grafana · krajorama · Apr 18, 2023 · Mar 13, 2023 · Mar 13, 2023 · Mar 13, 2023
diff --git a/cmd/promtool/main.go b/cmd/promtool/main.go
@@ -89,7 +89,6 @@ func main() {
 	app.HelpFlag.Short('h')
 
 	checkCmd := app.Command("check", "Check the resources for validity.")
-	checkCmd.Flag("http.config.file", "HTTP client configuration file for promtool to connect to Prometheus.").PlaceHolder("<filename>").ExistingFileVar(&httpConfigFilePath)
 
 	sdCheckCmd := checkCmd.Command("service-discovery", "Perform service discovery for the given job name and report the results, including relabeling.")
 	sdConfigFile := sdCheckCmd.Arg("config-file", "The prometheus config file.").Required().ExistingFile()
@@ -117,16 +116,12 @@ func main() {
 	).Required().ExistingFiles()
 
 	checkServerHealthCmd := checkCmd.Command("healthy", "Check if the Prometheus server is healthy.")
-	serverHealthURLArg := checkServerHealthCmd.Arg(
-		"server",
-		"The URL of the Prometheus server to check (e.g. http://localhost:9090)",
-	).URL()
+	checkServerHealthCmd.Flag("http.config.file", "HTTP client configuration file for promtool to connect to Prometheus.").PlaceHolder("<filename>").ExistingFileVar(&httpConfigFilePath)
+	checkServerHealthCmd.Flag("url", "The URL for the Prometheus server.").Default("http://localhost:9090").URLVar(&serverURL)
 
 	checkServerReadyCmd := checkCmd.Command("ready", "Check if the Prometheus server is ready.")
-	serverReadyURLArg := checkServerReadyCmd.Arg(
-		"server",
-		"The URL of the Prometheus server to check (e.g. http://localhost:9090)",
-	).URL()
+	checkServerReadyCmd.Flag("http.config.file", "HTTP client configuration file for promtool to connect to Prometheus.").PlaceHolder("<filename>").ExistingFileVar(&httpConfigFilePath)
+	checkServerReadyCmd.Flag("url", "The URL for the Prometheus server.").Default("http://localhost:9090").URLVar(&serverURL)
 
 	checkRulesCmd := checkCmd.Command("rules", "Check if the rule files are valid or not.")
 	ruleFiles := checkRulesCmd.Arg(
@@ -292,10 +287,10 @@ func main() {
 		os.Exit(CheckConfig(*agentMode, *checkConfigSyntaxOnly, newLintConfig(*checkConfigLint, *checkConfigLintFatal), *configFiles...))
 
 	case checkServerHealthCmd.FullCommand():
-		os.Exit(checkErr(CheckServerStatus(*serverHealthURLArg, checkHealth, httpRoundTripper)))
+		os.Exit(checkErr(CheckServerStatus(serverURL, checkHealth, httpRoundTripper)))
 
 	case checkServerReadyCmd.FullCommand():
-		os.Exit(checkErr(CheckServerStatus(*serverReadyURLArg, checkReadiness, httpRoundTripper)))
+		os.Exit(checkErr(CheckServerStatus(serverURL, checkReadiness, httpRoundTripper)))
 
 	case checkWebConfigCmd.FullCommand():
 		os.Exit(CheckWebConfig(*webConfigFiles...))
@@ -390,12 +385,10 @@ func (ls lintConfig) lintDuplicateRules() bool {
 	return ls.all || ls.duplicateRules
 }
 
