Re: Hash partitioning.

Now I just have two indices. One that indexes only hot tuples, it's
very heavily queried and works blazingly fast, and one that indexes by
(hotness, key). I include the hotness value on the query, and still
works quite fast enough. Luckily, I know things become cold after an
update to mark them cold, so I can do that. I included hotness on the
index to cluster updates on the hot part of the index, but I could
have just used a regular index and paid a small price on the updates.

Indeed, for a while it worked without the hotness, and there was no
significant trouble. I later found out that WAL bandwidth was
noticeably decreased when I added that hotness column, so I did, helps
a bit with replication. Has worked ever since.