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From: "David G. Johnston" <david.g.johnston@gmail.com>
Date: Tue, 9 Jan 2018 09:57:50 -0700
Message-ID: 
 <CAKFQuwbPWiAqu63fs3Ldx_ShaeBTYVmuGhR-E=yGDPVFv2qWXw@mail.gmail.com>
Subject: Re: Advice on Contiguous IDs
To: Brian McKiernan <brian.mckiernan@firstcircle.com>
Cc: pgsql-docs@postgresql.org
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On Tue, Jan 9, 2018 at 2:06 AM, Brian McKiernan <
brian.mckiernan@firstcircle.com> wrote:

> 1) What event would cause the CACHE clause in CREATE SEQUENCE to make an
> out of sequence next number?
>

=E2=80=8BNone - it will always issue the next sequential value when asked. =
 But the
transaction asking doesn't have to use the provided value as the PK for the
table or, and even if it does, if the transaction fails and rolls-back the
sequence value it received is discarded/lost.=E2=80=8B
=E2=80=8B
=E2=80=8BDavid J.=E2=80=8B
=E2=80=8B

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<div dir=3D"ltr"><div class=3D"gmail_default" style=3D"font-family:arial,he=
lvetica,sans-serif"><span style=3D"font-family:arial,sans-serif">On Tue, Ja=
n 9, 2018 at 2:06 AM, Brian McKiernan </span><span dir=3D"ltr" style=3D"fon=
t-family:arial,sans-serif">&lt;<a href=3D"mailto:brian.mckiernan@firstcircl=
e.com" target=3D"_blank">brian.mckiernan@firstcircle.com</a>&gt;</span><spa=
n style=3D"font-family:arial,sans-serif"> wrote:</span></div><div class=3D"=
gmail_extra"><div class=3D"gmail_quote"><blockquote class=3D"gmail_quote" s=
tyle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div=
>1) What event would cause the=C2=A0<span style=3D"font-family:sans-serif;f=
ont-size:12.7px;font-variant-ligatures:normal;background-color:rgb(255,255,=
255)">CACHE clause in CREATE SEQUENCE to make an out of sequence next numbe=
r?</span></div></blockquote><div><br></div><div><div class=3D"gmail_default=
" style=3D"font-family:arial,helvetica,sans-serif">=E2=80=8BNone - it will =
always issue the next sequential value when asked.=C2=A0 But the transactio=
n asking doesn&#39;t have to use the provided value as the PK for the table=
 or, and even if it does, if the transaction fails and rolls-back the seque=
nce value it received is discarded/lost.=E2=80=8B</div></div><div><span sty=
le=3D"font-family:arial,helvetica,sans-serif">=E2=80=8B</span></div><div><s=
pan style=3D"font-family:arial,helvetica,sans-serif"><div class=3D"gmail_de=
fault" style=3D"font-family:arial,helvetica,sans-serif;display:inline">=E2=
=80=8BDavid J.=E2=80=8B</div>=E2=80=8B</span></div></div></div></div>

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