| --- |
| layout: dev |
| title: "About Temp Files" |
| categories: development |
| permalink: /development/about_temp_files.html |
| --- |
| |
| As we reviewed the code we found that Kylin left lots of garbage files in: |
| |
| * Local file system of the CLI |
| * HDFS |
| * Local file system of the hadoop nodes. |
| |
| A ticket was opened to track this issue: |
| [https://issues.apache.org/jira/browse/KYLIN-926](https://issues.apache.org/jira/browse/KYLIN-926) |
| |
| For future developments, please: |
| |
| * Whenever you want to create temp files at Local, choose `File.createTempFile` or use the folder: `BatchConstants.CFG_KYLIN_LOCAL_TEMP_DIR(/tmp/kylin)`, do not randomly use another folder in `/tmp`, it will end up a mess, and look unprofessional. |
| * Whenever you create temp files at Local, remember to delete it after using it. It's best to use `FileUtils.forceDelete`, as it also works for deleting folders. Try avoid `deleteOnExit`, in case Kylin exits abnormally. |
| * Whenever you want to create files in HDFS, try to create it under `kylin.hdfs.working.dir` or `BatchConstants.CFG_KYLIN_HDFS_TEMP_DIR`, and remember to delete it after it is no longer useful. Try avoid throwing everything into hdfs:///tmp and leave it as garbage. |
