kvserver, storage: add bytes compressed/decompressed metrics

[RaduBerinde]

The motivation for these metrics is to enable estimating the CPU usage
impact of switching to a stronger compression method (which applies
only to L5/L6 data/value blocks).

Epic: none
Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[github-actions]

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[sumeerbhola]

@sumeerbhola reviewed 1 of 3 files at r1, all commit messages.
Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @DarrylWong and @shailendra-patel)

---

pkg/kv/kvserver/metrics.go line 1239 at r1 (raw file):

		Unit:        metric.Unit_CONST,
	}
	metaBytesCompressedL5Data = metric.Metadata{

how about using static label metrics for these metrics https://docs.google.com/document/d/1fn5KX0uPUCw1uW4KkCvmP9-svga0F6XSvhnqdg24MpE/edit?tab=t.0#heading=h.9ndo02nsmu? Should allow us to define 1 metric with {compresssed,decompressed}x{l5,l6}x{data,values}.

[RaduBerinde]

pkg/kv/kvserver/metrics.go line 1239 at r1 (raw file):

Previously, sumeerbhola wrote…

how about using static label metrics for these metrics https://docs.google.com/document/d/1fn5KX0uPUCw1uW4KkCvmP9-svga0F6XSvhnqdg24MpE/edit?tab=t.0#heading=h.9ndo02nsmu? Should allow us to define 1 metric with {compresssed,decompressed}x{l5,l6}x{data,values}.

Oooh, forgot about that. Great idea, I will work on that!

[RaduBerinde]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @aa-joshi, @Abhinav1299, @alyshanjahani-crl, @arjunmahishi, @DarrylWong, @shailendra-patel, and @sumeerbhola)

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pkg/kv/kvserver/metrics.go line 1239 at r1 (raw file):

Previously, RaduBerinde wrote…

Oooh, forgot about that. Great idea, I will work on that!

Done.

[sumeerbhola]

@sumeerbhola reviewed 3 of 3 files at r2, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @aa-joshi, @Abhinav1299, @alyshanjahani-crl, @arjunmahishi, @DarrylWong, and @shailendra-patel)

[blathers-crl]

Metrics change detected

This PR adds or updates one or more CRDB metrics. If you want these metrics to be exported by CRDB Cloud clusters to Internal CRL Datadog and/or included in the customer metric export integration (Essential metrics for standard deployment, and Essential metrics for advanced deployment), refer to this Installation and Usage guide of a CLI tool that syncs the metric mappings in managed-service. Run this CLI tool after your CRDB PR is merged.

• The CLI opens a PR in managed-service with the required config changes.
• Please track that PR and ensure it merges so your metrics become available to CRDB Cloud clusters.

Note: Your metric will appear in Internal CRL Datadog only after the managed-service PR merges and the new OTel configuration rolls out to at least one cluster running a CRDB build that includes this metric.

Docs: cockroach-metric-sync

Questions: reach out to @obs-india-prs

[RaduBerinde]

TFTR!

bors r+

[craig]

Build succeeded:

• docker_image_amd64
• local_roachtest_fips
• lint
• unit_tests
• linux_amd64_build
• local_roachtest
• examples_orms
• acceptance
• check_generated_code
• linux_amd64_fips_build