steveloughran commented on a change in pull request #575: HADOOP-13327 Output Stream Specification URL: https://github.com/apache/hadoop/pull/575#discussion_r341593810
########## File path: hadoop-common-project/hadoop-common/src/site/markdown/filesystem/outputstream.md ########## @@ -0,0 +1,857 @@ +<!--- + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. See accompanying LICENSE file. +--> + +<!-- MACRO{toc|fromDepth=1|toDepth=3} --> + +# Output: `OutputStream`, `Syncable` and `StreamCapabilities` + + +With the exception of `FileSystem.copyFromLocalFile()`, +all API operations which write data to a filesystem in Hadoop do so +through the Java "OutputStreams" API. More specifically, they do +so through `OutputStream` subclasses obtained through calls to +`FileSystem.create()`, `FileSystem.append()`, +or `FSDataOutputStreamBuilder.build()`. + +These all return instances of `FSDataOutputStream`, through which data +can be written through various `write()` methods. +After a stream's `close()` method is called, all data written to the +stream MUST BE persisted to the fileysystem and visible to oll other Review comment: Now you've scared me. Thought it had to be written across >1 replica. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
