( %s )', $subBuilder->getSQL()), 'sr')
-                ->innerJoin('sr', 'record', 'r', 'r.record_id = sr.rid_child')
-                ->where('sr.CPT BETWEEN :offset AND :maxresult')
-                ->andWhere('r.parent_record_id = 0')
-                ->setParameter('offset', $offset)
-                ->setParameter('maxresult', ($offset + $max_items -1))
-                ->orderBy('story_id, sr.CPT')
-            ;
-
-            if (null !== $user) {
-                $this->addUserFilter($builder, $user);
-            }
+            $parmValues[':offset'] = $offset;
+            $parmValues[':maxresult'] = ($offset + $max_items -1);
 
             $connection->executeQuery('SET @cpt = 1');
-
             $connection->executeQuery('SET @old_rid_parent = -1');
-
-
-            $data = $connection->fetchAll(
-                $builder->getSQL(),
-                array_merge($subBuilder->getParameters(), $builder->getParameters()),
-                array_merge($subBuilder->getParameterTypes(), $builder->getParameterTypes())
-            );
-
-        } else {
-            array_unshift($selects, 's.rid_parent as story_id');
-
-            $builder = $connection->createQueryBuilder();
-
-            $builder
-                ->select($selects)
-                ->from('regroup', 's')
-                ->innerJoin('s', 'record', 'r', 'r.record_id = s.rid_child')
-                ->where(
-                    's.rid_parent IN (:storyIds)',
-                    'r.parent_record_id = 0'
-                )
-                ->orderBy('s.ord', 'ASC')
-                ->setParameter('storyIds', $storyIds, Connection::PARAM_INT_ARRAY)
-            ;
-
-            if (null !== $user) {
-                $this->addUserFilter($builder, $user);
-            }
-
-            $data = $connection->fetchAll($builder->getSQL(), $builder->getParameters(), $builder->getParameterTypes());
         }
+        else {
+            //
+            // se want all children, easy
+            //
+            $sql = "SELECT " . join(', ', $selects) . "\n"
+                . "FROM (\n"
+                . "    SELECT g.ord, g.rid_parent, r.coll_id, r.record_id, r.credate, r.status, r.uuid, r.moddate, r.parent_record_id,r.type, r.originalname, r.sha256, r.mime\n"
+                . "    FROM regroup g\n"
+                . "         INNER JOIN record r ON r.record_id=g.rid_child\n"
+                . $userFilter
+                . "    WHERE g.rid_parent IN ( :storyIds )\n"
+                . "    ORDER BY g.rid_parent, g.ord ASC\n"
+                . ") r\n"
+            ;
+        }
+
+        $data = $connection->fetchAll($sql, $parmValues, $parmTypes);
 
         $records = $this->mapRecordsFromResultSet($data);
 
         $selections = array_map(
             function () {
-                return new \set_selection($this->app);
+                return new set_selection($this->app);
             },
             array_flip($storyIds)
         );
 
         foreach ($records as $index => $child) {
-            /** @var \set_selection $selection */
+            /** @var set_selection $selection */
             $selection = $selections[$data[$index]['story_id']];
 
             $child->setNumber($selection->get_count() + 1);
@@ -312,12 +316,12 @@ class LegacyRecordRepository implements RecordRepository
         $stories = $this->mapRecordsFromResultSet($data);
 
         $selections = array_map(function () {
-            return new \set_selection($this->app);
+            return new set_selection($this->app);
         }, array_flip($recordIds));
 
 
         foreach ($stories as $index => $child) {
-            /** @var \set_selection $selection */
+            /** @var set_selection $selection */
             $selection = $selections[$data[$index]['child_id']];
 
             $selection->add_element($child);
@@ -357,7 +361,7 @@ class LegacyRecordRepository implements RecordRepository
 
     /**
      * @param array $result
-     * @return \record_adapter[]
+     * @return record_adapter[]
      */
     private function mapRecordsFromResultSet(array $result)
     {
@@ -372,13 +376,13 @@ class LegacyRecordRepository implements RecordRepository
 
     /**
      * @param array                $row
-     * @param \record_adapter|null $record
-     * @return \record_adapter
+     * @param record_adapter|null $record
+     * @return record_adapter
      */
-    private function mapRecordFromResultRow(array $row, \record_adapter $record = null)
+    private function mapRecordFromResultRow(array $row, record_adapter $record = null)
     {
         if (null === $record) {
-            $record = new \record_adapter($this->app, $this->databox->get_sbas_id(), $row['record_id'], null, false);
+            $record = new record_adapter($this->app, $this->databox->get_sbas_id(), $row['record_id'], null, false);
         }
 
         $record->mapFromData($row);
@@ -400,15 +404,13 @@ class LegacyRecordRepository implements RecordRepository
             ->select('1')
             ->from('collusr', 'c')
             ->where(
-                'c.usr_id = :userId',
-                'c.site = :site',
+                'c.usr_id = ' . ($user instanceof User ? $user->getId() : (int)$user),
+                'c.site = \'' . $this->site . '\'',
                 '((r.status ^ c.mask_xor) & c.mask_and) = 0',
                 'c.coll_id = r.coll_id'
             );
 
         $builder
-            ->andWhere(sprintf('EXISTS(%s)', $subBuilder->getSQL()))
-            ->setParameter('userId', $user instanceof User ? $user->getId() : (int)$user)
-            ->setParameter('site', $this->site);
+            ->andWhere(sprintf('EXISTS(%s)', $subBuilder->getSQL()));
     }
 }