QuerySchemaCatalog

The Catalog (design §4, §5.2): compiles the query schema of every aggregate model this instance serves, one provider per aggregate and model, with its compiler (by default the model sources merged under the sensitivity policy, see QueryModelCompiler.of). Each storage only reports its native facts, through the storage adapter its backend factory supplies. Gateways, point reads and the capability descriptor all read their schema here.

Storage facts (indexes, mappings, validators) change outside deployments, so the catalog is revalidated periodically: each schema of aggregates is reloaded and published only if it compiles, otherwise the previous one stays and the failure is reported. A model without a backend, or whose backend reports an UnavailableQueryStorageAdapter, has nothing to load or revalidate: its provider fails every load and revalidation skips it.