Avoid negative memory result in IndicesQueryCache stats calculation

[dbwiddis]

Description

In the edge case where shardStats is an empty map (caused by removing the last document from an index through a means other than clearing the index), the stats map is also empty. However this case also leads to divide-by-zero calculation which gives a weight of Double.POSITIVE_INFINITY. This rounds to Long.MAX_VALUE for additionalRamBytesUsed for the shard.

Then later in calculating total memory, the max long value is added to other fields, resulting in overflow.

Issues Resolved

Fixes #4474

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)

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For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/13162/
• CommitID: 4555cc0
  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?

[dbwiddis]

Hmm, seems I made too strong of an assumption on tests:

java.lang.AssertionError: expected:<0> but was:<10480>

Will fix.

[dbwiddis]

Fun thing about that test failure is it let me figure out the root cause of the original bug!

        // This cache stores two things: filters, and doc id sets. At this time
        // we only know that there are no more doc id sets, but we still track
        // recently used queries, which we want to reclaim.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/13170/
• CommitID: 9408434
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/13176/
• CommitID: dd3b34f
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/13210/
• CommitID: d77ed6a
  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 (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/13233/
• CommitID: 4e14768

[codecov-commenter]

Codecov Report

Merging #6917 (a009248) into main (c85d33e) will increase coverage by 0.17%.
The diff coverage is 100.00%.

📣 This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@             Coverage Diff              @@
##               main    #6917      +/-   ##
============================================
+ Coverage     70.66%   70.83%   +0.17%     
- Complexity    59231    59315      +84     
============================================
  Files          4812     4812              
  Lines        283761   283763       +2     
  Branches      40917    40918       +1     
============================================
+ Hits         200519   201011     +492     
+ Misses        66784    66240     -544     
- Partials      16458    16512      +54     

Impacted Files	Coverage Δ
...java/org/opensearch/indices/IndicesQueryCache.java	90.64% <100.00%> (+0.13%)	⬆️

... and 471 files with indirect coverage changes

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[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/13240/
• CommitID: a009248

[opensearch-trigger-bot]

The backport to 1.x failed:

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

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/backport-1.x 1.x
# Navigate to the new working tree
pushd ../.worktrees/backport-1.x
# Create a new branch
git switch --create backport/backport-6917-to-1.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c0a8cf8823341cf92b932fe3d12909d427090a2f
# Push it to GitHub
git push --set-upstream origin backport/backport-6917-to-1.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/backport-1.x

Then, create a pull request where the base branch is 1.x and the compare/head branch is backport/backport-6917-to-1.x.

[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/backport-2.x
# Create a new branch
git switch --create backport/backport-6917-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c0a8cf8823341cf92b932fe3d12909d427090a2f
# Push it to GitHub
git push --set-upstream origin backport/backport-6917-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-6917-to-2.x.

[opensearch-trigger-bot]

The backport to 1.3 failed:

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

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/backport-1.3 1.3
# Navigate to the new working tree
pushd ../.worktrees/backport-1.3
# Create a new branch
git switch --create backport/backport-6917-to-1.3
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 c0a8cf8823341cf92b932fe3d12909d427090a2f
# Push it to GitHub
git push --set-upstream origin backport/backport-6917-to-1.3
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/backport-1.3

Then, create a pull request where the base branch is 1.3 and the compare/head branch is backport/backport-6917-to-1.3.