Re: Freeze avoidance of very large table.

On Wed, Feb 10, 2016 at 04:39:15PM +0900, Kyotaro HORIGUCHI wrote:
> > I still agree with this plugin approach, but I felt it's still
> > complicated a bit, and I'm concerned that patch size has been
> > increased.
> > Please give me feedbacks.
> 
> Yeah, I feel the same. What make it worse, the plugin mechanism
> will get further complex if we make it more flexible for possible
> usage as I proposed above. It is apparently too complicated for
> deciding whether to load *just one*, for now, converter
> function. And no additional converter is in sight.
> 
> I incline to pull out all the plugin stuff of pg_upgrade. We are
> so prudent to make changes of file formats so this kind of events
> will happen with several-years intervals. The plugin mechanism
> would be valuable if we are encouraged to change file formats
> more frequently and freely by providing it, but such situation
> absolutely introduces more untoward things..

I agreed on ripping out the converter plugin ability of pg_upgrade. 
Remember pg_upgrade was originally written by EnterpriseDB staff, and I
think they expected their closed-source fork of Postgres might need a
custom page converter someday, but it never needed one, and at this
point I think having the code in there is just making things more
complex.  I see _no_ reason for community Postgres to use a plugin
converter because we are going to need that code for every upgrade from
pre-9.6 to 9.6+, so why not just hard-code in the functions we need.  We
can remove it once 9.5 is end-of-life.

--  Bruce Momjian          http://momjian.us EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I. As I am, so you will be. +
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