Re: table as log (multiple writers and readers)

[Craig Ringer <craig@xxxxxxxxxxxxxxxxxxxxx>]

brian wrote:

> Use a timestamp column also.

That's subject to the same issues, because a transaction's 
current_timestamp() is determined at transaction start. So, in a 
situation like this:


WRITER 1    WRITER 2    READER 1
--------------------------------------------
BEGIN
            BEGIN
INSERT
            INSERT
            COMMIT
                        BEGIN
                        SELECT
COMMIT

then READER 1 will see the most recent timestamp as that inserted by 
WRITER 2, but it won't see the row inserted by WRITER 1 with an earlier 
timestamp.

I don't think it's even OK in the case of a single-statement INSERT 
(where the transaction is implicit) and/or with the use of 
clock_timestamp() ... though I'm less sure about that.

--
Craig Ringer