How do I store the lucene index in a database?

Question

This is my sample code:

MysqlDataSource dataSource = new MysqlDataSource();

dataSource.setUser("root");
dataSource.setPassword("ncl");
dataSource.setDatabaseName("userdb");
dataSource.setEmulateLocators(true); //This is important because we are dealing with a blob type data field
try{    
    JdbcDirectory jdbcDir = new JdbcDirectory(dataSource, new MySQLDialect(), "tttable");
    StandardAnalyzer analyzer = new StandardAnalyzer();
    IndexWriter writer = new IndexWriter(jdbcDir, analyzer,false);
    writer.optimize();
    writer.close();
}catch(Exception e){
System.out.print(e);
}

I am stuck at this line: IndexWriter writer = new IndexWriter(jdbcDir, analyzer,false);

Everytime I try to run this code, I receive the following exception:

------"org.apache.lucene.store.LockObtainFailedException: Lock obtain timed out: PhantomReadLock[write.lock/tttable]"------------

I cannot find what is wrong with the code. It may be it is a jar compatibility issue.

I am unable to get an IndexWriter object.

Answer 1

It seems like the index is locked. If you're sure it shouldn't be locked, then maybe some process crashed without proper cleanup.

Try adding the line

jdbcDir.clearLock();

before creating the indexWriter.

Don't leave it there, tough. You generally want to let Lucene manage the locks, to disallow two IndexWriters from writing to the same index.

Answer 2

I get the same thing. So do I have to turn back on the lock then?