Well since he's talking about prices in Euro I doubt newegg is an option there.
As for the DB: You can use
Code:
SELECT
relname AS objectname,
relkind AS objecttype,
reltuples AS "#entries", pg_size_pretty(relpages::bigint*8*1024) AS size
FROM pg_class
WHERE relpages >= 8
ORDER BY relpages DESC;
on a psql prompt to see the various object sizes in the database. (Source)
The 7700k is great for gaming but then you need a graphic card that can keep up with it, which puts you way beyond the 600 Euro mark. You could of course get the CPU now and then later upgrade the GPU, but unless you want top notch gaming performance (and pay for it) a Ryzen 5 is definitely the better option IMHO.
Ryzen 7 (8/16 cores) would probably exceed the budget a bit (a lot without overclocking) - it's slightly behind a 7700k when it comes to gaming especially in (older) games that depend on single thread performance. In return it's way better in multi threaded applications, however you don't appear to be using one, so I think a 6/12 or even a 4/8 core is sufficient.