-const promDefaultURL = "http://localhost:9090"
-
 // Check server status - healthy & ready.
 func CheckServerStatus(serverURL *url.URL, checkEndpoint string, roundTripper http.RoundTripper) error {
-	if serverURL == nil {
-		serverURL, _ = url.Parse(promDefaultURL)
+	if serverURL.Scheme == "" {
+		serverURL.Scheme = "http"
 	}
 
 	config := api.Config{

diff --git a/cmd/promtool/rules.go b/cmd/promtool/rules.go
@@ -163,7 +163,7 @@ func (importer *ruleImporter) importRule(ctx context.Context, ruleExpr, ruleName
 				})
 
 				lb.Set(labels.MetricName, ruleName)
-				lbls := lb.Labels(labels.EmptyLabels())
+				lbls := lb.Labels()
 
 				for _, value := range sample.Values {
 					if err := app.add(ctx, lbls, timestamp.FromTime(value.Timestamp.Time()), float64(value.Value)); err != nil {

diff --git a/cmd/promtool/unittest.go b/cmd/promtool/unittest.go
@@ -347,7 +347,7 @@ Outer:
 		for _, s := range got {
 			gotSamples = append(gotSamples, parsedSample{
 				Labels: s.Metric.Copy(),
-				Value:  s.V,
+				Value:  s.F,
 			})
 		}
 
@@ -447,7 +447,8 @@ func query(ctx context.Context, qs string, t time.Time, engine *promql.Engine, q
 		return v, nil
 	case promql.Scalar:
 		return promql.Vector{promql.Sample{
-			Point:  promql.Point{T: v.T, V: v.V},
+			T:      v.T,
+			F:      v.V,
 			Metric: labels.Labels{},
 		}}, nil
 	default:

diff --git a/config/config.go b/config/config.go
@@ -173,16 +173,16 @@ var (
 
 	// DefaultQueueConfig is the default remote queue configuration.
 	DefaultQueueConfig = QueueConfig{
-		// With a maximum of 200 shards, assuming an average of 100ms remote write
-		// time and 500 samples per batch, we will be able to push 1M samples/s.
-		MaxShards:         200,
+		// With a maximum of 50 shards, assuming an average of 100ms remote write
+		// time and 2000 samples per batch, we will be able to push 1M samples/s.
+		MaxShards:         50,
 		MinShards:         1,
-		MaxSamplesPerSend: 500,
+		MaxSamplesPerSend: 2000,
 
-		// Each shard will have a max of 2500 samples pending in its channel, plus the pending
-		// samples that have been enqueued. Theoretically we should only ever have about 3000 samples
-		// per shard pending. At 200 shards that's 600k.
-		Capacity:          2500,
+		// Each shard will have a max of 10,000 samples pending in its channel, plus the pending
+		// samples that have been enqueued. Theoretically we should only ever have about 12,000 samples
+		// per shard pending. At 50 shards that's 600k.
+		Capacity:          10000,
 		BatchSendDeadline: model.Duration(5 * time.Second),
 
 		// Backoff times for retrying a batch of samples on recoverable errors.
@@ -194,7 +194,7 @@ var (
 	DefaultMetadataConfig = MetadataConfig{
 		Send:              true,
 		SendInterval:      model.Duration(1 * time.Minute),
-		MaxSamplesPerSend: 500,
+		MaxSamplesPerSend: 2000,
 	}
 
 	// DefaultRemoteReadConfig is the default remote read configuration.

diff --git a/docs/command-line/promtool.md b/docs/command-line/promtool.md
@@ -58,7 +58,6 @@ Check the resources for validity.
 
 | Flag | Description |
 | --- | --- |
-| <code class="text-nowrap">--http.config.file</code> | HTTP client configuration file for promtool to connect to Prometheus. |
 | <code class="text-nowrap">--extended</code> | Print extended information related to the cardinality of the metrics. |
 
 
@@ -137,11 +136,12 @@ Check if the Prometheus server is healthy.
 
 
 
-###### Arguments
+###### Flags
 
-| Argument | Description |
-| --- | --- |
-| server | The URL of the Prometheus server to check (e.g. http://localhost:9090) |
+| Flag | Description | Default |
+| --- | --- | --- |
+| <code class="text-nowrap">--http.config.file</code> | HTTP client configuration file for promtool to connect to Prometheus. |  |
+| <code class="text-nowrap">--url</code> | The URL for the Prometheus server. | `http://localhost:9090` |
 
 
 
@@ -152,11 +152,12 @@ Check if the Prometheus server is ready.
 
