> Were you going to use WAL to get free space from old copies too?
Considerable approach.
> Vadim, I think I am missing something. You mentioned UNDO would be used
> for these cases and I don't understand the purpose of adding what would
> seem to be a pretty complex capability:
Yeh, we already won title of most advanced among simple databases, -:)
Yes, looking in list of IDs assigned to single transaction in tqual.c is much
easy to do than UNDO. As well as couple of fsyncs is easy than WAL.
> > 1. Reclaim space allocated by aborted transactions.
>
> Is there really a lot to be saved here vs. old tuples of committed
> transactions?
Are you able to protect COPY FROM from abort/crash?
Vadim