Re: [ZODB-Dev] The database root: It's a trap!
On Wed, May 12, 2010 at 7:07 AM, Jim Fulton j...@zope.com wrote: B. Change ZODB so that the root object is a variant of persistent mapping that either refuses to store more than a small number of objects, or at least issues a warning when more than a small number of objects is stored. A variation on this, either in addition or as an alternative, is to have the database warn and/or error when creating database records over some tunable size. Jim -- 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
Re: [ZODB-Dev] The database root: It's a trap!
On Wed, May 12, 2010 at 7:16 AM, Jens Vagelpohl j...@dataflake.org wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 5/12/10 13:07 , Jim Fulton wrote: B. Change ZODB so that the root object is a variant of persistent mapping that either refuses to store more than a small number of objects, or at least issues a warning when more than a small number of objects is stored. Where would you put that limit? Probably in the class. Jim -- 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
Re: [ZODB-Dev] The database root: It's a trap!
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 5/12/10 13:21 , Jim Fulton wrote: On Wed, May 12, 2010 at 7:16 AM, Jens Vagelpohl j...@dataflake.org wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 5/12/10 13:07 , Jim Fulton wrote: B. Change ZODB so that the root object is a variant of persistent mapping that either refuses to store more than a small number of objects, or at least issues a warning when more than a small number of objects is stored. Where would you put that limit? Probably in the class. Sorry, bad wording: How high would you set this limit? :-) jens -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.8 (Darwin) iEYEARECAAYFAkvqj7MACgkQRAx5nvEhZLKXnwCgglwOPUXe8z9ch10PR+BinvTt VrIAn2MWh94WgcWfCHrIReoM+ulIV4b9 =ichU -END PGP SIGNATURE- ___ 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
Re: [ZODB-Dev] The database root: It's a trap!
On Wed, May 12, 2010 at 7:23 AM, Jens Vagelpohl j...@dataflake.org wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 5/12/10 13:21 , Jim Fulton wrote: On Wed, May 12, 2010 at 7:16 AM, Jens Vagelpohl j...@dataflake.org wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 5/12/10 13:07 , Jim Fulton wrote: B. Change ZODB so that the root object is a variant of persistent mapping that either refuses to store more than a small number of objects, or at least issues a warning when more than a small number of objects is stored. Where would you put that limit? Probably in the class. Sorry, bad wording: How high would you set this limit? :-) Dunno, maybe 99. If we go with a warning, then the risk of setting this too low is minimal. Jim -- 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
Re: [ZODB-Dev] The database root: It's a trap!
Jim Fulton wrote: A. Change ZODB so that new databases have BTrees as root objects. This has the advantage that BTrees are scalable. It has a number of down sides: - BTrees should only be used when keys are known to have a stable ordering. If we had a scalable hash data structure, that would be better. - This encourages mistake 2 above. B. Change ZODB so that the root object is a variant of persistent mapping that either refuses to store more than a small number of objects, or at least issues a warning when more than a small number of objects is stored. C. I'd really like to be able to configure what the root object is as database creation time. That way it can be application specific. cheers, Chris -- Simplistix - Content Management, Batch Processing Python Consulting - http://www.simplistix.co.uk ___ 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
Re: [ZODB-Dev] The database root: It's a trap!
On Wed, 2010-05-12 at 20:16 +0100, Chris Withers wrote: Jim Fulton wrote: C. I'd really like to be able to configure what the root object is as database creation time. That way it can be application specific. That sounds reasonable, but doesn't address the default behavior. Default would be an OOBTree for me... Scales, no thinking or scary warnings required :-) I'm not sure that any particular default root object is going to solve this problem, because they're just going to put a dictionary into one of its keys and hurt themselves that way. I think the idea of a warning when a record exceeds a given size would be more generally helpful, although that of course doesn't prohibit using a different root too. - C ___ 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
