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Posted to commits@pinot.apache.org by GitBox <gi...@apache.org> on 2021/12/04 00:18:19 UTC
[GitHub] [pinot] mqliang opened a new pull request #7865: Use System.currentTimeMillis() instead of System.nanoTime() to measure wall clock duration
mqliang opened a new pull request #7865:
URL: https://github.com/apache/pinot/pull/7865
## Description
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A good description should include pointers to an issue or design document, etc.
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OS have an in memory counter/clock which provides millisecond accuracy. For nanosecond accuracy OS have to
read a hardware counter. Communicating with hardware is much slower then reading some value already in memory,
this will cause some performance problem as we measure for each query, especially when QPS is high. Thus, use
`System.currentTimeMillis()` instead of `System.nanoTime()` to measure wall clock duration. It will give us
millisecond resolution but that's fine, as most of queries takes > 1ms, if a query takes < 1ms, we can assume
systemActivitiesCpuTimeNs = 0.
## Upgrade Notes
Does this PR prevent a zero down-time upgrade? (Assume upgrade order: Controller, Broker, Server, Minion)
* [ ] Yes (Please label as **<code>backward-incompat</code>**, and complete the section below on Release Notes)
Does this PR fix a zero-downtime upgrade introduced earlier?
* [ ] Yes (Please label this as **<code>backward-incompat</code>**, and complete the section below on Release Notes)
Does this PR otherwise need attention when creating release notes? Things to consider:
- New configuration options
- Deprecation of configurations
- Signature changes to public methods/interfaces
- New plugins added or old plugins removed
* [ ] Yes (Please label this PR as **<code>release-notes</code>** and complete the section on Release Notes)
## Release Notes
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you MUST add text here that you would like to see appear in release notes of the
next release. -->
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## Documentation
<!-- If you have introduced a new feature or configuration, please add it to the documentation as well.
See https://docs.pinot.apache.org/developers/developers-and-contributors/update-document
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[GitHub] [pinot] mqliang closed pull request #7865: Use System.currentTimeMillis() instead of System.nanoTime() to measure wall clock duration
Posted by GitBox <gi...@apache.org>.
mqliang closed pull request #7865:
URL: https://github.com/apache/pinot/pull/7865
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