Fix SimpleSearchIT.testSimpleTerminateAfterTrackTotalHitsUpToSize flaky test

[prudhvigodithi]

Description

Fix SimpleSearchIT.doTestSimpleTerminateAfterTrackTotalHitsUpTo flaky test, coming from #16851 (comment) rather than updating the approximation code with +1 to get the relation": "gte", this PR is an attempt to fix the test with approximation behavior on long fields.

Falling back to +1 based on analysis part of #16851 (comment)

Background

Coming from the PR #18018 +1 is added and which was removed in this PR #18189 to honor the approximation behavior.

Related Issues

Coming from #16851 (comment)

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[andrross]

@harshavamsi Can you take a look here as well?

[github-actions]

❌ Gradle check result for 79c76a8: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

❕ Gradle check result for b285671: UNSTABLE

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.46%. Comparing base (560ac10) to head (1925af0).
Report is 13 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #18235      +/-   ##
============================================
- Coverage     72.56%   72.46%   -0.11%     
+ Complexity    67261    67169      -92     
============================================
  Files          5476     5476              
  Lines        310478   310478              
  Branches      45133    45133              
============================================
- Hits         225313   224996     -317     
- Misses        66840    67127     +287     
- Partials      18325    18355      +30     

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[prudhvigodithi]

Hey @andrross @harshavamsi based on analysis #16851 (comment) I have updated the PR to add +1.

Also I ran and did not see any failures.

for i in {1..500}; do
  SEED=$(od -vAn -N8 -tx8 < /dev/urandom | tr -d ' ' | tr 'a-f' 'A-F')
  SEED=$(printf "%016s" "$SEED")
  echo "The run is $i"
  ./gradlew ':server:internalClusterTest' --tests "org.opensearch.search.simple.SimpleSearchIT.testSimpleTerminateAfterTrackTotalHitsUpToSize"   -Dtests.seed=$SEED 
done

Thanks

[prudhvigodithi]

@andrross and @harshavamsi if you folks can take another review, falling back to +1 based on analysis part of #16851 (comment). Thanks

[andrross]

@prudhvigodithi What about Bowen's comment here? Can we improve the test to make it so it would consistently fail?

[prudhvigodithi]

@prudhvigodithi What about Bowen's comment here? Can we improve the test to make it so it would consistently fail?

If we are going with +1, its always "relation": "gte", so we dont need any if conditions. @bowenlan-amzn correct me if I'm wrong.

Ya based on the analysis part of #16851 (comment), we cannot have consistently get the same behavior even with test size < track_total_size and > conditions. So moving with +1 to get the same behavior which used be even before approximation.

[bowenlan-amzn]

@Prudhvi Godithi commented on May 8, 2025, 11:37 AM PDT:

What about Bowen's comment here? Can we improve the test to make it so it would consistently fail?

If we are going with +1, its always "relation": "gte", so we dont need any if conditions. correct me if I'm wrong.

Ya based on the analysis part of #16851 (comment), we cannot have consistently get the same behavior even with test size < track_total_size and > conditions. So moving with +1 to get the same behavior which used be even before approximation.

Basically if we separate that one random size test to 2 scenarios

1. size <= track_total_size(5)
2. size > track_total_size(5)

Scenario 2 should never fail regarding the approximation framework
Scenario 1 now is still flaky not consistently fail, thanks to @prudhvigodithi discovered "approximation" doesn't return exactly size length of docId iterator, it can return > size, and if > 5, then test pass.

I think still worth to refactor to express our understanding here. Seems just a few lines change.

[prudhvigodithi]

I think still worth to refactor to express our understanding here. Seems just a few lines change.

Just getting back to the PR, are you suggesting to update the tests by adding the following scenarios and remove the +1 ?
size <= track_total_size(5)
size > track_total_size(5)

Because with +1 it will look something like this.

        if (size <=5 ) {
            assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation());
        }
        if (size >= 5 ) {
            assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation());
        }

If we remove the +1 we can have something like

  if (size <= 5) {
      assertTrue(
          "Relation should be either EQUAL_TO or GREATER_THAN_OR_EQUAL_TO",
          searchResponse.getHits().getTotalHits().relation() == EQUAL_TO ||
          searchResponse.getHits().getTotalHits().relation() == GREATER_THAN_OR_EQUAL_TO
      );

  } else {
      assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation());
  }

Do we need an if condition if we go with +1 @bowenlan-amzn ?

[bowenlan-amzn]

No, the idea is to refactor testSimpleTerminateAfterTrackTotalHitsUpToSize to 2 tests, one for size <= 5, one for size >5
You see 5 is kind of a magic number here, which is the setTrackTotalHitsUpTo number used in the current flaky part.

searchResponse = client().prepareSearch("test")
            .setQuery(QueryBuilders.rangeQuery("field").gte(1).lte(numDocs))
            .setSize(size)
            .setTrackTotalHitsUpTo(5) <-- why 5
            .get();
        assertEquals(5, searchResponse.getHits().getTotalHits().value());
        assertEquals(GREATER_THAN_OR_EQUAL_TO, searchResponse.getHits().getTotalHits().relation()); <-- flaky line

[prudhvigodithi]

Make sense thanks @bowenlan-amzn, just updated the test please check.

[github-actions]

✅ Gradle check result for 1925af0: SUCCESS

[prudhvigodithi]

Here is the backport to 3.0 PR #18220.
Thanks