 
 
-###### Arguments
+###### Flags
 
-| Argument | Description |
-| --- | --- |
-| server | The URL of the Prometheus server to check (e.g. http://localhost:9090) |
+| Flag | Description | Default |
+| --- | --- | --- |
+| <code class="text-nowrap">--http.config.file</code> | HTTP client configuration file for promtool to connect to Prometheus. |  |
+| <code class="text-nowrap">--url</code> | The URL for the Prometheus server. | `http://localhost:9090` |
 
 
 

diff --git a/docs/querying/functions.md b/docs/querying/functions.md
@@ -17,9 +17,7 @@ _Notes about the experimental native histograms:_
   flag](../feature_flags/#native-histograms). As long as no native histograms
   have been ingested into the TSDB, all functions will behave as usual.
 * Functions that do not explicitly mention native histograms in their
-  documentation (see below) effectively treat a native histogram as a float
-  sample of value 0. (This is confusing and will change before native
-  histograms become a stable feature.)
+  documentation (see below) will ignore histogram samples.
 * Functions that do already act on native histograms might still change their
   behavior in the future.
 * If a function requires the same bucket layout between multiple native
@@ -404,6 +402,8 @@ For each timeseries in `v`, `label_join(v instant-vector, dst_label string, sepa
 using `separator` and returns the timeseries with the label `dst_label` containing the joined value.
 There can be any number of `src_labels` in this function.
 
+`label_join` acts on float and histogram samples in the same way.
+
 This example will return a vector with each time series having a `foo` label with the value `a,b,c` added to it:
 
 ```
@@ -419,6 +419,8 @@ of `replacement`, together with the original labels in the input. Capturing grou
 regular expression can be referenced with `$1`, `$2`, etc. If the regular expression doesn't
 match then the timeseries is returned unchanged.
 
+`label_replace` acts on float and histogram samples in the same way.
+
 This example will return timeseries with the values `a:c` at label `service` and `a` at label `foo`:
 
 ```
@@ -501,10 +503,21 @@ counter resets when your target restarts.
 
 For each input time series, `resets(v range-vector)` returns the number of
 counter resets within the provided time range as an instant vector. Any
-decrease in the value between two consecutive samples is interpreted as a
-counter reset.
-
-`resets` should only be used with counters.
+decrease in the value between two consecutive float samples is interpreted as a
+counter reset. A reset in a native histogram is detected in a more complex way:
+Any decrease in any bucket, including the zero bucket, or in the count of
+observation constitutes a counter reset, but also the disappearance of any
+previously populated bucket, an increase in bucket resolution, or a decrease of
+the zero-bucket width.
+
+`resets` should only be used with counters and counter-like native
+histograms.
+
+If the range vector contains a mix of float and histogram samples for the same
+series, counter resets are detected separately and their numbers added up. The
+change from a float to a histogram sample is _not_ considered a counter
+reset. Each float sample is compared to the next float sample, and each
+histogram is comprared to the next histogram.
 
 ## `round()`
 
@@ -526,7 +539,7 @@ have exactly one element, `scalar` will return `NaN`.
 ## `sort()`
 
 `sort(v instant-vector)` returns vector elements sorted by their sample values,
-in ascending order.
+in ascending order. Native histograms are sorted by their sum of observations.
 
 ## `sort_desc()`
 
@@ -545,7 +558,8 @@ expression is to be evaluated.
 ## `timestamp()`
 
 `timestamp(v instant-vector)` returns the timestamp of each of the samples of
-the given vector as the number of seconds since January 1, 1970 UTC.
+the given vector as the number of seconds since January 1, 1970 UTC. It also
+works with histogram samples.
 
 ## `vector()`
 
@@ -569,12 +583,15 @@ over time and return an instant vector with per-series aggregation results:
 * `quantile_over_time(scalar, range-vector)`: the φ-quantile (0 ≤ φ ≤ 1) of the values in the specified interval.
 * `stddev_over_time(range-vector)`: the population standard deviation of the values in the specified interval.
 * `stdvar_over_time(range-vector)`: the population standard variance of the values in the specified interval.
-* `last_over_time(range-vector)`: the most recent point value in specified interval.
+* `last_over_time(range-vector)`: the most recent point value in the specified interval.
 * `present_over_time(range-vector)`: the value 1 for any series in the specified interval.
 
