Re: multi-install PostgresNode fails with older postgres versions

Jehan-Guillaume de Rorthais <jgdr@dalibo.com>

From: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Mark Dilger <mark.dilger@enterprisedb.com>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-04-07T18:07:41Z
Lists: pgsql-hackers
On Wed, 7 Apr 2021 13:36:31 -0400
Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:

> On 2021-Apr-07, Jehan-Guillaume de Rorthais wrote:
> 
> > Yes, it would be much saner to make PostgresNode the factory class. Plus,
> > some more logic could be injected there to either auto-detect the version
> > (current behavior) or eg. use a given path to the binaries as Mark did in
> > its patch.  
> 
> I'm not sure what you mean about auto-detecting the version -- I assume
> we would auto-detect the version by calling pg_config from the
> configured path and parsing the binary, which is what Mark's patch is
> supposed to do already.  So I don't see what the distinction between
> those two things is.

My version is currently calling pg_config without any knowledge about its
absolute path.

Mark's patch is able to take an explicit binary path:

  my $a = PostgresNode->get_new_node('a', install_path => '/my/install/8.4');

> In order to avoid having an ever-growing plethora of 100-byte .pm files,
> we can put the version-specific classes in the same PostgresNode.pm
> file, at the bottom, "class PostgresNode96; use parent PostgresNode10;"
> followed by the routines that are overridden for each version.

Sure.

> > Let me know if it worth that I work on an official patch.  
> 
> Let's give it a try ...

OK

Regards,



Commits

  1. Teach PostgresVersion all the ways to mark non-release code

  2. Make PostgresNode version aware

  3. Avoid unfortunate IPC::Run path caching in PostgresNode

  4. Change pg_ctl to detect server-ready by watching status in postmaster.pid.