I am indexing 300 documents in following indexes
Index A: has a
synonym_filter with 25000 synonyms in the Index itself
Index B: the
synonym_filter refers the synonyms from a file
I observed a drastic difference in indexing speed for both in indices.
When synonyms were refered from a file, the indexing was way faster
When in "Index A" the synonyms are spread across multiple syn_filters with ~5000 synonyms each, the indexing takes ~1 min for one document!!!
Configuration: Elasticsearch is running on localhost itself, so no network issues in play.