HDFS-16184. De-flake TestBlockScanner#testSkipRecentAccessFile #3329
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💔 -1 overall
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🎊 +1 overall
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🎊 +1 overall
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Can you update the description with the reason for failure and detail about the fix |
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Done @ayushtkn. Thanks |
ayushtkn
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Aug 25, 2021
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Thanx @virajjasani for the fix, I tried reproducing this with a simple sleep, and got the same exception, and with the your fix that got sorted.
Changes LGTM
Will wait some time for Takanobu before pushing this.
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Thanks @ayushtkn for detailed review with cross-verification. |
tasanuma
approved these changes
Aug 25, 2021
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Also, it's good to see two consecutive +1s from QA bot for hadoop-hdfs. Haven't seen more than single +1 from QA build for long time on trunk. |
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Merged. Thanks for your contribution, @virajjasani. Thanks for your review, @ayushtkn.
That's true. QA results seem pretty good recently. Really thanks for fixing several flaky tests, @virajjasani. |
tasanuma
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Aug 25, 2021
Reviewed-by: Ayush Saxena <[email protected]> Signed-off-by: Takanobu Asanuma <[email protected]> (cherry picked from commit 1b9927a)
Thanks @tasanuma for all the reviews!! |
kiran-maturi
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Nov 24, 2021
…e#3329) Reviewed-by: Ayush Saxena <[email protected]> Signed-off-by: Takanobu Asanuma <[email protected]>
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Description of PR
Test TestBlockScanner#testSkipRecentAccessFile is flaky:
Reason for failure:
Thread in VolumnScanner keeps scanning blocks. Before block scan, it executes
TestScanResultHandler#setupand it keeps waiting oninfoobject until main thread intestSkipRecentAccessFile()notifiesinfoobject and sets it'sshouldRunto true for VolumnScanner thread to successfully return fromTestScanResultHandler#setup. Now in main test, we try to assert thatinfo.blocksScannedstays 0 which is only possible if VolumnScanner's block scanner thread does not reachinfo.blocksScanned++point, which cannot be guaranteed always and hence this test is flaky.Fix:
In order to fix this, the main thread in
testSkipRecentAccessFile()should initializeinfo.semas Semaphore (permitting only single thread to take a lock, Mutex) and take a lock by main thread so that until released, block scan thread cannot reach pointinfo.blocksScanned++and hence the test never fails. Before the block scanner thread reach the point of incrementing blocksScanned count, it has to acquire Semaphore and it gets blocked here until main thread releases the lock.How was this patch tested?
Unit tests