KYLIN-2620 Make the condition stricter to answer query with topN

[Wayne1c]

No description provided.

[asfgit]

Can one of the admins verify this patch?

[coveralls]

Pull Request Test Coverage Report for Build 4186

• 0 of 32 (0.0%) changed or added relevant lines in 6 files are covered.
• 4 unchanged lines in 3 files lost coverage.
• Overall coverage remained the same at 26.945%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
core-metadata/src/main/java/org/apache/kylin/metadata/realization/SQLDigest.java	0	1	0.0%
query/src/main/java/org/apache/kylin/query/relnode/OLAPContext.java	0	1	0.0%
query/src/main/java/org/apache/kylin/query/relnode/OLAPLimitRel.java	0	1	0.0%
core-cube/src/main/java/org/apache/kylin/cube/CubeInstance.java	0	2	0.0%
query/src/main/java/org/apache/kylin/query/relnode/OLAPSortRel.java	0	8	0.0%
core-metadata/src/main/java/org/apache/kylin/measure/topn/TopNMeasureType.java	0	19	0.0%

Files with Coverage Reduction	New Missed Lines	%
query/src/main/java/org/apache/kylin/query/relnode/OLAPSortRel.java	1	0.0%
core-cube/src/main/java/org/apache/kylin/cube/CubeInstance.java	1	43.88%
core-metadata/src/main/java/org/apache/kylin/measure/topn/TopNMeasureType.java	2	4.07%

Totals
Change from base Build 4187:	0.0%
Covered Lines:	18719
Relevant Lines:	69470

---

💛 - Coveralls

[Wayne1c]

CI passed

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@68bffc1). Click here to learn what that means.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master     #489   +/-   ##
=========================================
  Coverage          ?   24.46%           
  Complexity        ?     4963           
=========================================
  Files             ?     1144           
  Lines             ?    69470           
  Branches          ?     9912           
=========================================
  Hits              ?    16994           
  Misses            ?    50755           
  Partials          ?     1721

Impacted Files	Coverage Δ	Complexity Δ
...a/org/apache/kylin/query/relnode/OLAPLimitRel.java	0% <0%> (ø)	0 <0> (?)
.../main/java/org/apache/kylin/cube/CubeInstance.java	38.84% <0%> (ø)	52 <0> (?)
...va/org/apache/kylin/query/relnode/OLAPSortRel.java	0% <0%> (ø)	0 <0> (?)
...g/apache/kylin/metadata/realization/SQLDigest.java	0% <0%> (ø)	0 <0> (?)
...org/apache/kylin/measure/topn/TopNMeasureType.java	4.06% <0%> (ø)	3 <0> (?)
...va/org/apache/kylin/query/relnode/OLAPContext.java	0% <0%> (ø)	0 <0> (?)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 68bffc1...3aaf073. Read the comment docs.

[shaofengshi]

LGTM