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https://issues.apache.org/jira/browse/HBASE-17730?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16242991#comment-16242991
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Mike Drob commented on HBASE-17730:
-----------------------------------
Recording some upgrade experience here for future inclusion in the docs... Was
helping a user migrate from HBase 1.2 coprocessors to HBase 2.0 coprocessors
and they had {{extends BaseRegionObserver}} before. Initially, we tried
changing that to {{implements RegionObserver, Coprocessor}} based on the
original interfaces in 1.2
Later we figured out that we need to both {{implements RegionObserver,
RegionCoprocessor}} and add the method
{code}
@Override
public Optional<RegionObserver> getRegionObserver() {
return Optional.of(this);
}
{code}
After that, it seems like everything is working as it was before. Should have
notes like this in the eventual migration guide.
> Migration to 2.0 for coprocessors
> ----------------------------------
>
> Key: HBASE-17730
> URL: https://issues.apache.org/jira/browse/HBASE-17730
> Project: HBase
> Issue Type: Sub-task
> Components: documentation, migration
> Reporter: Appy
> Priority: Blocker
> Fix For: 2.0.0-beta-1
>
>
> Jiras breaking coprocessor compatibility should be marked with component '
> Coprocessor', and label 'incompatible'.
> Close to releasing 2.0, we should go through all such jiras and write down
> steps for migrating coprocessor easily.
> The idea is, it might be very hard to fix coprocessor breakages by reverse
> engineering errors, but will be easier we suggest easiest way to fix
> breakages resulting from each individual incompatible change.
> For eg. HBASE-17312 is incompatible change. It'll result in 100s of errors
> because BaseXXXObserver classes are gone and will probably result in a lot of
> confusion, but if we explicitly mention the fix which is just one line change
> - replace "Foo extends BaseXXXObserver" with "Foo implements XXXObserver" -
> it makes it very easy.
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