Re: Proposal: Commit timestamp - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: Proposal: Commit timestamp
Date
Msg-id 87k5z8oduh.fsf@stark.xeocode.com
Whole thread Raw
In response to Re: Proposal: Commit timestamp  (Jan Wieck <JanWieck@Yahoo.com>)
Responses Re: Proposal: Commit timestamp
List pgsql-hackers
Jan Wieck <JanWieck@Yahoo.com> writes:

> I think the system I described is a slightly modified Lamport generator. The
> maximum timestamp of any row updated in this transaction, you can consider that
> the "counters received from other nodes". Then I make sure that the next
> counter (timestamp) is higher than anything I know so far, and I add
> cluster-wide unique tie breaker to that.

If you know all the timestamps in the system then you don't need timestamps at
all, just use a counter that you increment by one each time.

Isn't the whole reason people use timestamps is so that you don't have to
depend on atomically knowing every timestamp in the system? So two
transactions can commit simultaneously on different systems and use the
timestamps to resolve conflicts later.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com



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