Thank you so much Michael and Grant for your suggestions. I haven't tried
SnapshotDeletionPolicy yet (thanks for the hint, I will do it now) and I guess
Incremental back up may not work in my case since I have periodic Index
cleaning jobs in RAMDirectory.
Thanks again,
Roger
----- Original Message ----
From: Michael McCandless <[EMAIL PROTECTED]>
To: java-user@lucene.apache.org
Sent: Friday, March 21, 2008 4:24:13 AM
Subject: Re: backup RAMDirectory to file
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
>
>
>
>
>
>
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