The Usage Statistics doesn't show up in Questions when Confluence is installed in Oracle 11g

015-03-16 19:19:14,703 ERROR [http-bio-8090-exec-2950] [common.error.jersey.ThrowableExceptionMapper] toResponse Uncaught exception thrown by REST service: StatementCallback; uncategorized SQLException for SQL [select count("tmp"."creator")
from ((select "CONTENT"."CREATOR" "creator"
from "CONTENT" "CONTENT"
where "CONTENT"."PLUGINKEY" in ('com.atlassian.confluence.plugins.confluence-questions:question', 'com.atlassian.confluence.plugins.confluence-questions:answer', 'com.atlassian.confluence.plugins.confluence-questions:comment') and "CONTENT"."PREVVER" is null)
union
(select "AO_B1DBB9_VOTE"."USER_KEY"
from "AO_B1DBB9_VOTE" "AO_B1DBB9_VOTE")) "tmp"]; SQL state [72000]; error code [12704]; ORA-12704: character set mismatch
; nested exception is java.sql.SQLException: ORA-12704: character set mismatch

 -- url: /confluence/rest/questions/1.0/statistics | userName: a4078 | referer: https://poc.amberroad.com/confluence/questions/stats
org.springframework.jdbc.UncategorizedSQLException: StatementCallback; uncategorized SQLException for SQL [select count("tmp"."creator")
from ((select "CONTENT"."CREATOR" "creator"
from "CONTENT" "CONTENT"
where "CONTENT"."PLUGINKEY" in ('com.atlassian.confluence.plugins.confluence-questions:question', 'com.atlassian.confluence.plugins.confluence-questions:answer', 'com.atlassian.confluence.plugins.confluence-questions:comment') and "CONTENT"."PREVVER" is null)
union
(select "AO_B1DBB9_VOTE"."USER_KEY"
from "AO_B1DBB9_VOTE" "AO_B1DBB9_VOTE")) "tmp"]; SQL state [72000]; error code [12704]; ORA-12704: character set mismatch
; nested exception is java.sql.SQLException: ORA-12704: character set mismatch

	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
	at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:407)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:458)
	at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:466)
	at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:474)
	at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:479)
	at org.springframework.jdbc.core.JdbcTemplate.queryForInt(JdbcTemplate.java:488)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.ContentTypeStatisticRepository.countUnion(ContentTypeStatisticRepository.java:154)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.ContentTypeStatisticRepository.getTotalContributors(ContentTypeStatisticRepository.java:111)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.ContentTypeStatisticRepository.getTotalContributors(ContentTypeStatisticRepository.java:97)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.CacheStatisticRepository$2.get(CacheStatisticRepository.java:76)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.CacheStatisticRepository$2.get(CacheStatisticRepository.java:72)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.CacheStatisticRepository.getFromCache(CacheStatisticRepository.java:201)
	at com.atlassian.confluence.plugins.questions.contenttype.repository.CacheStatisticRepository.getTotalContributors(CacheStatisticRepository.java:71)
	at com.atlassian.confluence.plugins.questions.service.StatisticServiceImpl$GetTotalContributersDTO.apply(StatisticServiceImpl.java:146)
	at com.atlassian.confluence.plugins.questions.service.StatisticServiceImpl$GetTotalContributersDTO.apply(StatisticServiceImpl.java:140)
	at com.atlassian.confluence.plugins.questions.service.StatisticServiceImpl.getStatistics(StatisticServiceImpl.java:74)
	at com.atlassian.confluence.plugins.questions.service.StatisticServiceImpl.getGlobalStatistics(StatisticServiceImpl.java:58)
	....
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: ORA-12704: character set mismatch

	at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:445)
	at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:396)
	...
	at com.mchange.v2.c3p0.impl.NewProxyStatement.executeQuery(NewProxyStatement.java:35)
	at org.springframework.jdbc.core.JdbcTemplate$1QueryStatementCallback.doInStatement(JdbcTemplate.java:443)
	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:396)
	... 272 more