kvserver: export secondary cache counter metrics

[joshimhoff]

Fixes #110899.

kvserver: export secondary cache counter metrics

This commits exports counter metrics regarding the secondary cache added at cockroachdb/pebble#2760. This commit doesn't export the histogram metrics added in that PR. While working on this one, I have realized a follow up PR is needed to export the bucketing scheme to CRDB.

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 

[RaduBerinde]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @itsbilal and @joshimhoff)

---

pkg/kv/kvserver/metrics.go line 772 at r1 (raw file):

	}
	metaSecondaryCacheSize = metric.Metadata{
		Name:        "storage.shared-storage.cache.size",

Let's name these storage.secondary-cache.*.

---

pkg/kv/kvserver/metrics.go line 773 at r1 (raw file):

	metaSecondaryCacheSize = metric.Metadata{
		Name:        "storage.shared-storage.cache.size",
		Help:        "The number of sstable bytes stored in the cache",

"in the secondary cache" (same below)

[joshimhoff]

Reviewable status: complete! 0 of 0 LGTMs obtained (waiting on @itsbilal)

---

pkg/kv/kvserver/metrics.go line 772 at r1 (raw file):

Previously, RaduBerinde wrote…

Let's name these storage.secondary-cache.*.

Done!

---

pkg/kv/kvserver/metrics.go line 773 at r1 (raw file):

Previously, RaduBerinde wrote…

"in the secondary cache" (same below)

Done.

[RaduBerinde]

Thanks!

Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @itsbilal)

[joshimhoff]

TFTR!

[joshimhoff]

bors r+

[craig]

Already running a review

[craig]

Build failed (retrying...):

• Bazel Essential CI (Cockroach)

[yuzefovich]

bors r-

This needs ./dev gen docs.

[craig]

Canceled.

[nvanbenschoten]

bors r-

This is failing CheckGeneratedCode/dev_generate. You'll need to run dev gen.

------- Stderr: -------
On branch staging
Your branch is up to date with 'origin/staging'.
You are in a sparse checkout with 100% of tracked files present.
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
  modified:   docs/generated/metrics/metrics.html
no changes added to commit (use "git add" and/or "git commit -a")
diff --git a/docs/generated/metrics/metrics.html b/docs/generated/metrics/metrics.html
index 84e75fb6ca8..9ff027dc5f6 100644
--- a/docs/generated/metrics/metrics.html
+++ b/docs/generated/metrics/metrics.html
@@ -653,6 +653,16 @@
 <tr><td>STORAGE</td><td>storage.l6-level-size</td><td>Size of the SSTables in level 6</td><td>Bytes</td><td>GAUGE</td><td>BYTES</td><td>AVG</td><td>NONE</td></tr>
 <tr><td>STORAGE</td><td>storage.marked-for-compaction-files</td><td>Count of SSTables marked for compaction</td><td>SSTables</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>
 <tr><td>STORAGE</td><td>storage.queue.store-failures</td><td>Number of replicas which failed processing in replica queues due to retryable store errors</td><td>Replicas</td><td>COUNTER</td><td>COUNT</td><td>AVG</td><td>NON_NEGATIVE_DERIVATIVE</td></tr>
+<tr><td>STORAGE</td><td>storage.secondary-cache.count</td><td>The count of cache blocks in the secondary cache (not sstable blocks)</td><td>Cache items</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>
+<tr><td>STORAGE</td><td>storage.secondary-cache.evictions</td><td>The number of times a cache block was evicted from the secondary cache</td><td>Num evictions</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>
+<tr><td>STORAGE</td><td>storage.secondary-cache.reads-full-hit</td><td>The number of reads where all data returned was read from the secondary cache</td><td>Num reads</td><td>GAUGE</td><td>COUNT</td><td>AVG</td><td>NONE</td></tr>

[joshimhoff]

Thanks! Apologies.

[joshimhoff]

bors r+

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)