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https://issues.apache.org/jira/browse/HBASE-15638?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15239659#comment-15239659
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stack commented on HBASE-15638:
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bq. we could make a module that creates a shaded/relocated version of the
protobuf version we want to use. Then we could use those relocated packages for
our internal use.
Is that what this patch does [~busbey]? hbase-protocol is the only place we
have a dependency on protobuf and it does the relocation that downstream
modules then make use of.
bq. That way, FanOutOneBlockAsyncDFSOutputSaslHelper can use the protobuf
version from hadoop like normal.
Hmm... Thanks for this. The 'fix' then would be to use the pb that hdfs has
pulled in... which would be com.google.protobuf. That'd work.
bq. It's probably still worth putting it in a module, just so the code is more
isolated (presuming we eventually want it in HDFS).
I could do this. I always thought that we could have a WAL module... but we'd
be talking of an explicit asyncwal module in this case?
> Shade protobuf
> --------------
>
> Key: HBASE-15638
> URL: https://issues.apache.org/jira/browse/HBASE-15638
> Project: HBase
> Issue Type: Bug
> Components: Protobufs
> Reporter: stack
> Attachments: as.far.as.server.patch
>
>
> Shade protobufs so we can move to a different version without breaking the
> world. We want to get up on pb3 because it has unsafe methods that allow us
> save on copies; it also has some means of dealing with BBs so we can pass it
> offheap DBBs. We'll probably want to change PB3 to open it up some more too
> so we can stay offheap as we traverse PB. This issue comes of [~anoop.hbase]
> and [~ram_krish]'s offheaping of the readpath work.
> This change is mostly straight-forward but there are some tricky bits:
> # How to interface with HDFS? It wants its ByteStrings. Here in particular
> in FanOutOneBlockAsyncDFSOutputSaslHelper:
> {code}
> if (payload != null) {
> builder.setPayload(ByteString.copyFrom(payload));
> }
> {code}
> # [~busbey] also points out that we need to take care of endpoints done as
> pb. Test at least.
> Let me raise this one on the dev list too.
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