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https://issues.apache.org/jira/browse/HADOOP-19270?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Erik Krogen resolved HADOOP-19270.
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Resolution: Fixed
Merged to trunk.
> Use stable sort in commandQueue
> -------------------------------
>
> Key: HADOOP-19270
> URL: https://issues.apache.org/jira/browse/HADOOP-19270
> Project: Hadoop Common
> Issue Type: Bug
> Components: tools
> Affects Versions: 3.4.0, 3.4.1
> Reporter: Kim gichan
> Priority: Major
> Labels: pull-request-available
> Fix For: 3.5.0
>
> Attachments: image-2024-09-19-16-40-34-947.png
>
>
> h2. Purpose
> - To remove possibility of wrong-ordered log simulation
> h2. Why this happens?
> - private DelayQueue<AuditReplayCommand> commandQueue is actually
> PriorityQueue that use unstable sort.
> - commandQueue can have order that is not same to original audit log order.
> - In real production, there is the commands that occur same time and should
> be fixed order.
> {code:bash}
> # getfileinfo before open
> 2024-07-01 19:27:12,886 INFO FSNamesystem.audit: allowed=true ugi=xx-xx
> (auth:TOKEN) via hive/[email protected] (auth:TOKEN)
> ip=/10.xx.xxx.xxx cmd=getfileinfo
> src=/user/hive/warehouse/a.db/b/date_id=2024-06-16/part-xxxx.gz.parquet
> dst=null perm=null proto=rpc
> 2024-07-01 19:27:12,886 INFO FSNamesystem.audit: allowed=true ugi=xx-xx
> (auth:TOKEN) via hive/[email protected] (auth:TOKEN)
> ip=/10.xx.xxx.xxx cmd=open
> src=/user/hive/warehouse/a.db/b/date_id=2024-06-16/part-xxxx.gz.parquet
> dst=null perm=null proto=rpc
> # create before setPermission
> # this examples have not exactly same time, but could be same when rate
> factor is high enough
> 2024-07-01 17:25:30,867 INFO FSNamesystem.audit: allowed=true
> [email protected] (auth:KERBEROS) ip=/10.xxx.xx.xxx cmd=create
> src=/user/yy-yy/.staging/job_1716867484406_290658/job.xml dst=null
> perm=yy-yy:zzz:rw-rw-r-- proto=rpc
> 2024-07-01 17:25:30,871 INFO FSNamesystem.audit: allowed=true
> [email protected] (auth:KERBEROS) ip=/10.xxx.xx.xxx
> cmd=setPermission
> src=/user/yy-yy/.staging/job_1716867484406_290658/job.xml dst=null
> perm=yy-yy:zzz:rw-r--r-- proto=rpc
> {code}
> h2. How much improve test accuracy when use stable sort?
> - Using stable sort, wrong ordered simulation could not occur.
> -- I fixed code to use line number of audit log in sorting criteria.
> -- Because it is not simple to change DelayQueue data structure to use
> stable sort
> - Multi threading or client-ip-based-partitioning could be occur in real
> production and affect log order, but not critical.
> -- Client-ip-based-partitioning is even similar to real production choas log
> order
> - This is the graph that
> -- use real production hdfs audit log
> -- compare stable sort and unstable sort with different rate(1~4)
> -- use 5 minutes simulation(in rate 1) ip-based-partitioned-audit-log
> -- shows total valid command, total read latency, total write latency
> !image-2024-09-19-16-40-34-947.png|width=615,height=740!
> - Conclusion
> -- Stable sort ensure almost similar valid command number.
> -- Unstable sort sometimes extremely high latency because of wrong ordered
> log simulation.
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