* Mike Mascari (mascarm@mascari.com) wrote: > Stephen Frost wrote: > > >delete from x;/truncate x; > > --> Creates a new, empty, file and makes it the 'current' file > > --> Marks the old file for deletion, but it is kept around for any > > transactions which were started before the truncate; > > --> New transactions use the empty file > > --> Once all transactions using the old file have completed, the old > > file can be deleted. > > --> Old transactions which insert rows would need to use the new file > > or scan the old file for rows which they added, I suppose. > > And when the transaction that issued the TRUNCATE aborts after step 3, > but newer transactions commit?
The newer transactions would have to check for that situation. It's not
completely thought through, but at the same time I don't necessairly
think it's something that would be completely impossible to do and still
retain most of the performance benefits, at least in the most common
case.
Thanks,
Stephen
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