Alvaro Herrera wrote:
Excerpts from Richard Walker's message of jue may 20 02:19:17 -0400 2010:
(a) (ii) It seems a breach is possible via the xmin values.
In that case, what about doing updates inside a transaction
that does a trivial update of all rows, e.g.:
begin transaction;
update mytable ....; -- change one row
update mytable set id=id; -- change all rows
commit;
So now all rows have the same xmin values.
Does this work? Performance is not so good, is it?
Is there a better way?
The easiest way to do this is probably VACUUM FREEZE.
Thank you very much - that works perfectly to solve
case (a) (ii).
It turns out it doesn't solve my case (b)
in which the hacker can read the raw files.
After a little bit of experimenting I found
that VACUUM FREEZE followed by CLUSTER gives
me a fresh raw table file with no transaction
history. Now all I need is a way to deal
with the WAL . . .
--
Richard Walker
Software Improvements Pty Ltd
Phone: +61 2 6273 2055
Fax: +61 2 6273 2082
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