From b2d1267806ae0c32a16904fca72a032c224435a1 Mon Sep 17 00:00:00 2001
From: Raphael 'kena' Poss <knz@thaumogen.net>
Date: Mon, 30 Jan 2023 16:51:14 +0100
Subject: [PATCH 1/2] spanconfig: rename setting to
 `spanconfig.storage_coalesce_adjacent.enabled`

Our terminology is "tenant" vs "storage cluster". The word "host" is
not used anywhere in CockroachDB (it is a term specific to CC
Serverless) and so should not be included in setting names.

There is no release note because the functionality is not yet visible
to end-users.

Release note: None
---
 pkg/settings/registry.go                     |  2 ++
 pkg/spanconfig/spanconfigstore/span_store.go | 22 ++++++++++----------
 pkg/sql/generate_objects_test.go             |  2 +-
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/pkg/settings/registry.go b/pkg/settings/registry.go
index 23679af657a5..efbbb3e4e4fd 100644
--- a/pkg/settings/registry.go
+++ b/pkg/settings/registry.go
@@ -159,6 +159,8 @@ var retiredSettings = map[string]struct{}{
 	"sql.distsql.drain.cancel_after_wait.enabled":    {},
 	"changefeed.active_protected_timestamps.enabled": {},
 	"jobs.scheduler.single_node_scheduler.enabled":   {},
+	// renamed.
+	"spanconfig.host_coalesce_adjacent.enabled": {},
 }
 
 // sqlDefaultSettings is the list of "grandfathered" existing sql.defaults
diff --git a/pkg/spanconfig/spanconfigstore/span_store.go b/pkg/spanconfig/spanconfigstore/span_store.go
index fe5b6eb3e0a2..269da4e8379f 100644
--- a/pkg/spanconfig/spanconfigstore/span_store.go
+++ b/pkg/spanconfig/spanconfigstore/span_store.go
@@ -24,23 +24,23 @@ import (
 	"github.com/cockroachdb/errors"
 )
 
-// tenantCoalesceAdjacentSetting is a hidden cluster setting that controls
-// whether we coalesce adjacent ranges in the tenant keyspace if they have the
-// same span config.
+// tenantCoalesceAdjacentSetting is a hidden cluster setting that
+// controls whether we coalesce adjacent ranges across all secondary
+// tenant keyspaces if they have the same span config.
 var tenantCoalesceAdjacentSetting = settings.RegisterBoolSetting(
 	settings.SystemOnly,
 	"spanconfig.tenant_coalesce_adjacent.enabled",
-	`collapse adjacent ranges with the same span configs`,
+	`collapse adjacent ranges with the same span configs across all secondary tenant keyspaces`,
 	true,
 )
 
-// hostCoalesceAdjacentSetting is a hidden cluster setting that controls
-// whether we coalesce adjacent ranges in the host tenant keyspace if they have
-// the same span config.
-var hostCoalesceAdjacentSetting = settings.RegisterBoolSetting(
+// storageCoalesceAdjacentSetting is a hidden cluster setting that
+// controls whether we coalesce adjacent ranges outside of the
+// secondary tenant keyspaces if they have the same span config.
+var storageCoalesceAdjacentSetting = settings.RegisterBoolSetting(
 	settings.SystemOnly,
-	"spanconfig.host_coalesce_adjacent.enabled",
-	`collapse adjacent ranges with the same span configs`,
+	"spanconfig.storage_coalesce_adjacent.enabled",
+	`collapse adjacent ranges with the same span configs for the ranges specific to the system tenant`,
 	false,
 )
 
@@ -152,7 +152,7 @@ func (s *spanConfigStore) computeSplitKey(start, end roachpb.RKey) (roachpb.RKey
 			// ranges.
 			systemTableUpperBound := keys.SystemSQLCodec.TablePrefix(keys.MaxReservedDescID + 1)
 			if roachpb.Key(rem).Compare(systemTableUpperBound) < 0 ||
-				!hostCoalesceAdjacentSetting.Get(&s.settings.SV) {
+				!storageCoalesceAdjacentSetting.Get(&s.settings.SV) {
 				return roachpb.RKey(match.span.Key), nil
 			}
 		} else {
diff --git a/pkg/sql/generate_objects_test.go b/pkg/sql/generate_objects_test.go
index 2bbac07973b7..9903629b83bf 100644
--- a/pkg/sql/generate_objects_test.go
+++ b/pkg/sql/generate_objects_test.go
@@ -46,7 +46,7 @@ func BenchmarkGenerateObjects(b *testing.B) {
 
 	// Disable auto stats and range splits, which introduce noise.
 	db.Exec(b, `SET CLUSTER SETTING sql.stats.automatic_collection.enabled = false`)
-	db.Exec(b, `SET CLUSTER SETTING spanconfig.host_coalesce_adjacent.enabled = true`)
+	db.Exec(b, `SET CLUSTER SETTING spanconfig.storage_coalesce_adjacent.enabled = true`)
 
 	for _, bench := range benches {
 		b.Run(bench.name, func(b *testing.B) {

From 5205e67fd1238cf698c2c74e1610609d565a8679 Mon Sep 17 00:00:00 2001
From: Erik Grinaker <grinaker@cockroachlabs.com>
Date: Sat, 28 Jan 2023 12:40:28 +0000
Subject: [PATCH 2/2] cli/cliflags: update `max-offset` help text

The max offset was recently allowed to differ between nodes to allow
changing it via a rolling restart. This patch updates the `--max-offset`
help text to reflect this.

Epic: none
Release note: None
---
 pkg/cli/cliflags/flags.go | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/pkg/cli/cliflags/flags.go b/pkg/cli/cliflags/flags.go
index 779a1e95090b..e8be1bd6208c 100644
--- a/pkg/cli/cliflags/flags.go
+++ b/pkg/cli/cliflags/flags.go
@@ -901,9 +901,11 @@ failures as well as the frequency of uncertainty-based read restarts.
 <PRE>
 
 </PRE>
-Note that this value must be the same on all nodes in the cluster. In order to
-change it, all nodes in the cluster must be stopped simultaneously and restarted
-with the new value.`,
+This value should be the same on all nodes in the cluster. It is allowed to
+differ such that the max-offset value can be changed via a rolling restart of
+the cluster, in which case the real clock offset between nodes must be below the
+smallest max-offset value of any node.
+`,
 	}
 
 	Store = FlagInfo{