Andrew Olson created CRUNCH-698:
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Summary: Avro DataFileReader creation can hang
Key: CRUNCH-698
URL: https://issues.apache.org/jira/browse/CRUNCH-698
Project: Crunch
Issue Type: Bug
Components: Core
Reporter: Andrew Olson
Assignee: Josh Wills
A severe Avro bug [AVRO-2944|https://issues.apache.org/jira/browse/AVRO-2944]
was recently found in the static method for creating a DataFileReader instance,
where it can get stuck in an infinite loop while trying to read the 4 byte
"magic" header of the file.
This was fixed in Avro 1.10.1 but has not yet been patched to any other Avro
versions. The issue has existed since Avro 1.5 although we have encountered it
recently. It does not happen in normal circumstances, there has to be some very
unusual input stream behavior (partial/throttled read, or unexpected EOF)
causing it. We've only seen it with the S3AFileSystem's S3AInputStream,
suddenly starting a few days ago for no apparent reason. Even now it is
sporadic, happening a small percent of the time in job tasks that read many S3
files but often enough to be problematic. An AWS support case is open to
attempt to find out what could have caused this.
To avoid the external dependency on a particular Avro version to fix this, we
can probably just patch this locally in Crunch since it's only one static
method and apart from one legacy constant everything we need access to in the
Avro code is public.
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