Is Quora really big outside the US or something? I find it difficult to reconcile their scale challenges with the fact that I don't know a single person that uses Quora outside of when the come up in google search results.
<p><pre><code> A couple of years ago, our infrastructure team
implemented the ability to move a table from one
MySQL host to another. This allowed us to have
multiple masters with different tables on different
masters, which we refer to as “vertical sharding”.
Each one of these masters, along with its slaves,
is called as a “partition” at Quora.
</code></pre>
I nearly stopped reading here.<p>Naming things is hard, but why would they choose a term ("partition") that has already existed for many decades in the same context?<p>That's nonsensical.
<a href="https://www.raphkoster.com/2009/01/08/database-sharding-came-from-uo/" rel="nofollow">https://www.raphkoster.com/2009/01/08/database-sharding-came...</a><p>Nice article from Raph Koster. Especially if you played Ultima Online by any chance.
'shard user scale data, centralize or mirror small scale data' (the A1 A2 B C D E diagram) is a useful point<p>'obvious in retrospect' I suspect to a lot of teams that add sharding to their system
> The result is that we do very few joins in MySQL<p>I realize depending on your data model some of this is unavoidable once you shard, but it sounds like they did this even before sharding.<p>What's the reason to do that? Seems like you either end up with long transactions or doing MVCC in app code