Contributed by Steve Loughran.
This patch avoids issuing any HEAD path request when creating a file with overwrite=true,
so 404s will not end up in the S3 load balancers unless someone calls getFileStatus/exists/isFile
in their own code.
The Hadoop FsShell CommandWithDestination class is modified to not register uncreated files
for deleteOnExit(), because that calls exists() and so can place the 404 in the cache, even
after S3A is patched to not do it itself.
Because S3Guard knows when a file should be present, it adds a special FileNotFound retry policy
independently configurable from other retry policies; it is also exponential, but with
different parameters. This is because every HEAD request will refresh any 404 cached in
the S3 Load Balancers. It's not enough to retry: we have to have a suitable gap between
attempts to (hopefully) ensure any cached entry wil be gone.
The options and values are:
fs.s3a.s3guard.consistency.retry.interval: 2s
fs.s3a.s3guard.consistency.retry.limit: 7
The S3A copy() method used during rename() raises a RemoteFileChangedException which is not caught
so not downgraded to false. Thus: when a rename is unrecoverable, this fact is propagated.
Copy operations without S3Guard lack the confidence that the file exists, so don't retry the same way:
it will fail fast with a different error message. However, because create(path, overwrite=false) no
longer does HEAD path, we can at least be confident that S3A itself is not creating those cached
404 markers.
Change-Id: Ia7807faad8b9a8546836cb19f816cccf17cca26d
Contributed by Steve Loughran
Contains
- HADOOP-16397. Hadoop S3Guard Prune command to support a -tombstone option.
- HADOOP-16406. ITestDynamoDBMetadataStore.testProvisionTable times out intermittently
This patch doesn't fix the underlying problem but it
* changes some tests to clean up better
* does a lot more in logging operations in against DDB, if enabled
* adds an entry point to dump the state of the metastore and s3 tables (precursor to fsck)
* adds a purge entry point to help clean up after a test run has got a store into a mess
* s3guard prune command adds -tombstone option to only clear tombstones
The outcome is that tests should pass consistently and if problems occur we have better diagnostics.
Change-Id: I3eca3f5529d7f6fec398c0ff0472919f08f054eb
Contributed by Steve Loughran.
This patch
* changes the default for the staging committer to append, as we get for the classic FileOutputFormat committer
* adds a check for the dest path being a file not a dir
* adds tests for this
* Changes AbstractCommitTerasortIT. to not use the simple parser, so fails if the file is present.
Change-Id: Id53742958ed1cf321ff96c9063505d64f3254f53
Contributed by Ben Roling.
S3Guard will now track the etag of uploaded files and, if an S3
bucket is versioned, the object version.
You can then control how to react to a mismatch between the data
in the DynamoDB table and that in the store: warn, fail, or, when
using versions, return the original value.
This adds two new columns to the table: etag and version.
This is transparent to older S3A clients -but when such clients
add/update data to the S3Guard table, they will not add these values.
As a result, the etag/version checks will not work with files uploaded by older clients.
For a consistent experience, upgrade all clients to use the latest hadoop version.
This is the first step for on-demand operations: things recognize when they are using on-demand tables,
as do the tests.
Contributed by Steve Loughran.
S3A to implement S3 Select through this API.
The new openFile() API is asynchronous, and implemented across FileSystem and FileContext.
The MapReduce V2 inputs are moved to this API, and you can actually set must/may
options to pass in.
This is more useful for setting things like s3a seek policy than for S3 select,
as the existing input format/record readers can't handle S3 select output where
the stream is shorter than the file length, and splitting plain text is suboptimal.
Future work is needed there.
In the meantime, any/all filesystem connectors are now free to add their own filesystem-specific
configuration parameters which can be set in jobs and used to set filesystem input stream
options (seek policy, retry, encryption secrets, etc).
Contributed by Steve Loughran
