Date: Thu, 4 Jan 2018 12:53:42 -0500
From: Bruce Momjian <bruce@momjian.us>
To: =?iso-8859-1?B?TOlv?= FERLIN SUTTON <lferlin@mailjet.com>
Cc: pgsql-admin@lists.postgresql.org
Subject: Re: Slow pg_dump affecting pg_upgrade speed
Message-ID: <20180104175342.GA5478@momjian.us>
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On Tue, Dec 12, 2017 at 02:24:54PM +0100, Léo FERLIN SUTTON wrote:
> We believe this is related to the size of our pg_catalog, we have
> thousands (if not hundred of thousands of views) on most of our
> databases. Here is an example on cluster A :
...
> We are completely aware that this is a *bad* idea, and our newer

I appreciate your candor.  :-)

> developments are all moving far far away for this type of schema,
> however we are currently stuck with this for at least a few more
> months if not years.
> 
> My question to this mailing list is : Are we missing something that
> could speed up the pg_dump ?

There isn't much we can do to speed it up anymore.  We optimized the
schema restore in the past, at least with the ideas we had.  A new idea
we discussed last month was to allow the schema dump/restore while the
old server is running.  You can see the discussion here:

	https://www.postgresql.org/message-id/flat/20171205140135.GA25023%40momjian.us#20171205140135.GA25023@momjian.us

That is only brainstorming at this point and it is not clear we will
even implement it.

The bottom line is that pg_upgrade is much more effective on large
databases with a smaller number of database objects than the reverse.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +