public function continueIndex($interval = 0)
{
   if ($interval > 0)
      $endTime = microtime(true) + $interval;
   else
      $endTime = 0;

   $indexedCount = 0;

   if ($this->lastElementId === null)
      $lastElementId = $this->storage->getLastStoredElementId();
   else
      $lastElementId = $this->lastElementId;

   $elementList = $this->getElementsCursor($lastElementId);
   while ($element = $elementList->fetch())
   {
      $this->indexElement($element["ID"]);   <-----------
      $indexedCount++;
      $this->lastElementId = $element["ID"];
      if ($endTime > 0 && $endTime < microtime(true))
         break;
   }
   return $indexedCount;
}

public function indexElement($elementId)
{
   $element = new Element($this->iblockId, $elementId);
   $element->loadFromDatabase();

   $elementSections = $element->getSections();
   $elementIndexValues = $this->getSectionIndexEntries($element);
   
   foreach ($element->getParentSections() as $sectionId)        <-------------
   {
      foreach ($elementIndexValues as $facetId => $values)      <-------------
      {
         foreach ($values as $value)                            <-------------
         {
            $this->storage->addIndexEntry(
               $sectionId,
               $elementId,
               $facetId,
               $value["VALUE"],
               $value["VALUE_NUM"],
               in_array($sectionId, $elementSections)
            );
         }
      }
   }

   foreach ($elementIndexValues as $facetId => $values)
   {
      foreach ($values as $value)
      {
         $this->storage->addIndexEntry(
            0,
            $elementId,
            $facetId,
            $value["VALUE"],
            $value["VALUE_NUM"],
            empty($elementSections)
         );
      }
   }
}

public function addIndexEntry($sectionId, $elementId, $facetId, $value, $valueNum, $includeSubsections)
{
   $connection = \Bitrix\Main\Application::getConnection();

   try
   {
      $connection->query("                                      <-----------
         INS ERT IN TO ".$this->getTableName()." (
            SECTION_ID
            ,ELEMENT_ID
            ,FACET_ID
            ,VALUE
            ,VALUE_NUM
            ,INCLUDE_SUBSECTIONS
         ) VALUES (
            ".intval($sectionId)."
            ,".intval($elementId)."
            ,".intval($facetId)."
            ,".intval($value)."
            ,".doubleval($valueNum)."
            ,".($includeSubsections > 0? 1: 0)."
         )
      ");
   }
   catch (\Bitrix\Main\DB\SqlException $e)
   {
      return false;
   }

   return true;
}