keys: rename RangeLastGCKey to RangeGCThresholdKey

The key `RangeLastGCKey` was not actually used to store the last GC
timestamp, but rather the last GC threshold. This commit renames the key
to the more appropriate `RangeGCThresholdKey`.

Release note: None

pkg/ccl/storageccl/export.go

@@ -62,7 +62,7 @@ func declareKeysExport(
 	latchSpans, lockSpans *spanset.SpanSet,
 ) {
 	batcheval.DefaultDeclareIsolatedKeys(rs, header, req, latchSpans, lockSpans)
-	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeLastGCKey(header.RangeID)})
+	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeGCThresholdKey(header.RangeID)})
 }
 
 // evalExport dumps the requested keys into files of non-overlapping key ranges

pkg/keys/constants.go

@@ -77,8 +77,9 @@ var (
 	LocalAbortSpanSuffix = []byte("abc-")
 	// localRangeFrozenStatusSuffix is DEPRECATED and remains to prevent reuse.
 	localRangeFrozenStatusSuffix = []byte("fzn-")
-	// LocalRangeLastGCSuffix is the suffix for the last GC.
-	LocalRangeLastGCSuffix = []byte("lgc-")
+	// LocalRangeGCThresholdSuffix is the suffix for the GC threshold. It keeps
+	// the lgc- ("last GC") representation for backwards compatibility.
+	LocalRangeGCThresholdSuffix = []byte("lgc-")
 	// LocalRangeAppliedStateSuffix is the suffix for the range applied state
 	// key.
 	LocalRangeAppliedStateSuffix = []byte("rask")

pkg/keys/doc.go

@@ -186,7 +186,7 @@ var _ = [...]interface{}{
 	//   Typical examples are MVCC stats and the abort span. They all share
 	//   `LocalRangeIDPrefix` and `LocalRangeIDReplicatedInfix`.
 	AbortSpanKey,                // "abc-"
-	RangeLastGCKey,              // "lgc-"
+	RangeGCThresholdKey,         // "lgc-"
 	RangeAppliedStateKey,        // "rask"
 	RaftAppliedIndexLegacyKey,   // "rfta"
 	RaftTruncatedStateLegacyKey, // "rftt"

pkg/keys/keys.go

@@ -284,12 +284,10 @@ func RangeStatsLegacyKey(rangeID roachpb.RangeID) roachpb.Key {
 	return MakeRangeIDPrefixBuf(rangeID).RangeStatsLegacyKey()
 }
 
-// RangeLastGCKey returns a system-local key for last used GC threshold on the
+// RangeGCThresholdKey returns a system-local key for last used GC threshold on the
 // user keyspace. Reads and writes <= this timestamp will not be served.
-//
-// TODO(tschottdorf): should be renamed to RangeGCThresholdKey.
-func RangeLastGCKey(rangeID roachpb.RangeID) roachpb.Key {
-	return MakeRangeIDPrefixBuf(rangeID).RangeLastGCKey()
+func RangeGCThresholdKey(rangeID roachpb.RangeID) roachpb.Key {
+	return MakeRangeIDPrefixBuf(rangeID).RangeGCThresholdKey()
 }
 
 // RangeVersionKey returns a system-local for the range version.
@@ -971,9 +969,9 @@ func (b RangeIDPrefixBuf) RangeStatsLegacyKey() roachpb.Key {
 	return append(b.replicatedPrefix(), LocalRangeStatsLegacySuffix...)
 }
 
-// RangeLastGCKey returns a system-local key for the last GC.
-func (b RangeIDPrefixBuf) RangeLastGCKey() roachpb.Key {
-	return append(b.replicatedPrefix(), LocalRangeLastGCSuffix...)
+// RangeGCThresholdKey returns a system-local key for the GC threshold.
+func (b RangeIDPrefixBuf) RangeGCThresholdKey() roachpb.Key {
+	return append(b.replicatedPrefix(), LocalRangeGCThresholdSuffix...)
 }
 
