[CI] IndexDiskUsageAnalyzerTests testKnnVectors failing

[elasticsearchmachine]

Build Scans:

• elasticsearch-periodic-platform-support #8033 / debian-12_platform-support-unix
• elasticsearch-pull-request #70024 / part-1

Reproduction Line:

./gradlew ":server:test" --tests "org.elasticsearch.action.admin.indices.diskusage.IndexDiskUsageAnalyzerTests.testKnnVectors" -Dtests.seed=28E89D2D651EB806 -Dtests.locale=twq-Latn-NE -Dtests.timezone=SystemV/MST7 -Druntime.java=24

Applicable branches:
main

Reproduces locally?:
N/A

Failure History:
See dashboard

Failure Message:

java.lang.AssertionError: numDocs=1013
Expected: a value greater than <4052L>
     but: <4045L> was less than <4052L>

Issue Reasons:

• [main] 2 failures in test testKnnVectors (0.3% fail rate in 597 executions)

Note:
This issue was created using new test triage automation. Please report issues or feedback to es-delivery.

[elasticsearchmachine]

This has been muted on branch main

Mute Reasons:

• [main] 2 failures in test testKnnVectors (0.3% fail rate in 597 executions)

Build Scans:

• elasticsearch-periodic-platform-support #8033 / debian-12_platform-support-unix
• elasticsearch-pull-request #70024 / part-1

[elasticsearchmachine]

Pinging @elastic/es-search (Team:Search)

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)

[benwtrent]

This one is weird, maybe its due to the Apache Lucene upgrade. We didn't really change the foot-print hugely, but we did optimize merges.

@mayya-sharipova do you think this would be due to the merge improvements?