Re: [PATCH 10/16] Introduce the concept that wal has a 'origin' node

On Wed, Jun 20, 2012 at 9:25 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On 20 June 2012 21:19, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Wed, Jun 20, 2012 at 5:47 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>> The idea that logical rep is some kind of useful end goal in itself is
>>> slightly misleading. If the thought is to block multi-master
>>> completely on that basis, that would be a shame. Logical rep is the
>>> mechanism for implementing multi-master.
>>
>> If you're saying that single-master logical replication isn't useful,
>> I disagree.  Of course, having both single-master and multi-master
>> replication together is even more useful.
>
>> But I think getting even
>> single-master logical replication working well in a single release
>> cycle is going to be a job and a half.
>
> OK, so your estimate is 1.5 people to do that. And if we have more
> people, should they sit around doing nothing?

Oh, give me a break. You're willfully missing my point. And to quote
Fred Brooks, nine women can't make a baby in one month.

>> Thinking that we're going to
>> get MMR in one release is not realistic.
>
> If you block it, then the above becomes true, whether or not it starts true.

If I had no rational basis for my objections, that would be true.
You've got four people objecting to this patch now, all of whom happen
to be committers. Whether or not MMR goes into core, who knows, but
it doesn't seem that this patch is going to fly.

My main point in bringing this up is that if you pick a project that
is too large, you will fail. As I would rather see this project
succeed, I recommend that you don't do that. Both you and Andres seem
to believe that MMR is a reasonable first target to shoot at, but I
don't think anyone else - including the Slony developers who have
commented on this issue - endorses that position. At PGCon, you were
talking about getting a new set of features into PG over the next 3-5
years. Now, it seems like you want to compress that timeline to a
year. I don't think that's going to work. You also requested that
people tell you sooner when large patches were in danger of not making
the release. Now I'm doing that, VERY early, and you're apparently
angry about it. If the only satisfactory outcome of this conversation
is that everyone agrees with the design pattern you've already decided
on, then you haven't left yourself very much room to walk away
satisfied.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company