 // RangeVersionKey returns a system-local key for the range version.

pkg/keys/printer.go

@@ -171,7 +171,7 @@ var (
 		{name: "RangeLease", suffix: LocalRangeLeaseSuffix},
 		{name: "RangePriorReadSummary", suffix: LocalRangePriorReadSummarySuffix},
 		{name: "RangeStats", suffix: LocalRangeStatsLegacySuffix},
-		{name: "RangeLastGC", suffix: LocalRangeLastGCSuffix},
+		{name: "RangeGCThreshold", suffix: LocalRangeGCThresholdSuffix},
 		{name: "RangeVersion", suffix: LocalRangeVersionSuffix},
 	}
 

pkg/keys/printer_test.go

@@ -76,7 +76,7 @@ func TestPrettyPrint(t *testing.T) {
 		{keys.RangeLeaseKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangeLease", revertSupportUnknown},
 		{keys.RangePriorReadSummaryKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangePriorReadSummary", revertSupportUnknown},
 		{keys.RangeStatsLegacyKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangeStats", revertSupportUnknown},
-		{keys.RangeLastGCKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangeLastGC", revertSupportUnknown},
+		{keys.RangeGCThresholdKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangeGCThreshold", revertSupportUnknown},
 		{keys.RangeVersionKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/r/RangeVersion", revertSupportUnknown},
 
 		{keys.RaftHardStateKey(roachpb.RangeID(1000001)), "/Local/RangeID/1000001/u/RaftHardState", revertSupportUnknown},

pkg/kv/kvserver/batcheval/cmd_gc.go

@@ -45,7 +45,7 @@ func declareKeysGC(
 	// request first to bump the thresholds, and then another one that actually does work
 	// but can avoid declaring these keys below.
 	if !gcr.Threshold.IsEmpty() {
-		latchSpans.AddNonMVCC(spanset.SpanReadWrite, roachpb.Span{Key: keys.RangeLastGCKey(rs.GetRangeID())})
+		latchSpans.AddNonMVCC(spanset.SpanReadWrite, roachpb.Span{Key: keys.RangeGCThresholdKey(rs.GetRangeID())})
 	}
 	// Needed for Range bounds checks in calls to EvalContext.ContainsKey.
 	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeDescriptorKey(rs.GetStartKey())})

pkg/kv/kvserver/batcheval/cmd_revert_range.go

@@ -36,7 +36,7 @@ func declareKeysRevertRange(
 	// We look up the range descriptor key to check whether the span
 	// is equal to the entire range for fast stats updating.
 	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeDescriptorKey(rs.GetStartKey())})
-	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeLastGCKey(rs.GetRangeID())})
+	latchSpans.AddNonMVCC(spanset.SpanReadOnly, roachpb.Span{Key: keys.RangeGCThresholdKey(rs.GetRangeID())})
 }
 
 // isEmptyKeyTimeRange checks if the span has no writes in (since,until].

pkg/kv/kvserver/debug_print.go

@@ -274,7 +274,7 @@ func tryRangeIDKey(kv storage.MVCCKeyValue) (string, error) {
 	case bytes.Equal(suffix, keys.LocalAbortSpanSuffix):
 		msg = &roachpb.AbortSpanEntry{}
 
-	case bytes.Equal(suffix, keys.LocalRangeLastGCSuffix):
+	case bytes.Equal(suffix, keys.LocalRangeGCThresholdSuffix):
 		msg = &hlc.Timestamp{}
 
 	case bytes.Equal(suffix, keys.LocalRangeVersionSuffix):

pkg/kv/kvserver/kvserverpb/state.proto

@@ -54,7 +54,7 @@ message ReplicaState {
   roachpb.Lease lease = 4;
   // The truncation state of the Raft log.
   roachpb.RaftTruncatedState truncated_state = 5;
-  // gcThreshold is the GC threshold of the Range, typically updated when keys
+  // GCThreshold is the GC threshold of the Range, typically updated when keys
   // are garbage collected. Reads and writes at timestamps <= this time will
   // not be served.
   util.hlc.Timestamp gc_threshold = 6 [(gogoproto.customname) = "GCThreshold"];

