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https://issues.apache.org/jira/browse/HADOOP-18190?focusedWorklogId=795163&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-795163
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ASF GitHub Bot logged work on HADOOP-18190:
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Author: ASF GitHub Bot
Created on: 26/Jul/22 07:44
Start Date: 26/Jul/22 07:44
Worklog Time Spent: 10m
Work Description: ahmarsuhail commented on PR #4458:
URL: https://github.com/apache/hadoop/pull/4458#issuecomment-1195125809
thanks for reviewing @steveloughran, looks like checkstyle is happy now
Issue Time Tracking
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Worklog Id: (was: 795163)
Time Spent: 3h 50m (was: 3h 40m)
> s3a prefetching streams to collect iostats on prefetching operations
> --------------------------------------------------------------------
>
> Key: HADOOP-18190
> URL: https://issues.apache.org/jira/browse/HADOOP-18190
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Affects Versions: 3.4.0
> Reporter: Steve Loughran
> Assignee: Ahmar Suhail
> Priority: Major
> Labels: pull-request-available
> Time Spent: 3h 50m
> Remaining Estimate: 0h
>
> There is a lot more happening in reads, so there's a lot more data to collect
> and publish in IO stats for us to view in a summary at the end of processes
> as well as get from the stream while it is active.
> Some useful ones would seem to be:
> counters
> * is in memory. using 0 or 1 here lets aggregation reports count total #of
> memory cached files.
> * prefetching operations executed
> * errors during prefetching
> gauges
> * number of blocks in cache
> * total size of blocks
> * active prefetches
> + active memory used
> duration tracking count/min/max/ave
> * time to fetch a block
> * time queued before the actual fetch begins
> * time a reader is blocked waiting for a block fetch to complete
> and some info on cache use itself
> * number of blocks discarded unread
> * number of prefetched blocks later used
> * number of backward seeks to a prefetched block
> * number of forward seeks to a prefetched block
> the key ones I care about are
> # memory consumption
> # can we determine if cache is working (reads with cache hit) and when it is
> not (misses, wasted prefetches)
> # time blocked on executors
> The stats need to be accessible on a stream even when closed, and aggregated
> into the FS. once we get per-thread stats contexts we can publish there too
> and collect in worker threads for reporting in task commits
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