kvserver: remove deprecated last split qps

This patch removes the deprecated 'lastSplitQPS' value throughout the
split/merge code. This field was deprecated in 22.1 in favor or
`maxSplitQPS` and stopped being consulted in 22.2.

A remaining field `max_queries_per_second_set` will remain until 23.2
where it can be removed as no node should consult it.

Now only `maxSplitQPS` is consulted and set in `RangeStatsResponse`.

Release note: None

pkg/kv/kvserver/batcheval/cmd_range_stats.go

@@ -44,7 +44,6 @@ func RangeStats(
 ) (result.Result, error) {
 	reply := resp.(*roachpb.RangeStatsResponse)
 	reply.MVCCStats = cArgs.EvalCtx.GetMVCCStats()
-	reply.DeprecatedLastQueriesPerSecond = cArgs.EvalCtx.GetLastSplitQPS(ctx)
 	if qps, ok := cArgs.EvalCtx.GetMaxSplitQPS(ctx); ok {
 		reply.MaxQueriesPerSecond = qps
 	} else {

pkg/kv/kvserver/batcheval/eval_context.go

@@ -94,14 +94,6 @@ type EvalContext interface {
 	// is disabled.
 	GetMaxSplitQPS(context.Context) (float64, bool)
 
-	// GetLastSplitQPS returns the Replica's most recent queries/s request rate.
-	//
-	// NOTE: This should not be used when the load based splitting cluster setting
-	// is disabled.
-	//
-	// TODO(nvanbenschoten): remove this method in v22.1.
-	GetLastSplitQPS(context.Context) float64
-
 	GetGCThreshold() hlc.Timestamp
 	ExcludeDataFromBackup() bool
 	GetLastReplicaGCTimestamp(context.Context) (hlc.Timestamp, error)
@@ -248,9 +240,6 @@ func (m *mockEvalCtxImpl) GetMVCCStats() enginepb.MVCCStats {
 func (m *mockEvalCtxImpl) GetMaxSplitQPS(context.Context) (float64, bool) {
 	return m.QPS, true
 }
-func (m *mockEvalCtxImpl) GetLastSplitQPS(context.Context) float64 {
-	return m.QPS
-}
 func (m *mockEvalCtxImpl) CanCreateTxnRecord(
 	context.Context, uuid.UUID, []byte, hlc.Timestamp,
 ) (bool, roachpb.TransactionAbortedReason) {

pkg/kv/kvserver/merge_queue.go

@@ -199,13 +199,8 @@ func (mq *mergeQueue) requestRangeStats(
 
 	desc = &res.RangeInfo.Desc
 	stats = res.MVCCStats
-	if res.MaxQueriesPerSecondSet {
-		qps = res.MaxQueriesPerSecond
-		qpsOK = qps >= 0
-	} else {
-		qps = res.DeprecatedLastQueriesPerSecond
-		qpsOK = true
-	}
+	qps = res.MaxQueriesPerSecond
+	qpsOK = qps >= 0
 	return desc, stats, qps, qpsOK, nil
 }
 

pkg/kv/kvserver/replica.go

@@ -1298,16 +1298,6 @@ func (r *Replica) GetMaxSplitQPS(ctx context.Context) (float64, bool) {
 	return r.loadBasedSplitter.MaxQPS(ctx, r.Clock().PhysicalTime())
 }
 
-// GetLastSplitQPS returns the Replica's most recent queries/s request rate.
-//
-// NOTE: This should only be used for load based splitting, only
-// works when the load based splitting cluster setting is enabled.
-//
-// Use QueriesPerSecond() for current QPS stats for all other purposes.
-func (r *Replica) GetLastSplitQPS(ctx context.Context) float64 {
-	return r.loadBasedSplitter.LastQPS(ctx, r.Clock().PhysicalTime())
-}
-
 // ContainsKey returns whether this range contains the specified key.
 //
 // TODO(bdarnell): This is not the same as RangeDescriptor.ContainsKey.

pkg/kv/kvserver/replica_eval_context_span.go

@@ -135,12 +135,6 @@ func (rec SpanSetReplicaEvalContext) GetMaxSplitQPS(ctx context.Context) (float6
 	return rec.i.GetMaxSplitQPS(ctx)
 }
 
-// GetLastSplitQPS returns the Replica's most recent queries/s rate for
-// splitting and merging purposes.
-func (rec SpanSetReplicaEvalContext) GetLastSplitQPS(ctx context.Context) float64 {
-	return rec.i.GetLastSplitQPS(ctx)
-}
-
 // CanCreateTxnRecord determines whether a transaction record can be created
 // for the provided transaction information. See Replica.CanCreateTxnRecord
 // for details about its arguments, return values, and preconditions.

pkg/kv/kvserver/split_queue.go

@@ -267,6 +267,7 @@ func (sq *splitQueue) processAttempt(
 		batchHandledQPS := loadStats.QueriesPerSecond
 		raftAppliedQPS := loadStats.WriteKeysPerSecond
 		splitQPS := r.loadBasedSplitter.LastQPS(ctx, now)
+
 		reason := fmt.Sprintf(
 			"load at key %s (%.2f splitQPS, %.2f batches/sec, %.2f raft mutations/sec)",
 			splitByLoadKey,

pkg/roachpb/api.proto

@@ -2104,13 +2104,6 @@ message RangeStatsResponse {
     (gogoproto.customname) = "MVCCStats"
   ];
 
-  // DeprecatedLastQueriesPerSecond is the most recent rate of request/s or QPS
-  // for the range. The field is deprecated in favor of MaxQueriesPerSecond.
-  //
-  // TODO(nvanbenschoten): remove this field in v22.1 when all nodes in the
-  // cluster are guaranteed to return MaxQueriesPerSecond.
-  double deprecated_last_queries_per_second = 3;
-
   // MaxQueriesPerSecond is the maximum rate of request/s or QPS that the range
   // has served over a configured measurement period. Set to -1 if the replica
   // serving the RangeStats request has not been the leaseholder long enough to
@@ -2123,15 +2116,15 @@ message RangeStatsResponse {
   // by the server. Used to distinguish 0 qps set by a new server from the field
   // not being set at all by an old server.
   //
-  // TODO(nvanbenschoten): stop consulting this field on the receiver in v22.1
-  // when all nodes in the cluster are guaranteed to return MaxQueriesPerSecond.
-  //
-  // TODO(nvanbenschoten): stop setting this field and remove it in v22.2 when
+  // TODO(kvoli): stop setting this field and remove it in v23.2 when
   // no nodes in the cluster consult this field.
   bool max_queries_per_second_set = 6;
 
+
   // range_info contains descriptor and lease information.
   RangeInfo range_info = 4 [(gogoproto.nullable) = false];
+
+  reserved 3;
 }
 
 // MigrateRequest is used instruct all ranges overlapping with it to exercise