pkg/kv/kvserver/rditer/replica_data_iter_test.go

@@ -80,7 +80,7 @@ func createRangeData(
 	}{
 		{keys.AbortSpanKey(desc.RangeID, testTxnID), ts0},
 		{keys.AbortSpanKey(desc.RangeID, testTxnID2), ts0},
-		{keys.RangeLastGCKey(desc.RangeID), ts0},
+		{keys.RangeGCThresholdKey(desc.RangeID), ts0},
 		{keys.RangeAppliedStateKey(desc.RangeID), ts0},
 		{keys.RaftAppliedIndexLegacyKey(desc.RangeID), ts0},
 		{keys.RaftTruncatedStateLegacyKey(desc.RangeID), ts0},

pkg/kv/kvserver/replica_eval_context_span.go

@@ -178,7 +178,7 @@ func (rec SpanSetReplicaEvalContext) CanCreateTxnRecord(
 // not be served.
 func (rec SpanSetReplicaEvalContext) GetGCThreshold() hlc.Timestamp {
 	rec.ss.AssertAllowed(spanset.SpanReadOnly,
-		roachpb.Span{Key: keys.RangeLastGCKey(rec.GetRangeID())},
+		roachpb.Span{Key: keys.RangeGCThresholdKey(rec.GetRangeID())},
 	)
 	return rec.i.GetGCThreshold()
 }

pkg/kv/kvserver/spanset/spanset_test.go

@@ -29,11 +29,11 @@ func TestSpanSetGetSpansScope(t *testing.T) {
 
 	var ss SpanSet
 	ss.AddNonMVCC(SpanReadOnly, roachpb.Span{Key: roachpb.Key("a")})
-	ss.AddNonMVCC(SpanReadOnly, roachpb.Span{Key: keys.RangeLastGCKey(1)})
+	ss.AddNonMVCC(SpanReadOnly, roachpb.Span{Key: keys.RangeGCThresholdKey(1)})
 	ss.AddNonMVCC(SpanReadOnly, roachpb.Span{Key: roachpb.Key("b"), EndKey: roachpb.Key("c")})
 
 	exp := []Span{
-		{Span: roachpb.Span{Key: keys.RangeLastGCKey(1)}},
+		{Span: roachpb.Span{Key: keys.RangeGCThresholdKey(1)}},
 	}
 	if act := ss.GetSpans(SpanReadOnly, SpanLocal); !reflect.DeepEqual(act, exp) {
 		t.Errorf("get local spans: got %v, expected %v", act, exp)
@@ -70,7 +70,7 @@ func TestSpanSetIterate(t *testing.T) {
 	spA := roachpb.Span{Key: roachpb.Key("a")}
 	spRO := roachpb.Span{Key: roachpb.Key("r"), EndKey: roachpb.Key("o")}
 	spRW := roachpb.Span{Key: roachpb.Key("r"), EndKey: roachpb.Key("w")}
-	spLocal := roachpb.Span{Key: keys.RangeLastGCKey(1)}
+	spLocal := roachpb.Span{Key: keys.RangeGCThresholdKey(1)}
 
 	ss := new(SpanSet)
 	ss.AddNonMVCC(SpanReadOnly, spLocal)
@@ -104,7 +104,7 @@ func TestSpanSetMerge(t *testing.T) {
 	spBC := roachpb.Span{Key: roachpb.Key("b"), EndKey: roachpb.Key("c")}
 	spCE := roachpb.Span{Key: roachpb.Key("c"), EndKey: roachpb.Key("e")}
 	spBE := roachpb.Span{Key: roachpb.Key("b"), EndKey: roachpb.Key("e")}
-	spLocal := roachpb.Span{Key: keys.RangeLastGCKey(1)}
+	spLocal := roachpb.Span{Key: keys.RangeGCThresholdKey(1)}
 
