Re: MVCC, undo log, and HOT

"Andrew Dunstan" <andrew@dunslane.net> writes:

> HOT is cool, but it really doesn't solve the whole problem. It works for a
> significant class of problems, but for example it won't have any significant
> effect on the app I'm currently working on which is very index-rich. It would
> be a major mistake to think there's no work left to do in improving update
> performance.

Another use case it doesn't address is updating a large fraction of the table.
If you do a single unconstrained "UPDATE foo SET x=y" your table and indexes
will double in size and never shrink back.

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