Andrew Hammond wrote:
> On 6/22/07, Bill Moran <wmoran at collaborativefusion.com> wrote:
>> In response to Craig James <craig_james at emolecules.com>:
>>
>> > When you create a cluster, it appears that "Node 1" is special
>>
>> It isn't.  Sure seems that way, though, doesn't it.  We went round and
>> round with this.  One thing that creates this illusion is the fact that
>> many commands assume that node 1 is the master if you don't specify
>> otherwise.
>
> Node 1 is the default for commands that need a node. I've often
> thought that it'd be better to have no default since there's no reason
> to believe that node 1 is the correct node to connect to in many
> cases. If we _must_ have a default, then the lowest node number should
> be default since there's no reason to believe that node 1 will always
> exist.
>
> I actually think that this is a good argument for avoiding having a
> node 1 in clusters in general.
>
I tend to agree.

The behaviour tends to be that events are submitted to node #1 if there
is no obvious default for that command and if no event node is specified.

I make sure that tests include cases where there is no node #1.
>> > -- there
>> > doesn't seem to be a "store node 1" command to create "node 1" in the
>> > first place, whereas for subsequent nodes, you have to issue "store
>> node
>> > N".  Now, suppose node 1 happens to crash and burn, and I use
>> "failover"
>> > to make Node 2 the master.  Questions:
>>
>> The first node has an implied "store node" so that command isn't
>> explicitly
>> used.  You can make the first node be any valid # though.
>>
>> > Does Node 2 stay node 2, or does it become node 1?  (I'm pretty sure
>> > it stays node 2, but I want to be certain).
>>
>> Node #s never change.
>
> Unless you're dangerously crazy. Speaking of dangerously crazy, has
> anyone written a script to change node numbers yet?

I thought I had sent something over to the list quite a while back in
support of a "CLONE NODE" command; Jan thinks he'll try to have
something like that in Slony-I 2.x...

>> > If I get node 1's server back online, discard its database, and
>> recreate
>> > the schema, can I use add it to the cluster as "node 1" again, or do I
>> > need to pick a different node number?
>>
>> AFAIK, as long as you've dropped that node from all other nodes, you can
>> add it back in with the same #.
>
> While this should theoretically be possible, why would you want to?
> Being lazy about defaults to node 1 seems a poor reason. I would not
> recommend doing it in practice. It can cause very big, nasty problems
> if the previously dropped node's cruft is not completely purged before
> you create the new node. If your scripts are so fragile that they hard
> code some node number then fix your scripts.
I'd not be keen on recreating a node number previously used within the
same day as its deletion...