On 2013-11-18 17:29, Shane Hathaway wrote:
On 11/15/2013 06:01 PM, Jens W. Klein wrote:
The idea is simple:
- iterate over all transactions starting with the lowest
transaction id (tid)
- for each transaction load the object states connected with tid
- for each state fetch its outgoing references and fill a table where
all incoming references of an object are stored as an array.
if an state has no references write it anyway to the table with empty
outgoing references
I would describe the RelStorage packing algorithm with the same words,
but since you reimplemented the algorithm from scratch, you found a more
optimal implementation for your database. Good work!
Thanks for the feedback!
The only change I made is regarding to arrays - they are difficult to
handle in postgres (no fun at all). It is much easier (and faster!) to
add one row for each incoming reference (plus a reference to self).
Deleting is now easy by fetching all references with only the
self-reference and removing the objects, its left self-reference and
deleting incoming references of the objects referenced by the deleted
object.
My SQL was a bit rusty after zome years of ODBs. I'am sure a person with
deeper SQL knowledge may optimize the queries in some way.
regards Jens
--
Klein & Partner KG, member of BlueDynamics Alliance
_______________________________________________
For more information about ZODB, see http://zodb.org/
ZODB-Dev mailing list - ZODB-Dev@zope.org
https://mail.zope.org/mailman/listinfo/zodb-dev
