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java.lang.Object org.apache.lucene.store.Directory org.apache.lucene.store.NRTCachingDirectory
public class NRTCachingDirectory
Wraps a RAMDirectory
around any provided delegate directory, to
be used during NRT search. Make sure you pull the merge
scheduler using getMergeScheduler()
and pass that to your
IndexWriter
; this class uses that to keep track of which
merges are being done by which threads, to decide when to
cache each written file.
This class is likely only useful in a near-real-time context, where indexing rate is lowish but reopen rate is highish, resulting in many tiny files being written. This directory keeps such segments (as well as the segments produced by merging them, as long as they are small enough), in RAM.
This is safe to use: when your app calls {IndexWriter#commit}, all cached files will be flushed from the cached and sync'd.
NOTE: this class is somewhat sneaky in its approach for spying on merges to determine the size of a merge: it records which threads are running which merges by watching ConcurrentMergeScheduler's doMerge method. While this works correctly, likely future versions of this class will take a more general approach.
Here's a simple example usage:
Directory fsDir = FSDirectory.open(new File("/path/to/index")); NRTCachingDirectory cachedFSDir = new NRTCachingDirectory(fsDir, 5.0, 60.0); IndexWriterConfig conf = new IndexWriterConfig(Version.LUCENE_32, analyzer); conf.setMergeScheduler(cachedFSDir.getMergeScheduler()); IndexWriter writer = new IndexWriter(cachedFSDir, conf);
This will cache all newly flushed segments, all merges whose expected segment size is <= 5 MB, unless the net cached bytes exceeds 60 MB at which point all writes will not be cached (until the net bytes falls below 60 MB).
Field Summary |
---|
Fields inherited from class org.apache.lucene.store.Directory |
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isOpen, lockFactory |
Constructor Summary | |
---|---|
NRTCachingDirectory(org.apache.lucene.store.Directory delegate,
double maxMergeSizeMB,
double maxCachedMB)
We will cache a newly created output if 1) it's a flush or a merge and the estimated size of the merged segmnt is <= maxMergeSizeMB, and 2) the total cached bytes is <= maxCachedMB |
Method Summary | |
---|---|
void |
clearLock(String name)
|
void |
close()
Close thius directory, which flushes any cached files to the delegate and then closes the delegate. |
org.apache.lucene.store.IndexOutput |
createOutput(String name)
|
void |
deleteFile(String name)
|
protected boolean |
doCacheWrite(String name)
Subclass can override this to customize logic; return true if this file should be written to the RAMDirectory. |
boolean |
fileExists(String name)
|
long |
fileLength(String name)
|
long |
fileModified(String name)
|
org.apache.lucene.index.MergeScheduler |
getMergeScheduler()
|
String[] |
listAll()
|
String[] |
listCachedFiles()
|
org.apache.lucene.store.Lock |
makeLock(String name)
|
org.apache.lucene.store.IndexInput |
openInput(String name)
|
org.apache.lucene.store.IndexInput |
openInput(String name,
int bufferSize)
|
long |
sizeInBytes()
Returns how many bytes are being used by the RAMDirectory cache |
void |
sync(Collection<String> fileNames)
|
void |
touchFile(String name)
Deprecated. |
Methods inherited from class org.apache.lucene.store.Directory |
---|
copy, copy, ensureOpen, getLockFactory, getLockID, setLockFactory, sync, toString |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
---|
public NRTCachingDirectory(org.apache.lucene.store.Directory delegate, double maxMergeSizeMB, double maxCachedMB)
Method Detail |
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public String[] listAll() throws IOException
listAll
in class org.apache.lucene.store.Directory
IOException
public long sizeInBytes()
public boolean fileExists(String name) throws IOException
fileExists
in class org.apache.lucene.store.Directory
IOException
public long fileModified(String name) throws IOException
fileModified
in class org.apache.lucene.store.Directory
IOException
@Deprecated public void touchFile(String name) throws IOException
touchFile
in class org.apache.lucene.store.Directory
IOException
public void deleteFile(String name) throws IOException
deleteFile
in class org.apache.lucene.store.Directory
IOException
public long fileLength(String name) throws IOException
fileLength
in class org.apache.lucene.store.Directory
IOException
public String[] listCachedFiles()
public org.apache.lucene.store.IndexOutput createOutput(String name) throws IOException
createOutput
in class org.apache.lucene.store.Directory
IOException
public void sync(Collection<String> fileNames) throws IOException
sync
in class org.apache.lucene.store.Directory
IOException
public org.apache.lucene.store.IndexInput openInput(String name) throws IOException
openInput
in class org.apache.lucene.store.Directory
IOException
public org.apache.lucene.store.IndexInput openInput(String name, int bufferSize) throws IOException
openInput
in class org.apache.lucene.store.Directory
IOException
public org.apache.lucene.store.Lock makeLock(String name)
makeLock
in class org.apache.lucene.store.Directory
public void clearLock(String name) throws IOException
clearLock
in class org.apache.lucene.store.Directory
IOException
public void close() throws IOException
close
in interface Closeable
close
in class org.apache.lucene.store.Directory
IOException
public org.apache.lucene.index.MergeScheduler getMergeScheduler()
protected boolean doCacheWrite(String name)
|
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