From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@enterprisedb.com>
cc: Noah Misch <noah@leadboat.com>, Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: DSM segment handle generation in background workers
In-reply-to: 
 <CAEepm=2xEKGUWJadcqXUWQQDfPy-urJ3hgJT50Svj7n8e6st-A@mail.gmail.com>
References: <17043.1539046409@sss.pgh.pa.us>
 <CAEepm=2RqzvRyEXWxq8B9zR8p45tt-xsvA4S8ZNKNwpiUzMVKA@mail.gmail.com>
 <CAEepm=1xxETRCZexNSxkABpNg-65U6Z2pxynJ8V0vURqob+Rqw@mail.gmail.com>
 <9879.1539233472@sss.pgh.pa.us>
 <CAEepm=20PEf5bM3FAtD=CL7x0_WxFXfQ4Se9N9nConKucsr8pg@mail.gmail.com>
 <20181112083358.GA1073796@rfd.leadboat.com>
 <CAEepm=1+1jZiNHuRKaHgKZz1f=RFd8BnFpSgVsxEFNafjsqWZg@mail.gmail.com>
 <32455.1542033541@sss.pgh.pa.us> <20181114022435.GC1096408@rfd.leadboat.com>
 <CAEepm=1COuNcj_va0Qt2KTEE4rDvhWCixZ-pyh8iUbrusEVBzQ@mail.gmail.com>
 <20181114053412.GD1096408@rfd.leadboat.com>
 <CAEepm=2xEKGUWJadcqXUWQQDfPy-urJ3hgJT50Svj7n8e6st-A@mail.gmail.com>
Comments: In-reply-to Thomas Munro <thomas.munro@enterprisedb.com>
	message dated "Wed, 14 Nov 2018 20:22:42 +1300"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <7672.1542209103.1@sss.pgh.pa.us>
Date: Wed, 14 Nov 2018 10:25:03 -0500
Message-ID: <7673.1542209103@sss.pgh.pa.us>
Precedence: bulk

Thomas Munro <thomas.munro@enterprisedb.com> writes:
> What do you think about the attached?

I think you need to cast MyStartTimestamp to uint64 before shifting
to ensure portable behavior of the shifts.  In principle it wouldn't
matter because the int64 sign bit is nowhere near the part we care
about, but I've heard some pretty wild claims about what compiler
writers are entitled to do with "undefined" cases.

			regards, tom lane