Re: Savepoints

> Now, with MVCC, the backend has to read through the redo segment to get

You mean rollback segment, but ...

> the original data value for that row.

Will only need to be looked up if the row is currently beeing modified by 
a not yet comitted txn (at least in the default read committed mode)  

> 
> Now, while rollback segments do help with cleaning out old UPDATE rows,
> how does it improve DELETE performance?  Seems it would just mark it as
> expired like we do now.

delete would probably be: 
1. mark original deleted and write whole row to RS

I don't think you would like to mix looking up deleted rows in heap
but updated rows in RS

Andreas

PS: not that I like overwrite with MVCC now
If you think of VACUUM as garbage collection PG is highly trendy with
the non-overwriting smgr.