The generate_index_content function is being called inside the tainacan-api-item-updated hook. There should be a check there to avoid parsing the content every time the item is update, unless there has been an actual change to the document itself.

This was reported here: https://tainacan.discourse.group/t/pdf-com-mais-de-110mb-causando-lentidoes-ao-salvar-item/2525