Re: pgsql: Add parallel-aware hash joins.

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com>
Cc: Andres Freund <andres(at)anarazel(dot)de>, pgsql-committers <pgsql-committers(at)postgresql(dot)org>
Subject: Re: pgsql: Add parallel-aware hash joins.
Date: 2018-01-22 15:01:50
Message-ID: 21339.1516633310@sss.pgh.pa.us
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Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> writes:
> On Mon, Jan 22, 2018 at 11:17 PM, Thomas Munro
> <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
>> It looks to me like longfin's average and
>> variation increased half way between fa330f9a and 18042840, somewhere
>> near Dec 7 to 9, when we went from ~40s +/- 1 to ~50s with several
>> seconds' variation. Was there some other environmental change then on
>> that machine?

> Ahh. That corresponds to the release of this patch:
> https://support.apple.com/en-nz/HT208331

Yeah, I'm pretty sure that I installed that update immediately when
it came out.

There were some other strange things going on on that machine too;
I remember having noticed and killed a daemon process that seemed to be
stuck at 100% CPU. That might explain the sudden dropoff in runtimes in
early January. And seeing that the times seem to be back up, I looked
just now, and there it is again:

PID COMMAND %CPU TIME #TH #WQ #PORT MEM PURG CMPRS PGRP
360 fontworker 75.9 238 hrs 4 4 45- 28M 0B 0B 360
359 fontd 25.3 86:18:50 4/1 3/1 74 33M+ 0B 1396K 359
76 logd 12.7 26:25:16 5 5 611 31M- 0B 0B 76
46241 top 2.6 00:01.04 1/1 0 23 2140K 0B 0B 46241

Weird --- my other macOS machines aren't doing that.

Anyway, it looks like we should write off these longfin timings as
ambient noise :-(

regards, tom lane

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