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https://issues.apache.org/jira/browse/KYLIN-4315?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17135096#comment-17135096
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ASF GitHub Bot commented on KYLIN-4315:
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RupengWang commented on pull request #1024:
URL: https://github.com/apache/kylin/pull/1024#issuecomment-643741849
### Check list
- [x] Step 1. [**OPTIONAL**]Understand background/root cause/design
basically(one hour EST) . Its issue type is
- [ ] bug fix
- [ ] new feature
- [x] enhancement
- [x] Step 2. Test cases are designed and documented (30 minutes EST).
- [x] Step 3. Prepare specific env, for example:
- mock data (maybe some specific data type)
- test env (maybe install a RDBMS instance).
- [x] Step 4. Verify and make sure test cases passed.
- [x] Step 5. Paste manual important steps and screenshots here (20 minutes
EST).
- If you find difficulty in pick most important evidence, please attach
diagnosis package.
- [x] Step 6. Do more check in user perspective (20 minutes EST)
- [x] Doc need be updated? And if it is updated? Ask help for release
manager if so.
- [x] If it is a breaking change so we should notify Kylin community?
Ask help for release manager if so.
- [x] Step 7. Summarize this test (20 minutes EST).
### Total estimate
- 4 hours for small issue from optimistic estimate.
### Note
If you find some unexpected and **unrelated** error/mistake, please DO
report it if it is truly a mistake, I think we may research and fix it in the
future.
If you find background information/root cause analysis is not complete or
ambiguous, please try to contact to author or do a quick research and record
what you find. It is a good chance to learn something interesting.
If you find it is not easy to design testcase, please notify release manager.
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> Use metadata numRows in beeline client for quick row counting
> -------------------------------------------------------------
>
> Key: KYLIN-4315
> URL: https://issues.apache.org/jira/browse/KYLIN-4315
> Project: Kylin
> Issue Type: Improvement
> Components: Job Engine
> Reporter: Congling Xia
> Assignee: Congling Xia
> Priority: Major
> Fix For: v3.1.0
>
>
> Hi, I find that in `BeelineHiveClient`, method `getHiveTableRows` uses
> "select count(*) from <tb_name>" for table row counting. The method is
> invoked in flat intermediate table redistribution step in cube building.
> This stats can be loaded in metastore. It costs much less time than scanning
> all rows in Hive table. Since intermediate tables are created and inserted by
> Kylin, statistics will be automatically calculated and stored in metastore
> when
> `[hive.stats.autogather|https://cwiki.apache.org/confluence/display/Hive/Configuration+Properties#ConfigurationProperties-hive.stats.autogather]`
> is enabled (which is the default setting for Hive).
> ref Hive wiki for more detail about `numRows` stats:
> [https://cwiki.apache.org/confluence/display/Hive/StatsDev#StatsDev-ExistingTables%E2%80%93ANALYZE]
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