From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
cc: Andres Freund <andres@anarazel.de>,
        pgsql-committers <pgsql-committers@postgresql.org>
Subject: Re: pgsql: Add parallel-aware hash joins.
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Comments: In-reply-to Thomas Munro <thomas.munro@enterprisedb.com>
	message dated "Tue, 23 Jan 2018 00:47:17 +1300"
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Date: Mon, 22 Jan 2018 10:01:50 -0500
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Thomas Munro <thomas.munro@enterprisedb.com> writes:
> On Mon, Jan 22, 2018 at 11:17 PM, Thomas Munro
> <thomas.munro@enterprisedb.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