Those who have been with the community from long ago might remember
discussion about implementing a undo log. The big advantage of this is
that it allows UPDATE to _replace_ rows and limits the amount of cleanup
required for UPDATEs.
I am hoping that with HOT we will no longer have any need to even
consider undo.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://postgres.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +