postgres=# select * from sessions where video_id = 'bfPdLjdQvwU';

Vibe Hacking with Dmitry Fomin

· 81:56 · Observability

Wait-event observability and precise tracing ideas.

session summary

Dmitry Fomin presented his first core patch after tracing synchronous-replication latency spikes to blocking fdatasync calls in the standby WAL receiver, even under synchronous_commit=remote_write. His prototype batches flushes by byte threshold or timeout. Review uncovered unsafe defaults for stronger synchronous modes and suggested a separate flusher process as a cleaner long-term design. They rebased the old patch onto master, removed redundant unflushed-byte state, compiled it, and prepared it for pgsql-hackers discussion.

timecodes

  1. Production SyncRep latency problem
  2. fdatasync stalls in remote_write mode
  3. Batching WAL flushes by bytes or timeout
  4. What synchronous replication actually guarantees
  5. Reviewing the new WAL-receiver settings
  6. Defaults break stronger synchronous-commit modes
  7. Alternative design with a separate WAL flusher
  8. Rebasing, reviewing, and preparing the patch