Re: backup RAMDirectory to file

Fri, 21 Mar 2008 04:24:52 -0700
I think both the original approach and addIndexes below will work here, though the original approach should be faster. 


But, there are some caveats.  You have to make sure you do the backup  
with the writer on the ramDir closed.  If there is a writer open, it  
could be changing files during your backup which will corrupt the  
backup image.



Alternatively, you could do a true "hot backup" (not having to close  
the writer on the ramDir) by using SnapshotDeletionPolicy.



You may want to do an incremental backup of the index.  Since Lucene  
is write-once, you only have to look for new filenames to copy (old  
filenames will never be changed).


Mike

Grant Ingersoll wrote:

I think you could try:

IndexWriter writer = new IndexWriter(fileDirectory, ...)
writer.addIndexes(ramDir)

-Grant

On Mar 20, 2008, at 2:47 PM, roger dimitri wrote:


Hi,

 I am using the Directory class's copy method to periodically sync  
my RAM based index to a file based index that's supposed to serve  
as a hot backup. I want to know if this is the right way to  
maintain a periodic backup of my RAM based index and, if Yes, then  
is it reliable in a production instance with almost 12 to 15 GB of  
Lucene index loaded into the RAMDirectory.

Any advice is greatly appreciated.
I have a sample working code snippet here:

public class RAMtoFILEcopy_test1 {


   static String[] queries = {
       "a OR b AND c",
       "(a OR b) AND c",
       "a OR (b AND c)",
       "a AND b",
       "a AND b OR c AND d",
       "(a AND b) OR (c AND d)",
       "a AND (b OR c) AND d",
       "((a AND b) OR c) AND d",
       "a AND (b OR (c AND d))",
       "a AND b AND c AND d",

       "a OR b AND NOT c",
       "(a OR b) AND NOT c",
       "a OR (b AND NOT c)",
       "a AND NOT d",
       "a AND NOT b OR c AND NOT d",
       "(a AND NOT b) OR (c AND NOT d)",
       "a AND NOT (b OR c) AND NOT d",
       "((a AND NOT b) OR c) AND NOT d",
       "a AND NOT (b OR (c AND NOT d))",
       "a AND NOT b AND NOT c AND NOT d",

   "a OR NOT b",
   "a OR NOT a",

   "a b",
   "a b c",
   "a b (c d e)",
   "+a +b",
   "a -b",
   "a +b -c",
   "+a b -c",
   "+a -b c",
   "a -b -c",
   "-a b c",

   "a OR b c AND d",
   "a OR b c",
   "a AND b c",
   "a OR b c OR d",
   "a OR b c d OR e",
   "a AND b c AND d",
   "a AND b c d AND e"
   };

   public static void main(String argv[]) throws Exception {
       Directory dir = new RAMDirectory();
       Analyzer analyzer = new StandardAnalyzer();

       IndexWriter writer = new IndexWriter(dir, analyzer, true);

       for ( int i=0; i < queries.length; i++ ) {
           Document doc = new Document();

           doc.add(new Field("text", queries[i], Field.Store.YES,  
Field.Index.TOKENIZED));

           writer.addDocument(doc);
       }
       writer.close();



       Directory dir2 = FSDirectory.getDirectory("/tmp/ 
TestHotbackup", true);

       dir.copy(dir, dir2, true);

   }

}


Thanks a lot,
Roger





      
_____________________________________________________________________ 
_______________

Never miss a thing.  Make Yahoo your home page.
http://www.yahoo.com/r/hs


--------------------------
Grant Ingersoll
http://www.lucenebootcamp.com
Next Training: April 7, 2008 at ApacheCon Europe in Amsterdam

Lucene Helpful Hints:
http://wiki.apache.org/lucene-java/BasicsOfPerformance
http://wiki.apache.org/lucene-java/LuceneFAQ






---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]




---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]























					Reply via email to