[HDFS-11644] Support for querying outputstream capabilities

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha1
• Fix Version/s: 2.9.0, 3.0.0-alpha4
• Component/s: erasure-coding
• Labels: hdfs-ec-3.0-must-do
• Target Version/s: 3.0.0-alpha4
• Assignee: Manoj Govindassamy
• Reporter: Andrew Wang
• Created: 11/Apr/17 23:37
• Updated: 11/Mar/19 13:33
• Resolved: 14/May/17 04:41

Description

FSDataOutputStream#hsync checks if a stream implements Syncable, and if so, calls hsync. Otherwise, it just calls flush. This is used, for instance, by YARN's FileSystemTimelineWriter.

DFSStripedOutputStream extends DFSOutputStream, which implements Syncable. However, DFSStripedOS throws a runtime exception when the Syncable methods are called.

We should refactor the inheritance structure so DFSStripedOS does not implement Syncable.

Issue Links

• is cloned by: HDFS-11718 DFSStripedOutputStream hsync/hflush should not throw UnsupportedOperationException
• is depended upon by: HADOOP-14402 roll out StreamCapabilities across output streams of all filesystems
• is related to: HDFS-12251 Add document for StreamCapabilities
• is related to: HDFS-12260 StreamCapabilities.StreamCapability should be public.
• is related to: HADOOP-9565 Add a Blobstore interface to add to blobstore FileSystems
• is related to: HADOOP-15149 CryptoOutputStream should implement StreamCapabilities
• relates to: HADOOP-13327 Add OutputStream + Syncable to the Filesystem Specification
• relates to: HADOOP-14365 Stabilise FileSystem builder-based create API
• relates to: HDFS-11170 Add builder-based create API to FileSystem