1) I should be calling release of writer and searcher after every call. Is
it always mandatory in cases like searcher, when I am sure that I havn't
written anything since the last search ?
You have to be careful here. It works like this: a single searcher is
cached and returned every time. Once all references to the cached Writer
are returned, all of the cached Searchers (one per Similarity your
using) are reopened -- but only after all the Searcher references are
returned. So you must return the Searcher as soon as you are done with
the search...otherwise when you return the last reference to the cached
Writer it will wait around until you do return that Searcher. Use it and
return it as quick as you can. The cost is very small, its just a
reference count decrement to release. You do have to pay the sync cost,
but thats the cost of sharing resources across threads. Test for speed
if your worried...its beyond anything I have needed.
Be careful with the Writer -- you want to return it fairly often as
well, but you will will want to batch load if you are adding a lot of
docs at once. Get the Writer, add all the docs, release the Writer. But
keep in mind that you won't see the added docs until the # of threads
referencing the Writer hits 0 -- you might want to release it every 50
docs or something (arbitrary there). If your just updating a doc or
adding a doc randomly, get it, update/add, release it.
Always release the Writers and Searchers in a finally block to ensure
they get released regardless of exceptions.
2) Based on 1), is it okay to cache the instance of writer and Searcher
object locally ?
I wouldn't, but you can. You will hold things up though...everything
works based on them getting released. The IndexAccessor code properly
caches them for you. That one of its main goals...properly caching
Writers/Searchers and reopening Searchers when a Writer has made a
change. If you hold a Searcher out, when a Writer is released by the
last thread that had a reference to it, the thread that released the
Writer will be hung up waiting around for that Searcher to get released.
You wouldnt want this to be a long time.
3) Are there any plans to push these to the trunk? Also, are there any
blocking/critical issues before we can start using it in production ?
Its doubtful. The original code has been around for years and has yet to
see any trunk excitement. I think the commiters prefer to keep this type
of thing out of the core and generally prefer Solr. I think that since
many of the committers work on/use Solr, there hasn't been much
incentive for them to use LuceneIndexAccessor. Who knows really though.
I only know that I have no say in the matter <g>
No blocking or critical issues that I know of. This is based on work I
did over a year ago (based on the original LuceneIndexAcessor code of
course), and while its not the same code, I have been using that code at
6 24/7 sites for about a year now on index sizes ranging from 200,000 to
3 million article sized documents. I did this based on my experience
with that.
This is the code that I plan to use for any future projects, so feel
free to email me with any questions or suggestions. I have had a great
experience with this model of operating an interactive, multi-threaded,
Lucene index. I'll be on any bugs like white on rice <g> I am very
confident in the code though. Feel free to extend the test classes if
you are worried about anything in particular.
- Mark
Thanks!
On Feb 2, 2008 3:41 AM, Mark Miller <[EMAIL PROTECTED]> wrote:
You are not seeing the doc because you need to close the IndexWriter
first.
To have an interactive index you can:
A: roll your own.
B: use Solr.
C: use the original LuceneIndexAccessor
https://issues.apache.org/jira/browse/LUCENE-390
D: use my updated IndexAccessor
https://issues.apache.org/jira/browse/LUCENE-1026
I have actually just added the ability to warm searchers before putting
them into to use for option D, but i havn't gotten around to posting the
new code yet.
- Mark Miller
codetester wrote:
Hi All,
A newbie out here.... I am using lucene 2.3.0. I need to use lucene to
perform live searching and indexing. To achieve that, I tried the
following
FSDirectory directory = FSDirectory.getDirectory(location);
IndexReader reader = IndexReader.open(directory );
IndexWriter writer = new IndexWriter(directory , new SimpleAnalyzer(),
true); // <- I want to recreate the index every time
IndexSearcher searcher = new IndexSearcher( reader );
For Searching, I have the following code
QueryParser queryParser = new QueryParser("xyz", new
StandardAnalyzer());
Hits hits = searcher .search(queryParser.parse(displayName + "*"));
And for adding records, I have the following code
// Create doc object
writer.addDocument(doc);
IndexReader newIndexReader = reader.reopen() ;
if ( newIndexReader != reader ) {
reader.close() ;
}
reader = newIndexReader ;
searcher.close() ;
searcher = new IndexSearcher(reader );
So the issues that I face are
1) The addition of new record is not reflected in the search ( even
though I
have reinited IndexSearcher )
2) Obviously, the add record code is not thread safe. I am trying to
close
and update the reference to IndexSearcher object. I could add a sync
block,
but the bigger question would be that what is the ideal way to achieve
this
case where I need to add and search record real-time ?
Thanks !
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