We have finished alfa version of Astrologer: tool that allows to ingest or export historical data from Stellar Core to ElasticSearch.
It stores ledgers, transactions, operations with results and metas in ES and makes you able to search all the data in very flexible way using all the black magic of ElasticSearch engine.
For instance, you could easily build a query which answers the question "What was the most popular operation type three days ago in the whole network?" or "What was the daily average balance of specific account?" or "What was the biggest payment made last week?" or simply find all payments with specific memo value.
Check the repo:
https://github.com/astroband/astrologer, it contains some sample queries in Postman collection.
Astrologer can be used in isolation, as a separate tool, but we are now integrating it into Astrograph. Our first goal is to query operations from ES instead of Horizon (it's almost done), add more search criterias and make some useful aggregation results available via Astrograph GraphQL API.
Ultimate goal is to completely get rid of our dependency on Horizon, and Astrologer integration would be the first step.
We'll be grateful if anyone has any thoughts on queries or use cases which we could implement onset.