kv: fix redaction in merge logging

This commit is like the previous commit, but for range merges instead of
range splits. It improves the redaction so that the "reason" field will
be usable when debugging cloud clusters.

Epic: None
Release note: None

pkg/kv/kvserver/merge_queue.go

@@ -12,7 +12,6 @@ package kvserver
 
 import (
 	"context"
-	"fmt"
 	"math"
 	"time"
 
@@ -28,6 +27,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/util/humanizeutil"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/errors"
+	"github.com/cockroachdb/redact"
 )
 
 const (
@@ -273,7 +273,7 @@ func (mq *mergeQueue) process(
 	mergedStats.Add(rhsStats)
 
 	lhsLoadSplitSnap := lhsRepl.loadBasedSplitter.Snapshot(ctx, mq.store.Clock().PhysicalTime())
-	var loadMergeReason string
+	var loadMergeReason redact.RedactableString
 	if lhsRepl.SplitByLoadEnabled() {
 		var canMergeLoad bool
 		if canMergeLoad, loadMergeReason = canMergeRangeLoad(
@@ -387,7 +387,7 @@ func (mq *mergeQueue) process(
 	}
 
 	log.VEventf(ctx, 2, "merging to produce range: %s-%s", mergedDesc.StartKey, mergedDesc.EndKey)
-	reason := fmt.Sprintf("lhs+rhs size (%s+%s=%s) below threshold (%s) %s",
+	reason := redact.Sprintf("lhs+rhs size (%s+%s=%s) below threshold (%s) %s",
 		humanizeutil.IBytes(lhsStats.Total()),
 		humanizeutil.IBytes(rhsStats.Total()),
 		humanizeutil.IBytes(mergedStats.Total()),
@@ -448,7 +448,7 @@ func (mq *mergeQueue) updateChan() <-chan time.Time {
 
 func canMergeRangeLoad(
 	ctx context.Context, lhs, rhs split.LoadSplitSnapshot,
-) (can bool, reason string) {
+) (can bool, reason redact.RedactableString) {
 	// When load is a consideration for splits and, by extension, merges, the
 	// mergeQueue is fairly conservative. In an effort to avoid thrashing and to
 	// avoid overreacting to temporary fluctuations in load, the mergeQueue will
@@ -471,7 +471,7 @@ func canMergeRangeLoad(
 	// just after changing the split objective to a different value, where
 	// there is a mismatch.
 	if lhs.SplitObjective != rhs.SplitObjective {
-		return false, fmt.Sprintf("LHS load measurement is a different type (%s) than the RHS (%s)",
+		return false, redact.Sprintf("LHS load measurement is a different type (%s) than the RHS (%s)",
 			lhs.SplitObjective,
 			rhs.SplitObjective,
 		)
@@ -486,7 +486,7 @@ func canMergeRangeLoad(
 	conservativeLoadBasedSplitThreshold := 0.5 * lhs.Threshold
 
 	if merged >= conservativeLoadBasedSplitThreshold {
-		return false, fmt.Sprintf("lhs+rhs %s (%s+%s=%s) above threshold (%s)",
+		return false, redact.Sprintf("lhs+rhs %s (%s+%s=%s) above threshold (%s)",
 			obj,
 			obj.Format(lhs.Max),
 			obj.Format(rhs.Max),
@@ -495,7 +495,7 @@ func canMergeRangeLoad(
 		)
 	}
 
-	return true, fmt.Sprintf("lhs+rhs %s (%s+%s=%s) below threshold (%s)",
+	return true, redact.Sprintf("lhs+rhs %s (%s+%s=%s) below threshold (%s)",
 		obj,
 		obj.Format(lhs.Max),
 		obj.Format(rhs.Max),

pkg/kv/kvserver/replica_command.go

@@ -595,7 +595,7 @@ func (r *Replica) executeAdminCommandWithDescriptor(
 // The supplied RangeDescriptor is used as a form of optimistic lock. See the
 // comment of "AdminSplit" for more information on this pattern.
 func (r *Replica) AdminMerge(
-	ctx context.Context, args kvpb.AdminMergeRequest, reason string,
+	ctx context.Context, args kvpb.AdminMergeRequest, reason redact.RedactableString,
 ) (kvpb.AdminMergeResponse, *kvpb.Error) {
 	var reply kvpb.AdminMergeResponse