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https://issues.apache.org/jira/browse/CRUNCH-368?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13956592#comment-13956592
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Chao Shi commented on CRUNCH-368:
---------------------------------
bq. But in the snippet you provided, wouldn't comparing to a non-IntWritable
type fail w/a ClassCastException?
Yes, it will fail.
Before this patch, I think the compareTo will fail if v1 and v2 are of
different type. Is it intended?
{code}
Writable v1 = ta.get(index);
Writable v2 = tb.get(index);
if (v1 != v2 && (v1 != null && !v1.equals(v2))) {
if (v1 instanceof WritableComparable && v2 instanceof
WritableComparable) {
int cmp = ((WritableComparable) v1).compareTo((WritableComparable)
v2);
if (cmp != 0) {
return order * cmp;
}
} else {
int cmp = v1.hashCode() - v2.hashCode();
if (cmp != 0) {
return order * cmp;
}
}
}
{code}
> TupleWritable.Comparator
> ------------------------
>
> Key: CRUNCH-368
> URL: https://issues.apache.org/jira/browse/CRUNCH-368
> Project: Crunch
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.10.0, 0.8.3
> Reporter: Chao Shi
> Assignee: Chao Shi
> Attachments: crunch-368 benchmark.pdf, crunch-368.patch, gen_data.py
>
>
> This patch should improve comparison performance on TupleWritables. It saves
> the deserialization overhead. It is particularly useful when the input tuple
> are large, e.g. contains long strings.
> Please note that this changes the binary format of TupleWritable. It adds a
> var-int indicating size of field after each type code. This is a limitation
> of the writable system. We do not know the size of each field until fully
> desalinizing it.
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