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https://issues.apache.org/jira/browse/HDFS-16043?focusedWorklogId=705443&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-705443
]
ASF GitHub Bot logged work on HDFS-16043:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Jan/22 10:07
Start Date: 08/Jan/22 10:07
Worklog Time Spent: 10m
Work Description: tomscut commented on a change in pull request #3063:
URL: https://github.com/apache/hadoop/pull/3063#discussion_r780055220
##########
File path:
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java
##########
@@ -4909,6 +4932,75 @@ public long getLastRedundancyMonitorTS() {
return lastRedundancyCycleTS.get();
}
+ /**
+ * Periodically deletes the marked block.
+ */
+ private class MarkedDeleteBlockScrubber implements Runnable {
+ private Iterator<BlockInfo> toDeleteIterator = null;
+ private boolean isSleep;
+
+ private void remove(long time) {
+ if (checkToDeleteIterator()) {
+ namesystem.writeLock();
+ try {
+ while (toDeleteIterator.hasNext()) {
+ removeBlock(toDeleteIterator.next());
+ if (Time.monotonicNow() - time > deleteBlockLockTimeMs) {
+ isSleep = true;
+ break;
+ }
+ }
+ } finally {
+ namesystem.writeUnlock();
+ }
+ }
+ }
+
+ private boolean checkToDeleteIterator() {
+ return toDeleteIterator != null && toDeleteIterator.hasNext();
+ }
+
+ @Override
+ public void run() {
+ LOG.info("Start MarkedDeleteBlockScrubber thread");
+ while (namesystem.isRunning() &&
+ !Thread.currentThread().isInterrupted()) {
+ if (!markedDeleteQueue.isEmpty() || checkToDeleteIterator()) {
+ try {
+ NameNodeMetrics metrics = NameNode.getNameNodeMetrics();
+ metrics.setDeleteBlocksQueued(markedDeleteQueue.size());
+ isSleep = false;
+ long startTime = Time.monotonicNow();
+ remove(startTime);
+ while (!isSleep && !markedDeleteQueue.isEmpty() &&
+ !Thread.currentThread().isInterrupted()) {
+ List<BlockInfo> markedDeleteList = markedDeleteQueue.poll();
+ if (markedDeleteList != null) {
+ toDeleteIterator = markedDeleteList.listIterator();
+ }
+ remove(startTime);
+ }
+ } catch (Exception e){
+ LOG.warn("MarkedDeleteBlockScrubber encountered an exception" +
+ " during the block deletion process, " +
+ " the deletion of the block will retry in {} millisecond.",
+ deleteBlockUnlockIntervalTimeMs, e);
+ }
+ }
+ if (isSleep) {
Review comment:
At present, there are warn logs whose lock holding exceeds the
threshold. The same logs are generated here. Can we change the log level to
DEBUG?
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Issue Time Tracking
-------------------
Worklog Id: (was: 705443)
Time Spent: 7h 10m (was: 7h)
> Add markedDeleteBlockScrubberThread to delete blocks asynchronously
> -------------------------------------------------------------------
>
> Key: HDFS-16043
> URL: https://issues.apache.org/jira/browse/HDFS-16043
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs, namanode
> Affects Versions: 3.4.0
> Reporter: Xiangyi Zhu
> Assignee: Xiangyi Zhu
> Priority: Major
> Labels: pull-request-available
> Attachments: 20210527-after.svg, 20210527-before.svg
>
> Time Spent: 7h 10m
> Remaining Estimate: 0h
>
> The deletion of the large directory caused NN to hold the lock for too long,
> which caused our NameNode to be killed by ZKFC.
> Through the flame graph, it is found that its main time-consuming
> calculation is QuotaCount when removingBlocks(toRemovedBlocks) and deleting
> inodes, and removeBlocks(toRemovedBlocks) takes a higher proportion of time.
> h3. solution:
> 1. RemoveBlocks is processed asynchronously. A thread is started in the
> BlockManager to process the deleted blocks and control the lock time.
> 2. QuotaCount calculation optimization, this is similar to the optimization
> of this Issue HDFS-16000.
> h3. Comparison before and after optimization:
> Delete 1000w Inode and 1000w block test.
> *before:*
> remove inode elapsed time: 7691 ms
> remove block elapsed time :11107 ms
> *after:*
> remove inode elapsed time: 4149 ms
> remove block elapsed time :0 ms
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