SOLR how can I trigger deletion using $deleteDocById with DIH

Question

I need to delete some documents during full-import with dataimporter.request.clean == false. This limits the options open to me and it seems that using $deleteDocById would be my best option. However I cannot find a good example of how to achieve this.

I am using sometihing along the lines of:

<document>
    <entity query="select id, text
        IF(yadda.dateyyy <= NOW(),yadda.id,NULL) AS $deleteDocById,
        IF(yadda.dateyyy <= NOW(),yadda.id,NULL) AS $skipDoc,
        from yadda">
    </entity>
 </document>

the GET parameters ?command=full-import&clean=false seems to trigger correctly with the final report including Indexing completed. Added/Updated: 72 documents. Deleted 4 documents. however when query the supposedly deleted documents are still in the index.

Answer 1

$skipDoc needed to be set to the string value "true" in order for this to work.

<document>
    <entity query="select id, text
        IF(yadda.dateyyy <= NOW(),yadda.id,NULL) AS $deleteDocById,
        IF(yadda.dateyyy <= NOW(),"true",NULL) AS $skipDoc,
        from yadda">
    </entity>
 </document>