Can lookups work at ingestion time? I tried setting a transform like:

lookup('CAD', 'test')

But I get an error:

Failed to sample data: Lookup [test] not found

...which I suspect really means that it hasn't been implemented for ingestion time; since

SELECT LOOKUP('CAD', 'test')

works at query time.

You can, but the middlemanager must have ``druid.lookup.enableLookupSyncOnStartup=true``