[SPARK-46567][CORE] Remove ThreadLocal for ReadAheadInputStream#44563
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beliefer wants to merge 1 commit intoapache:masterfrom
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[SPARK-46567][CORE] Remove ThreadLocal for ReadAheadInputStream#44563beliefer wants to merge 1 commit intoapache:masterfrom
beliefer wants to merge 1 commit intoapache:masterfrom
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LuciferYang
reviewed
Jan 2, 2024
| // short path - just get one byte. | ||
| return activeBuffer.get() & 0xFF; | ||
| } else { | ||
| byte[] oneByteArray = oneByte.get(); |
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The original writing seems to be to avoid creating byte[1] repeatedly. Have you encountered any bad cases? The new writing seems to create more objects of type byte[1]
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byte[1] is very cheap and change it to local variable could avoid GC.
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We can decorate it with private final if we really need to avoid creating byte[1] repeatedly.
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ping @dongjoon-hyun @srowen cc @sitalkedia |
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The GA failure is unrelated. |
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I agree with this change, I would be surprised if it's even an optimization |
LuciferYang
approved these changes
Jan 3, 2024
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Merged to master. |
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Thank you, @beliefer and all. |
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@srowen @dongjoon-hyun @LuciferYang Thank you！ |
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What changes were proposed in this pull request?
This PR propose to remove
ThreadLocalforReadAheadInputStream.Why are the changes needed?
ReadAheadInputStreamhas a fieldoneBytedeclared asTheadLocal.In fact,
oneByteonly used in read.We can remove it by the way that the closure of local variables in instance methods can provide thread safety guarantees.
On the other hand, the
TheadLocaloccupies a certain amount of space in the heap and there are allocation and GC costs.Does this PR introduce any user-facing change?
'No'.
How was this patch tested?
Exists test cases.
Was this patch authored or co-authored using generative AI tooling?
'No'.