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https://issues.apache.org/jira/browse/HDFS-8386?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14573846#comment-14573846
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Tsz Wo Nicholas Sze commented on HDFS-8386:
-------------------------------------------
In trunk, the streamer synchronization bug does not exist since streamer is
only initialized in constructors.
Also, simply replacing streamer with getStreamer() may not be really fix
synchronization bugs if there is any. For example, in adjustChunkBoundary()
below, would it work if getStreamer() returns a different object each time?
{code}
protected void adjustChunkBoundary() {
- if (streamer.getAppendChunk() &&
- streamer.getBytesCurBlock() % bytesPerChecksum == 0) {
- streamer.setAppendChunk(false);
+ if (getStreamer().getAppendChunk() &&
+ getStreamer().getBytesCurBlock() % bytesPerChecksum == 0) {
+ getStreamer().setAppendChunk(false);
resetChecksumBufSize();
}
- if (!streamer.getAppendChunk()) {
- int psize = Math.min((int)(blockSize- streamer.getBytesCurBlock()),
+ if (!getStreamer().getAppendChunk()) {
+ int psize = Math.min((int)(blockSize- getStreamer().getBytesCurBlock()),
dfsClient.getConf().getWritePacketSize());
computePacketChunkSize(psize, bytesPerChecksum);
}
{code}
I suggest revert the committed patch since it may potentially hide some
synchronization bugs in the HDFS-7285 branch.
> Improve synchronization of 'streamer' reference in DFSOutputStream
> ------------------------------------------------------------------
>
> Key: HDFS-8386
> URL: https://issues.apache.org/jira/browse/HDFS-8386
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: hdfs-client
> Reporter: Rakesh R
> Assignee: Rakesh R
> Fix For: 2.8.0
>
> Attachments: HDFS-8386-00.patch, HDFS-8386-01.patch
>
>
> Presently {{DFSOutputStream#streamer}} object reference is accessed
> inconsistently with respect to synchronization. It would be good to improve
> this part. This has been noticed when implementing the erasure coding feature.
> Please refer the related [discussion
> thread|https://issues.apache.org/jira/browse/HDFS-8294?focusedCommentId=14541411&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14541411]
> in the jira HDFS-8294 for more details.
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