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.

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

Release note: None

docs/generated/settings/settings.html

@@ -44,9 +44,11 @@
 <tr><td><div id="setting-jobs-retention-time" class="anchored"><code>jobs.retention_time</code></div></td><td>duration</td><td><code>336h0m0s</code></td><td>the amount of time to retain records for completed jobs before</td></tr>
 <tr><td><div id="setting-kv-allocator-load-based-lease-rebalancing-enabled" class="anchored"><code>kv.allocator.load_based_lease_rebalancing.enabled</code></div></td><td>boolean</td><td><code>true</code></td><td>set to enable rebalancing of range leases based on load and latency</td></tr>
 <tr><td><div id="setting-kv-allocator-load-based-rebalancing" class="anchored"><code>kv.allocator.load_based_rebalancing</code></div></td><td>enumeration</td><td><code>leases and replicas</code></td><td>whether to rebalance based on the distribution of load across stores [off = 0, leases = 1, leases and replicas = 2]</td></tr>
+<tr><td><div id="setting-kv-allocator-load-based-rebalancing-dimension" class="anchored"><code>kv.allocator.load_based_rebalancing_dimension</code></div></td><td>enumeration</td><td><code>store_cpu</code></td><td>what dimension of load does rebalancing consider [qps = 0, store_cpu = 1]</td></tr>
 <tr><td><div id="setting-kv-allocator-load-based-rebalancing-interval" class="anchored"><code>kv.allocator.load_based_rebalancing_interval</code></div></td><td>duration</td><td><code>1m0s</code></td><td>the rough interval at which each store will check for load-based lease / replica rebalancing opportunities</td></tr>
 <tr><td><div id="setting-kv-allocator-qps-rebalance-threshold" class="anchored"><code>kv.allocator.qps_rebalance_threshold</code></div></td><td>float</td><td><code>0.1</code></td><td>minimum fraction away from the mean a store&#39;s QPS (such as queries per second) can be before it is considered overfull or underfull</td></tr>
 <tr><td><div id="setting-kv-allocator-range-rebalance-threshold" class="anchored"><code>kv.allocator.range_rebalance_threshold</code></div></td><td>float</td><td><code>0.05</code></td><td>minimum fraction away from the mean a store&#39;s range count can be before it is considered overfull or underfull</td></tr>
+<tr><td><div id="setting-kv-allocator-store-cpu-rebalance-threshold" class="anchored"><code>kv.allocator.store_cpu_rebalance_threshold</code></div></td><td>float</td><td><code>0.1</code></td><td>minimum fraction away from the mean a store&#39;s cpu usage can be before it is considered overfull or underfull</td></tr>
 <tr><td><div id="setting-kv-bulk-io-write-max-rate" class="anchored"><code>kv.bulk_io_write.max_rate</code></div></td><td>byte size</td><td><code>1.0 TiB</code></td><td>the rate limit (bytes/sec) to use for writes to disk on behalf of bulk io ops</td></tr>
 <tr><td><div id="setting-kv-bulk-sst-max-allowed-overage" class="anchored"><code>kv.bulk_sst.max_allowed_overage</code></div></td><td>byte size</td><td><code>64 MiB</code></td><td>if positive, allowed size in excess of target size for SSTs from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory</td></tr>
 <tr><td><div id="setting-kv-bulk-sst-target-size" class="anchored"><code>kv.bulk_sst.target_size</code></div></td><td>byte size</td><td><code>16 MiB</code></td><td>target size for SSTs emitted from export requests; export requests (i.e. BACKUP) may buffer up to the sum of kv.bulk_sst.target_size and kv.bulk_sst.max_allowed_overage in memory</td></tr>

pkg/kv/kvserver/batcheval/cmd_range_stats.go

@@ -44,14 +44,12 @@ 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 {
 		// See comment on MaxQueriesPerSecond. -1 means !ok.
 		reply.MaxQueriesPerSecond = -1
 	}
-	reply.MaxQueriesPerSecondSet = true
 	reply.RangeInfo = cArgs.EvalCtx.GetRangeInfo(ctx)
 	return result.Result{}, nil
 }

pkg/kv/kvserver/batcheval/eval_context.go

@@ -89,14 +89,6 @@ 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)
@@ -242,9 +234,6 @@ 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, hlc.Timestamp, 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

@@ -1123,16 +1123,6 @@ 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

@@ -2083,13 +2083,6 @@ 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
@@ -2098,19 +2091,11 @@ message RangeStatsResponse {
   // base important decisions off of.
   double max_queries_per_second = 5;
 
-  // MaxQueriesPerSecondSet indicates that the MaxQueriesPerSecond field is set
-  // 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
-  // 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;
+  reserved 6;
 }
 
 // MigrateRequest is used instruct all ranges overlapping with it to exercise