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From: Magnus Hagander <magnus@hagander.net>
Date: Tue, 28 Aug 2018 19:02:06 +0200
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 <CABUevEy3vxzC7w20R-SbMb1H0RMo6HprZXAhDrm7QbvVt2UCBQ@mail.gmail.com>
Subject: Re: retroactive pg10 relnotes: sequence changes
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Pg Docs <pgsql-docs@postgresql.org>
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On Tue, Aug 28, 2018 at 6:34 PM, Alvaro Herrera <alvherre@2ndquadrant.com>
wrote:

> Hello
>
> A customer of ours was taken by surprise by a change in Postgres 10 on a
> trial upgrade from 9.6.  They were using sequences from SERIAL columns a
> little unorthodoxly, and their stuff stopped working: essentially, they
> hacked the default expression so that it'd automatically use negative
> numbers when the sequence reached INT_MAX.  Since pg10 changed sequences
> to stop emitting values at that point, it raised an error rather than
> emit the negative numbers.
>
> (In 9.6 and prior, the sequence would emit values past INT_MAX; it was
> the column that raised the error.  In pg10 things were changed so that
> it is now the sequence that raises the error.)
>
> My proposal now is to document this issue in the Postgres 10 release
> notes.  "It's a little late for that!" I hear you say, but keep this in
> mind: many users have *not* yet upgraded to 10, and they'll keep doing
> it for years to come still.  So I disagree that now is too late.  We
> failed to warn people that already upgraded, but we're still on time to
> alert people yet to upgrade.
>
> I attach both the patch and a screenshot to show how minor the visual
> effect of the change is.
>
> (If people hate this, another option is to make it a separate bullet
> point.)
>

Looks reasonable to me. And I definitely think we should do it -- people
will be upgrading to 10 for years to come, so claiming it's too late is
definitely not correct.

-- 
 Magnus Hagander
 Me: https://www.hagander.net/ <http://www.hagander.net/>
 Work: https://www.redpill-linpro.com/ <http://www.redpill-linpro.com/>

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><div class=3D"gmail_quo=
te">On Tue, Aug 28, 2018 at 6:34 PM, Alvaro Herrera <span dir=3D"ltr">&lt;<=
a href=3D"mailto:alvherre@2ndquadrant.com" target=3D"_blank">alvherre@2ndqu=
adrant.com</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello<br=
>
<br>
A customer of ours was taken by surprise by a change in Postgres 10 on a<br=
>
trial upgrade from 9.6.=C2=A0 They were using sequences from SERIAL columns=
 a<br>
little unorthodoxly, and their stuff stopped working: essentially, they<br>
hacked the default expression so that it&#39;d automatically use negative<b=
r>
numbers when the sequence reached INT_MAX.=C2=A0 Since pg10 changed sequenc=
es<br>
to stop emitting values at that point, it raised an error rather than<br>
emit the negative numbers.<br>
<br>
(In 9.6 and prior, the sequence would emit values past INT_MAX; it was<br>
the column that raised the error.=C2=A0 In pg10 things were changed so that=
<br>
it is now the sequence that raises the error.)<br>
<br>
My proposal now is to document this issue in the Postgres 10 release<br>
notes.=C2=A0 &quot;It&#39;s a little late for that!&quot; I hear you say, b=
ut keep this in<br>
mind: many users have *not* yet upgraded to 10, and they&#39;ll keep doing<=
br>
it for years to come still.=C2=A0 So I disagree that now is too late.=C2=A0=
 We<br>
failed to warn people that already upgraded, but we&#39;re still on time to=
<br>
alert people yet to upgrade.<br>
<br>
I attach both the patch and a screenshot to show how minor the visual<br>
effect of the change is.<br>
<br>
(If people hate this, another option is to make it a separate bullet<br>
point.)<br></blockquote><div><br></div><div>Looks reasonable to me. And I d=
efinitely think we should do it -- people will be upgrading to 10 for years=
 to come, so claiming it&#39;s too late is definitely not correct.=C2=A0</d=
iv></div><div><br></div>-- <br><div class=3D"gmail_signature" data-smartmai=
l=3D"gmail_signature"><div dir=3D"ltr"><div>=C2=A0Magnus Hagander<br>=C2=A0=
Me: <a href=3D"http://www.hagander.net/" target=3D"_blank">https://www.haga=
nder.net/</a><br>=C2=A0Work: <a href=3D"http://www.redpill-linpro.com/" tar=
get=3D"_blank">https://www.redpill-linpro.com/</a></div></div></div>
</div></div>

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