[Bucardo-general] Multi-master replication and sequences

[Michelle Sullivan]

Federico Fanton wrote:
> On 14/07/2015 14:18, Michelle Sullivan wrote:
>
>>> I'm (still) setting up multi-master replication between two nodes.
>>> What is the recommended way to handle sequences? I've seen posts
>>> saying that you should make one instance generate even numbers while
>>> the other should generate odd numbers, but they were quite old
>>> posts... Is this still the recommended way?
>>>
>
>> Sequences can be replicated but if you're going to have concurrent
>> inserts into both DBs you probably should go with the offset sequences
>> or do as I did add a 'server ID' to the pks and not worry about
>> replicating the sequences.
>
> What do you mean by "server ID"? Defining PKs as "nodeN_" + sequence?
> Something like this?
Yes - though I did 'server-id' as a separate col and set the default using:


postgresql.conf:

custom_variable_classes = 'server_info'
server_info.location = 'AT1, USA'
server_info.id = 102
server_info.admin = 'michelle at xxx.net'
server_info.hostname = 'corkscrew.xxx.net'

and tables defined like this:

# \d hosts
                                     Table "public.hosts"
    Column    |       Type        |                        
Modifiers                         
--------------+-------------------+------------------------------------------------------------
 hostsid      | bigint            | not null default
nextval('hosts_hostsid_seq'::regclass)
 host         | character varying | not null
 sysstatus    | integer           | not null
 serverid     | integer           | default
(current_setting('server_info.id'::text))::integer
Indexes:
    "hosts_pk" PRIMARY KEY, btree (hostsid,serverid), tablespace "indexes"



-- 
Michelle Sullivan
http://www.mhix.org/