Clojurians Log v2
datomic
Happy to announce that we have a new Datomic Pro version 1.0.7266 now available! Be sure to check out the new feature Read-only connections and the new api rseek-datoms! We'll have some guidance on using rseek-datoms for common patterns in the coming weeks, but really excited to deliver Read Only Connections.
We hope this new Read Only feature will further empower users of Datomic to share Datomic DBs (i.e. connect to a public S3 backup of a Datomic DB), operate systems more cheaply and robustly without the need for a transactor where it's not required, provide a new approach for evaluating performance against real datasets and a method for investigating incidents without touching production. Excited to hear about how you end up using it!
https://forum.datomic.com/t/datomic-1-0-7266-pro-now-available/2620
Wow. Read-only connections .... is it conceivable that Datomic Cloud could get support for this via peer? IOW, a read-only connection that uses the S3 segments for a read-only connection? Start a peer in a REPL and get a very different performance profile for queries and Read-Only guarantees. I see application to Datomic Analytics as well...
(In case it was not obvious, I am jealous)
that is a banger, great job Datomic team! also loving the investment in the reverse index use-case, it's very useful!
• Performance: Reduce log write amplification for systems with many transactions so what would log write amplification be?
@dimitar.ouzounoff we identified an improvement in log writes that will reduce cost, reduce the reads to underlying storage, and improve cache efficiency.
Datomic maintains a B-tree over the transactions in the log. The segment representing the root of this B-tree can grow to be much larger than other segments in the tree, which is not what you want for constant time updates. This change remedies the large root segment (without forcing a breaking storage format change)
Ahead of schedule, but as promised... @kharper and @dave.liepmann delivered the rseek supplemental docs, beyond the api doc string: https://docs.datomic.com/indexes/rseek-datoms.html