Some stuff could be stored as child documents in solr

• repeaters
• worfklow entries
• attachments
• chunks

Gain :

• No need to unindex them separately
• Later we could rewrite queries to increase perfs

https://solr.apache.org/guide/solr/latest/indexing-guide/indexing-nested-documents.html
https://solr.apache.org/guide/solr/latest/query-guide/block-join-query-parser.html