On Tue, 2011-05-31 at 21:13 +0200, Johan Corveleyn wrote:
> On Tue, May 31, 2011 at 7:37 PM, <philip_at_apache.org> wrote:
> > Author: philip
> > Date: Tue May 31 17:37:33 2011
> > New Revision: 1129818
> >
> > URL: http://svn.apache.org/viewvc?rev=1129818&view=rev
> > Log:
> > * subversion/libsvn_wc/wc-checks.sql
> > (validation_03): Use EXISTS rather than COUNT.
> >
> > Modified:
> > subversion/trunk/subversion/libsvn_wc/wc-checks.sql
> >
> > Modified: subversion/trunk/subversion/libsvn_wc/wc-checks.sql
> > URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_wc/wc-checks.sql?rev=1129818&r1=1129817&r2=1129818&view=diff
> > ==============================================================================
> > --- subversion/trunk/subversion/libsvn_wc/wc-checks.sql (original)
> > +++ subversion/trunk/subversion/libsvn_wc/wc-checks.sql Tue May 31 17:37:33 2011
> > @@ -54,10 +54,9 @@ CREATE TEMPORARY TRIGGER validation_03 B
> > WHEN NOT (
> > (new.op_depth = relpath_depth(new.local_relpath))
> > OR
> > - ((SELECT COUNT(*) FROM nodes
> > - WHERE wc_id = new.wc_id AND op_depth = new.op_depth
> > - AND local_relpath = new.parent_relpath
> > - LIMIT 2) == 1)
> > + (EXISTS (SELECT 1 FROM nodes
> > + WHERE wc_id = new.wc_id AND op_depth = new.op_depth
> > + AND local_relpath = new.parent_relpath))
> > )
> > BEGIN
> > SELECT RAISE(FAIL, 'WC DB validity check 03 failed');
>
> I don't know the context, but are you sure this is a non-functional change?
>
> The SELECT COUNT you removed checked for == 1. The EXISTS allows for
> >= 1. So if there are 2 such nodes, the condition you removed would
> have been false, but the one you put in place would be true.
I was concerned about that. I didn't notice this a little earlier when
I wrote the "LIMIT 2", but in fact there can never be more than one row
matching the WHERE clause because (wc_id, op_depth, local_relpath) is
the table's primary key.
- Julian
Received on 2011-05-31 21:28:00 CEST