Re: pgbench more operators & functions

From: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Stephen Frost <sfrost(at)snowman(dot)net>, Jeevan Ladhe <jeevan(dot)ladhe(at)enterprisedb(dot)com>, PostgreSQL Developers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: pgbench more operators & functions
Date: 2016-10-05 16:48:18
Message-ID: alpine.DEB.2.20.1610051832050.20888@lancre
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers


Hello Tom,

>> (2) The benchmark specification requires the client application to get
>> hold of query results, which are currently discarded by pgbench, so
>> pgbench does not really comply. I have submitted a patch to do that, see:
>
> I find this completely bogus. The data is delivered to the client,
> ie it's inside the pgbench process.

Hmmm... It is delivered to libpq, and the client discards it... In a
benchmarking context I think that this is not exactly the same:

For instance, one could implement a library protocol that would tell that
the result is ready without actually transfering the result, getting a
slight benefit by not doing so.

In order to avoid that kind of doubtful optimization, the benchmark
requires that the final balance is returned to the "test driver", which is
the client application, and not some subsystem linked to the database. I
think that this is a pretty sensible requirement.

Moreover, the teller's branch must be used in some case, not sure how to
do that without getting this value out anyway...

> What's the grounds for arguing that something else has to happen to it?

In my view the "ground" is the benchmarking specification which wants to
ensure that the tester/implementers/vendors cannot cheat to get better
than deserved performance results...

--
Fabien.

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Robert Haas 2016-10-05 16:52:51 Re: Hash Indexes
Previous Message Daniel Gustafsson 2016-10-05 16:47:53 Re: WIP: Secure Transport support as OpenSSL alternative on macOS