Marcell Ortutay commented on PHOENIX-4666:

Ah! got it, thank

> Add a subquery cache that persists beyond the life of a query
> -------------------------------------------------------------
>                 Key: PHOENIX-4666
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-4666
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Marcell Ortutay
>            Assignee: Marcell Ortutay
>            Priority: Major
> The user list thread for additional context is here: 
> [https://lists.apache.org/thread.html/e62a6f5d79bdf7cd238ea79aed8886816d21224d12b0f1fe9b6bb075@%3Cuser.phoenix.apache.org%3E]
> ----
> A Phoenix query may contain expensive subqueries, and moreover those 
> expensive subqueries may be used across multiple different queries. While 
> whole result caching is possible at the application level, it is not possible 
> to cache subresults in the application. This can cause bad performance for 
> queries in which the subquery is the most expensive part of the query, and 
> the application is powerless to do anything at the query level. It would be 
> good if Phoenix provided a way to cache subquery results, as it would provide 
> a significant performance gain.
> An illustrative example:
>     SELECT * FROM table1 JOIN (SELECT id_1 FROM large_table WHERE x = 10) 
> expensive_result ON table1.id_1 = expensive_result.id_2 AND table1.id_1 = 
> \{id}
> In this case, the subquery "expensive_result" is expensive to compute, but it 
> doesn't change between queries. The rest of the query does because of the 
> \{id} parameter. This means the application can't cache it, but it would be 
> good if there was a way to cache expensive_result.
> Note that there is currently a coprocessor based "server cache", but the data 
> in this "cache" is not persisted across queries. It is deleted after a TTL 
> expires (30sec by default), or when the query completes.
> This is issue is fairly high priority for us at 23andMe and we'd be happy to 
> provide a patch with some guidance from Phoenix maintainers. We are currently 
> putting together a design document for a solution, and we'll post it to this 
> Jira ticket for review in a few days.

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