 Note that all values in the specified interval have the same weight in the
 aggregation even if the values are not equally spaced throughout the interval.
 
+`count_over_time`, `last_over_time`, and `present_over_time` handle native
+histograms as expected. All other functions ignore histogram samples.
+
 ## Trigonometric Functions
 
 The trigonometric functions work in radians:

diff --git a/go.mod b/go.mod
@@ -5,7 +5,7 @@ go 1.19
 require (
 	github.com/Azure/azure-sdk-for-go v65.0.0+incompatible
 	github.com/Azure/go-autorest/autorest v0.11.28
-	github.com/Azure/go-autorest/autorest/adal v0.9.22
+	github.com/Azure/go-autorest/autorest/adal v0.9.23
 	github.com/alecthomas/kingpin/v2 v2.3.2
 	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137
 	github.com/aws/aws-sdk-go v1.44.217

diff --git a/go.sum b/go.sum
@@ -45,8 +45,8 @@ github.com/Azure/go-autorest v14.2.0+incompatible/go.mod h1:r+4oMnoxhatjLLJ6zxSW
 github.com/Azure/go-autorest/autorest v0.11.28 h1:ndAExarwr5Y+GaHE6VCaY1kyS/HwwGGyuimVhWsHOEM=
 github.com/Azure/go-autorest/autorest v0.11.28/go.mod h1:MrkzG3Y3AH668QyF9KRk5neJnGgmhQ6krbhR8Q5eMvA=
 github.com/Azure/go-autorest/autorest/adal v0.9.18/go.mod h1:XVVeme+LZwABT8K5Lc3hA4nAe8LDBVle26gTrguhhPQ=
-github.com/Azure/go-autorest/autorest/adal v0.9.22 h1:/GblQdIudfEM3AWWZ0mrYJQSd7JS4S/Mbzh6F0ov0Xc=
-github.com/Azure/go-autorest/autorest/adal v0.9.22/go.mod h1:XuAbAEUv2Tta//+voMI038TrJBqjKam0me7qR+L8Cmk=
+github.com/Azure/go-autorest/autorest/adal v0.9.23 h1:Yepx8CvFxwNKpH6ja7RZ+sKX+DWYNldbLiALMC3BTz8=
+github.com/Azure/go-autorest/autorest/adal v0.9.23/go.mod h1:5pcMqFkdPhviJdlEy3kC/v1ZLnQl0MH6XA5YCcMhy4c=
 github.com/Azure/go-autorest/autorest/date v0.3.0 h1:7gUk1U5M/CQbp9WoqinNzJar+8KY+LPI6wiWrP/myHw=
 github.com/Azure/go-autorest/autorest/date v0.3.0/go.mod h1:BI0uouVdmngYNUzGWeSYnokU+TrmwEsOqdt8Y6sso74=
 github.com/Azure/go-autorest/autorest/mocks v0.4.1/go.mod h1:LTp+uSrOhSkaKrUy935gNZuuIPPVsHlr9DSOxSayd+k=
@@ -828,6 +828,7 @@ golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5y
 golang.org/x/crypto v0.0.0-20220622213112-05595931fe9d/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/crypto v0.0.0-20220829220503-c86fa9a7ed90/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/crypto v0.6.0/go.mod h1:OFC/31mSvZgRz0V1QTNCzfAI1aIRzbiufJtkMIlEp58=
 golang.org/x/crypto v0.7.0 h1:AvwMYaRytfdeVt3u6mLaxYtErKYjxA2OXjJ1HHq6t3A=
 golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
@@ -911,6 +912,7 @@ golang.org/x/net v0.0.0-20211029224645-99673261e6eb/go.mod h1:9nx3DQGgdP8bBQD5qx
 golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
+golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
 golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -1002,11 +1004,13 @@ golang.org/x/sys v0.0.0-20220728004956-3c1f35247d10/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220908164124-27713097b956/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0 h1:MVltZSvRTcU2ljQOhs94SXPftV6DCNnZViHeQps87pQ=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.1.0/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
 golang.org/x/term v0.6.0 h1:clScbb1cHjoCkyRbWwBEUZ5H/tIFu5TAXIqaZD0Gcjw=
 golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/text v0.0.0-20170915032832-14c0d48ead0c/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -1018,6 +1022,7 @@ golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.8.0 h1:57P1ETyNKtuIjB4SRd15iJxuhj8Gc416Y78H3qgMh68=
 golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/time v0.0.0-20180412165947-fbb02b2291d2/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=

