My Solr data source is a SQL database where the primary key is compound (i.e. it's two fields).
This is fine for my main DIH
query, I just concatenate the fields and that becomes my Solr primary key. However it's unclear from the documentation how I'd write a delta-import query to support this.
The documentation suggests I need two queries - one to find the primary key of the changed rows, and another to then actually retrieve the individual documents corresponding to each of those keys. There's no example showing this for compound keys though.
Ideally I don't want those two separate queries at all, it would put less load on the database if those two queries were simply combined such that the only difference between
deltaQuery is the
WHERE clause that filters based on
So, if my main
SELECT key1 || key2 as pk FROM table
What would the relevant
deltaImportQuery) look like?
I tried just adding the
WHERE clause but after the query ran I got a warning about the missing
deltaImportQuery and then a null-pointer exception.