Encoding of CLOB (XWD_CONTENT) after Oracle DB Upgrade causes ? instead of special chars

Help / Discuss
1

We upgraded our Oracle DB 11g to 12c (with pluggable Database). No encoding or languagesettings were changed in XWiki or the Database.
XWiki is no longer able to display special Characters /German Umlaute (ä,ö,ü) and prints an “?” instead. The special characters are displayed correctly in the database. The problem appears only with the content of a page (databasetable XWIKI.XWIKIDOC, column XWD_CONTENT), which is of datatype “CLOB”.
At the rest of the HTML-page and the page titles (column XWD_CONTENT, type “VARCHAR2”) the special characters are displayed correctly.

image

Versions:

Oracle DB 12.2.0.1
Apache Tomcat 9.0.43
Xwiki 12.10.9 (same error with 5.0.3)
Linux Red Hat 7

These parameters are the same in both environments:

NLS_CHARACTERSET=WE8ISO8859P15
nls_length_semantics=CHAR
LANG=de_DE.UTF-8
NLS_LANGUAGE=AMERICAN
NLS_TERRITORY=AMERICA

These are our current settings:

1) html 

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

2) hibernate.cfg.xml 

 <property name="hibernate.connection.url">jdbc:oracle:thin:@host:port/servicename-pluggable-db</property>
    <property name="hibernate.connection.username">xwiki</property>
    <property name="hibernate.connection.password">xxxxxxxx</property>
    <property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
    <property name="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</property>
    <property name="hibernate.connection.SetBigStringTryClob">true</property>
    <property name="hibernate.jdbc.batch_size">0</property>
    <property name="hibernate.jdbc.use_streams_for_binary">false</property>
    <property name="hibernate.dbcp.poolPreparedStatements">true</property>
    <property name="hibernate.dbcp.maxOpenPreparedStatements">20</property>

    <property name="hibernate.connection.charSet">UTF-8</property>
    <property name="hibernate.connection.useUnicode">true</property>
    <property name="hibernate.connection.characterEncoding">utf8</property>

    <mapping resource="xwiki.oracle.hbm.xml"/>
    <mapping resource="feeds.oracle.hbm.xml"/>
    <mapping resource="instance.hbm.xml"/>
    <mapping resource="notification-filter-preferences.hbm.xml"/>
    <mapping resource="mailsender.oracle.hbm.xml"/>

3) xwiki.cfg 

xwiki.encoding=UTF-8

4) web.xml

 <param-name>encoding</param-name>
 <param-value>UTF-8</param-value>

5) javaoptions:

CATALINA_OPTS="-Xmx1024m -Dfile.encoding=UTF-8 -Dappserver.home=$CATALINA_HOME -Dappserver.base=$CATALINA_HOME  $XWIKI_OPTS"

6) XWiki AdminTools > XWiki Configuration Check > Encoding Configuration

System environment
•LANG :de_DE.UTF-8
•PWD :/usr/TOMCAT/apache-tomcat-9.0.43/bin

Java command line
•file.encoding: UTF-8
•mail.mime.charset: null

Tomcat configuration
•Procotol HTTP/1.1 has encoding UTF-8

XWiki Configuration
•XWiki encoding used on server: UTF-8
•XWiki encoding from config file: UTF-8

Our question is:

Why are CLOBs interpreted differently when Oracle DB12 is used? Is something missing in hibernate.cfg.xml?

2

I’m really not an Oracle expert, but on Hibernate side I see that a Oracle12cDialect exist, so that might help. That being said setting the dialect is generally not needed in the configuration as Hibernate is supposed to find the right one automatically.

3

Thanks, I tried using “Oracle12cDialect” and also uncommenting the whole dialect line. But in both cases no effect after restart and flushing cache.

4

It really wasn’t a XWiki Problem, but a Oracle DB 12.2 Database Bug (# 26380097).
This is fixed by appying the Patch with the same number.
JDBC has a problem with reading the CLOB entries.