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From "Alexandru Popescu" <the.mindstorm.mailingl...@gmail.com>
Subject Re: document order related questions
Date Fri, 31 Mar 2006 11:43:56 GMT
On 3/31/06, Tobias Bocanegra <tobias.bocanegra@day.com> wrote:
> hi alex,
> the ordering of childnodes is optional to implement by a repository.
> even if the nodetype defines a 'hasOrderableChildNodes', the
> repository must not support this.
>
> but, if it supports it, the result sets of the query must be in the
> correct order. since the result set retrieved by lucene is in
> arbitrary order internally, it is sorted before returned to the
> client. this has an impact on performance.
>

Should I read in the above that the document order is in fact the
order in which the child nodes are added? Is this the correct
definition of "document order"?

> so, if the correct ordering
> is not needed by your application, you can disable it.
once again many thanks in advance,

The insert order is definitely not important to me. I need data in
whatever order (in case I am accesing child nodes through their
parent) or in most query cases I need it in my specific order. So,
most probably I should set the document order to false.

Once again many many thanks in advance for any clarifications to the
raised questions.

./alex
--
.w( the_mindstorm )p.


> the reason it is enabled by default is, that it is demanded by the
> spec and jackrabbit is jsr170 reference implementation.
>
> regards, toby
>
> On 3/31/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
> > Ohhhh... and I forgot the question about the document order disabling
> > in searchs: I have read quite a few posts on the ML about bad
> > performance queries. For most of them, the answer was disable document
> > order. If this is a known problem, why isn't it by default disabled? I
> > guess the other answers may clarify this one too, but I thought I
> > should mention it for further reference. Thanks again.
> >
> > Eagerly waiting for some light :-).
> >
> > ./alex
> > --
> > .w( the_mindstorm )p.
> >
> >
> > On 3/31/06, Alexandru Popescu <the.mindstorm.mailinglist@gmail.com> wrote:
> > > Hi!
> > >
> > > I have been trying to understand what exactly is the document order and why
it is set by default to
> > > true in the queries, even if it is known its bad impact on performance.
> > >
> > > I have been rechecking the spec, but I couldn't find any definition of this
term. A definition can
> > > probably be deduced from the 6.4.2 Document View XML Mapping chapter, but this
would lead to a
> > > vicious circle imo.
> > >
> > > So, what is the document order? Please give me any details that might enlighten
me about this term.
> > >
> > > Related to this document order there is another paragraph in the spec that
is not absolutely clear
> > > to me. I am refering to 6.6.4.2 Document Order:
> > >
> > > [quote]
> > > If document order searching is supported, then the context
> > > functions related to document order, last() and position(), must
> > > also be supported.
> > > [/quote]
> > >
> > > This paragraph should be read like: last(), position() can be used _only_ in
queries that use the
> > > document order?
> > >
> > > If this is the case, than optimization queries like position() > x (for
paging) will not work when a
> > > specific order is used (and I know there is already a JIRA issue about position()
being able to
> > > handle only equality :-) ). Than you will need to rely on the NodeIterator.skip()
that is not
> > > required to be lazy.
> > >
> > > Can you please give me some details, comments, opinions, anything that might
remove the shaddow on
> > > this points? Many, many thanks in advance,
> > >
> > > ./alex
> > > --
> > > .w( the_mindstorm )p.
> > >
> >
>
>
> --
> -----------------------------------------< tobias.bocanegra@day.com >---
> Tobias Bocanegra, Day Management AG, Barfuesserplatz 6, CH - 4001 Basel
> T +41 61 226 98 98, F +41 61 226 98 97
> -----------------------------------------------< http://www.day.com >---
>

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