Re: Reduce timing overhead of EXPLAIN ANALYZE using rdtsc?

David Geier <geidav.pg@gmail.com>

From: David Geier <geidav.pg@gmail.com>

To: Robert Haas <robertmhaas@gmail.com>, Álvaro Herrera <alvherre@kurilemu.de>

Cc: Lukas Fittl <lukas@fittl.com>, Andres Freund <andres@anarazel.de>, pgsql-hackers <pgsql-hackers@postgresql.org>, Pavel Stehule <pavel.stehule@gmail.com>, vignesh C <vignesh21@gmail.com>, Michael Paquier <michael@paquier.xyz>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, Maciek Sakrejda <m.sakrejda@gmail.com>, Tomas Vondra <tomas@vondra.me>

Date: 2025-11-19T07:20:25Z

Lists: pgsql-hackers

Commits

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

pg_test_timing: Also test RDTSC[P] timing, report time source, TSC frequency
- 16fca4825483 19 (unreleased) landed
Allow retrieving x86 TSC frequency/flags from CPUID
- bcb2cf41f964 19 (unreleased) landed
instrumentation: Standardize ticks to nanosecond conversion method
- 0022622c93d9 19 (unreleased) landed
instrumentation: Use Time-Stamp Counter on x86-64 to lower overhead
- 294520c44487 19 (unreleased) landed
Zero initialize uses of instr_time about to trigger compiler warnings
- 25b2aba0c3a5 16.0 landed
instr_time: Represent time as an int64 on all platforms
- 03023a2664f8 16.0 landed
Add 250c8ee07ed to git-blame-ignore-revs
- ff23b592ad66 16.0 cited

On 20.10.2025 21:59, Robert Haas wrote:
> On Sun, Oct 19, 2025 at 2:16 PM Álvaro Herrera <alvherre@kurilemu.de> wrote:
>> If I were
>> a consultant trying to understand a customer's system, I would have to
>> ask them to run it twice just in case 'fast' is supported, and I don't
>> think that's very helpful.
> 
> Big +1 from me.
> 

That makes sense. I'm planning to rebase the patch the next days. Then
I'll also take care of that.

--
David Geier