[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

MaterializationService.THREAD_INSTANCE vs INSTANCE


I'm trying to use Calcite to optimize queries rewriting the queries to use materialized views.

First, I found the following doc page about materialization in Calcite website by googling but I coudn't find a link to it in Calcite's website. Anyway, it does not explain how to add materialized views to the schema.


I'm trying to follow how Cassandra Adapter does it.  It uses de Hook.TRIMMED to be called to add the materialized views.
Is that the recommended approach?

I noticed that MaterializationService.instance() first tries to get an instance from a ThreadLocal field (THREAD_INSTANCE) and if it is null then uses the field instance (INSTANCE). The comments in the class says that ThreadLocal instance is supposed to be used for testing.

However, THREAD_INSTANCE field is initialized with ThreadLocal.withInitial(MaterializationService::new), so it seems that it will never be null, making instance() method always return the THREAD_INSTANCE instance.

The problem is that I'm running the statements in worker threads and sometimes the materialized view is used and sometimes not. I think the problem is that the materialization is not available when running in a different thread.

Is that a bug?

Any tips on how to add materialized views to an AbstractSchema?


Luis Fernando