[
https://issues.apache.org/jira/browse/MAPREDUCE-7446?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17748139#comment-17748139
]
ASF GitHub Bot commented on MAPREDUCE-7446:
-------------------------------------------
tomicooler commented on code in PR #5895:
URL: https://github.com/apache/hadoop/pull/5895#discussion_r1276203099
##########
hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/IFile.java:
##########
@@ -433,8 +434,11 @@ public boolean nextRawKey(DataInputBuffer key) throws
IOException {
}
public void nextRawValue(DataInputBuffer value) throws IOException {
+ long targetSizeLong = currentValueLength + (currentValueLength >> 1);
Review Comment:
This overflows like this. Example:
```
class HelloWorld {
public static void main(String[] args) {
int currentValueLength = Integer.MAX_VALUE >> 3;
final int ARRAY_MAX_SIZE = Integer.MAX_VALUE - 8;
for (int i = 0; i < 10; i++) {
long targetSizeLong = currentValueLength + (currentValueLength
>> 1);
int targetSize = (int) Math.min(targetSizeLong, ARRAY_MAX_SIZE);
System.out.println("targetSizeLong: " + targetSizeLong + "
targetSize: " + targetSize);
currentValueLength = targetSize;
}
}
}
```
```
targetSizeLong: 402653182 targetSize: 402653182
targetSizeLong: 603979773 targetSize: 603979773
targetSizeLong: 905969659 targetSize: 905969659
targetSizeLong: 1358954488 targetSize: 1358954488
targetSizeLong: 2038431732 targetSize: 2038431732
targetSizeLong: -1237319698 targetSize: -1237319698
targetSizeLong: -1855979547 targetSize: -1855979547
targetSizeLong: 1510997975 targetSize: 1510997975
targetSizeLong: -2028470334 targetSize: -2028470334
targetSizeLong: 1252261795 targetSize: 1252261795
```
Fix:
```
long targetSizeLong = currentValueLength + (long)(currentValueLength >> 1);
```
With the fix (casting the second part to `long`):
```
targetSizeLong: 402653182 targetSize: 402653182
targetSizeLong: 603979773 targetSize: 603979773
targetSizeLong: 905969659 targetSize: 905969659
targetSizeLong: 1358954488 targetSize: 1358954488
targetSizeLong: 2038431732 targetSize: 2038431732
targetSizeLong: 3057647598 targetSize: 2147483639
targetSizeLong: 3221225458 targetSize: 2147483639
targetSizeLong: 3221225458 targetSize: 2147483639
targetSizeLong: 3221225458 targetSize: 2147483639
targetSizeLong: 3221225458 targetSize: 2147483639
```
BTW allocating 2.14 GB at once, probably will fail anyway.
> NegativeArraySizeException when running MR jobs with large data size
> --------------------------------------------------------------------
>
> Key: MAPREDUCE-7446
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-7446
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Reporter: Peter Szucs
> Assignee: Peter Szucs
> Priority: Major
> Labels: pull-request-available
>
> We are using bit shifting to double the byte array in IFile's
> [nextRawValue|https://github.infra.cloudera.com/CDH/hadoop/blob/bef14a39c7616e3b9f437a6fb24fc7a55a676b57/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/IFile.java#L437]
> method to store the byte values in it. With large dataset it can easily
> happen that we shift the leftmost bit when we are calculating the size of the
> array, which can lead to a negative number as the array size, causing the
> NegativeArraySizeException.
> It would be safer to expand the backing array with a 1.5x factor, and have a
> check not to extend Integer's max value during that.
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