Re: Proposal: Commit timestamp

On 2/1/2007 11:23 PM, Jim Nasby wrote:
> On Jan 25, 2007, at 6:16 PM, Jan Wieck wrote:
>> If a per database configurable tslog_priority is given, the
>> timestamp will be truncated to milliseconds and the increment logic
>> is done on milliseconds. The priority is added to the timestamp.
>> This guarantees that no two timestamps for commits will ever be
>> exactly identical, even across different servers.
>
> Wouldn't it be better to just store that information separately,
> rather than mucking with the timestamp?
>
> Though, there's anothe issue here... I don't think NTP is good for
> any better than a few milliseconds, even on a local network.
>
> How exact does the conflict resolution need to be, anyway? Would it
> really be a problem if transaction B committed 0.1 seconds after
> transaction A yet the cluster thought it was the other way around?

Since the timestamp is basically a Lamport counter which is just bumped
be the clock as well, it doesn't need to be too precise.

Jan

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