apache
[hotfix] Fixed flaky-test: StateTtlHintTest#testJoinStateTtlHintWithView
What is the purpose of the change
This pull request identifies a flaky-test and proposes a fix.
Brief change log
The following method asserts a flaky test: org.apache.flink.table.planner.plan.hints.stream.StateTtlHintTest#testJoinStateTtlHintWithView
Failed assertion:
expected: <
Join(joinType=[InnerJoin], where=[=(a1, a3)], select=[a1, b1, a3, b3], leftInputSpec=[NoUniqueKey], rightInputSpec=[NoUniqueKey], stateTtlHints=[[[STATE_TTL options:{LEFT=2d, RIGHT=1d}]]])
:- Exchange(distribution=[hash[a1]])
: +- TableSourceScan(table=[[default_catalog, default_database, T1]], fields=[a1, b1])
+- Exchange(distribution=[hash[a3]])
+- TableSourceScan(table=[[default_catalog, default_database, T3]], fields=[a3, b3])
> but was: <
Join(joinType=[InnerJoin], where=[=(a1, a3)], select=[a1, b1, a3, b3], leftInputSpec=[NoUniqueKey], rightInputSpec=[NoUniqueKey], stateTtlHints=[[[STATE_TTL options:{RIGHT=1d, LEFT=2d}]]])
:- Exchange(distribution=[hash[a1]])
: +- TableSourceScan(table=[[default_catalog, default_database, T1]], fields=[a1, b1])
+- Exchange(distribution=[hash[a3]])
+- TableSourceScan(table=[[default_catalog, default_database, T3]], fields=[a3, b3])
>
Precisely (String comparison failure)
Expected: stateTtlHints=[[[STATE_TTL options:{LEFT=2d, RIGHT=1d}]]]
Actual: stateTtlHints=[[[STATE_TTL options:{RIGHT=1d, LEFT=2d}]]]
FAILURE REASON
RelExplainUtil.scala => hintsToString uses ImmutableMap.toString() function to convert kvOptions to string representation. Map.toString() is unreliable and gives non-deterministic output where sorting of Entries depends on current hashcode generation logic, and could be different for each toString call.
Fix
Added a method that sorts entries in lexographical order and returns same result as map.toString(). Sorting makes it deterministic.
Confirmed test failure using nondex
For particular test:
mvn -pl ./flink-table/flink-table-planner edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=org.apache.flink.table.planner.plan.hints.stream.StateTtlHintTest#testJoinStateTtlHintWithView -DnondexRuns=10 -Dspotless.check.skip=true
For entire repo
Suggested command to check flaky tests :
mvn nondex:nondex
For more information : https://github.com/TestingResearchIllinois/NonDex
Verifying this change
Please make sure both new and modified tests in this PR follow the conventions for tests defined in our code quality guide.
This change added tests and can be verified as follows:
- Added fixes in code to generate deterministic output for non-flaky (deterministic) assertion
Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): no
- The public API, i.e., is any changed class annotated with
@Public(Evolving): no - The serializers: no
- The runtime per-record code paths (performance sensitive): no
- Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
- The S3 file system connector: no
