Class SearcherLifetimeManager
- java.lang.Object
-
- org.apache.lucene.search.SearcherLifetimeManager
-
- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public class SearcherLifetimeManager extends java.lang.Object implements java.io.Closeable
Keeps track of current plus old IndexSearchers, closing the old ones once they have timed out. Use it like this:SearcherLifetimeManager mgr = new SearcherLifetimeManager();
Per search-request, if it's a "new" search request, then obtain the latest searcher you have (for example, by usingSearcherManager
), and then record this searcher:// Record the current searcher, and save the returend // token into user's search results (eg as a hidden // HTML form field): long token = mgr.record(searcher);
When a follow-up search arrives, for example the user clicks next page, drills down/up, etc., take the token that you saved from the previous search and:// If possible, obtain the same searcher as the last // search: IndexSearcher searcher = mgr.acquire(token); if (searcher != null) { // Searcher is still here try { // do searching... } finally { mgr.release(searcher); // Do not use searcher after this! searcher = null; } } else { // Searcher was pruned -- notify user session timed // out, or, pull fresh searcher again }
Finally, in a separate thread, ideally the same thread that's periodically reopening your searchers, you should periodically prune old searchers:mgr.prune(new PruneByAge(600.0));
NOTE: keeping many searchers around means you'll use more resources (open files, RAM) than a single searcher. However, as long as you are using
DirectoryReader.openIfChanged(DirectoryReader)
, the searchers will usually share almost all segments and the added resource usage is contained. When a large merge has completed, and you reopen, because that is a large change, the new searcher will use higher additional RAM than other searchers; but large merges don't complete very often and it's unlikely you'll hit two of them in your expiration window. Still you should budget plenty of heap in the JVM to have a good safety margin.
-
-
Nested Class Summary
Nested Classes Modifier and Type Class Description static class
SearcherLifetimeManager.PruneByAge
Simple pruner that drops any searcher older by more than the specified seconds, than the newest searcher.static interface
SearcherLifetimeManager.Pruner
-
Constructor Summary
Constructors Constructor Description SearcherLifetimeManager()
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description IndexSearcher
acquire(long version)
Retrieve a previously recordedIndexSearcher
, if it has not yet been closedvoid
close()
Close this to future searching; any searches still in process in other threads won't be affected, and they should still callrelease(org.apache.lucene.search.IndexSearcher)
after they are done.void
prune(SearcherLifetimeManager.Pruner pruner)
Calls providedSearcherLifetimeManager.Pruner
to prune entries.long
record(IndexSearcher searcher)
Records that you are now using this IndexSearcher.void
release(IndexSearcher s)
Release a searcher previously obtained fromacquire(long)
.
-
-
-
Method Detail
-
record
public long record(IndexSearcher searcher) throws java.io.IOException
Records that you are now using this IndexSearcher. Always call this when you've obtained a possibly newIndexSearcher
, for example fromSearcherManager
. It's fine if you already passed the same searcher to this method before.This returns the long token that you can later pass to
acquire(long)
to retrieve the same IndexSearcher. You should record this long token in the search results sent to your user, such that if the user performs a follow-on action (clicks next page, drills down, etc.) the token is returned.- Throws:
java.io.IOException
-
acquire
public IndexSearcher acquire(long version)
Retrieve a previously recordedIndexSearcher
, if it has not yet been closedNOTE: this may return null when the requested searcher has already timed out. When this happens you should notify your user that their session timed out and that they'll have to restart their search.
If this returns a non-null result, you must match later call
release(org.apache.lucene.search.IndexSearcher)
on this searcher, best from a finally clause.
-
release
public void release(IndexSearcher s) throws java.io.IOException
Release a searcher previously obtained fromacquire(long)
.NOTE: it's fine to call this after close.
- Throws:
java.io.IOException
-
prune
public void prune(SearcherLifetimeManager.Pruner pruner) throws java.io.IOException
Calls providedSearcherLifetimeManager.Pruner
to prune entries. The entries are passed to the Pruner in sorted (newest to oldest IndexSearcher) order.NOTE: you must peridiocally call this, ideally from the same background thread that opens new searchers.
- Throws:
java.io.IOException
-
close
public void close() throws java.io.IOException
Close this to future searching; any searches still in process in other threads won't be affected, and they should still callrelease(org.apache.lucene.search.IndexSearcher)
after they are done.NOTE: you must ensure no other threads are calling
record(org.apache.lucene.search.IndexSearcher)
while you call close(); otherwise it's possible not all searcher references will be freed.- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Throws:
java.io.IOException
-
-