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https://issues.apache.org/jira/browse/HBASE-22072?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16919269#comment-16919269
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ramkrishna.s.vasudevan commented on HBASE-22072:
------------------------------------------------

[~aoxiang]
The patch here has gone into 2.1.5. As per what I see now is that since we have 
closeLock in place it is either updateReaders() or close() that can happen. As 
per the previous comments - you can see that if close(false) has happened, then 
close(true) is bound to happen when the Storescanner actually gets closed. So 
if updateREaders() happened the memstoreflushers though updated will anyway get 
closed, when the final close(true) happens. Previously it was multithreaded, 
now they are not. So if the issue over in HBASE-22929 can be checked with 
HBASE-2.1.5 probably the issue won't be there? Lemme know if am missing 
something.

> High read/write intensive regions may cause long crash recovery
> ---------------------------------------------------------------
>
>                 Key: HBASE-22072
>                 URL: https://issues.apache.org/jira/browse/HBASE-22072
>             Project: HBase
>          Issue Type: Bug
>          Components: Performance, Recovery
>    Affects Versions: 2.0.0
>            Reporter: Pavel
>            Assignee: ramkrishna.s.vasudevan
>            Priority: Major
>              Labels: compaction
>             Fix For: 2.2.0, 2.3.0, 2.0.6, 2.1.5
>
>         Attachments: HBASE-22072.HBASE-21879-v1.patch
>
>
> Compaction of high read loaded region may leave compacted files undeleted 
> because of existing scan references:
> INFO org.apache.hadoop.hbase.regionserver.HStore - Can't archive compacted 
> file hdfs://hdfs-ha/hbase... because of either isCompactedAway=true or file 
> has reference, isReferencedInReads=true, refCount=1, skipping for now
> If region is either high write loaded this happens quite often and region may 
> have few storefiles and tons of undeleted compacted hdfs files.
> Region keeps all that files (in my case thousands) untill graceful region 
> closing procedure, which ignores existing references and drop obsolete files. 
> It works fine unless consuming some extra hdfs space, but only in case of 
> normal region closing. If region server crashes than new region server, 
> responsible for that overfiling region, reads hdfs folder and try to deal 
> with all undeleted files, producing tons of storefiles, compaction tasks and 
> consuming abnormal amount of memory, wich may lead to OutOfMemory Exception 
> and further region servers crash. This stops writing to region because number 
> of storefiles reach *hbase.hstore.blockingStoreFiles* limit, forces high GC 
> duty and may take hours to compact all files into working set of files.
> Workaround is a periodically check hdfs folders files count and force region 
> assign for ones with too many files.
> It could be nice if regionserver had a setting similar to 
> hbase.hstore.blockingStoreFiles and invoke attempt to drop undeleted 
> compacted files if number of files reaches this setting.



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