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ASF GitHub Bot logged work on HADOOP-17461: ------------------------------------------- Author: ASF GitHub Bot Created on: 17/Jun/22 18:31 Start Date: 17/Jun/22 18:31 Worklog Time Spent: 10m Work Description: steveloughran commented on PR #4352: URL: https://github.com/apache/hadoop/pull/4352#issuecomment-1159135030 we need a single IOStatisticsContext for all FS instances, so that a task reading from one fs and writing to another would have the stats updated from both actions. And it needs to be in hadoop-common, just like the common audit context, so that code can compile and link against it even without having hadoop-aws or hadoop-azure on the classpath. Making the context a weak ref map ensures that GCs will trigger cleanup. This would lose stats, but not while any stream was active, *or if some code picked up a reference to the thread stats before executing work. That is what I plan to do in spark; we will grab that ref before starting the work, and after it is finished, take a snapshot of it. Oh, and reset the values before work starts -we need that context there too. Issue Time Tracking ------------------- Worklog Id: (was: 782504) Time Spent: 1h 20m (was: 1h 10m) > Add thread-level IOStatistics Context > ------------------------------------- > > Key: HADOOP-17461 > URL: https://issues.apache.org/jira/browse/HADOOP-17461 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs, fs/azure, fs/s3 > Affects Versions: 3.3.1 > Reporter: Steve Loughran > Assignee: Mehakmeet Singh > Priority: Major > Labels: pull-request-available > Time Spent: 1h 20m > Remaining Estimate: 0h > > For effective reporting of the iostatistics of individual worker threads, we > need a thread-level context which IO components update. > * this contact needs to be passed in two background thread forming work on > behalf of a task. > * IO Components (streams, iterators, filesystems) need to update this context > statistics as they perform work > * Without double counting anything. > I imagine a ThreadLocal IOStatisticContext which will be updated in the > FileSystem API Calls. This context MUST be passed into the background threads > used by a task, so that IO is correctly aggregated. > I don't want streams, listIterators &c to do the updating as there is more > risk of double counting. However, we need to see their statistics if we want > to know things like "bytes discarded in backwards seeks". And I don't want to > be updating a shared context object on every read() call. > If all we want is store IO (HEAD, GET, DELETE, list performance etc) then the > FS is sufficient. > If we do want the stream-specific detail, then I propose > * caching the context in the constructor > * updating it only in close() or unbuffer() (as we do from S3AInputStream to > S3AInstrumenation) > * excluding those we know the FS already collects. -- This message was sent by Atlassian Jira (v8.20.7#820007) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org