cluster: remove VersionPushTxnToInclusive and PushTxnReq.DeprecatedNow

I had it commented that we could also remove `InclusivePushTo` in 19.2,
but I now think that was incorrect. We still need to set it to true to
prevent 19.1 nodes that have yet to hear about the `VersionPushTxnToInclusive`
becoming active from thinking that the Replica sending the PushTxnRequest
is a 2.1 node (which sent exclusive push to timestamps).

Release note: None

pkg/roachpb/api.proto

@@ -873,15 +873,8 @@ message PushTxnRequest {
   // is the timestamp they want the transaction to be pushed to, instead of
   // the timestamp before the one they want the transaction to be pushed to.
   // It is used to assist that field's migration.
-  // TODO(nvanbenschoten): Remove this field in 19.2.
+  // TODO(nvanbenschoten): Remove this field in 19.3.
   bool inclusive_push_to = 9;
-  // DeprecatedNow holds the timestamp used to compare the last heartbeat of the
-  // pushee against.
-  //
-  // The field remains for compatibility with 2.1 nodes. Users should set the
-  // same value for this field and the batch header timestamp.
-  // TODO(nvanbenschoten): Remove this field in 19.2.
-  util.hlc.Timestamp deprecated_now = 5 [(gogoproto.nullable) = false];
   // Readers set this to PUSH_TIMESTAMP to move pushee_txn's provisional
   // commit timestamp forward. Writers set this to PUSH_ABORT to request
   // that pushee_txn be aborted if possible. Inconsistent readers set
@@ -892,7 +885,7 @@ message PushTxnRequest {
   // in PushTxn to either abort or push the timestamp.
   bool force = 7;
 
-  reserved 8;
+  reserved 5, 8;
 }
 
 // A PushTxnResponse is the return value from the PushTxn() method. It

pkg/settings/cluster/cockroach_versions.go

@@ -34,7 +34,6 @@ const (
 	Version2_1
 	VersionUnreplicatedRaftTruncatedState // see versionsSingleton for details
 	VersionSideloadedStorageNoReplicaID   // see versionsSingleton for details
-	VersionPushTxnToInclusive
 	VersionSnapshotsWithoutLog
 	Version19_1
 	VersionStart19_2
@@ -442,11 +441,12 @@ var versionsSingleton = keyedVersions([]keyedVersion{
 		Key:     VersionSideloadedStorageNoReplicaID,
 		Version: roachpb.Version{Major: 2, Minor: 1, Unstable: 9},
 	},
-	{
-		// VersionPushTxnToInclusive is https://github.com/cockroachdb/cockroach/pull/35297.
-		Key:     VersionPushTxnToInclusive,
-		Version: roachpb.Version{Major: 2, Minor: 1, Unstable: 10},
-	},
+	// Removed.
+	// {
+	// 	// VersionPushTxnToInclusive is https://github.com/cockroachdb/cockroach/pull/35297.
+	// 	Key:     VersionPushTxnToInclusive,
+	// 	Version: roachpb.Version{Major: 2, Minor: 1, Unstable: 10},
+	// },
 	{
 		// VersionSnapshotsWithoutLog is https://github.com/cockroachdb/cockroach/pull/36714.
 		Key:     VersionSnapshotsWithoutLog,

pkg/storage/intentresolver/contention_queue.go

@@ -267,7 +267,6 @@ func (cq *contentionQueue) add(
 					PusheeTxn:       *pusheeTxn,
 					PushTo:          h.Timestamp.Next(),
 					InclusivePushTo: true,
-					DeprecatedNow:   b.Header.Timestamp,
 					PushType:        roachpb.PUSH_ABORT,
 				})
 				log.VEventf(ctx, 3, "%s pushing %s to detect dependency cycles", txnID(curPusher.txn), pusheeTxn.ID.Short())

pkg/storage/intentresolver/intent_resolver.go

@@ -431,7 +431,6 @@ func (ir *IntentResolver) MaybePushTransactions(
 			PusheeTxn:       pushTxn,
 			PushTo:          h.Timestamp.Next(),
 			InclusivePushTo: true,
-			DeprecatedNow:   b.Header.Timestamp,
 			PushType:        pushType,
 		})
 	}
@@ -693,7 +692,6 @@ func (ir *IntentResolver) CleanupTxnIntentsOnGCAsync(
 						TxnMeta: enginepb.TxnMeta{Priority: enginepb.MaxTxnPriority},
 					},
 					PusheeTxn:       txn.TxnMeta,
-					DeprecatedNow:   b.Header.Timestamp,
 					PushType:        roachpb.PUSH_ABORT,
 					InclusivePushTo: true,
 				})

pkg/storage/replica.go

@@ -1453,7 +1453,6 @@ func (r *Replica) maybeWatchForMerge(ctx context.Context) error {
 					TxnMeta: enginepb.TxnMeta{Priority: enginepb.MinTxnPriority},
 				},
 				PusheeTxn:       intent.Txn,
-				DeprecatedNow:   b.Header.Timestamp,
 				PushType:        roachpb.PUSH_ABORT,
 				InclusivePushTo: true,
 			})

pkg/storage/store.go

@@ -2804,32 +2804,6 @@ func (s *Store) Send(
 		return nil, roachpb.NewError(err)
 	}
 
-	// In 2.1 it was possible for nodes to send PushTxn requests without
-	// properly reflecting the time that they wanted the push to happen
-	// in the batch's header timestamp. Ensure that this timestamp is
-	// sufficiently advanced to prevent lost timestamp cache updates.
-	// TODO(nvanbenschoten): Remove this all in 19.2.
-	if !s.cfg.Settings.Version.IsActive(cluster.VersionPushTxnToInclusive) {
-		for _, union := range ba.Requests {
-			if pushReq, ok := union.GetInner().(*roachpb.PushTxnRequest); ok {
-				ba.Timestamp.Forward(pushReq.DeprecatedNow)
-
-				// While here, correct the request's PushTo arg. Before
-				// VersionPushTxnToInclusive, pushers would provide _their_
-				// timestamp instead of one logical tick past their timestamp
-				// for the PushTo arg. Handle this by bumping the PushTo arg.
-				// We only do this if the InclusivePushTo arg is false, which
-				// allows us to distinguish between 2.1 nodes and 19.1. nodes.
-				// Since we only observe this field when the cluster version
-				// is not active, we don't need to send it or observe it in
-				// 19.2.
-				if !pushReq.InclusivePushTo {
-					pushReq.PushTo = pushReq.PushTo.Next()
-				}
-			}
-		}
-	}
-
 	if s.cfg.TestingKnobs.ClockBeforeSend != nil {
 		s.cfg.TestingKnobs.ClockBeforeSend(s.cfg.Clock, ba)
 	}
@@ -3163,7 +3137,6 @@ func (s *Store) maybeWaitForPushee(
 		// to push a txn which has expired.
 		now := s.Clock().Now()
 		ba.Timestamp.Forward(now)
-		pushReqCopy.DeprecatedNow.Forward(now)
 		ba.Requests = nil
 		ba.Add(&pushReqCopy)
 	} else if ba.IsSingleQueryTxnRequest() {