Proposed changes

Issue(s)

Closes #19082

How to test or reproduce

Screenshots

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Hotfix (a major bugfix that has to be merged asap)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

Changelog

A missing configuration was not limiting the new oplog tailing to pool the database frequently even when no data was available, leading to both node and mongodb process been consuming high CPU even with low usage. This case was happening for installations using mmapv1 database engine or when no admin access was granted to the database user, both preventing the usage of the new Change Streams implementation and fallbacking to our custom oplog implementation in replacement to the Meteor's one what was able to be disabled and use the native implementation via the environmental variable USE_NATIVE_OPLOG=true.

Further comments