KYLIN-4235 Failed to load table metadata from JDBC data source

[guangxuCheng]

See: https://issues.apache.org/jira/browse/KYLIN-4235

[asf-ci]

Can one of the admins verify this patch?

[codecov-io]

Codecov Report

Merging #918 into master will decrease coverage by <.01%.
The diff coverage is 76.92%.

@@             Coverage Diff              @@
##             master     #918      +/-   ##
============================================
- Coverage     25.44%   25.44%   -0.01%     
- Complexity     6112     6113       +1     
============================================
  Files          1412     1412              
  Lines         85030    85032       +2     
  Branches      11921    11921              
============================================
- Hits          21636    21635       -1     
- Misses        61306    61308       +2     
- Partials       2088     2089       +1

Impacted Files	Coverage Δ	Complexity Δ
.../java/org/apache/kylin/source/jdbc/JdbcSource.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...ava/org/apache/kylin/source/jdbc/JdbcExplorer.java	36.3% <100%> (+0.43%)	11 <2> (+1)	⬆️
...org/apache/kylin/rest/util/QueryRequestLimits.java	35.71% <0%> (-4.77%)	5% <0%> (-1%)
.../apache/kylin/cube/cuboid/TreeCuboidScheduler.java	63.84% <0%> (-2.31%)	0% <0%> (ø)
...rg/apache/kylin/cube/inmemcubing/MemDiskStore.java	69.6% <0%> (+0.3%)	7% <0%> (ø)	⬇️
...he/kylin/dict/lookup/cache/RocksDBLookupTable.java	78.37% <0%> (+5.4%)	7% <0%> (+1%)	⬆️

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[coveralls]

Pull Request Test Coverage Report for Build 5177

• 10 of 13 (76.92%) changed or added relevant lines in 2 files are covered.
• 8 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-0.0007%) to 27.904%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
source-jdbc/src/main/java/org/apache/kylin/source/jdbc/JdbcSource.java	0	3	0.0%

Files with Coverage Reduction	New Missed Lines	%
server-base/src/main/java/org/apache/kylin/rest/util/QueryRequestLimits.java	1	47.62%
source-jdbc/src/main/java/org/apache/kylin/source/jdbc/JdbcSource.java	1	0.0%
core-cube/src/main/java/org/apache/kylin/cube/cuboid/TreeCuboidScheduler.java	2	68.46%
core-cube/src/main/java/org/apache/kylin/cube/inmemcubing/MemDiskStore.java	4	78.12%

Totals
Change from base Build 5175:	-0.0007%
Covered Lines:	23727
Relevant Lines:	85032

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💛 - Coveralls

[nichunen]

LGTM

[RupengWang]

Check list

• Step 1. [OPTIONAL]Understand background/root cause/design basically(one hour EST) . Its issue type is
  • bug fix
  • new feature
  • enhancement
• Step 2. Test cases are designed and documented (30 minutes EST).
• Step 3. Prepare specific env, for example:
  • mock data (maybe some specific data type)
  • test env (maybe install a RDBMS instance).
• Step 4. Verify and make sure test cases passed.
• 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.
• Step 6. Do more check in user perspective (20 minutes EST)
  • Doc need be updated? And if it is updated? Ask help for release manager if so.
  • If it is a breaking change so we should notify Kylin community? Ask help for release manager if so.
• 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.

[RupengWang]

Design test cases

Prepare test env

• Using Mysql as JDBC source

Case

check if the table meta can be loaded

[RupengWang]

Prepare data and env

• Built on commit_SHA : bbb5acb
• Hadoop env : CDH 5.7
• Just sample tables is OK.

[RupengWang]

Verify test case

Case

The table meta can be loaded normally