Basho Product Alert: Serious Bug with Maps in upgrade to 2.0.4
russell.brown at me.com
Wed Jan 21 04:33:30 EST 2015
Basho Engineering has uncovered a bug in the new Map and Set data structures  in Riak version 2.0.4. This code incorrectly handles a format upgrade resulting in the inability to read maps written by pre-2.0.4 releases on a 2.0.4 node. The issue manifests as a crash message in the log, and a timeout reading the map.
We’re working on a fix.
If you have Map data written pre-2.0.4 please hold off upgrading to 2.0.4. If you have no existing Map data it is safe to use 2.0.4.
Sadly, downgrading from 2.0.4 to 2.0.2 will be an issue if you have written Map data in 2.0.4, as 2.0.2 will not be able to read the 2.0.4 Maps, due to backwards incompatibility also.
The plan is as follows:
1. Address the compatibility issue so riak-2.0.5 will be able to read prior version map data, making upgrades safe
2. Provide a command you can run from the console to downgrade any map data from 2.0.4+ to a version readable by 2.0.x<4. Making downgrades possible
Again, we’re extremely sorry, and we’re working on a fix right now, and reviewing the processes that lead to this issue.
There will soon be a Riak-2.0.5 release for hose wishing to upgrade from earlier 2.0.x releases, please wait for that.
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