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https://issues.apache.org/jira/browse/AVRO-3094?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17315696#comment-17315696
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radai rosenblatt edited comment on AVRO-3094 at 4/6/21, 5:23 PM:
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Hi [~rskraba],
Thanks for accepting the patch.
I was wondering if a back-port to the 1.9 branch (which I'd be happy to do)
would be accepted - can there be a 1.9.3 with this?
Reason I'm asking as that at LinkedIn we do put the effort into cross-version
compatibility (see [https://github.com/linkedin/avro-util] ) and this issue is
hurting our modernization efforts.
was (Author: radai):
Hi [~rskraba],
Thanks for accepting the patch.
I was wondering if a back-port to the 1.9 branch (which I'd be happy to do)
would be accepted - can there be a 1.9.3 with this?
Reason I'm asking as that at LinkedIn we do put the effort into cross-version
compatibility (see [#https://github.com/linkedin/avro-util]) and this issue is
hurting our modernization efforts.
> performance regression in SpecificData.getForClass() when run with code
> generated by older avro
> -----------------------------------------------------------------------------------------------
>
> Key: AVRO-3094
> URL: https://issues.apache.org/jira/browse/AVRO-3094
> Project: Apache Avro
> Issue Type: Bug
> Components: java
> Affects Versions: 1.9.2, 1.10.2
> Reporter: radai rosenblatt
> Assignee: Radai Rosenblatt
> Priority: Major
> Fix For: 1.11.0
>
> Attachments: model$.png
>
>
> starting with 1.9, avro SpecificData supports per-class MODEL$ definitions,
> and looks for them on specific classes:
> {code:java}
> public static <T> SpecificData getForClass(Class<T> c) {
> if (SpecificRecordBase.class.isAssignableFrom(c)) {
> final Field specificDataField;
> try {
> specificDataField = c.getDeclaredField("MODEL$");
> specificDataField.setAccessible(true);
> return (SpecificData) specificDataField.get(null);
> } catch (NoSuchFieldException e) {
> // Return default instance
> return SpecificData.get(); <======= EXPENSIVE
> } catch (IllegalAccessException e) {
> throw new AvroRuntimeException(e);
> }
> }
> return SpecificData.get();
> } {code}
> when this is run vs specific record classes generated by older avro, which do
> not have field MODEL$ this reslts in a serious performance degradation. we've
> measured the impact on user code to be x3 slower in one case. here's a flame
> graph:
> !model$.png!
> under java 7+ it should be completely possible to cache the existence (or
> lack thereof) of MODEL$ using
> [ClassValue|https://docs.oracle.com/javase/7/docs/api/java/lang/ClassValue.html]
> which would also speed this up when operating on classes generated by more
> modern avro since it would avoid reflection
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