Very slow 101-feeling design/query..

This feels very 101 but I feel like it should be much faster:

A table "joints" with a PK of play_uuid, target_id, joint_seq,
joint_timestamp.

"joints" is partitioned using RANGE on joint_timestamp for monthly
partitions 1/1 - 2/1, 2-1 - 3/1, etc.

"joints" has an FK where play_uuid refers to table "plays" and
column "play_uuid" where "play_uuid" is the PK.

"plays" additionally has an indexed column game_id.

"joints" has 1133,932,391 rows across 12 monthly partitions for 2021, and
"plays has 585,627 rows. We made a view called "vw_joints" which just does:

SELECT * FROM joints JOIN plays USING (play_id);

Then doing:

SELECT DISTINCT game_id FROM vw_joints

Takes 35-45 minutes. Which seems nuts. We do this kind of design in a few
different plays to normalize things, but it comes at the cost of these
agonizingly slow (and seemingly dead simple) qeuries.

Is there any optimization to do here beyond flattening table and
de-normalizing data? Is the partitioning causing a slowness here? I feel
like partitioning is creating some difficulty...

Appreciate it.

--
Wells Oliver
wells(dot)oliver(at)gmail(dot)com <wellsoliver(at)gmail(dot)com>