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Jonathan Hsieh commented on HBASE-6710: --------------------------------------- +1 for ted's suggestion. > 0.92/0.94 compatibility issues due to HBASE-5206 > ------------------------------------------------ > > Key: HBASE-6710 > URL: https://issues.apache.org/jira/browse/HBASE-6710 > Project: HBase > Issue Type: Bug > Reporter: Gregory Chanan > Assignee: Gregory Chanan > Priority: Critical > Fix For: 0.94.2 > > Attachments: HBASE-6710-v3.patch > > > HBASE-5206 introduces some compatibility issues between {0.94,0.94.1} and > {0.92.0,0.92.1}. The release notes of HBASE-5155 describes the issue > (HBASE-5206 is a backport of HBASE-5155). > I think we can make 0.94.2 compatible with both {0.94.0,0.94.1} and > {0.92.0,0.92.1}, although one of those sets will require configuration > changes. > The basic problem is that there is a znode for each table > "zookeeper.znode.tableEnableDisable" that is handled differently. > On 0.92.0 and 0.92.1 the states for this table are: > [ disabled, disabling, enabling ] or deleted if the table is enabled > On 0.94.1 and 0.94.2 the states for this table are: > [ disabled, disabling, enabling, enabled ] > What saves us is that the location of this znode is configurable. So the > basic idea is to have the 0.94.2 master write two different znodes, > "zookeeper.znode.tableEnableDisabled92" and > "zookeeper.znode.tableEnableDisabled94" where the 92 node is in 92 format, > the 94 node is in 94 format. And internally, the master would only use the > 94 format in order to solve the original bug HBASE-5155 solves. > We can of course make one of these the same default as exists now, so we > don't need to make config changes for one of 0.92 or 0.94 clients. I argue > that 0.92 clients shouldn't have to make config changes for the same reason I > argued above. But that is debatable. > Then, I think the only question left is the question of how to bring along > the {0.94.0, 0.94.1} crew. A {0.94.0, 0.94.1} client would work against a > 0.94.2 cluster by just configuring "zookeeper.znode.tableEnableDisable" in > the client to be whatever "zookeeper.znode.tableEnableDisabled94" is in the > cluster. A 0.94.2 client would work against both a {0.94.0, 0.94.1} and > {0.92.0, 0.92.1} cluster if it had HBASE-6268 applied. About rolling upgrade > from {0.94.0, 0.94.1} to 0.94.2 -- I'd have to think about that. Do the > regionservers ever read the tableEnableDisabled znode? > On the mailing list, Lars H suggested the following: > "The only input I'd have is that format we'll use going forward will not have > a version attached to it. > So maybe the 92 version would still be called > "zookeeper.znode.tableEnableDisable" and the new node could have a different > name "zookeeper.znode.tableEnableDisableNew" (or something)." -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira