Interpret byte array as primitive using VarHandles

[ketanv3]

Description

This PR replaces manual conversion of byte[] to long|int|short with VarHandles. This is more readable and performant, since it would ultimately call Unsafe.unalignedAccess() to read contiguous memory.

Performance was already fast, so I don't expect much reduction in latency. But no harm in making it 2.7x faster.
Benchmark code: https://gist.github.com/ketanv3/22fb565dfea619b2307f25b161d2c522

Benchmark                           Mode  Cnt           Score          Error  Units
InterpretBitsBenchmark.manual      thrpt    5   543160590.013 ± 17214484.939  ops/s
InterpretBitsBenchmark.varHandle   thrpt    5  1448471902.400 ± 61356063.495  ops/s

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

❌ Gradle check result for 26797f8: 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]

Compatibility status:

Checks if related components are compatible with change 4f9d188

Incompatible components

Skipped components

Compatible components

Compatible components: [https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/security-analytics.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/reporting.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/opensearch-oci-object-storage.git, https://github.com/opensearch-project/sql.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/custom-codecs.git, https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/ml-commons.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/neural-search.git, https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/performance-analyzer.git]

[github-actions]

❌ Gradle check result for 20411ce: 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 3487bb6: SUCCESS

[codecov]

Codecov Report

Attention: 10 lines in your changes are missing coverage. Please review.

Comparison is base (f7f3500) 71.37% compared to head (4f9d188) 71.39%.

Files	Patch %	Lines
...search/core/common/io/stream/BytesStreamInput.java	40.00%	7 Missing and 2 partials ⚠️
...ch/index/translog/BufferedChecksumStreamInput.java	66.66%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #11362      +/-   ##
============================================
+ Coverage     71.37%   71.39%   +0.02%     
- Complexity    59113    59139      +26     
============================================
  Files          4893     4893              
  Lines        277831   277835       +4     
  Branches      40367    40367              
============================================
+ Hits         198288   198374      +86     
+ Misses        63042    63018      -24     
+ Partials      16501    16443      -58     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[andrross]

Any reason not to add InterpretBitsBenchmark to our microbenchmarks in this PR as well?

[ketanv3]

Any reason not to add InterpretBitsBenchmark to our microbenchmarks in this PR as well?

@andrross Mainly because the implementation comes straight from JDK and has known performance benefits. Since it's unrelated to OpenSearch anyways and is faster in all situations, adding these benchmarks felt excessive. For analogy, this is like comparing System.arraycopy(...) with naive implementation of copying an array element-wise.

[backslasht]

LGTM!

[andrross]

Any reason not to add InterpretBitsBenchmark to our microbenchmarks in this PR as well?

@andrross Mainly because the implementation comes straight from JDK and has known performance benefits. Since it's unrelated to OpenSearch anyways and is faster in all situations, adding these benchmarks felt excessive. For analogy, this is like comparing System.arraycopy(...) with naive implementation of copying an array element-wise.

Thanks @ketanv3, that makes sense. Can you rebase this PR then we can get it merged?

[github-actions]

❕ Gradle check result for 4f9d188: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.remotestore.RemoteIndexPrimaryRelocationIT.testPrimaryRelocationWhileIndexing

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-11362-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 d8755582c76e1b2e297e38db0b2b3f4a7299e3c6
# Push it to GitHub
git push --set-upstream origin backport/backport-11362-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-11362-to-2.x.

[reta]

@ketanv3 could you please backport to 2.x manually? thank you