On 10-12-04 01:38 PM, Simon Riggs wrote:
> On Fri, 2010-12-03 at 12:26 -0500, Christopher Browne wrote:
>> === Commit timestamps ===
>> * per Jan Wieck
>> * Requires PostgreSQL extension
>> * Eliminates need for periodic generation of SYNC events
>> * Simplifies queries for searching for sl_log_* data
>> * Enables carryover of commit times to subscribers
>
> It should be possible to do this using LISTEN/NOTIFY.
> Now we can pass a payload with the NOTIFY, we just need to pass the
> transaction id. That can be handled automatically by trigger.
>

What happens if the server crashes before the process listening does 
what it needs to?  I don't think the notification queue gets persisted.

> What we need is commit order, not commit timestamp, yes?
> NOTIFY happens in commit sequence. It doesn't provide the commit
> timestamp, but perhaps that can be provided by the LISTENer, if you
> really need it.

If all one wants to do is replace sync generation then you just need the 
ordering not the timestamps.  Personally I don't see a huge amount of 
motivation to eliminate sync generation.