[ovs-dev] [PATCH monitor_cond V4 01/17] ovsdb: create column index mapping between ovsdb row to monitor row

[Liran Schour]

Ben Pfaff <blp at ovn.org> wrote on 25/02/2016 06:47:36 PM:

> On Thu, Feb 18, 2016 at 11:46:39AM +0000, Liran Schour wrote:
> > Columns indexing is different in ovsdb_row then in ovsdb_monitor_row.
> > We need mapping between the 2 for condition evaluation.
> > 
> > signed-off-by: Liran Schour <lirans at il.ibm.com>
> > 
> > ---
> > v2->v3:
> > * Describe columns_index_map in comment
> > * Init columns_index_map with invalid value (-1)
> 
> It's not obvious at this point in the series whether adding the new
> 'columns_index_map' member is better than adding a new member to struct
> ovsdb_monitor_column.  What's the rationale?
> 

We have couple of reasons here:
1. Condition.c does not know about ovsdb_monitor_column deceleration.
2. When calling for condition evaluation, ovsdb_condition_evaluate() 
evaluates all clauses so we need to be able to map many column->index to 
the index inside ovsb_montior_row->[old|new].
3. We use the same condition instance for evaluating ovsdb_monitro_row and 
ovsdb_row.