Please see the linked JIRA for more information.
Martin Gencur <mgencur> made a comment on jira ISPN-3618 Jakub, can you check which encoding is configured in the database you're testing (with admins)? If it's not UTF, then it might be a problem of the database server's configuration. AFAIK, Infinispan needs UTF-8.
Jakub Markos <jmarkos> made a comment on jira ISPN-3618 The encoding is SQL_Latin1_General_CP1_CI_AS . Microsoft SQL servers don't even support UTF-8.
Martin Gencur <mgencur> made a comment on jira ISPN-3618 Yeah, the Microsoft SQL server does not seem to support UTF-8. It means that for string-based cache stores only "String" can be used as a key. The other types (coverted with Key2StringMapper) cannot. AFAIK, it also means that string-based cache store cannot be used at all if data is stored via HotRod. That's because HotRod does not send plain strings.
Martin Gencur <mgencur> made a comment on jira ISPN-3618 The solution/workaround could be to convert the UTF-8 data to UCS-2 which is supported by MS SQL server, but only if MS SQL server is used. Otherwise UTF-8 could remain.
*** Bug 1022916 has been marked as a duplicate of this bug. ***
Microsoft suggests storing the actual UTF-8 data on the server using the BINARY/VARBINARY/IMAGE columns, but that has its downsides too. http://support.microsoft.com/kb/232580
I was supposed to check with upstream Infinispan whether this has been fixed. I've just looked at the code of DefaultTwoWayKey2StringMapper and there hasn't been any change in two years. This means that the data is still prepended with '\uFEFF' which won't work with MS SQL Server.