Thanks! I'll review and presumably merge this as soon as I can. JIm
On Mon, Jun 7, 2010 at 12:45 PM, Laurence Rowe <l...@lrowe.co.uk> wrote: > Hi Jim, > > I've created a new branch for my savepoint release changes following > the 1.1 release here: > > svn+ssh://svn.zope.org/repos/main/transaction/branches/elro-savepoint-release-1.1 > > This does seem to be a real requirement, as I've had another request > to provide this functionality for zope.sqlalchemy - when a large > number of savepoints are used, the eventual commit can lead to a > `RuntimeError: maximum recursion depth exceeded` in SQLAlchemy as it > attempts to unroll its nested substransactions. > > Laurence > > On 17 January 2010 15:45, Laurence Rowe <l...@lrowe.co.uk> wrote: >> 2010/1/17 Jim Fulton <j...@zope.com>: >>> On Sat, Jan 16, 2010 at 1:03 PM, Laurence Rowe <l...@lrowe.co.uk> wrote: >>>> I've had a request to add savepoint release support to zope.sqlalchemy >>>> as some databases seem to limit the number of savepoints in a >>>> transaction. >>>> >>>> I've added this in a branch of transaction here: >>>> svn+ssh://svn.zope.org/repos/main/transaction/branches/elro-savepoint-release >>>> >>>> >From the changelog: >>>> >>>> * Add support for savepoint.release(). Some databases only support a >>>> limited >>>> number of savepoints or subtransactions, this provides an opportunity for >>>> a >>>> data manager to free those resources. >>>> >>>> * Rename InvalidSavepointRollbackError to InvalidSavepointError (BBB >>>> provided.) >>>> >>>> If there are no objections, I shall merge this to trunk. >>> >>> I'll review and merge. >> >> Great, thanks! >> >>> What does it mean to "release" a savepoint? How is this different from >>> aborting >>> a save point? I ask particularly in light of: >>> >>> On Sat, Jan 16, 2010 at 2:26 PM, Laurence Rowe <l...@lrowe.co.uk> wrote: >>>> 2010/1/16 Laurence Rowe <l...@lrowe.co.uk>: >>>>> I'm still not sure this will allow me to add savepoint release support >>>>> to zope.sqlalchemy, as SQLAlchemy has a concept of nested transactions >>>>> rather than savepoints. >>>>> http://groups.google.com/group/sqlalchemy/browse_thread/thread/7a4632587fd97724 >>>> >>>> Michael Bayer noted on the sqlalchemy group that on RELEASE SAVEPOINT >>>> Postgresql destroys all subsequent savepoints. My branch now >>>> implements this behaviour. >> >> For zope.sqlalchemy I commit the sqlalchemy substransaction on >> savepoint.release(). This translates to a RELEASE SAVEPOINT on >> postgresql, best described by their docs here: >> >> """ >> RELEASE SAVEPOINT destroys a savepoint previously defined in the >> current transaction. >> >> Destroying a savepoint makes it unavailable as a rollback point, but >> it has no other user visible behavior. It does not undo the effects of >> commands executed after the savepoint was established. (To do that, >> see ROLLBACK TO SAVEPOINT.) Destroying a savepoint when it is no >> longer needed allows the system to reclaim some resources earlier than >> transaction end. >> >> RELEASE SAVEPOINT also destroys all savepoints that were established >> after the named savepoint was established. >> """ >> http://developer.postgresql.org/pgdocs/postgres/sql-release-savepoint.html >> >> Laurence >> > -- Jim Fulton _______________________________________________ For more information about ZODB, see the ZODB Wiki: http://www.zope.org/Wikis/ZODB/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
