clusterversion,storage: use range tombstones unconditionally in 23.1

Currently, MVCC range tombstones are only enabled when the
`storage.mvcc.range_tombstones.enabled` cluster setting is `true`.
Originally, the plan for 23.1 was to remove this cluster setting
entirely, which would enable the feature unconditionally. However, it
was decided that for 23.1, the setting would remain, along with the
utility methods that determine whether or not the feature is enabled.

As there is still an expectation that the feature is enabled in 23.1,
add an internal cluster version that is used as a feature gate. If the
cluster is at least of version
`V23_1_MVCCRangeTombstonesUnconditionallyEnabled`, MVCC range tombstones
are _unconditionally_ enabled, irrespective of whether the cluster
setting is enabled or not.

Fix #91147.

Release note: None.

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

@@ -297,4 +297,4 @@ trace.jaeger.agent	string		the address of a Jaeger agent to receive traces using
 trace.opentelemetry.collector	string		address of an OpenTelemetry trace collector to receive traces using the otel gRPC protocol, as <host>:<port>. If no port is specified, 4317 will be used.
 trace.span_registry.enabled	boolean	true	if set, ongoing traces can be seen at https://<ui>/#/debug/tracez
 trace.zipkin.collector	string		the address of a Zipkin instance to receive traces, as <host>:<port>. If no port is specified, 9411 will be used.
-version	version	1000022.2-56	set the active cluster version in the format '<major>.<minor>'
+version	version	1000022.2-58	set the active cluster version in the format '<major>.<minor>'

docs/generated/settings/settings.html

@@ -238,6 +238,6 @@
 <tr><td><div id="setting-trace-opentelemetry-collector" class="anchored"><code>trace.opentelemetry.collector</code></div></td><td>string</td><td><code></code></td><td>address of an OpenTelemetry trace collector to receive traces using the otel gRPC protocol, as &lt;host&gt;:&lt;port&gt;. If no port is specified, 4317 will be used.</td></tr>
 <tr><td><div id="setting-trace-span-registry-enabled" class="anchored"><code>trace.span_registry.enabled</code></div></td><td>boolean</td><td><code>true</code></td><td>if set, ongoing traces can be seen at https://&lt;ui&gt;/#/debug/tracez</td></tr>
 <tr><td><div id="setting-trace-zipkin-collector" class="anchored"><code>trace.zipkin.collector</code></div></td><td>string</td><td><code></code></td><td>the address of a Zipkin instance to receive traces, as &lt;host&gt;:&lt;port&gt;. If no port is specified, 9411 will be used.</td></tr>
-<tr><td><div id="setting-version" class="anchored"><code>version</code></div></td><td>version</td><td><code>1000022.2-56</code></td><td>set the active cluster version in the format &#39;&lt;major&gt;.&lt;minor&gt;&#39;</td></tr>
+<tr><td><div id="setting-version" class="anchored"><code>version</code></div></td><td>version</td><td><code>1000022.2-58</code></td><td>set the active cluster version in the format &#39;&lt;major&gt;.&lt;minor&gt;&#39;</td></tr>
 </tbody>
 </table>

pkg/clusterversion/cockroach_versions.go

@@ -444,6 +444,15 @@ const (
 	// backfilled.
 	V23_1DatabaseRoleSettingsRoleIDColumnBackfilled
 
+	// V23_1_MVCCRangeTombstonesUnconditionallyEnabled is a version gate at and
+	// after which Cockroach will always write MVCC Range Tombstones, regardless
+	// of the value of the storage.mvcc.range_tombstones.enabled cluster setting.
+	// Prior to this version, it was possible for a cluster to be writing MVCC
+	// Range Tombstones, but only if the cluster had been opted in manually, under
+	// a specific set of circumstances (i.e. appropriate 22.2.x version, Cockroach
+	// Cloud cluster, etc.).
+	V23_1_MVCCRangeTombstonesUnconditionallyEnabled
+
 	// *************************************************
 	// Step (1): Add new versions here.
 	// Do not add new versions to a patch release.
@@ -769,6 +778,10 @@ var rawVersionsSingleton = keyedVersions{
 		Key:     V23_1DatabaseRoleSettingsRoleIDColumnBackfilled,
 		Version: roachpb.Version{Major: 22, Minor: 2, Internal: 56},
 	},
+	{
+		Key:     V23_1_MVCCRangeTombstonesUnconditionallyEnabled,
+		Version: roachpb.Version{Major: 22, Minor: 2, Internal: 58},
+	},
 
 	// *************************************************
 	// Step (2): Add new versions here.

pkg/storage/mvcc.go

@@ -22,6 +22,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/cockroachdb/cockroach/pkg/clusterversion"
 	"github.com/cockroachdb/cockroach/pkg/keys"
 	"github.com/cockroachdb/cockroach/pkg/kv/kvnemesis/kvnemesisutil"
 	"github.com/cockroachdb/cockroach/pkg/kv/kvpb"
@@ -83,18 +84,25 @@ var minWALSyncInterval = settings.RegisterDurationSetting(
 // If disabled after being enabled, this will prevent new range tombstones from
 // being written, but already written tombstones will remain until GCed. The
 // above note on jobs also applies in this case.
+//
+// If the version of the cluster is at or beyond the version
+// V23_1_MVCCRangeTombstonesUnconditionallyEnabled, the feature is
+// unconditionally enabled.
 var MVCCRangeTombstonesEnabled = settings.RegisterBoolSetting(
 	settings.TenantReadOnly,
 	"storage.mvcc.range_tombstones.enabled",
 	"enables the use of MVCC range tombstones",
 	true)
 
-// CanUseMVCCRangeTombstones returns true if the caller can begin writing
-// MVCC range tombstones, by setting DeleteRangeRequest.UseRangeTombstone.
-// It requires the MVCCRangeTombstones version gate to be active, and the
-// setting storage.mvcc.range_tombstones.enabled to be enabled.
+// CanUseMVCCRangeTombstones returns true if the caller can begin writing MVCC
+// range tombstones, by setting DeleteRangeRequest.UseRangeTombstone. It
+// requires the storage.mvcc.range_tombstones.enabled cluster setting to be
+// enabled, OR the cluster version is at or beyond the
+// V23_1_MVCCRangeTombstonesUnconditionallyEnabled version (i.e. in 23.1, the
+// feature is unconditionally enabled).
 func CanUseMVCCRangeTombstones(ctx context.Context, st *cluster.Settings) bool {
-	return MVCCRangeTombstonesEnabled.Get(&st.SV)
+	return st.Version.IsActive(ctx, clusterversion.V23_1_MVCCRangeTombstonesUnconditionallyEnabled) ||
+		MVCCRangeTombstonesEnabled.Get(&st.SV)
 }
 
 // MaxIntentsPerWriteIntentError sets maximum number of intents returned in