[
https://issues.apache.org/jira/browse/HBASE-5204?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13192267#comment-13192267
]
stack commented on HBASE-5204:
------------------------------
Yes, agree, adding patch to trunk would be silly. Lets drop it. The codes
should never have been changed. Hopefully your warning...
{code}
1231985 stack
////////////////////////////////////////////////////////////////////////////
1231985 stack // WARNING: Please do not insert, remove or swap any
line in this static //
1231985 stack // block. Doing so would change or shift all the codes
used to serialize //
1231985 stack // objects, which makes backwards compatibility very
hard for clients. //
1231985 stack // New codes should always be added at the end. Code
removal is //
1231985 stack // discouraged because code is a short now.
//
1231985 stack
////////////////////////////////////////////////////////////////////////////
{code}
.... will help w/ that.
Can we check in an asynchbase unit test that exercises all apis you need so we
fail fast in case we mess up again (HBase has 16 committers now and hard to
have them all on message)
> Backward compatibility fixes for 0.92
> -------------------------------------
>
> Key: HBASE-5204
> URL: https://issues.apache.org/jira/browse/HBASE-5204
> Project: HBase
> Issue Type: Bug
> Components: ipc
> Reporter: Benoit Sigoure
> Assignee: Benoit Sigoure
> Priority: Blocker
> Labels: backwards-compatibility
> Fix For: 0.92.0
>
> Attachments:
> 0001-Add-some-backward-compatible-support-for-reading-old.patch,
> 0002-Make-sure-that-a-connection-always-uses-a-protocol.patch,
> 0003-Change-the-code-used-when-serializing-HTableDescript.patch, 5204-92.txt,
> 5204-trunk.txt, 5204.addendum
>
>
> Attached are 3 patches that are necessary to allow compatibility between
> HBase 0.90.x (and previous releases) and HBase 0.92.0.
> First of all, I'm well aware that 0.92.0 RC4 has been thumbed up by a lot of
> people and would probably wind up being released as 0.92.0 tomorrow, so I
> sincerely apologize for creating this issue so late in the process. I spent
> a lot of time trying to work around the quirks of 0.92 but once I realized
> that with a few very quasi-trivial changes compatibility would be made
> significantly easier, I immediately sent these 3 patches to Stack, who
> suggested I create this issue.
> The first patch is required as without it clients sending a 0.90-style RPC to
> a 0.92-style server causes the server to die uncleanly. It seems that 0.92
> ships with {{\-XX:OnOutOfMemoryError="kill \-9 %p"}}, and when a 0.92 server
> fails to deserialize a 0.90-style RPC, it attempts to allocate a large buffer
> because it doesn't read fields of 0.90-style RPCs properly. This allocation
> attempt immediately triggers an OOME, which causes the JVM to die abruptly of
> a {{SIGKILL}}. So whenever a 0.90.x client attempts to connect to HBase, it
> kills whichever RS is hosting the {{\-ROOT-}} region.
> The second patch fixes a bug introduced by HBASE-2002, which added support
> for letting clients specify what "protocol" they want to speak. If a client
> doesn't properly specify what protocol to use, the connection's {{protocol}}
> field will be left {{null}}, which causes any subsequent RPC on that
> connection to trigger an NPE in the server, even though the connection was
> successfully established from the client's point of view. The fix is to
> simply give the connection a default protocol, by assuming the client meant
> to speak to a RegionServer.
> The third patch fixes an oversight that slipped in HBASE-451, where a change
> to {{HbaseObjectWritable}} caused all the codes used to serialize
> {{Writables}} to shift by one. This was carefully avoided in other changes
> such as HBASE-1502, which cleanly removed entries for {{HMsg}} and
> {{HMsg[]}}, so I don't think this breakage in HBASE-451 was intended.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
