+1 to the design proposed here Looks like there is already a session proposed for Grizzly summit: http://summit.openstack.org/cfp/details/63
best, Joe On Wed, Oct 3, 2012 at 10:07 AM, Federico Innocenti < federico.innoce...@hp.com> wrote: > > +1 to the design proposed here. > > Even without embracing anything nova specific but simply from a database > perspective the soft-delete approach is proven to be a poor solution to > most of the problems it promises to solve. > > In addition to what Stan already pointed out, let me recap something that > you may already know but so that we have a complete picture, this time > solely from a db point of view: > > - restoring a record is more than doing set deleted=0. It is about > recovering the all graph of references in the database. Beside the > complexity of a restore procedure, it makes not possible to selectively > recover just the information we want. > > - tables grow also when alive data (deleted=0) are a small percentage of > the total. This takes more space/time for backups and maintenance > operations. > > - all queries require for every table involved an additional filter on > deleted=0 and thus an additional scan, even though likely most DBMS are > able to optimize queries discriminating on a binary flag. > > - using unique constraints and foreign keys is impossible. The nova > database schema is now holding more foreign keys than in the old days, but > unless normal deletions are performed they are worthless as they cannot > protect the database from inconsistencies. And in Nova we saw a certain > number of inconsistencies arising in a large usage context. > > > What the soft delete approach tries (badly) to do is in practice to keep > an archive of historical data. The best archiving solution could be left to > the choice of the single vendor for the time being (until a more > comprehensive notification system is in place), since every major DBMS > provides its own facilities to implement it. In MySQL as in many other > databases you can write db triggers which insert the row being deleted to a > shadow table in the same db or in another db. > > Cheers, > Federico Innocenti > > > > ______________________________**_________________ > Mailing list: > https://launchpad.net/~**openstack<https://launchpad.net/~openstack> > Post to : openstack@lists.launchpad.net > Unsubscribe : > https://launchpad.net/~**openstack<https://launchpad.net/~openstack> > More help : > https://help.launchpad.net/**ListHelp<https://help.launchpad.net/ListHelp> >
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