[HN Gopher] XTDB 2.x Early Access
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XTDB 2.x Early Access
Author : gemstones
Score : 85 points
Date : 2023-04-27 19:42 UTC (3 hours ago)
(HTM) web link (www.xtdb.com)
(TXT) w3m dump (www.xtdb.com)
| kevinmershon wrote:
| We use XTDB 1 and have a multi replica production instance with
| about 600GB of data at ~100 million transactions. The biggest
| problem we have is with minor versions bumping the underlying
| RocksDB i dex version, requiring a full reindex of the main
| "golden" data store taking days to weeks.
|
| AFAIK this is not solved in XTDB 1. I'm hoping XTDB 2 provides a
| better upgrade path for modestly sized databases like ours.
| refset wrote:
| XTDB 2 will compute and maintain incremental indexes on-the-fly
| based on the raw data, so index updates will present far less
| operational impact. This also means the transaction log is now
| ~ephemeral in the new architecture (no more event-sourcing-
| style replays required, ever).
| kevinmershon wrote:
| That is incredibly exciting! Glad to hear it.
| vosper wrote:
| My understanding is the XTDB is either a fork of Datomic, or was
| inspired by it? I suppose it's timely, given the top story on HN
| right now is "Datomic is Free" [0]
|
| Is there anyone who's familiar with both and would like to share
| their thoughts on the two?
|
| https://news.ycombinator.com/item?id=35727967
| newlisp wrote:
| They have completely different data models though, XTDB is a
| schemaless document data store, think mongodb but with
| SQL/Datalog querying and bi-temporality.
|
| Datomic's data model is something they call the 'universal
| schema' where you just specify the attributes and then create
| entities however you like from them. Datomic aligns more with
| how you structure data in Clojure, avoiding the impedance
| mismatch.
| refset wrote:
| Datomic's "immutable database + Datalog" was definitely the
| biggest source of inspiration but XTDB has a lot of differences
| - I wrote this FAQ entry up a few years back:
| https://docs.xtdb.com/resources/faq/#comparisons (note this
| comparison is for XTDB 1.x and Datomic On-Prem only, so needs
| revisiting!)
|
| Arguably the biggest difference is that XTDB has a schemaless,
| dynamic core. Having a sane schema is of course important when
| building complex things, but we believe that the flexibility to
| experiment with schema (fully) in userspace is essential for
| moving the state of the art forwards. For instance a lots
| Clojure users these days prefer relying on
| https://github.com/metosin/malli for _all_ their schema needs.
| baq wrote:
| > XTDB is a bitemporal and dynamic relational database for SQL
|
| You have my attention. I actually raised an eyebrow reading that,
| last time this happened was when ChatGPT was released.
|
| Temporal is a world of pain in SQL, bitemporal... nice.
|
| edit: for those who haven't heard what bitemporal is, Wikipedia
| has an example:
| https://en.wikipedia.org/wiki/Temporal_database#Using_two_ax...
| seabass-labrax wrote:
| XTDB is a very interesting database to me. Not only is it
| distributed, but the 'bi-temporality' which is mentioned on this
| page means that it has essentially a built-in audit trail
| mechanism. I'm working on writing an RDF library for Clojure, and
| am looking forward to seeing whether XTDB really is as good as an
| RDF datastore as I suspect it is!
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(page generated 2023-04-27 23:00 UTC)