[1x] Deprecate index.merge.policy.max_merge_at_once_explicit (#1981)

[nknize]

Backport of #1981. max_merge_at_once_explicit is removed in lucene 9 so the index setting is deprecated for removal in the next major release.

[opensearch-ci-bot]

Can one of the admins verify this patch?

[opensearch-ci-bot]

❌   Gradle Check failure bf78928
Log 2081

Reports 2081

[opensearch-ci-bot]

❌   Gradle Check failure 99d0898
Log 2085

Reports 2085

[nknize]

The stackOverflow troll appears

@reta can you open a PR to backport #1900 to 1.x?

REPRODUCE WITH: ./gradlew ':modules:transport-netty4:internalClusterTest' --tests "org.opensearch.transport.netty4.OpenSearchLoggingHandlerIT.testLoggingHandler" -Dtests.seed=17FE0224EA35F310 -Dtests.security.manager=true -Dtests.jvm.argline="-XX:TieredStopAtLevel=1 -XX:ReservedCodeCacheSize=64m" -Dtests.locale=id -Dtests.timezone=America/Indiana/Vevay -Druntime.java=17

org.opensearch.transport.netty4.OpenSearchLoggingHandlerIT > testLoggingHandler FAILED
java.lang.AssertionError:
Expected: an empty collection
but: 🤮

[nknize]

start gradle check

[opensearch-ci-bot]

❌   Gradle Check failure 99d0898
Log 2088

Reports 2088

[reta]

@nknize we actually backported it to 1.x (#1906) but seems like the cause of StackOverflowError is different, could you please reopen #1767? I will look at it again, thanks!

[nknize]

could you please reopen #1767? I will look at it again, thanks!

sure thing! thx a lot!

[nknize]

Another stackOverflow failure

REPRODUCE WITH: ./gradlew ':modules:transport-netty4:internalClusterTest' --tests "org.opensearch.transport.netty4.OpenSearchLoggingHandlerIT.testLoggingHandler" -Dtests.seed=2F5FB0F2417965EE -Dtests.security.manager=true -Dtests.jvm.argline="-XX:TieredStopAtLevel=1 -XX:ReservedCodeCacheSize=64m" -Dtests.locale=mk-MK -Dtests.timezone=Asia/Katmandu -Druntime.java=17

org.opensearch.transport.netty4.OpenSearchLoggingHandlerIT > testLoggingHandler FAILED
    java.lang.AssertionError: 
    Expected: an empty collection
         but: <[org.apache.logging.log4j.spi.AbstractLogger caught java.lang.StackOverflowError logging ReusableSimpleMessage: [id: 0x3a409119, L:/127.0.0.1:39109 - R:/127.0.0.1:34496] WRITE: 31891B
             +-------------------------------------------------+
             |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
    +--------+-------------------------------------------------+----------------+
    |00000000| 45 53 00 00 7c 8d 00 00 00 00 00 00 00 05 01 08 |ES..|...........|
    |00000010| 0f b7 d3 00 00 00 02 00 00 58 54 45 53 54 2d 54 |.........XTEST-T|
    |00000020| 45 53 54 5f 57 4f 52 4b 45 52 5f 56 4d 3d 5b 33 |EST_WORKER_VM=[3|

[nknize]

start gradle check

[opensearch-ci-bot]

❌   Gradle Check failure 99d0898
Log 2095

Reports 2095

[opensearch-ci-bot]

✅   Gradle Check success 09cb792
Log 2098

Reports 2098