Disables block prefetching on ABFS InputStreams, by setting
fs.azure.enable.readahead to false in core-default.xml and
the matching java constant.
This prevents
HADOOP-18521. ABFS ReadBufferManager buffer sharing across concurrent HTTP requests.
Once a fix for that is committed, this change can be reverted.
Contributed by Mehakmeet Singh.
* HADOOP-18517. ABFS: Add fs.azure.enable.readahead option to disable readahead
Adds new config option to turn off readahead
* also allows it to be passed in through openFile(),
* extends ITestAbfsReadWriteAndSeek to use the option, including one
replicated test...that shows that turning it off is slower.
Important: this does not address the critical data corruption issue
HADOOP-18521. ABFS ReadBufferManager buffer sharing across concurrent HTTP requests
What is does do is provide a way to completely bypass the ReadBufferManager.
To mitigate the problem, either fs.azure.enable.readahead needs to be set to false,
or set "fs.azure.readaheadqueue.depth" to 0 -this still goes near the (broken)
ReadBufferManager code, but does't trigger the bug.
For safe reading of files through the ABFS connector, readahead MUST be disabled
or the followup fix to HADOOP-18521 applied
Contributed by Steve Loughran
ABFS rename fails intermittently when the Storage-blob tracking
metadata is in an incomplete state. This surfaces as the error code
404 and an error message of "RenameDestinationParentPathNotFound"
To mitigate this issue, when a request fails with this response.
the ABFS client issues a HEAD call on the source file
and then retries the rename operation again
ABFS filesystem statistics track when this occurs with new counters
rename_recovery
metadata_incomplete_rename_failures
rename_path_attempts
This is very rare occurrence and appears to be triggered under certain
heavy load conditions, just as with HADOOP-18163.
Contributed by Mehakmeet Singh.
Stops the abfs connector warning if openFile().withFileStatus()
is invoked with a FileStatus is not an abfs VersionedFileStatus.
Contributed by Steve Loughran.
Change-Id: I85076b365eb30aaef2ed35139fa8714efd4d048e
Follow-on patch to MAPREDUCE-7341, adding ABFS support and tests
* resilient rename
* tests for job commit through the manifest committer.
contains
- HADOOP-17976. ABFS etag extraction inconsistent between LIST and HEAD calls
- HADOOP-16204. ABFS tests to include terasort
Contributed by Steve Loughran.
Change-Id: I0a7d4043bdf19bcb00c033fc389730109b93b77f
Cut modtime-based rename recovery as object modification time
is not updated during rename operation.
Applications will have to use etag API of HADOOP-17979
and implement it themselves.
Why not do the HEAD and etag recovery in ABFS client?
Cuts the IO capacity in half so kills job commit performance.
The manifest committer of MAPREDUCE-7341 will do this recovery
and act as the reference implementation of the algorithm.
Contributed by: Steve Loughran
Change-Id: I810054c9fd05041dac552f13d31fb15d7524721b
Addresses transient failures in the following test classes:
* ITestAbfsStreamStatistics: Uses a filesystem level static instance to record read/write statistics, which also tracks these operations in other tests running in parallel. Marked for sequential-only run to avoid transient failure
* ITestAbfsRestOperationException: The use of a static member to track retry count causes transient failures when two tests of this class happen to run together. Switch to non-static variable for assertions on retry count
closes#3341
Contributed by Sumangala Patki
Change-Id: Ied4dec35c81e94efe5f999acae4bb8fde278202e
Addresses the problem of processes running out of memory when
there are many ABFS output streams queuing data to upload,
especially when the network upload bandwidth is less than the rate
data is generated.
ABFS Output streams now buffer their blocks of data to
"disk", "bytebuffer" or "array", as set in
"fs.azure.data.blocks.buffer"
When buffering via disk, the location for temporary storage
is set in "fs.azure.buffer.dir"
For safe scaling: use "disk" (default); for performance, when
confident that upload bandwidth will never be a bottleneck,
experiment with the memory options.
The number of blocks a single stream can have queued for uploading
is set in "fs.azure.block.upload.active.blocks".
The default value is 20.
Contributed by Mehakmeet Singh.
This patch cuts down the size of directory trees used for
distcp contract tests against object stores, so making
them much faster against distant/slow stores.
On abfs, the test only runs with -Dscale (as was the case for s3a already),
and has the larger scale test timeout.
After every test case, the FileSystem IOStatistics are logged,
to provide information about what IO is taking place and
what it's performance is.
There are some test cases which upload files of 1+ MiB; you can
increase the size of the upload in the option
"scale.test.distcp.file.size.kb"
Set it to zero and the large file tests are skipped.
Contributed by Steve Loughran.
Introducing fs.azure.readahead.range parameter which can be set by the user.
Data will be populated in buffer for random reads as well which leads to fewer
remote calls.
This patch also changes the seek implementation to perform a lazy seek. The
actual seek is done when a read is initiated and data is not present in the buffer else
data is returned from the buffer thus reducing the number of remote storage calls.
Contributed By: Mukund Thakur
Change-Id: Ib920eedd0087caa150afa4d4c23e89df56b29e83
When the S3A and ABFS filesystems are closed,
their IOStatistics are logged at debug in the log:
org.apache.hadoop.fs.statistics.IOStatisticsLogging
Set `fs.iostatistics.logging.level` to `info` for the statistics
to be logged at info. (also: `warn` or `error` for even higher
log levels).
Contributed by: Mehakmeet Singh
Change-Id: I56d44ad89fc1c0dd4baf701681834e7fd96c544f
The ABFS Filesystem and its input and output streams now implement
the IOStatisticSource interface and provide IOStatistics on
their interactions with Azure Storage.
This includes the min/max/mean durations of all REST API calls.
Contributed by Mehakmeet Singh <mehakmeet.singh@cloudera.com>
This moves the mock account name --which is required to never exist-- from
"mockAccount" to an account name containing a static UUID.
Contributed by Steve Loughran.
This defines what output streams and especially those which implement
Syncable are meant to do, and documents where implementations (HDFS; S3)
don't. With tests.
The file:// FileSystem now supports Syncable if an application calls
FileSystem.setWriteChecksum(false) before creating a file -checksumming
and Syncable.hsync() are incompatible.
Contributed by Steve Loughran.
Change-Id: I892d768de6268f4dd6f175b3fe3b7e5bcaa91194
The ABFS connector now implements listStatusIterator() with
asynchronous prefetching of the next page(s) of results.
For listing large directories this can provide tangible speedups.
If for any reason this needs to be disabled, set
fs.azure.enable.abfslistiterator to false.
Contributed by Bilahari T H.
Change-Id: Ic9a52b80df1d0ffed4c81beae92c136e2a12698c
When 403 is returned from an ABFS HTTP call, an AccessDeniedException is raised.
The exception text is unchanged, for any application string matching on the getMessage() contents.
Contributed by Steve Loughran.
Change-Id: I519d50ccd657968fd8ee72d132518099de901e15
