Member since
01-05-2016
21
Posts
11
Kudos Received
1
Solution
My Accepted Solutions
| Title | Views | Posted |
|---|---|---|
| 9951 | 01-08-2019 01:29 AM |
01-08-2019
01:29 AM
1 Kudo
Hello Somnath, This is a known issue and recorded in https://issues.apache.org/jira/browse/KYLIN-3607. The workaround is: "After I added hbase-hadoop2-compat-*.jar and hbase-hadoop-compat-*.jar into $KYLIN_HOME/spark/jars, then it worked." The two jar files can be found in HBase's lib folder; As you already make the Spark assembly jar, you may need to re-package that and then upload to HDFS. After doting that, just resume Kylin's fail job, it will re-submit the spark job. Ideally, it will be okay.
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01-07-2019
10:19 AM
1 Kudo
Hello Somnath, Kylin 2.5 needs Spark 2.1 (not Spark 2.2); The guide for Kylin 2.5 is in https://kylin.apache.org/docs/tutorial/cube_spark.html; (the link you provided above is the tutorial for Kylin 2.0, not matched with your version); Please try this: 1) build the assembly jar from the spark 2.1 that shipped with Kylin; 2) copy the sample cube to a new one, edit it, and then change the "engine type" to "spark"; Just take a try, it should be minor issue as many users are using Spark now.
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01-05-2019
09:55 AM
What's the version of Kylin and HDP that you're running? Please provide the full error trace for analysis. Also, please set SPARK_HOME to KYLIN_HOME/spark before starting up Kylin. Building Cube
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01-05-2016
08:38 AM
(sorry for splitting my comments into several posts, as this forum doesn't allow comment more than 600 characters... )
Welcome to join our dev mailing list dev@kylin.apache.org (send to dev-subscribe@kylin.apache.org to subscribe), there are a lot of discussions; Regards, shaofengshi@apache.org
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01-05-2016
08:38 AM
1 Kudo
6. "The more segments the slower performance can get (more scans)" comment: Yes, usually we suggest user to control the segment number e.g no more than 10, to gain a better query performance; But if the partition date column appears in the filtering condition, Kylin can smartly skip those unrelated segments, for this case, the segment number doesn't matter.
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01-05-2016
08:32 AM
1 Kudo
5. “MDX adoption is very low, therefore its not currently supported” comment: If anyone want to do MDX using Kylin, we suggest try Mondrian, some users has been able to run that successfully, here is a document: https://www.inovex.de/fileadmin/files/Vortraege/2015/big-data-mdx-with-mondrian-and-apache-kylin-sebastien-jelsch-pcm-11-2015.pdf
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01-05-2016
08:30 AM
1 Kudo
3. "Simple measures only (counts, max, min and sum). No custom calcs, ratios, etc." comment: the custom measure support is on the way, and will be released soon: https://issues.apache.org/jira/browse/KYLIN-976 4. "16 dimensions seem like an upper limit, but that's not confirmed." comment: the real upper limit is 64, but usually we suggest user to control the cube expansion rate by picking no more than 20 dimensions;
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01-05-2016
08:29 AM
1 Kudo
2. "MR overhead with building cubes (“query yesterdays data”). Lots of shuffling. Does aggregations on the reduce side" comment: you're right, as-is cube algorithm may cause a lot of shuffling among the hadoop nodes; We have realized this and introduced a new algorithm called "fast-cubing", which will do mapper side aggregation, aming to reduce the network IO and reduce the MR time; it will be released in Kylin v2.0.
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01-05-2016
08:29 AM
1 Kudo
Hello ccasano, This is Shaofeng from Apache Kylin community; Thanks for the trial and compose such a good summary on Kylin, we think it is very helpful for end users; Here I want to add some comments regarding some of your questions: 1. "base level data resides in Hive and not the cube. The cube contains only aggregate data." comment: you're correct; so far Kylin doesn't save the raw data; but it has been under development; In a future release, user will be able to query both aggregated data as well as raw data from Kylin: https://issues.apache.org/jira/browse/KYLIN-1122
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