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Ben Roling commented on HADOOP-15625: ------------------------------------- Thanks Steve. I'll implement the configuration and testing as you suggest, although perhaps {{etag}} and {{client}} should be named {{etag-server}} and {{etag-client}}? This way if object version support is added {{client}} won't be ambiguous (client-side etag check or client-side versionId check)? Can we go back to the Exception type discussion briefly? Do you definitely want a subclass of EOFException for this? As I was stating in previous comments, it is seeming somewhat difficult to ensure such an exception doesn't get swallowed with a normal -1 response in some read() cases. > S3A input stream to use etags to detect changed source files > ------------------------------------------------------------ > > Key: HADOOP-15625 > URL: https://issues.apache.org/jira/browse/HADOOP-15625 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 > Affects Versions: 3.2.0 > Reporter: Brahma Reddy Battula > Assignee: Brahma Reddy Battula > Priority: Major > Attachments: HADOOP-15625-001.patch, HADOOP-15625-002.patch, > HADOOP-15625-003.patch > > > S3A input stream doesn't handle changing source files any better than the > other cloud store connectors. Specifically: it doesn't noticed it has > changed, caches the length from startup, and whenever a seek triggers a new > GET, you may get one of: old data, new data, and even perhaps go from new > data to old data due to eventual consistency. > We can't do anything to stop this, but we could detect changes by > # caching the etag of the first HEAD/GET (we don't get that HEAD on open with > S3Guard, BTW) > # on future GET requests, verify the etag of the response > # raise an IOE if the remote file changed during the read. > It's a more dramatic failure, but it stops changes silently corrupting things. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org