MixedClusterClientYamlTestSuiteIT: Multisearch test with typed_keys parameter for sampler and significant terms failure

[davidkyle]

Build scan:
https://gradle-enterprise.elastic.co/s/qaucfxmv5kp76

Repro line:

 ./gradlew ':qa:mixed-cluster:v6.8.10#mixedClusterTest' --tests "org.elasticsearch.backwards.MixedClusterClientYamlTestSuiteIT.test {p0=msearch/20_typed_keys/Multisearch test with typed_keys parameter for sampler and significant terms}" \
  -Dtests.seed=A0B72CC161F91CA5 \
  -Dtests.security.manager=true \
  -Dtests.locale=is \
  -Dtests.timezone=Indian/Mahe \
  -Druntime.java=8

Reproduces locally?:
No

Applicable branches:
7.x

Failure history:
Many failures since May 30th all on the 7.x branch in a mixed cluster with 6.8.y

https://build-stats.elastic.co/app/kibana#/discover?_g=(refreshInterval:(pause:!t,value:0),time:(from:now-7d,mode:quick,to:now))&_a=(columns:!(branch),index:e58bf320-7efd-11e8-bf69-63c8ef516157,interval:auto,query:(language:lucene,query:'%22Multisearch%20test%22'),sort:!(time,desc))

Failure excerpt:

java.lang.AssertionError: Failure at [msearch/20_typed_keys:107]: responses.0.aggregations.sampler#test_sampler.sigsterms#test_significant_terms.doc_count didn't match expected value:
responses.0.aggregations.sampler#test_sampler.sigsterms#test_significant_terms.doc_count: expected Integer [5] but was Integer [4]

	at __randomizedtesting.SeedInfo.seed([A0B72CC161F91CA5:28E3131BCF05715D]:0)
	at org.elasticsearch.test.rest.yaml.ESClientYamlSuiteTestCase.executeSection(ESClientYamlSuiteTestCase.java:405)
	at org.elasticsearch.test.rest.yaml.ESClientYamlSuiteTestCase.test(ESClientYamlSuiteTestCase.java:382)
	at sun.reflect.GeneratedMethodAccessor19.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.carrotsearch.randomizedtesting.RandomizedRunner.invoke(RandomizedRunner.java:1750)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$8.evaluate(RandomizedRunner.java:938)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$9.evaluate(RandomizedRunner.java:974)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$10.evaluate(RandomizedRunner.java:988)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at org.apache.lucene.util.TestRuleSetupTeardownChained$1.evaluate(TestRuleSetupTeardownChained.java:49)
	at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:45)
	at org.apache.lucene.util.TestRuleThreadAndTestName$1.evaluate(TestRuleThreadAndTestName.java:48)
	at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:64)
	at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:47)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:368)
	at com.carrotsearch.randomizedtesting.ThreadLeakControl.forkTimeoutingTask(ThreadLeakControl.java:817)
	at com.carrotsearch.randomizedtesting.ThreadLeakControl$3.evaluate(ThreadLeakControl.java:468)
	at com.carrotsearch.randomizedtesting.RandomizedRunner.runSingleTest(RandomizedRunner.java:947)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$5.evaluate(RandomizedRunner.java:832)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$6.evaluate(RandomizedRunner.java:883)
	at com.carrotsearch.randomizedtesting.RandomizedRunner$7.evaluate(RandomizedRunner.java:894)
	at org.apache.lucene.util.AbstractBeforeAfterRule$1.evaluate(AbstractBeforeAfterRule.java:45)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at org.apache.lucene.util.TestRuleStoreClassName$1.evaluate(TestRuleStoreClassName.java:41)
	at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
	at com.carrotsearch.randomizedtesting.rules.NoShadowingOrOverridesOnMethodsRule$1.evaluate(NoShadowingOrOverridesOnMethodsRule.java:40)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at org.apache.lucene.util.TestRuleAssertionsRequired$1.evaluate(TestRuleAssertionsRequired.java:53)
	at org.apache.lucene.util.TestRuleMarkFailure$1.evaluate(TestRuleMarkFailure.java:47)
	at org.apache.lucene.util.TestRuleIgnoreAfterMaxFailures$1.evaluate(TestRuleIgnoreAfterMaxFailures.java:64)
	at org.apache.lucene.util.TestRuleIgnoreTestSuites$1.evaluate(TestRuleIgnoreTestSuites.java:54)
	at com.carrotsearch.randomizedtesting.rules.StatementAdapter.evaluate(StatementAdapter.java:36)
	at com.carrotsearch.randomizedtesting.ThreadLeakControl$StatementRunner.run(ThreadLeakControl.java:368)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.AssertionError: responses.0.aggregations.sampler#test_sampler.sigsterms#test_significant_terms.doc_count didn't match expected value:
responses.0.aggregations.sampler#test_sampler.sigsterms#test_significant_terms.doc_count: expected Integer [5] but was Integer [4]

	at org.elasticsearch.test.rest.yaml.section.MatchAssertion.doAssert(MatchAssertion.java:93)
	at org.elasticsearch.test.rest.yaml.section.Assertion.execute(Assertion.java:76)
	at org.elasticsearch.test.rest.yaml.ESClientYamlSuiteTestCase.executeSection(ESClientYamlSuiteTestCase.java:398)
	... 37 more

[elasticmachine]

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

[davidkyle]

Muted on 7.x in #57406

[elasticmachine]

Pinging @elastic/es-analytics-geo (:Analytics/Aggregations)

[jimczi]

@nik9000 could it be related to your recent change on the sig terms agg ?