changefeedccl: set server.child_metrics.enabled public

column to true

Since we're expecting people to use this setting to
use metrics labels, it should show up when running SHOW
ALL CLUSTER SETTINGS.

Release note (enterprise change): The public column
of setting server.child_metrics.enabled will be set
to true.

Release justification: This change is very small and low
risk

docs/generated/settings/settings-for-tenants.txt

@@ -47,6 +47,7 @@ security.ocsp.timeout	duration	3s	timeout before considering the OCSP server unr
 server.auth_log.sql_connections.enabled	boolean	false	if set, log SQL client connect and disconnect events (note: may hinder performance on loaded nodes)
 server.auth_log.sql_sessions.enabled	boolean	false	if set, log SQL session login/disconnection events (note: may hinder performance on loaded nodes)
 server.authentication_cache.enabled	boolean	true	enables a cache used during authentication to avoid lookups to system tables when retrieving per-user authentication-related information
+server.child_metrics.enabled	boolean	false	enables the exporting of child metrics, additional prometheus time series with extra labels
 server.clock.forward_jump_check_enabled	boolean	false	if enabled, forward clock jumps > max_offset/2 will cause a panic
 server.clock.persist_upper_bound_interval	duration	0s	the interval between persisting the wall time upper bound of the clock. The clock does not generate a wall time greater than the persisted timestamp and will panic if it sees a wall time greater than this value. When cockroach starts, it waits for the wall time to catch-up till this persisted timestamp. This guarantees monotonic wall time across server restarts. Not setting this or setting a value of 0 disables this feature.
 server.eventlog.enabled	boolean	true	if set, logged notable events are also stored in the table system.eventlog

docs/generated/settings/settings.html

@@ -58,6 +58,7 @@
 <tr><td><code>server.auth_log.sql_connections.enabled</code></td><td>boolean</td><td><code>false</code></td><td>if set, log SQL client connect and disconnect events (note: may hinder performance on loaded nodes)</td></tr>
 <tr><td><code>server.auth_log.sql_sessions.enabled</code></td><td>boolean</td><td><code>false</code></td><td>if set, log SQL session login/disconnection events (note: may hinder performance on loaded nodes)</td></tr>
 <tr><td><code>server.authentication_cache.enabled</code></td><td>boolean</td><td><code>true</code></td><td>enables a cache used during authentication to avoid lookups to system tables when retrieving per-user authentication-related information</td></tr>
+<tr><td><code>server.child_metrics.enabled</code></td><td>boolean</td><td><code>false</code></td><td>enables the exporting of child metrics, additional prometheus time series with extra labels</td></tr>
 <tr><td><code>server.clock.forward_jump_check_enabled</code></td><td>boolean</td><td><code>false</code></td><td>if enabled, forward clock jumps > max_offset/2 will cause a panic</td></tr>
 <tr><td><code>server.clock.persist_upper_bound_interval</code></td><td>duration</td><td><code>0s</code></td><td>the interval between persisting the wall time upper bound of the clock. The clock does not generate a wall time greater than the persisted timestamp and will panic if it sees a wall time greater than this value. When cockroach starts, it waits for the wall time to catch-up till this persisted timestamp. This guarantees monotonic wall time across server restarts. Not setting this or setting a value of 0 disables this feature.</td></tr>
 <tr><td><code>server.consistency_check.max_rate</code></td><td>byte size</td><td><code>8.0 MiB</code></td><td>the rate limit (bytes/sec) to use for consistency checks; used in conjunction with server.consistency_check.interval to control the frequency of consistency checks. Note that setting this too high can negatively impact performance.</td></tr>

pkg/server/status/recorder.go

@@ -90,7 +90,7 @@ type storeMetrics interface {
 var childMetricsEnabled = settings.RegisterBoolSetting(
 	settings.TenantWritable, "server.child_metrics.enabled",
 	"enables the exporting of child metrics, additional prometheus time series with extra labels",
-	false)
+	false).WithPublic()
 
 // MetricsRecorder is used to periodically record the information in a number of
 // metric registries.