[ovs-dev] [PATCH] ovsdb: Force columns that contain weak references to be immutable.

[Ben Pfaff]

I was on vacation last week; I'm back now.

On Mon, Apr 11, 2016 at 02:50:21AM +0000, Elluru, Krishna Mohan wrote:
> HI Ben,
> 	Gentle reminder, in case you missed it :). I am still waiting for your reply.
> 
> Thanks
> Krishna Mohan
> 
> -----Original Message-----
> From: dev [mailto:dev-bounces at openvswitch.org] On Behalf Of Elluru, Krishna Mohan
> Sent: Monday, April 04, 2016 9:32 AM
> To: Ben Pfaff <blp at ovn.org>
> Cc: dev at openvswitch.org
> Subject: Re: [ovs-dev] [PATCH] ovsdb: Force columns that contain weak references to be immutable.
> 
> HI Ben,
> 	How does column which is weak reference  and also configured as an Index? If it is mutable, and the corresponding UUID going away(deletion of record) leaves column value as NULL right? And what would be the behavior if the table is a Root table also?
> I am listing down, my assumptions:
> 
> 	1. In table X, If the column is index and a weak reference to table y, on table y row deletion, the index field would become NULL and since it is an index, constraint violation would occur and to avoid, it is expected to remove the row first in table X and table Y row deletion can happen in same txn or consequent transactions. Correct?
> 	2. If the table X is also a root table, and one of its column is an index and weak reference to table Y, on row deletion in table Y, constraint violation would occur, hence similar to above table X row cleanup is expected to happen prior to table Y row deletion.
> 
> 	If above 2 statements is true, index with weak reference is becoming equivalent to strong reference. Am I correct?
> 
> Thanks
> Krishna Mohan
> 
> -----Original Message-----
> From: Ben Pfaff [mailto:blp at ovn.org]
> Sent: Monday, April 04, 2016 9:03 AM
> To: Elluru, Krishna Mohan <elluru.kri.mohan at hpe.com>
> Cc: dev at openvswitch.org
> Subject: Re: [ovs-dev] [PATCH] ovsdb: Force columns that contain weak references to be immutable.
> 
> Yes, that's what this patch proposes.  Comments welcome.
> 
> On Mon, Apr 04, 2016 at 02:51:25AM +0000, Elluru, Krishna Mohan wrote:
> > HI Ben,
> > 	So, the fix is instead of throwing error, we apply mutable:true property to the weak reference column, though the schema passed it as mutable:false?
> > 
> > Thanks
> > Krishna Mohan
> > 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at openvswitch.org] On Behalf Of Ryan Moats
> > Sent: Sunday, April 03, 2016 1:37 AM
> > To: Ben Pfaff <blp at ovn.org>
> > Cc: dev at openvswitch.org
> > Subject: Re: [ovs-dev] [PATCH] ovsdb: Force columns that contain weak references to be immutable.
> > 
> > 
> > 
> > "dev" <dev-bounces at openvswitch.org> wrote on 04/02/2016 11:46:30 AM:
> > 
> > > From: Ben Pfaff <blp at ovn.org>
> > > To: dev at openvswitch.org
> > > Cc: Ben Pfaff <blp at ovn.org>
> > > Date: 04/02/2016 11:46 AM
> > > Subject: [ovs-dev] [PATCH] ovsdb: Force columns that contain weak 
> > > references to be immutable.
> > > Sent by: "dev" <dev-bounces at openvswitch.org>
> > >
> > > An immutable weak reference is a hole in the constraint system: if 
> > > referenced rows are deleted, then the weak reference needs to change.
> > > Therefore, force columsn that contain weak references to be mutable.
> > >
> > > Reported-by: "Elluru, Krishna Mohan" <elluru.kri.mohan at hpe.com>
> > > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > > ---
> > >  AUTHORS                 |  1 +
> > >  ovsdb/column.c          | 24 +++++++++++++++---------
> > >  ovsdb/ovsdb-server.1.in |  6 ++++++  python/ovs/db/schema.py |  8
> > > +++++++-
> > >  tests/ovsdb-schema.at   | 19 ++++++++++++++++++-
> > >  5 files changed, 47 insertions(+), 11 deletions(-)
> > 
> > Acked-by: Ryan Moats <rmoats at us.ibm.com> 
> > _______________________________________________
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> > dev at openvswitch.org
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