It works pretty well and fairly quickly. We use the array_agg and other json features in a Postgres to Elasticsearch ETL. Postgres is able to spit out the exact

It works pretty well and fairly quickly. We use the array_agg and other json features in a Postgres to Elasticsearch ETL. Postgres is able to spit out the exact format that we need, so the application code isn't really doing much more than coordinating the reads and writes.