The best search performance is achieved using a single IndexSearcher
shared by multiple threads. Peter Keegan has demonstrated rates of up
to 400 searches per second on eight-CPU machines using this approach:
http://www.mail-archive.com/java-user@lucene.apache.org/msg05074.html
So the synchronization is probably not hurting your performance.
Doug
yueyu lin wrote:
One IndexSearcher is one IndexSearcher instance. The instance has a lot of
functions. Unfortunately they will call another synchronized function in
other class's instance (TermInfosReader). That's the point why we need two
IndexSearchers. But two searchers will cost double cache memory. It's not
worthy. So if Lucene team can modify the codes slightly, the
synchronization
problem will be gone.
On 5/9/06, Chris Hostetter <[EMAIL PROTECTED]> wrote:
: We found if we were using 2 IndexSearcher, we would get 10%
performance
: benefit.
: But if we increased the number of IndexSearcher from 2, the
performance
: improvement became slight even worse.
Why use more then 2 IndexSearchers?
Typically 1 is all you need, except for when you want to open and "warm
up" a new Searcher because you know your index has changed on disk and
you're ready for those changes to be visible.
(I'm not arguing against your change -- concurrancy isn't my forte so i
have no opinion on wether your suggesting is good or not, i'm just
questioning the goal)
Acctually .. i don't know a lot about the internals of IndexSearcher and
TermInfosReader, but according to your description of the problem...
: The class org.apache.lucene.index.TermInfosReader , as you know,
every
: IndexSearcher will have one TermInfosReader. Every query, one method in
the
: class must be called:
: private synchronized void ensureIndexIsRead() throws IOException .
Notice
If the method isn't static, then how can two differnet instances of
IndexSearcher, each with their own TermInfosReader, block one another?
-Hoss
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Yueyu Lin
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