At 2012-02-22 13:05, Ger Timmens wrote:
> Hi,
>
> We are currently using slony 2.1.1/postgresql 9.1.2.
>
> We were wondering if it will be possible  in future versions of slony to
> replicate
> depending on the contents of some fields in a table record.
> So in our current implemenation we have
>
> table SomeTable ( name varchar, ......);
>
> on the master. This table is succesfully replicated to several slaves
> (slave1, slave2, ......).
>
> What we would like is depending on the value of 'name', replicate the
> record,
> to e.g.
>
> slave1 if (name like 'a%'),
> slave2 if (name like 'b%),
>
> etc...
>
> Are there any thoughts for slony being capable of doing this ?
> How can we help developing this ? Are there other replication solutions
> that are capable of doing this ?
>

Some time ago I had to implement such thing. I did it by

- on Master and SlaveA, create "shadow table" SomeTablePartA , identical 
to SomeTable but holding only its well-defined subset.
- on Master, create triggers on SomeTable, to maintain the subset in 
SomeTablePartA
- add SomeTablePartA to replication set - so it is replicated like any 
other table to SlaveA
- on SlaveA database, create a trigger on SomeTablePartA (trigger active 
on slave - must be added to Slony config), which populated changes back 
to SomeTable on SlaveA.