Horton

Re: logical changeset generation v4 - Heikki's thoughts about the patch state

Joshua D. Drake <jd@commandprompt.com>

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From: "Joshua D. Drake" <jd@commandprompt.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@2ndquadrant.com>, Heikki Linnakangas <hlinnakangas@vmware.com>, Stephen Frost <sfrost@snowman.net>, Tom Lane <tgl@sss.pgh.pa.us>, Pavan Deolasee <pavan.deolasee@gmail.com>, Phil Sorber <phil@omniti.com>, Josh Berkus <josh@agliodbs.com>, Dimitri Fontaine <dimitri@2ndquadrant.fr>, Jeff Janes <jeff.janes@gmail.com>, Simon Riggs <simon@2ndquadrant.com>, Magnus Hagander <magnus@hagander.net>, Abhijit Menon-Sen <ams@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Bruce Momjian <bruce@momjian.us>, Michael Paquier <michael.paquier@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2013-01-24T01:21:00Z
Lists: pgsql-hackers 
On 01/23/2013 05:17 PM, Robert Haas wrote:

> Of course, I have no evidence that that will happen.  But it is a
> really big piece of code, and therefore unless you are superman, it's
> probably got a really large number of bugs.  The scary thing is that
> it is not as if we can say, well, this is a big hunk of code, but it
> doesn't really touch the core of the system, so if it's broken, it'll
> be broken itself, but it won't break anything else.  Rather, this code
> is deeply in bed with WAL, with MVCC, and with the on-disk format of
> tuples, and makes fundamental changes to the first two of those.  You
> agreed with Tom that 9.2 is the buggiest release in recent memory, but
> I think logical replication could easily be an order of magnitude
> worse.

Command Prompt worked for YEARS to get logical replication right and we 
never got it to the point where I would have been happy submitting it to 
-core.

It behooves .Org to be extremely conservative about this feature. 
Granted, it is a feature we should have had years ago but still. It is 
not a simple thing, it is not an easy thing. It is complicated and 
complex to get correcft.



JD




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