On 10/15/12 5:33 PM, Simon Riggs wrote:
> There are a few options
> 1) Manual separation of the value space, so that N1 has 50% of
> possible values and N2 has 50%. That has problems when we reconfigure
> the cluster, and requires complex manual reallocation of values. So it
> starts good but ends badly.
> 2) Automatic separation of the value space. This could mimic the
> manual operation, so it does everything for you - but thats just
> making a bad idea automatic
> 3) Lazy allocation from the value space. When a node is close to
> running out of values, it requests a new allocation and coordinates
> with all nodes to confirm the new allocation is good.
What would the allocation service look like? Is it another PostgreSQL
server? What's the communication protocol? How would backups work?
Crash recovery?
Option 4 is of course to use UUIDs.