Re: I'd like to discuss scaleout at PGCon

From: Alvaro Herrera
> Maybe an easy (hah) thing to do is use 2PC for DDL, agree on a OID
> that's free on every node, then create the object in all servers at
the
> same time.  We currently use the system-wide OID generator to assign
the
> OID, but seems an easy thing to change (much harder is to prevent
> concurrent creation of objects using the arranged OID; maybe can
reuse
> speculative tokens in btrees for this).

Would it mean that DDL execution requires all (primary) nodes to be
running?  I don't say it's an immediate problem yet, but FYI, Oracle
Sharding records all DDL statements and re-send them to the down nodes
later.


> Doing this imposes a cost at
> DDL-execution-time only, which seems much better than imposing the
cost
> of translating name to OID on every server for every query.

Agreed.

Regards
MauMau