Discussion summary
The discussion covers Postgres data stored in Parquet on S3 using LTAP architecture, with considerations on cost, compatibility, and architecture integration.
What the discussion says
- Parquet files are more compact than row-based storage.
- S3 bandwidth costs are negligible within the same region.
- LTAP architecture can support zero-downtime upgrades.
“Parquet files are smaller than row based storage in a database.”
“There’s no S3 bandwidth bill for traffic to and from EC2 in the same region.”
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- Hacker News
- How does LTAP architecture deals with major Postgres upgrade? Is it truly zero-downtime for both upstream and downstream?by hasyimibhar
- So then would LTAP sit to both the left and the right of the medallion architecture? Meaning would you on the left of Bronze use it as an OLTP and to the right of Gold use it as an OLAP? Currently we've been mainly utilizing it to the right of Gold to develop analytic PERN applications that allow us to reuse the RBAC/ACLs set in Unity Catalog, but from this article it seems like that's only half of its utility?by scritty-dev
- I have to wonder: What's the open protocol - some sort of LTAP read/write path - for compute engines to target LTAP / lakebases? Sort of like how iceberg > deltalake, except now one layer up (OLTP+OLAP).
LTAP / lakebase poses an interesting gap we have been tracking ever since iceberg as we build gfql (the first oss fully-vectorized property graph compute engine with CPU+GPU targets): There's a natural desire to support both OLAP + OLTP modes for new engines, but also a gap for the cloud-native storage tier we don't want to own.
Iceberg etc were exciting as introducing more write-friendly standards-based OLAP backends better than just S3, eg, gives atomicity, and via iceberg, with open governance for code+protocol. LTAP introduces the pattern we can target in theory for OLTP+OLAP backends... but in practice, via a proprietary manner. A potential 'open' form of writers is to support postgres for oltp path writes + spark writers (presumably arrow-flight-friendly) for olap path writes, but that is so hacky.
by lmeyerov - Here's what I don't understand:
Part of the value of doing an ETL pipeline via streaming replication is you get the full history of data in a table. An SCD type 2 table where each row also has a valid_from and valid_to timestamp column.
How would someone do the same thing with this architecture?
- But why? I’m skeptical of the idea of unifying storage just because it sounds “elegant” or “cool”. It’s not obvious to me how a single storage engine can compete with purpose-built OLTP and OLAP systems like Postgres and ClickHouse, without significant tradeoffs.
You also mention removing CDC pipelines. I’m curious if the materialization (conversion across formats) can catchup to an OLTP workload that is heavy (50K+ tps), which is pretty common these days. Also CDC if done right and with care can be magical for users and stays native to the OLTP/OLAP data-store.
Third, data Lakes and open formats are suitable for Data Warehousing / Data analyst use-cases than real-time customer facing apps. Sure, you might work on changing that, which is what you are upto, but you’ll always run into tradeoffs, which will make it hard to unleash the best performance, much needed for the latter category.
by saisrirampur - Super cool stuff. Being able to combine your analytical platform and transactional database into one storage layer without having to set up ETL pipelines in between is really a game changer. Especially since it's just postgres, instead of some proprietary database.by Avalaxy
- Surprisingly, I'm already encountering a second solution that involves storing data chunks on S3 — and this is all within the same week.
This is becoming popular. At Playcode, we built what we believe is a revolutionary file system for our Playcode Cloud (https://playcode.io/cloud), which enables the creation of full-stack web software. The FS built completely from scratch using Rust. We thought we were the smartest ones around and that nobody else had figured this out. But it turns out Databricks, Neon, and several others have as well.
The idea behind a *Bottomless File System* is really cool, and it works very well for us. Essentially, as described here:
- There is a *page server* - A *Linux file system* split into chunks (let's call them chunks instead of pages) - A *cache on NVMe* - And of course, *object storage*, where everything is asynchronously synchronized
It works quite well, though it has its downsides.
One clear advantage is that NVMe drives have become expensive lately, while object storage remains cheap — so the benefits are undeniable. That said, latency is also a factor.
On top of that, uplink costs are rising. To run an object storage-backed file system, you need a very strong uplink with consistent speed — 1 Gbps is simply not enough. Ideally, you want *5 to 10 Gbps*, depending on the load.
We spend a lot of time optimizing and experimenting with different hosting providers — specifically bare metal hardware. The main challenges are:
- *Slow disks* - *Slow uplink* - And as it turns out, *object storage can be unreliable* — unless you're using S3
But AWS hardware is expensive, so nothing in life is ever that simple.
by ianberdin - Maybe I'm too stupid to understand the article... How does this achieve performant querying for olap and oltp purposes?
Based on my understanding, olap queries will go to the parquet files which are stored in a columnar fashion and oltp style queries will go to a caching layer that sits on top of those parquet files?
What's the special sauce here? Seems like they're just caching the data which, for all intents and purposes, seems like the same solution of storing another copy of the data which is what they say they're avoiding.
by dsauerbrun