Optimize checksum creation for remote cluster state

[himshikha]

Description

This change parallelizes checksum creation for cluster state components, with the aim to reduce remote state publication latency.

Related Issues

Resolves #[Issue number to be closed when this PR is merged]

Check List

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

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[github-actions]

❌ Gradle check result for 1b5edaa: 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?

[Bukhtawar]

Thanks @himshikha would you be able to share the perf numbers with this change

[github-actions]

❌ Gradle check result for 542d709: 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 93f9a43: 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?

[himshikha]

❌ Gradle check result for 93f9a43: 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?

Flaky test #14324

[github-actions]

❌ Gradle check result for f14898c: 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?

[himshikha]

❌ Gradle check result for f14898c: 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?

Flaky test #15944, #15812

[github-actions]

❕ Gradle check result for 989e4fe: UNSTABLE

• TEST FAILURES:

      3 org.opensearch.index.shard.RemoteIndexShardTests.classMethod
      1 org.opensearch.search.SearchTimeoutIT.testSimpleTimeout {p0={"search.concurrent_segment_search.enabled":"true"}}
      1 org.opensearch.index.shard.RemoteIndexShardTests.testSegmentReplication_With_EngineClosedConcurrently

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

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.x
# Create a new branch
git switch --create backport/backport-16046-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 a767e92f3eeaf57c066deb9ad075d40ed00f4a58
# Push it to GitHub
git push --set-upstream origin backport/backport-16046-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-16046-to-2.x.

[himshikha]

Backport PR #16150

[sandeshkr419]

Thanks @himshikha for this change.

@Bukhtawar @himshikha - I think changes like this should have a changelog so that they can be called out in performance gains / optimizations as part of release notes.