From: Sacheen Birhade <sacheen.birhade@veritas.com>
To: "pgsql-novice@postgresql.org" <pgsql-novice@postgresql.org>
Subject: How to choose new master from slaves.
Thread-Topic: How to choose new master from slaves.
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Date: Thu, 4 Aug 2022 07:33:00 +0000
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Hi All,

I have a very basic question about streaming replication feature of Postgre=
s.
Let's assume I have servers A, B, C, D, & E with postgres installed with st=
reaming replication as follow:
A  -->  B ( sync replication )
A  -->  C ( async replication )
A  -->  D ( async replication )
A  -->  E ( async replication )
A is master & rest are slaves.

Now my question is:
Assume replication link between A & B may/may not stable.  If A goes down, =
how will I choose my new master from slaves? What are criteria to choose ne=
w master?

Thanks,
Sacheen Birhade

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<p class=3D"MsoNormal">Hi All,<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal">I have a very basic question about streaming replica=
tion feature of Postgres.<o:p></o:p></p>
<p class=3D"MsoNormal">Let&#8217;s assume I have servers A, B, C, D, &amp; =
E with postgres installed with streaming replication as follow:<o:p></o:p><=
/p>
<p class=3D"MsoNormal">A&nbsp; <span style=3D"font-family:Wingdings">&agrav=
e;</span>&nbsp; B ( sync replication )<o:p></o:p></p>
<p class=3D"MsoNormal">A &nbsp;<span style=3D"font-family:Wingdings">&agrav=
e;</span>&nbsp; C ( async replication )<o:p></o:p></p>
<p class=3D"MsoNormal">A &nbsp;<span style=3D"font-family:Wingdings">&agrav=
e;</span>&nbsp; D ( async replication )
<o:p></o:p></p>
<p class=3D"MsoNormal">A &nbsp;<span style=3D"font-family:Wingdings">&agrav=
e;</span>&nbsp; E ( async replication )
<o:p></o:p></p>
<p class=3D"MsoNormal">A is master &amp; rest are slaves.<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal">Now my question is: <o:p></o:p></p>
<p class=3D"MsoNormal">Assume replication link between A &amp; B may/may no=
t stable.&nbsp; If A goes down, how will I choose my new master from slaves=
? What are criteria to choose new master?
<o:p></o:p></p>
<p class=3D"MsoNormal"><o:p>&nbsp;</o:p></p>
<p class=3D"MsoNormal">Thanks,<o:p></o:p></p>
<p class=3D"MsoNormal">Sacheen Birhade<o:p></o:p></p>
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