Re: Replication identifiers, take 4

On 4/7/15 9:30 AM, Andres Freund wrote:
> On 2015-03-28 23:50:20 +0100, Petr Jelinek wrote:
>> And finally I have issue with how the new identifiers are allocated.
>> Currently, if you create identifier 'foo', remove identifier 'foo' and
>> create identifier 'bar', the identifier 'bar' will have same id as the old
>> 'foo' identifier. This can be problem because the identifier id is used as
>> origin of the data and the replication solution using the replication
>> identifiers can end up thinking that data came from node 'bar' even though
>> they came from the node 'foo' which no longer exists. This can have bad
>> effects for example on conflict detection or debugging problems with
>> replication.
>>
>> Maybe another reason to use standard Oids?
>
> As the same reason exists for oids, just somewhat less likely, I don't
> see it as a reason for much. It's really not that hard to get oid
> conflicts once your server has lived for a while. As soon as the oid
> counter has wrapped around once, it's not unlikely to have
> conflicts. And with temp tables (or much more extremely WITH OID tables)
> and such it's not that hard to reach that point. The only material
> difference this makes is that it's much easier to notice the problem
> during development.

Why not just create a sequence? I suspect it may not be as fast to
assign as an OID, but it's not like you'd be doing this all the time.
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com