Thanks for the quick reply!

On Sat, Jul 4, 2020 at 1:02 AM Sergei Golubchik <serg@mariadb.org> wrote:
Hi, Dan!

On Jul 03, Dan Hill wrote:
> Hi!
>
> I'm evaluating if I can use Maria's JDBC connector to join tables from
> Apache Pinot (they have a prototype jdbc connector).
>
> When external tables are used (like JDBC or FederatedX), are group bys
> pushed down or do these connectors return the raw rows to Maria?  I
> see comments about lack of filter pushdowns for FederatedX.  I
> wouldn't the raw level data coming back from Pinot (there are too many
> rows to be performant).

No, at the moment neither FederatedX nor CONNECT engines
support group by pushdown.

The server supports it, some engines support it (namely, ColumnStore and
Spider), but not all.

Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org