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https://issues.apache.org/jira/browse/HBASE-21247?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16659153#comment-16659153
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Sean Busbey commented on HBASE-21247:
-------------------------------------
Catching a {{Throwable}} is v dangerous and IMHO not justified for a code path
that is essentially just handling config fallback. Also why do another lookup
on WAL_PROVIDER instead of just passing in DEFAULT_WAL_PROVIDER?
With the shift to taking a {{Class<? extends WALProvider>}} for the default
then the call in {{getMetaProvider}} can just look like this:
{code}
provider = createProvider(getProviderClass(META_WAL_PROVIDER,
this.provider.class));
{code}
This makes it very clear that should META_WAL_PROVIDER be undefined we'll use
the same class as the non-meta wal provider. It also coincidentally avoids
doing repeated look ups on the WAL_PROVIDER config.
We can remove the {{DEFAULT_WAL_PROVIDER}} constant entirely and update the
WALFactory constructor that creates {{this.provider}} to use
{{Providers.defaultProvider.clazz}} directly.
Much nicer, no?
> Custom WAL Provider cannot be specified by configuration whose value is
> outside the enums in Providers
> ------------------------------------------------------------------------------------------------------
>
> Key: HBASE-21247
> URL: https://issues.apache.org/jira/browse/HBASE-21247
> Project: HBase
> Issue Type: Bug
> Reporter: Ted Yu
> Assignee: Ted Yu
> Priority: Major
> Fix For: 3.0.0
>
> Attachments: 21247.v1.txt, 21247.v2.txt, 21247.v3.txt, 21247.v4.tst,
> 21247.v4.txt, 21247.v5.txt, 21247.v6.txt, 21247.v7.txt, 21247.v8.txt,
> 21247.v9.txt
>
>
> Currently all the WAL Providers acceptable to hbase are specified in
> Providers enum of WALFactory.
> This restricts the ability for additional WAL Providers to be supplied - by
> class name.
> This issue fixes the bug by allowing the specification of new WAL Provider
> class name using the config "hbase.wal.provider".
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