Hello Inigo, This is a good question.
The MySQL metadata store was introduced in Kylin 2.5, as preparation for the no-HBase deployment. There is no evidence to say the MySQL meta store will have better performance, or be more stable. But at least, when HBase has a problem, Kylin service won't be impacted. To migrate to MySQL meta store, you can just 1) dump all metadata to local disk; 2) change Kylin configuration to use MySQL meta store; 3) restore metadata from local disk. MySQL will use two tables to persist the metadata, one for static resources (project, cube, etc), the other for job outputs. But this is transparent to end user. Best regards, Shaofeng Shi 史少锋 Apache Kylin PMC Email: [email protected] Apache Kylin FAQ: https://kylin.apache.org/docs/gettingstarted/faq.html Join Kylin user mail group: [email protected] Join Kylin dev mail group: [email protected] Na Zhai <[email protected]> 于2019年3月17日周日 下午9:28写道： > Hi, Iñigo Martínez. > > > > If you meet too many problems with HBase, you can try to use MySQL > instead. Hope this can help you. > http://kylin.apache.org/docs/tutorial/mysql_metastore.html. In HBase, > there is one metadata_table. In MySQL, there are two metadata_tables. So I > think you can not migrate metadata from HBase to MySQL directly. > > > > > > 发送自 Windows 10 版邮件 <https://go.microsoft.com/fwlink/?LinkId=550986>应用 > > > ------------------------------ > *发件人:* Iñigo Martínez <[email protected]> > *发送时间:* Thursday, March 14, 2019 10:40:27 PM > *收件人:* [email protected] > *主题:* Upgrade from 2.4.1 to 2.6.1 > > Now that 2.6.1 is launched, we are planning an upgrade (with a transition > period and an extensive test plan) from 2.4.1. I have a few questions for > developers and / or system administrators. > > - Do you recommend use mysql as kylin metadata storage? Until now, most of > our problems are related with hbase since we rebuild cubes very frequently > and kylin_metadata table grows a lot. Do you notice performance loss or > gain? Is it stable enough? > > - If using mysql as metadata backend, can we export / import metadata in > order to migrate from hbase to mysql without having rebuild existing cubes? > > Thanks in advance. > >
