postgres=# select * from sessions where video_id = '6kqpjnpl5Gc';
Precise wait-event tracing, part 2
Low-overhead per-event timing and trace capture.
session summary
The group compared pg_wait_tracer's external eBPF hardware-watchpoint tracing with Dmitri Fomin's new Postgres patch, which records wait transitions into per-backend lock-free ring buffers. They designed a shared-buffer-thrashing benchmark to stress transition overhead, explored transition, concurrency, and query-profile visualizations, and discussed eventual EXPLAIN integration. Preliminary claims of roughly 2% patched overhead were treated as unverified; the agreed next steps were finish benchmarks, publish the tool, review the code, and prepare a pgsql-hackers proposal.
timecodes
- How precise wait-event tracing works
- ASH dashboard, AAS, and wait hierarchy
- Why tracing needs a Postgres patch
- Designing a transition-heavy overhead benchmark
- Per-backend lock-free ring-buffer design
- Transition paths and concurrency analysis
- Toward wait events in EXPLAIN
- Publishing and presenting the patch upstream