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https://issues.apache.org/jira/browse/HADOOP-16836?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17060426#comment-17060426
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Wei-Chiu Chuang commented on HADOOP-16836:
------------------------------------------

Updated target version. Unless I am wrong, this is also a blocker for Hadoop 
3.3.0.

[~brahma] fyi.

> Bug in widely-used helper function caused valid configuration value to fail 
> on multiple tests, causing build failure
> --------------------------------------------------------------------------------------------------------------------
>
>                 Key: HADOOP-16836
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16836
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: common
>    Affects Versions: 3.3.0, 3.2.1
>            Reporter: Ctest
>            Priority: Blocker
>              Labels: configuration, easyfix, patch, test
>         Attachments: HADOOP-16836-000.patch, HADOOP-16836-000.patch
>
>
> Test helper function 
> `org.apache.hadoop.io.file.tfile.TestTFileByteArrays#readRecords(org.apache.hadoop.fs.FileSystem,
>  org.apache.hadoop.fs.Path, int, org.apache.hadoop.conf.Configuration)` 
> (abbreviate as `readRecords()` below) are called in 4 actively-used tests 
> below:
>  
> {code:java}
> org.apache.hadoop.io.file.tfile.TestTFileStreams#testOneEntryMixedLengths1
> org.apache.hadoop.io.file.tfile.TestTFileStreams#testOneEntryUnknownLength
> org.apache.hadoop.io.file.tfile.TestTFileLzoCodecsStreams#testOneEntryMixedLengths1
> org.apache.hadoop.io.file.tfile.TestTFileLzoCodecsStreams#testOneEntryUnknownLength{code}
>  
> These tests first call 
> `org.apache.hadoop.io.file.tfile.TestTFileStreams#writeRecords(int count, 
> boolean knownKeyLength, boolean knownValueLength, boolean close)` to write 
> `key-value` pair records in a `TFile` object, then call the helper function 
> `readRecords()` to assert the `key` part and the `value` part of `key-value` 
> pair records stored matched with what they wrote perviously. The `value` 
> parts of `key-value` pairs from these tests are hardcode strings with a 
> length of 6.
> Assertions in `readRecords()` are directly related to the value of the 
> configuration parameter `tfile.io.chunk.size`. The formal definition of 
> `tfile.io.chunk.size` is "Value chunk size in bytes. Default to 1MB. Values 
> of the length less than the chunk size is guaranteed to have known value 
> length in read time (See also 
> TFile.Reader.Scanner.Entry.isValueLengthKnown())".
> When `tfile.io.chunk.size` is configured to a value less than the length of 
> the `value` part of the `key-value` pairs from these 4 tests, these tests 
> will fail, even though the configured value for `tfile.io.chunk.size` is 
> correct in semantic.
>  
> *Consequence*
> At least 4 actively-used tests failed on correctly configured parameters. 
> Tests used `readRecords()` could fail if the length of the hardcoded `value` 
> part they tested is larger than the configured value of 
> `tfile.io.chunk.size`. This caused build failure of Hadoop-Common if these 
> tests are not skipped.
>  
> *Root Cause*
> `readRecords()` used 
> `org.apache.hadoop.io.file.tfile.TFile.Reader.Scanner.Entry#getValueLength()` 
> (abbreviate as `getValueLength()` below) to get the full length of the 
> `value` part in the `key-value` pair. But `getValueLength()` can only get the 
> full length of the `value` part when the full length is less than 
> `tfile.io.chunk.size`, otherwise, `getValueLength()` throws an exception, 
> causing `readRecords()` to fail, and thus resulting in failures in the 
> aforementioned 4 tests. This is because `getValueLength()` do not know the 
> full length of the `value` part when `value` part's size is larger than 
> `tfile.io.chunk.size`.
>  
> *Fixes*
> `readRecords()` should instead call 
> `org.apache.hadoop.io.file.tfile.TFile.Reader.Scanner.Entry#getValue(byte[])` 
> (abbreviate as `getValue()` below), which returns the correct full length of 
> the `value` part despite whether the `value` length is larger than 
> `tfile.io.chunk.size`.



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