On 7/3/2007 12:33 PM, Christopher Browne wrote:
"Andrew Hammond" <[EMAIL PROTECTED]> writes:
Also, ISTM that the big reason we don't like statement based
replication is that SQL has many non-deterministic aspects. However,
there is probably a pretty darn big subset of SQL which is provably
non-deterministic. And for that subset, would it be any less
rigorous to transmit those statements than to transmit the per-row
change statments like we currently do?
Well, by capturing the values, we have captured a deterministic form
of the update.
How to figure out what is deterministic and what isn't? A simple
insert into summary select id, sum(value) from detail group by id;
seems pretty deterministic, doesn't it? But the result of it depends on
the exact commit order and the transaction isolation level. We don't
capture the commit order of single transactions, nor do we care for it
anywhere in the Slony-I logic.
Jan
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