shared_buffers smaller than max_wal_size

From: Vladimir Mihailenco <vladimir(dot)webdev(at)gmail(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: shared_buffers smaller than max_wal_size
Date: 2017-09-22 11:28:38
Message-ID: CAGzYotcP78vG51KbFCRwQhR0exMPNSW76xbKm+Lf_3050V0U8w@mail.gmail.com
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Hi,

I wonder what is the point of setting max WAL size bigger than shared
buffers, e.g.

shared_buffers = 512mb
max_wal_size = 2gb

As I understand a checkpoint happens after 2gb of data were modified
(writter to WAL), but shared buffers can contain at most 512mb of dirty
pages to be flushed to the disk. Is it still a win or I am missing
something?

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