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Re: svn commit: r999837 - /subversion/trunk/subversion/libsvn_wc/wc-queries.sql

From: Erik Huelsmann <ehuels_at_gmail.com>
Date: Thu, 23 Sep 2010 18:53:19 +0200

On Wed, Sep 22, 2010 at 11:25 PM, Greg Stein <gstein_at_gmail.com> wrote:

> On Wed, Sep 22, 2010 at 05:39, <philip_at_apache.org> wrote:
> >...
> > +++ subversion/trunk/subversion/libsvn_wc/wc-queries.sql Wed Sep 22
> 09:39:45 2010
> > @@ -215,7 +215,7 @@ update nodes set properties = ?3
> > where wc_id = ?1 and local_relpath = ?2
> > and op_depth in
> > (select op_depth from nodes
> > - where wc_id = ?1 and local_relpath = ?2
> > + where wc_id = ?1 and local_relpath = ?2 and op_depth > 0
> > order by op_depth desc
> > limit 1);
>
> Wouldn't it be better to do:
>
> where wc_id = ?1 and local_relpath = ?2
> and op_depth = (select max(op_depth) from nodes
> where wc_id=?1 and local_relpath=?2 and op_depth > 0);
>
> It seems that eliminating the "order by" and "limit", in favor of
> max() will tell sqlite what we're really searching for: the maximal
> value.
>
>
I wrote those queries like that because Bert said it would introduce an
aggregation function - at the time he said it, that sounded like it was
something negative.

> Also note that the above query uses "op_depth in (...)"
>
> yet:
>
> >
> > @@ -312,7 +312,7 @@ WHERE wc_id = ?1 AND local_relpath = ?2;
> > update nodes set translated_size = ?3, last_mod_time = ?4
> > where wc_id = ?1 and local_relpath = ?2
> > and op_depth = (select op_depth from nodes
> > - where wc_id = ?1 and local_relpath = ?2
> > + where wc_id = ?1 and local_relpath = ?2 and op_depth >
> 0
> > order by op_depth desc
> > limit 1);
>
> This one does not. The rest of the statements you converted all use
> the "in" variant.
>

 The "in" variant is probably better, because - especially with the op_depth
> 0 restriction - the result set can probably be empty.

Bye,

Erik.
Received on 2010-09-23 18:53:58 CEST

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