Remove legacy EmergencyReparentShard stats

changelog/20.0/20.0.0/summary.md

@@ -7,6 +7,7 @@
  - [MySQL binaries in the vitess/lite Docker images](#vitess-lite)
  - [vitess/base and vitess/k8s Docker images](#base-k8s-images)
  - [`gh-ost` binary and endtoend tests](#gh-ost-binary-tests-removal)
+ - [Legacy `EmergencyReparentShard` stats](#legacy-emergencyshardreparent-stats)
  - **[Breaking changes](#breaking-changes)**
  - [`shutdown_grace_period` Default Change](#shutdown-grace-period-default)
  - [New `unmanaged` Flag and `disable_active_reparents` deprecation](#unmanaged-flag)
@@ -95,6 +96,19 @@ Vitess 20.0 drops support for `gh-ost` DDL strategy.
 
 Vitess' endtoend tests no longer use nor test `gh-ost` migrations.
 
+#### <a id="legacy-emergencyshardreparent-stats"/>Legacy `EmergencyReparentShard` stats
+
+The following `EmergencyReparentShard` stats were deprecated in Vitess 18.0 and are removed in Vitess 20.0:
+- `ers_counter`
+- `ers_success_counter`
+- `ers_failure_counter`
+
+These counters are replaced by the following stats _(introduced in Vitess 18.0)_:
+- `emergency_reparent_counts` - Number of times `EmergencyReparentShard` has been run. It is further subdivided by the keyspace, shard and the result of the operation.
+- `planned_reparent_counts` - Number of times `PlannedReparentShard` has been run. It is further subdivided by the keyspace, shard and the result of the operation.
+
+Also, the `reparent_shard_operation_timings` stat was added to provide per-operation timings of reparent operations.
+
 ### <a id="breaking-changes"/>Breaking Changes
 
 #### <a id="shutdown-grace-period-default"/>`shutdown_grace_period` Default Change
@@ -256,4 +270,4 @@ The internal gRPC client now caches the static auth credentials and supports rel
 #### <a id="updated-node"/>vtadmin-web updated to node v20.12.2 (LTS)
 
 Building `vtadmin-web` now requires node >= v20.12.0 (LTS). Breaking changes from v18 to v20 can be found at https://nodejs.org/en/blog/release/v20.12.0 -- with no known issues that apply to VTAdmin.
-Full details on the node v20.12.2 release can be found at https://nodejs.org/en/blog/release/v20.12.2.
+Full details on the node v20.12.2 release can be found at https://nodejs.org/en/blog/release/v20.12.2.

go/vt/vtctl/reparentutil/emergency_reparenter.go

@@ -68,15 +68,8 @@ type EmergencyReparentOptions struct {
 }
 
 // counters for Emergency Reparent Shard
-var (
- // TODO(timvaillancourt): remove legacyERS* gauges in v19+.
- legacyERSCounter = stats.NewGauge("ers_counter", "Number of times Emergency Reparent Shard has been run")
- legacyERSSuccessCounter = stats.NewGauge("ers_success_counter", "Number of times Emergency Reparent Shard has succeeded")
- legacyERSFailureCounter = stats.NewGauge("ers_failure_counter", "Number of times Emergency Reparent Shard has failed")
-
- ersCounter = stats.NewCountersWithMultiLabels("emergency_reparent_counts", "Number of times Emergency Reparent Shard has been run",
- []string{"Keyspace", "Shard", "Result"},
- )
+var ersCounter = stats.NewCountersWithMultiLabels("emergency_reparent_counts", "Number of times Emergency Reparent Shard has been run",
+ []string{"Keyspace", "Shard", "Result"},
 )
 
 // NewEmergencyReparenter returns a new EmergencyReparenter object, ready to
@@ -125,11 +118,9 @@ func (erp *EmergencyReparenter) ReparentShard(ctx context.Context, keyspace stri
  reparentShardOpTimings.Add("EmergencyReparentShard", time.Since(startTime))
  switch err {
  case nil:
- legacyERSSuccessCounter.Add(1)
  ersCounter.Add(append(statsLabels, successResult), 1)
  event.DispatchUpdate(ev, "finished EmergencyReparentShard")
  default:
- legacyERSFailureCounter.Add(1)
  ersCounter.Add(append(statsLabels, failureResult), 1)
  event.DispatchUpdate(ev, "failed EmergencyReparentShard: "+err.Error())
  }
@@ -154,7 +145,6 @@ func (erp *EmergencyReparenter) getLockAction(newPrimaryAlias *topodatapb.Tablet
 func (erp *EmergencyReparenter) reparentShardLocked(ctx context.Context, ev *events.Reparent, keyspace, shard string, opts EmergencyReparentOptions) (err error) {
  // log the starting of the operation and increment the counter
  erp.logger.Infof("will initiate emergency reparent shard in keyspace - %s, shard - %s", keyspace, shard)
- legacyERSCounter.Add(1)
 
  var (
  stoppedReplicationSnapshot *replicationSnapshot

go/vt/vtctl/reparentutil/emergency_reparenter_test.go

@@ -2725,9 +2725,6 @@ func TestEmergencyReparenter_waitForAllRelayLogsToApply(t *testing.T) {
 
 func TestEmergencyReparenterStats(t *testing.T) {
  ersCounter.ResetAll()
- legacyERSCounter.Reset()
- legacyERSSuccessCounter.Reset()
- legacyERSFailureCounter.Reset()
  reparentShardOpTimings.Reset()
 
  emergencyReparentOps := EmergencyReparentOptions{}
@@ -2860,11 +2857,6 @@ func TestEmergencyReparenterStats(t *testing.T) {
  require.EqualValues(t, map[string]int64{"testkeyspace.-.success": 1}, ersCounter.Counts())
  require.EqualValues(t, map[string]int64{"All": 1, "EmergencyReparentShard": 1}, reparentShardOpTimings.Counts())
 
- // check the legacy counter values
- require.EqualValues(t, 1, legacyERSCounter.Get())
- require.EqualValues(t, 1, legacyERSSuccessCounter.Get())
- require.EqualValues(t, 0, legacyERSFailureCounter.Get())
-
  // set emergencyReparentOps to request a non existent tablet
  emergencyReparentOps.NewPrimaryAlias = &topodatapb.TabletAlias{
  Cell: "bogus",
@@ -2878,11 +2870,6 @@ func TestEmergencyReparenterStats(t *testing.T) {
  // check the counter values
  require.EqualValues(t, map[string]int64{"testkeyspace.-.success": 1, "testkeyspace.-.failure": 1}, ersCounter.Counts())
  require.EqualValues(t, map[string]int64{"All": 2, "EmergencyReparentShard": 2}, reparentShardOpTimings.Counts())
-
- // check the legacy counter values
- require.EqualValues(t, 2, legacyERSCounter.Get())
- require.EqualValues(t, 1, legacyERSSuccessCounter.Get())
- require.EqualValues(t, 1, legacyERSFailureCounter.Get())
 }
 
 func TestEmergencyReparenter_findMostAdvanced(t *testing.T) {