Thanks for the tip.
One small improvement on the IndexAccessorFactory might be to allow user
to specify the Analyzer instead of using a default KeywordAnalyzer,
which of course will make your static init of the cached accessors
difficult unless you add more interfaces to the accessor to allow reset
analyzer/Dir as in my own version.
Jay
Mark Miller wrote:
One final note....if you are using the IndexAccessor and you are only
accessing the index from one JVM, you can use the NoLockFactory and save
some sync cost there.
Jay Yu wrote:
Mark,
Great effort getting the original lucene index accessor package in
this shape. I am sure this will benefit a lot of people using Lucene
in a multithread env.
I have a quick question to ask you:
Do you have to use the core Lucene 2.3-dev in order to use the accessor?
I will take a look at your codes to see if I could help. I used a
slightly modified version of the original package in my project but it
breaks some of my tests. I hope your version works better.
Thanks a lot!
Jay
Mark Miller wrote:
I have sat down and rewrote IndexAccessor from scratch. I copied in
the same reference counting logic, pruned some things, and tried to
make the whole package a bit simpler to use. I have a few things to
do, but its pretty solid already. The only major thing I'd still like
to do is add an option to warm searchers before putting them in the
Searcher cache. Id like to writer some more tests as well. Any help
greatly appreciated if your interested in using the thing.
http://myhardshadow.com/indexaccessor/trunk/src/test/com/mhs/indexaccessor/SimpleSearchServer.java
Here is a an example of a class that can be instantiated in one of
multiple threads and read /modify a single index without worrying
about what any
of the other threads are doing to the index at any given time. This
is a very simple example of how to use the IndexAccessor and not
necessarily an
example of best practices. The main idea is that you get your Writer,
Searcher, or Reader, and then be sure to release it as soon as your
done with it
in a finally block. For loading, you will want to load many docs with
a Writer (batch them) before releasing it, but remember that Readers
will not get a new view
of the index until you release all of the Writers. So beware hogging
a Writer unless you thats what your intending.
JavaDoc:
http://myhardshadow.com/indexaccessorapi/
Code:
http://myhardshadow.com/indexaccessor/trunk/
Jar:
http://myhardshadow.com/indexaccessorreleases/indexaccessor.jar
Your synchronized block concerns:
The synchronized blocks that control accesss to the IndexAccessor do
not have a huge impact on performance. Keep in mind that all of the
work is not done in a synchonrized block, just the retrieval of the
Searcher, Writer, Reader. Even if the synchronization makes the
method twice as expensive, it is still overpowered by the cost of
parsing queries and searching the index. This applies with or without
contention. I wrote a simple test and included the output below. You
might use the IBM Lock Analyzer for Java to further analyze these
costs. Trust me, this thing is speedy. Its many times better than
using IndexModifier.
Without Contention
Just retrieve and release Searcher 100000 times
----
avg time:6.3E-4 ms
total time:63 ms
Parse query and search on 1 doc 100000 times
----
avg time:0.03107 ms
total time:3107 ms
With Contention (40 other threads running 80000 searches)
Just retrieve and release Searcher 100000 times
----
avg time:0.04643 ms
total time:4643 ms
Parse query and search on 1 doc 100000 times
----
avg time:0.64337 ms
total time:64337 ms
- Mark
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