diff --git a/model/labels/labels.go b/model/labels/labels.go
@@ -570,24 +570,18 @@ func contains(s []Label, n string) bool {
 	return false
 }
 
-// Labels returns the labels from the builder, adding them to res if non-nil.
-// Argument res can be the same as b.base, if caller wants to overwrite that slice.
+// Labels returns the labels from the builder.
 // If no modifications were made, the original labels are returned.
-func (b *Builder) Labels(res Labels) Labels {
+func (b *Builder) Labels() Labels {
 	if len(b.del) == 0 && len(b.add) == 0 {
 		return b.base
 	}
 
-	if res == nil {
-		// In the general case, labels are removed, modified or moved
-		// rather than added.
-		res = make(Labels, 0, len(b.base))
-	} else {
-		res = res[:0]
+	expectedSize := len(b.base) + len(b.add) - len(b.del)
+	if expectedSize < 1 {
+		expectedSize = 1
 	}
-	// Justification that res can be the same slice as base: in this loop
-	// we move forward through base, and either skip an element or assign
-	// it to res at its current position or an earlier position.
+	res := make(Labels, 0, expectedSize)
 	for _, l := range b.base {
 		if slices.Contains(b.del, l.Name) || contains(b.add, l.Name) {
 			continue
@@ -637,3 +631,9 @@ func (b *ScratchBuilder) Labels() Labels {
 	// Copy the slice, so the next use of ScratchBuilder doesn't overwrite.
 	return append([]Label{}, b.add...)
 }
+
+// Write the newly-built Labels out to ls.
+// Callers must ensure that there are no other references to ls, or any strings fetched from it.
+func (b *ScratchBuilder) Overwrite(ls *Labels) {
+	*ls = append((*ls)[:0], b.add...)
+}
diff --git a/model/labels/labels_string.go b/model/labels/labels_string.go
@@ -158,7 +158,7 @@ func (ls Labels) MatchLabels(on bool, names ...string) Labels {
 		b.Del(MetricName)
 		b.Del(names...)
 	}
-	return b.Labels(EmptyLabels())
+	return b.Labels()
 }
 
 // Hash returns a hash value for the label set.
@@ -624,10 +624,9 @@ func contains(s []Label, n string) bool {
 	return false
 }
 
-// Labels returns the labels from the builder, adding them to res if non-nil.
-// Argument res can be the same as b.base, if caller wants to overwrite that slice.
+// Labels returns the labels from the builder.
 // If no modifications were made, the original labels are returned.
-func (b *Builder) Labels(res Labels) Labels {
+func (b *Builder) Labels() Labels {
 	if len(b.del) == 0 && len(b.add) == 0 {
 		return b.base
 	}
@@ -637,7 +636,7 @@ func (b *Builder) Labels(res Labels) Labels {
 	a, d := 0, 0
 
 	bufSize := len(b.base.data) + labelsSize(b.add)
-	buf := make([]byte, 0, bufSize) // TODO: see if we can re-use the buffer from res.
+	buf := make([]byte, 0, bufSize)
 	for pos := 0; pos < len(b.base.data); {
 		oldPos := pos
 		var lName string
@@ -812,7 +811,7 @@ func (b *ScratchBuilder) Labels() Labels {
 }
 
 // Write the newly-built Labels out to ls, reusing an internal buffer.
-// Callers must ensure that there are no other references to ls.
+// Callers must ensure that there are no other references to ls, or any strings fetched from it.
 func (b *ScratchBuilder) Overwrite(ls *Labels) {
 	size := labelsSize(b.add)
 	if size <= cap(b.overwriteBuffer) {