Re: HDFS, FSDataOutputStream, flush(), sync(), close()

[Raghu Angadi]

Hmm.. neither of these filesystems seems to implement flush(). Can you 
file a jira on it?

HDFS implements sync() and data should be on the disk after that, but 
might not be able available to a reader yet. How did you test if it data 
is on the disk?

Raghu.

Christoph Graf wrote:
    Hi everybody,


I have a simple test case which creates a file, writes two lines into
the FSDataOutputStream and then flushes, syncs and closes the stream. I
am using hadoop 0.18.0 with cygwin.

What I observe (in contrast of using java.io.DataOutputStream) is that
the lines get written to the disk only after close() was executed. This
behaviour is true for the local filesystem as well as hdfs.

Can you point me to my mistake?

   
    thanks,


Christoph



        final String PATH = "file:///C:/tmp/test.txt";
       
        Configuration conf = new Configuration();
        conf.set("fs.default.name", PATH);
        FileSystem fs = FileSystem.get(conf);
           
        FSDataOutputStream out = fs.create(new Path(PATH), true);
       
        out.writeBytes("Test line 1 \n");
        out.writeBytes("Test line 2 \n");
       
        out.flush();
        out.sync();
        out.close();