You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@kylin.apache.org by "XiaoXiang Yu (JIRA)" <ji...@apache.org> on 2018/11/15 12:00:00 UTC
[jira] [Commented] (KYLIN-3686) Top_N metric code requires cube
storage type to be ID_SHARDED_HBASE, but the Web UI defaults to ID_HBASE
and provides no safeguards against storage type mismatch
[ https://issues.apache.org/jira/browse/KYLIN-3686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16687920#comment-16687920 ]
XiaoXiang Yu commented on KYLIN-3686:
-------------------------------------
Let me check it.
> Top_N metric code requires cube storage type to be ID_SHARDED_HBASE, but the Web UI defaults to ID_HBASE and provides no safeguards against storage type mismatch
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: KYLIN-3686
> URL: https://issues.apache.org/jira/browse/KYLIN-3686
> Project: Kylin
> Issue Type: Improvement
> Components: Measure - TopN, Metadata, Web
> Affects Versions: v2.5.0
> Environment: HDP 2.5.6, Kylin 2.5
> Reporter: Vsevolod Ostapenko
> Assignee: XiaoXiang Yu
> Priority: Major
>
> When new cube is defined via Kylin 2.5 UI, the default cube storage type is set to 0 (ID_HBASE).
> Top_N metric support is currently hard coded to expect cube storage type 2 (ID_SHARDED_HBASE), and it *_does not_* check if the cube storage type is the "sharded HBASE".
> UI provides no safeguards either to prevent a user from defining a cube with Top_N metric that would blow up on the cube building stage with a perplexing stack trace like the following:
> {quote}2018-10-22 16:15:50,388 ERROR [main] org.apache.kylin.engine.mr.KylinMapper:
> java.lang.ArrayIndexOutOfBoundsException
> at java.lang.System.arraycopy(Native Method)
> at org.apache.kylin.engine.mr.common.NDCuboidBuilder.buildKeyInternal(NDCuboidBuilder.java:106)
> at org.apache.kylin.engine.mr.common.NDCuboidBuilder.buildKey(NDCuboidBuilder.java:71)
> at org.apache.kylin.engine.mr.steps.NDCuboidMapper.doMap(NDCuboidMapper.java:112)
> at org.apache.kylin.engine.mr.steps.NDCuboidMapper.doMap(NDCuboidMapper.java:47)
> at org.apache.kylin.engine.mr.KylinMapper.map(KylinMapper.java:77)
> at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:146)
> {quote}
> Please, either:
> – modify Top_N code to support all cube storage types (not only ID_SHARDED_HBASE),
> or
> – modify Top_N code to perform explicit check for cube storage type and raise descriptive exception, when cube storage is not the one that is expected. Plus update the UI to prevent the user from creating cube definitions that are incompatible with the storage type compatible with Top_N measure
> PS: NDCCuboidBuilder,java contains the following line:
> {quote}int offset = RowConstants.ROWKEY_SHARDID_LEN + RowConstants.ROWKEY_CUBOIDID_LEN; // skip shard and cuboidId{quote}
> If cube storage type is not ID_SHARDED_HBASE, offset is calculated incorrectly, which leads to ArrayIndexOutOfBounds exception.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)