create local file in tasktracker node

[lei liu <li...@gmail.com>]

I want to use hadoop to  create Berkeley DB index, so I need create one
directory to store Berkeley DB index, There are below code in reduce :

        String tmp = job.get("hadoop.tmp.dir");
        String shardName = "shard" + this.shardNum + "_" +
UUID.randomUUID().toString();
        this.localIndexFile = new File(tmp, shardName);
        if (!localIndexFile.exists()) {
            boolean isSuccessfull = localIndexFile.mkdir();

            LOG.info("create directory " + this.localIndexFile + ": " +
isSuccessfull);
        }


but the localIndexFile.mkdir() method return false, could everyone tell me
why the method return false, whether my reduce task instance don't have the
permission？



Thanks，


LiuLei