Class FallbackSyntheticSourceBlockLoader

java.lang.Object
org.elasticsearch.index.mapper.FallbackSyntheticSourceBlockLoader
All Implemented Interfaces:
BlockLoader

public abstract class FallbackSyntheticSourceBlockLoader extends Object implements BlockLoader
Block loader for fields that use fallback synthetic source implementation.
Usually fields have doc_values or stored fields and block loaders use them directly. In some cases neither is available and we would fall back to (potentially synthetic) _source. However, in case of synthetic source, there is actually no need to construct the entire _source. We know that there is no doc_values and stored fields, and therefore we will be using fallback synthetic source. That is equivalent to just reading _ignored_source stored field directly and doing an in-place synthetic source just for this field.
See IgnoredSourceFieldMapper.