Dave,
What's the typical size of a DESC element? It sounds like they must be
fairly large to have a noticeable effect on performance: 100-kB? 500-kB?
Do you anticipate needing to write queries that AND something in the
main document with terms in the DESC element? Perhaps an and-query of
the patent title with words in the body, or something like that?
I'm asking because the best solution might change according to the
features you need. If you need to write queries that join something in
the main document with something in the DESC element, then you may be
better off leaving the document un-fragmented. The index entries point
to fragments, so it's tricky to query terms that live in two different
fragments.
If you do not need to write such queries, then you should probably
contact support and see if we can come up with an appropriate solution.
-- Mike
On 2009-04-28 10:41, Dave Feldmeier wrote:
Mike,
You are correct - I meant to say that DESC is a fragment root, not a
fragment parent.
The reason that I fragment is for performance. In my application, I
display a set of lines of bibliographic info (title, inventor, various
dates, etc.), one line per document. I split the document into two
pieces: bibliographic information and the main text (which is larger
than the bibliographic info).
After implementing fragmenting, the search performance is better because
I need only fetch the bibliographic info and not then entire document. I
also allow the user to sort on various columns, so if the user clicks on
a column name, I repeat the most recent search terms but request the
appropriate sort order for the returned results. I only return the first
page of results and a page tends to be in the range of 20 to 30
documents, depending on the user. It's this latter operation for which
I'm trying to improve the performance.
-Dave
Message: 2
Date: Mon, 27 Apr 2009 15:47:50 -0700
From: Michael Blakeley<[email protected]>
Subject: Re: [MarkLogic Dev General] Questions about results ordering
with element range indices
To: General Mark Logic Developer Discussion
<[email protected]>
Message-ID:<[email protected]>
Content-Type: text/plain; charset=UTF-8; format=flowed
Dave,
One correction: the fragment root behaves the way you've described. A
fragment parent on DESC creates a new sub-fragment for every child of
DESC. That could create many more fragments than you want.
But I wonder why you decided to fragment these documents at all?
-- Mike
On 2009-04-27 13:30, Dave Feldmeier wrote:
Mike,
Indexing is complete. The search element and sort element should be in the same
fragment. An abbreviated form of my XML structure is:
<PATENT>
<PATNUM>
<ASSS>
several layers down<ASSS_AESNC>
<DESC>
other stuff
All tags are unique at all levels of the XML hierarchy (e.g., PATNUM appears only at
the top level and not within<DESC>).
I have set<DESC> as a fragment parent. My understanding is that<DESC> and below
will be one fragment and everything else will be in a second fragment. In this case, ASSC_AENSC
and PATNUM shoud be in the same fragment, correct? Do I also need to set<PATENT> as a
fragment root?
In some cases,<DESC> does not exist and my guess is that it's for these cases
in which the document has a single fragment that the ordering constraint help (only
two documents in the example that I gave).
Also, I have the default namespace. However, all documents in the system have
the same XML structure, so I didn't think that there would be a problem.
What am I missing here? Thanks.
-Dave
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