#databases

2 posts · All tags

• Spanner: TrueTime, commit wait and external consistency, explained

  Nov 8, 2026 10 min read

  How Google Spanner orders transactions worldwide: TrueTime intervals, commit wait, Paxos groups, two-phase commit over Paxos, safe time and lock-free reads.

  • #distributed systems
  • #databases
  • #spanner
  • #consistency
  • #papers

• How Discord stores trillions of messages: from MongoDB to Cassandra to ScyllaDB

  Oct 3, 2026 14 min read

  How Discord moved chat history from MongoDB to Cassandra to ScyllaDB: time-bucketed partitions, tombstone traps, hot partitions, and Rust request coalescing.

  • #distributed systems
  • #databases
  • #data modeling
  • #systems at scale