 	var ss SpanSet
 	ss.AddNonMVCC(SpanReadOnly, spLocal)
@@ -205,7 +205,7 @@ func TestSpanSetCheckAllowedAtTimestamps(t *testing.T) {
 	ss.AddMVCC(SpanReadOnly, roachpb.Span{Key: roachpb.Key("g")}, hlc.Timestamp{WallTime: 2})
 	ss.AddMVCC(SpanReadWrite, roachpb.Span{Key: roachpb.Key("m"), EndKey: roachpb.Key("o")}, hlc.Timestamp{WallTime: 2})
 	ss.AddMVCC(SpanReadWrite, roachpb.Span{Key: roachpb.Key("s")}, hlc.Timestamp{WallTime: 2})
-	ss.AddNonMVCC(SpanReadWrite, roachpb.Span{Key: keys.RangeLastGCKey(1)})
+	ss.AddNonMVCC(SpanReadWrite, roachpb.Span{Key: keys.RangeGCThresholdKey(1)})
 
 	var allowedRO = []struct {
 		span roachpb.Span
@@ -225,8 +225,8 @@ func TestSpanSetCheckAllowedAtTimestamps(t *testing.T) {
 		{roachpb.Span{Key: roachpb.Key("s")}, hlc.Timestamp{WallTime: 1}},
 
 		// Local keys.
-		{roachpb.Span{Key: keys.RangeLastGCKey(1)}, hlc.Timestamp{}},
-		{roachpb.Span{Key: keys.RangeLastGCKey(1)}, hlc.Timestamp{WallTime: 1}},
+		{roachpb.Span{Key: keys.RangeGCThresholdKey(1)}, hlc.Timestamp{}},
+		{roachpb.Span{Key: keys.RangeGCThresholdKey(1)}, hlc.Timestamp{WallTime: 1}},
 	}
 	for _, tc := range allowedRO {
 		if err := ss.CheckAllowedAt(SpanReadOnly, tc.span, tc.ts); err != nil {
@@ -257,7 +257,7 @@ func TestSpanSetCheckAllowedAtTimestamps(t *testing.T) {
 		{roachpb.Span{Key: roachpb.Key("m"), EndKey: roachpb.Key("n")}, hlc.Timestamp{WallTime: 3}},
 
 		// Local keys.
-		{roachpb.Span{Key: keys.RangeLastGCKey(1)}, hlc.Timestamp{}},
+		{roachpb.Span{Key: keys.RangeGCThresholdKey(1)}, hlc.Timestamp{}},
 	}
 	for _, tc := range allowedRW {
 		if err := ss.CheckAllowedAt(SpanReadWrite, tc.span, tc.ts); err != nil {

pkg/kv/kvserver/stateloader/stateloader.go

@@ -528,7 +528,7 @@ func (rsl StateLoader) LoadGCThreshold(
 	ctx context.Context, reader storage.Reader,
 ) (*hlc.Timestamp, error) {
 	var t hlc.Timestamp
-	_, err := storage.MVCCGetProto(ctx, reader, rsl.RangeLastGCKey(),
+	_, err := storage.MVCCGetProto(ctx, reader, rsl.RangeGCThresholdKey(),
 		hlc.Timestamp{}, &t, storage.MVCCGetOptions{})
 	return &t, err
 }
@@ -544,7 +544,7 @@ func (rsl StateLoader) SetGCThreshold(
 		return errors.New("cannot persist nil GCThreshold")
 	}
 	return storage.MVCCPutProto(ctx, readWriter, ms,
-		rsl.RangeLastGCKey(), hlc.Timestamp{}, nil, threshold)
+		rsl.RangeGCThresholdKey(), hlc.Timestamp{}, nil, threshold)
 }
 
 // LoadVersion loads the replica version.