[
https://issues.apache.org/jira/browse/FLUME-2973?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Yan Jian updated FLUME-2973:
----------------------------
Attachment: FLUME-2973-1.patch
I made smallest modification ([^FLUME-2973-1.patch]) to escape from
inconsistent code format and unrelated code smells in original code.
It just breaks {{circular wait}} condition by reversing the lock sequence in
rolling thread, avoiding lock transfer.
Turn to {{trunk}} branch, such classes ({{BucketWriter}}, {{HDFSEventSink}},
etc.) are reformatted, but still contain several code smells.
# Inappropriate naming, such as
{{org.apache.flume.sink.hdfs.BucketWriter.closed}}.
# Coupling between classes {{BucketWriter}} and {{HDFSEventSink}}.
# Meaningless duplicate closing of a bucket writer.
IMHO, it is necessary to refactor classes in {{org.apache.flume.sink.hdfs}}
package.
> Deadlock in hdfs sink
> ---------------------
>
> Key: FLUME-2973
> URL: https://issues.apache.org/jira/browse/FLUME-2973
> Project: Flume
> Issue Type: Bug
> Components: Sinks+Sources
> Affects Versions: v1.7.0
> Reporter: Denes Arvay
> Assignee: Denes Arvay
> Priority: Critical
> Labels: hdfssink
> Attachments: FLUME-2973-1.patch, FLUME-2973.patch
>
>
> Automatic close of BucketWriters (when open file count reached
> {{hdfs.maxOpenFiles}}) and the file rolling thread can end up in deadlock.
> When creating a new {{BucketWriter}} in {{HDFSEventSink}} it locks
> {{HDFSEventSink.sfWritersLock}} and the {{close()}} called in
> {{HDFSEventSink.sfWritersLock.removeEldestEntry}} tries to lock the
> {{BucketWriter}} instance.
> On the other hand if the file is being rolled in
> {{BucketWriter.close(boolean)}} it locks the {{BucketWriter}} instance first
> and in the close callback it tries to lock the {{sfWritersLock}}.
> The chances for this deadlock is higher when the {{hdfs.maxOpenFiles}}'s
> value is low (1).
> Script to reproduce:
> https://gist.github.com/adenes/96503a6e737f9604ab3ee9397a5809ff
> (put to
> {{flume-ng-sinks/flume-hdfs-sink/src/main/java/org/apache/flume/sink/hdfs}})
> Deadlock usually occurs before ~30 iterations.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
