CNDB-15971: Only init ReadExecutionController's histogram when tracing on

[michaeljmarshall]

What is the issue

Fixes: https://github.com/riptano/cndb/issues/15971
CNDB PR: https://github.com/riptano/cndb/pull/15986

What does this PR fix and why was it fixed

In #800, we added a histogram to the ReadExecutionController to track some metric, but it is only observed when tracing is enabled. I propose that instead of creating one and tracking for every query, we only do that when tracing is enabled.

Perhaps we could remove the logic entirely, but this solution will likely take care of all performance concerns related to unnecessary allocations and unnecessary tracking when updating the histogram.

[github-actions]

Checklist before you submit for review

• This PR adheres to the Definition of Done
• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits
• All new files should contain the DataStax copyright header instead of the Apache License one

[ekaterinadimitrova2]

Good catch! Nice to have some test as we mentioned in Slack. Let's see also what CI will say

[ekaterinadimitrova2]

The patch is ok on its own, we should decide whether we want the histogram at all, as mentioned. I do not have strong opinion. But I believe it is usage will be quite limited.

[ekaterinadimitrova2]

Approved but pending merged on CNDB PR opened. I did not find any?

[michaeljmarshall]

Here it is https://github.com/riptano/cndb/pull/15986

[ekaterinadimitrova2]

Here it is https://github.com/riptano/cndb/pull/15986

Thanks, I think you need to rebase this branch as CNDB is missing the latest committed changes in datastax/cassandra main branch here

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[cassci-bot]

✔️ Build ds-cassandra-pr-gate/PR-2118 approved by Butler

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Approved by Butler
See build details here