[ZODB-Dev] ZODB4 project plan

[Magnus Lycka]

At 20:02 2002-11-27 -0500, Phillip J. Eby wrote:
>That's only true if both transactions touch the same object in some way 
>(e.g. a ZCatalog).  Otherwise, transactions can be undone independently, 
>and this doesn't require either versions or subtransactions.

Great. Today I touch too many objects, since I store things like
cursor positions in ZODB, but I should move that out of there.

There is still a conceptual problem concerning ACID properties
and undo beyond someone elses commit. Another user might have
made a changed that didn't affect my object, but his changed
might have been prompted by his observation of the change I made.
Then I undo, and his actions are now based on something that
"never happened".

>Subtransactions or nested transactions, on the other hand, won't help your 
>use case even in theory.  :)

Ok. I was guessing that subtransactions weren't promoted to ZEO
until the main transaction commit, but that was false then?


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Magnus Lycka, Thinkware AB
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