Re: Stack-based tracking of per-node WAL/buffer usage

Zsolt Parragi <zsolt.parragi@percona.com>

From: Zsolt Parragi <zsolt.parragi@percona.com>

To: Lukas Fittl <lukas@fittl.com>

Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Andres Freund <andres@anarazel.de>, Tomas Vondra <tomas@vondra.me>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Peter Smith <smithpb2250@gmail.com>

Date: 2026-03-24T22:59:45Z

Lists: pgsql-hackers

I like the new approach, but doesn't `EXPLAIN (BUFFERS)` leak some
memory because the resource owner isn't registered on that path? It
seems to be visible with pg_log_backend_memory_contexts.

 #define INSTR_BUFUSAGE_ADD(fld,val) do { \
- pgBufferUsage.fld += val; \
+ instr_stack.current->bufusage.fld += val; \

 #define INSTR_WALUSAGE_ADD(fld,val) do { \
  pgWalUsage.fld += val; \
+ instr_stack.current->walusage.fld += val; \

Nitpick, but these could use += (val)

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

instrumentation: Allocate query level instrumentation in ExecutorStart
- 2c16deee2f7d 19 (unreleased) landed
instrumentation: Move ExecProcNodeInstr to allow inlining
- 544000288ec8 19 (unreleased) landed
instrumentation: Separate per-node logic from other uses
- 5a79e78501f4 19 (unreleased) landed
instrumentation: Separate trigger logic from other uses
- 7d9b74df53e9 19 (unreleased) landed
instrumentation: Rename INSTR_TIME_LT macro to INSTR_TIME_GT
- 3218825271bd 19 (unreleased) landed
instrumentation: Keep time fields as instrtime, convert in callers
- e5a5e0a90750 19 (unreleased) landed