The current basic_configs and data_driven_schema_configs try to create unknown fields. The problem is that the date processing "ParseDateFieldUpdateProcessorFactory" is not invoked if the doc is replayed from the tlog. Whether there are other places this is a problem I don't know, this is a concrete example that fails in the field.
So say I have a pattern for dates that omits the trialing 'Z', as:
This work fine when the doc is initially indexed. Now say the doc must be replayed from the tlog. The doc errors out with "unknown date format" since (apparently) this doesn't go through the same update chain, perhaps due to the sample configs defining ParseDateFieldUpdateProcessorFactory after DistributedUpdateProcessorFactory?