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https://issues.apache.org/jira/browse/AVRO-911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13122209#comment-13122209
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Scott Carey commented on AVRO-911:
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For a record that is filled with primitives, re-use is also valuable. There
are a few cases where it does not work so well:
Unions
string/bytes
Maps
In the above cases either it is difficult or unlikely for reuse to be effective
(Unions, Maps) or re-use has small benefit and causes unexpected behavior
(String, Bytes)
What about the following simplification:
* Utf8 is not re-used. (we may be able to re-use the empty string with itself,
or make Utf8 immutable and re-use equivalent copies, but that is not in scope
here)
* byte arrays are not re-used
* maps are not re-used
Arrays and Records, where the biggest gain of re-use is possible, remains.
> remove object reuse from Java APIs
> ----------------------------------
>
> Key: AVRO-911
> URL: https://issues.apache.org/jira/browse/AVRO-911
> Project: Avro
> Issue Type: Improvement
> Components: java
> Reporter: Doug Cutting
> Assignee: Doug Cutting
> Fix For: 1.6.0
>
> Attachments: perf-reuse.patch
>
>
> Avro's Java APIs were designed to permit object reuse when reading with the
> assumption that would provide performance advantages. In particular, the old
> parameter in DatumReader<T>.read(T old, Decoder), the Utf8 class, and the
> GenericArray.peek() method were all designed for this purpose. But I am
> unable to see significant performance improvements when objects are reused.
> I tried modifying Perf.java's GenericTest to reuse records, and its
> StringTest to not reuse Utf8 instances and, in both cases, performance is not
> substantially altered.
> If we were to remove these then issues such as AVRO-803 would disappear.
> Always using java.lang.String instead of Utf8 would remove a lot of user
> confusion.
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