Geoffrey Hendrey wrote:
Will you and other derby folks be at javaone?
Hi Geoff,
I'll be there along with the other Java DB folks. Don't know about other
community members.
Regards,
-Rick
Sent from my iPhone
On Mar 25, 2009, at 8:49 AM, Rick Hillegas <[email protected]> wrote:
Geoff hendrey wrote:
Interesting. I am reviewing the JavaDocs.
I am concerned that transactional integrity might not be an important
requirement. That probably will raise the hackles of database experts like the
Derby team, but I would prefer a non-transactional support for Lucene-derby
integration.
Thanks, Geoff. I think that a successful feature needs a real user like you.
Please consider the following things I would like:
1. ability to search an entire *row* as a document, not a
column-as-document model
OK. This makes sense to me. Each column would be a Lucene field, if I am
understanding the terms correctly.
1. ability to "look back in time" and see old versions of rows
This is interesting. What would you like the key to be? A two part invention
composed of the table's primary key plus a timestamp? Something else?
What about aborted changes? Would you be happy with a solution which recorded
index entries for changes which were subsequently discarded because, say, an
INSERT integrity violation rolled back a transaction to the savepoint laid down
before the INSERT ran?
Thanks,
-Rick
1. very high performance
2. high quality search results (from my experience you must combine
FuzzyLikeThisQuery with SnowballAnalyzer).
In my view, the lucene integration is more like a system that indexes a constant stream
of information that enters the database. Transactions are nice-to-have, but not really
needed to achieve the equivalent of a "search engine for the database". When I
execute a Lucene search, all I need to get back are row id's that I can use to
lazy-retrieve the row if the user wants to drill down on a particular search result. With
a web search engine like Google, it is possible that the page may no longer exist when
the user clicks on the search result (it happens from time to time).
This is why I don't think we really *need* transactional integrity on the
lucene search.
-geoff
“XML? Too much like HTML. It'll never work on the Web!”
-anonymous
*From:* Rick Hillegas <[email protected]>
*To:* Derby Discussion <[email protected]>
*Sent:* Tuesday, March 24, 2009 11:55:38 AM
*Subject:* Re: Lucene integration
Hi Geoffrey,
I'm hoping to have some time to look at Lucene integration after we put 10.5 to
bed. In the meantime, I was wondering if you have any experience with
implementations of Lucene Directory which place the Lucene indexes inside a
relational database? According to the following link, people have been
disappointed with the performance of this approach (don't know what that
means)--at first blush, however, the approach seems like an attractive way to
keep the Lucene indexes transactionally consistent with the original character
data:
http://wiki.apache.org/lucene-java/LuceneFAQ#head-e55d8e6971f9f01daaf3e14ce1d2f34485adba6e
Thanks,
-Rick
Rick Hillegas wrote:
Hi Geoffrey,
I'm on the road right now but I'd like to make some suggestions after I gather
my thoughts and get over my jet lag. I think that it is definitely possible to
hook into the query processing layer in order to fork the tuple stream so that
a listener process can populate the Lucene indexes. I think that scraping the
replication log stream would raise a lot of issues around when work is really
committed vs. when savepoints are rolled back, and I would recommend against
that approach.
Regards,
-Rick
Geoffrey Hendrey wrote:
Ok, well on to plan B then. Is there some stage in the preparation of inserts,
updates, and deletes at which the logical identity of a row is established?
That could be a good place to provide a lucene hook, or a more general
interceptor.
On Mar 18, 2009, at 6:55 AM, Jørgen Løland <[email protected]
<mailto:[email protected]>> wrote:
Geoff hendrey wrote:
I've been folowing knuts pointers and reading the docs on the classes that
marshal themselves over the wire via their writeObject method.
So, question about this:
"Type=update, Table=employee, Page=4321, Index=4, field 3=50000"
Does the page and index, collectively, constitute a "row ID".
If it is always a constant, than these three field are sufficient to
permanently identify the row, and we can use that information to consititute a
document ID in lucene.
It's constant until the record is moved to another page (which means "no",
really).
