For example, it was only 2 years ago that Citus allowed the joining of data in "local" tables and data retrieved from distributed tables (https://www.citusdata.com/updates/v11-0). In this major update as well, Citus enabled _any_ node to handle queries, previously all queries (whether or not it was modifying data) had to go through the "coordinator" node in your cluster. This could turn into a pretty significant bottleneck which had ramifications for your cluster administration and choices made about how to shape your data (what goes into local tables, reference tables, or distributed tables).
Again, huge fan of Citus, but it's not a magic bullet that makes it so you no longer have to think about scale when using Postgres. It makes it _much_ easier and adds some killer features that push complexity down the stack such that it is _almost_ completely abstracted from application logic. But you still have be cognizant of it, sometimes even altering your data model to accommodate.
It's hard to account for the value of benefits that have yet to accrue, but this kind of analysis, even if you pretty heavily-discount that future value, tilts the ROI in favor of solutions like Citus, IMO. Especially if your time horizon is 5+ or 10+ years out.
Like you said, if they made this decision 3ish years ago, you would have had to be pretty trusting on that future value. A choice, made today, hinges less on that variable.
The line separating "build in-house" vs "use OSS" exists, and it's at a different layer of the stack in every company. IMO, for most companies in 2024, the line puts Citus on the same side as Postgres.
FWIW, I would have assumed that Citus would be on the other end of the line, until I had to look into Citus for work for a similar reason that Figma did. You can pick and choose among the orthogonal ideas they implement that most cleanly apply to the present stage of your business, and I would've chosen to build things the same way they did (TBH, Figma's choices superficially appear to be 1:1 to Citus's choices).
It'd be interesting to compare the expected capex of developing this in-house solution + the opex of maintaining it vs the same categories of expected costs for option (3) – because I imagine that's probably the most palatable option.
They also may have pre-paid for dedicated RDS instances for the next X years (before this horizontal scaling initiative began, to boot), as AWS allows companies to do this at a pretty steep discount rate, which would probably tilt them away from (3).
Maybe because CitusData was bought by Microsoft around the same time, so Microsoft could create “Azure Cosmos DB for Postgres Cluster”, yet another one of Microsoft’s typical product naming crapshoots.
Well said. I haven't seen any company as terrible as Microsoft at naming things. Anyone know why?
At a previous employer, I saw several cool-ish open source projects instantly doomed to obscurity by picking a name that either completely duplicated the name of an existing OSS project or were guaranteed to have terrible SEO for another reason.
However, Microsoft seems to have a unique crossover of fragmented business units and centralized marketing. That's why you end up with Azure -> Subproject -> Actual Product/Service word soup. Perviously, they did this with the Windows Live brand from 2005-2012, and "Xbox" for a wide range of gaming projects (many of which were on PC).
Not sure what your definition of massive is, I think Spanner would easily beat it.
Also, it's very use-case dependent, you can't "just use" Citus for everything, it's not quite as flexible as a bog-standard pgsql install due to the way it's sharding, you have to be a tad more careful with your data model.
Do your machines do compute heavy loads or something?
For a DB I'd expect a lot more storage per node
a 1U server has capacity for 8 drives, we used 2 slots for the OS (RAID1), 2 slots for the WAL volume (2 slots) leaving only 4 slots in RAID10.
So I'm already cheating a little and claiming WAL storage was part of total storage.
I doubt you're saturating the PCIe bus bandwidth on any of them?
I imagine your DB is extremely high performance, though!
I wonder if they were unaware of it or disregarded it for a reason —I currently am in a similar situation as the one described in the blog, trying to shard a massive Postgres DB.