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https://issues.apache.org/jira/browse/HDFS-7056?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14254471#comment-14254471
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Jing Zhao commented on HDFS-7056:
---------------------------------
maybe something like the following? I wrote it in a hurry, so the code may not
be in a good shape. but the general idea is to directly process on the diff
list instead of keeping calling {{getPrior}} and {{getDiffById}}.
{code}
public BlockInfo[] findBlocksAfter(INodeFile currentINode, int snapshot) {
if (snapshot == Snapshot.CURRENT_STATE_ID) {
return currentINode.getBlocks();
} else {
List<FileDiff> diffs = this.asList();
int i = Collections.binarySearch(diffs, snapshot);
i = i >= 0 ? i : -i - 1;
for (; i < diffs.size(); i++) {
final FileDiff diff = diffs.get(i);
if (diff.getBlocks() != null) {
return diff.getBlocks();
}
}
return currentINode.getBlocks();
}
}
{code}
> Snapshot support for truncate
> -----------------------------
>
> Key: HDFS-7056
> URL: https://issues.apache.org/jira/browse/HDFS-7056
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: 3.0.0
> Reporter: Konstantin Shvachko
> Assignee: Plamen Jeliazkov
> Attachments: HDFS-3107-HDFS-7056-combined.patch,
> HDFS-3107-HDFS-7056-combined.patch, HDFS-3107-HDFS-7056-combined.patch,
> HDFS-3107-HDFS-7056-combined.patch, HDFS-3107-HDFS-7056-combined.patch,
> HDFS-3107-HDFS-7056-combined.patch, HDFS-3107-HDFS-7056-combined.patch,
> HDFS-3107-HDFS-7056-combined.patch, HDFS-3107-HDFS-7056-combined.patch,
> HDFS-7056.patch, HDFS-7056.patch, HDFS-7056.patch, HDFS-7056.patch,
> HDFS-7056.patch, HDFS-7056.patch, HDFS-7056.patch, HDFS-7056.patch,
> HDFSSnapshotWithTruncateDesign.docx
>
>
> Implementation of truncate in HDFS-3107 does not allow truncating files which
> are in a snapshot. It is desirable to be able to truncate and still keep the
> old file state of the file in the snapshot.
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