Semantic conventions for OpenTelemetry SDK metrics

This document describes metrics emitted by the OpenTelemetry SDK components themselves about their internal state.

Span metrics
Log metrics
Metric metrics
- Metric: otel.sdk.exporter.metric_data_point.inflight
- Metric: otel.sdk.exporter.metric_data_point.exported
Operation Metrics
- Metric: otel.sdk.metric_reader.collection.duration
- Metric: otel.sdk.exporter.operation.duration

Span metrics

Metric: `otel.sdk.span.live`

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.span.live`	UpDownCounter	`{span}`	The number of created spans with `recording=true` for which the end operation has not been called yet.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.span.sampling_result`	string	The result value of the sampler for this span	`DROP`; `RECORD_ONLY`; `RECORD_AND_SAMPLE`	`Recommended`

otel.span.sampling_result has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`DROP`	The span is not sampled and not recording
`RECORD_AND_SAMPLE`	The span is sampled and recording
`RECORD_ONLY`	The span is not sampled, but recording

Metric: `otel.sdk.span.started`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.span.started`	Counter	`{span}`	The number of created spans. [1]

[1]: Implementations MUST record this metric for all spans, even for non-recording ones.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.span.parent.origin`	string	Determines whether the span has a parent span, and if so, whether it is a remote parent	`none`; `local`; `remote`	`Recommended`
`otel.span.sampling_result`	string	The result value of the sampler for this span	`DROP`; `RECORD_ONLY`; `RECORD_AND_SAMPLE`	`Recommended`

otel.span.parent.origin has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`local`	The span has a parent and the parent's span context isRemote() is false
`none`	The span does not have a parent, it is a root span
`remote`	The span has a parent and the parent's span context isRemote() is true

otel.span.sampling_result has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`DROP`	The span is not sampled and not recording
`RECORD_AND_SAMPLE`	The span is sampled and recording
`RECORD_ONLY`	The span is not sampled, but recording

Metric: `otel.sdk.processor.span.queue.size`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.span.queue.size`	UpDownCounter	`{span}`	The number of spans in the queue of a given instance of an SDK span processor. [1]

[1]: Only applies to span processors which use a queue, e.g. the SDK Batching Span Processor.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[2] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.processor.span.queue.capacity`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.span.queue.capacity`	UpDownCounter	`{span}`	The maximum number of spans the queue of a given instance of an SDK span processor can hold. [1]

[1]: Only applies to span processors which use a queue, e.g. the SDK Batching Span Processor.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[2] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.processor.span.processed`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.span.processed`	Counter	`{span}`	The number of spans for which the processing has finished, either successful or failed. [1]

[1]: For successful processing, error.type MUST NOT be set. For failed processing, error.type MUST contain the failure cause. For the SDK Simple and Batching Span Processor a span is considered to be processed already when it has been submitted to the exporter, not when the corresponding export call has finished.

Attribute	Type	Description	Examples	Requirement Level
`error.type`	string	A low-cardinality description of the failure reason. SDK Batching Span Processors MUST use `queue_full` for spans dropped due to a full queue. [1]	`queue_full`	`Recommended`
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [2]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [3]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] error.type: The error.type SHOULD be predictable, and SHOULD have low cardinality.

When error.type is set to a type (e.g., an exception type), its canonical class name identifying the type within the artifact SHOULD be used.

Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low. Telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time when no additional filters are applied.

If the operation has completed successfully, instrumentations SHOULD NOT set error.type.

If a specific domain defines its own set of error identifiers (such as HTTP or gRPC status codes), it's RECOMMENDED to:

Use a domain-specific attribute
Set error.type to capture all errors, regardless of whether they are defined within the domain-specific set or not.

[2] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[3] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

error.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`_OTHER`	A fallback error value to be used when the instrumentation doesn't define a custom value.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.exporter.span.inflight`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.exporter.span.inflight`	UpDownCounter	`{span}`	The number of spans which were passed to the exporter, but that have not been exported yet (neither successful, nor failed). [1]

[1]: For successful exports, error.type MUST NOT be set. For failed exports, error.type MUST contain the failure cause.

Attribute	Type	Description	Examples	Requirement Level
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`
`server.address`	string	Server domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [3]	`example.com`; `10.1.2.80`; `/tmp/my.sock`	`Recommended` when applicable
`server.port`	int	Server port number. [4]	`80`; `8080`; `443`	`Recommended` when applicable

[1] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[2] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

[3] server.address: When observed from the client side, and when communicating through an intermediary, server.address SHOULD represent the server address behind any intermediaries, for example proxies, if it's available.

