Horton

Re: pgbench - add pseudo-random permutation function

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Fabien COELHO <coelho@cri.ensmp.fr>, Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Thomas Munro <thomas.munro@gmail.com>, Hironobu SUZUKI <hironobu@interdb.jp>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, David Steele <david@pgmasters.net>
Date: 2020-01-30T17:43:41Z
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 →

  1. pgbench: Function to generate random permutations.

  2. Add basic support for using the POPCNT and SSE4.2s LZCNT opcodes

  3. Further improve code for probing the availability of ARM CRC instructions.

On 2020-01-05 10:02, Fabien COELHO wrote:
> 
>> This patch was marked as RFC on 2019-03-30, but since then there have
>> been a couple more issues pointed out in a review by Thomas Munro, and
>> it went through 2019-09 and 2019-11 without any attention. Is the RFC
>> status still appropriate?
> 
> Thomas review was about comments/documentation wording and asking for
> explanations, which I think I addressed, and the code did not actually
> change, so I'm not sure that the "needs review" is really needed, but do
> as you feel.

I read the whole thread, I still don't know what this patch is supposed 
to do.  I know what the words in the subject line mean, but I don't know 
how this helps a pgbench user run better benchmarks.  I feel this is 
also the sentiment expressed by others earlier in the thread.  You 
indicated that this functionality makes sense to those who want this 
functionality, but so far only two people, namely the patch author and 
the reviewer, have participated in the discussion on the substance of 
this patch.  So either the feature is extremely niche, or nobody 
understands it.  I think you ought to take about three steps back and 
explain this in more basic terms, even just in email at first so that we 
can then discuss what to put into the documentation.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services