[4] server.port: When observed from the client side, and when communicating through an intermediary, server.port SHOULD represent the server port behind any intermediaries, for example proxies, if it's available.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.exporter.span.exported`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.exporter.span.exported`	Counter	`{span}`	The number of spans for which the export has finished, either successful or failed. [1]

[1]: For successful exports, error.type MUST NOT be set. For failed exports, error.type MUST contain the failure cause. For exporters with partial success semantics (e.g. OTLP with rejected_spans), rejected spans MUST count as failed and only non-rejected spans count as success. If no rejection reason is available, rejected SHOULD be used as value for error.type.

Attribute	Type	Description	Examples	Requirement Level
`error.type`	string	Describes a class of error the operation ended with. [1]	`rejected`; `timeout`; `500`; `java.net.UnknownHostException`	`Recommended`
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [2]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [3]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`
`server.address`	string	Server domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [4]	`example.com`; `10.1.2.80`; `/tmp/my.sock`	`Recommended` when applicable
`server.port`	int	Server port number. [5]	`80`; `8080`; `443`	`Recommended` when applicable

[1] error.type: The error.type SHOULD be predictable, and SHOULD have low cardinality.

When error.type is set to a type (e.g., an exception type), its canonical class name identifying the type within the artifact SHOULD be used.

Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low. Telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time when no additional filters are applied.

If the operation has completed successfully, instrumentations SHOULD NOT set error.type.

If a specific domain defines its own set of error identifiers (such as HTTP or gRPC status codes), it's RECOMMENDED to:

Use a domain-specific attribute
Set error.type to capture all errors, regardless of whether they are defined within the domain-specific set or not.

[2] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[3] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

[4] server.address: When observed from the client side, and when communicating through an intermediary, server.address SHOULD represent the server address behind any intermediaries, for example proxies, if it's available.

[5] server.port: When observed from the client side, and when communicating through an intermediary, server.port SHOULD represent the server port behind any intermediaries, for example proxies, if it's available.

error.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`_OTHER`	A fallback error value to be used when the instrumentation doesn't define a custom value.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Log metrics

Metric: `otel.sdk.log.created`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.log.created`	Counter	`{log_record}`	The number of logs submitted to enabled SDK Loggers.

Metric: `otel.sdk.processor.log.queue.size`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.log.queue.size`	UpDownCounter	`{log_record}`	The number of log records in the queue of a given instance of an SDK log processor. [1]

[1]: Only applies to log record processors which use a queue, e.g. the SDK Batching Log Record Processor.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[2] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.processor.log.queue.capacity`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.log.queue.capacity`	UpDownCounter	`{log_record}`	The maximum number of log records the queue of a given instance of an SDK Log Record processor can hold. [1]

[1]: Only applies to Log Record processors which use a queue, e.g. the SDK Batching Log Record Processor.

Attribute	Type	Description	Examples	Requirement Level	Stability
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[2] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.processor.log.processed`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.processor.log.processed`	Counter	`{log_record}`	The number of log records for which the processing has finished, either successful or failed. [1]

[1]: For successful processing, error.type MUST NOT be set. For failed processing, error.type MUST contain the failure cause. For the SDK Simple and Batching Log Record Processor a log record is considered to be processed already when it has been submitted to the exporter, not when the corresponding export call has finished.

Attribute	Type	Description	Examples	Requirement Level
`error.type`	string	A low-cardinality description of the failure reason. SDK Batching Log Record Processors MUST use `queue_full` for log records dropped due to a full queue. [1]	`queue_full`	`Recommended`
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [2]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [3]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`

[1] error.type: The error.type SHOULD be predictable, and SHOULD have low cardinality.

When error.type is set to a type (e.g., an exception type), its canonical class name identifying the type within the artifact SHOULD be used.

Instrumentations SHOULD document the list of errors they report.

The cardinality of error.type within one instrumentation library SHOULD be low. Telemetry consumers that aggregate data from multiple instrumentation libraries and applications should be prepared for error.type to have high cardinality at query time when no additional filters are applied.

If the operation has completed successfully, instrumentations SHOULD NOT set error.type.

If a specific domain defines its own set of error identifiers (such as HTTP or gRPC status codes), it's RECOMMENDED to:

Use a domain-specific attribute
Set error.type to capture all errors, regardless of whether they are defined within the domain-specific set or not.

[2] otel.component.name: Implementations SHOULD ensure a low cardinality for this attribute, even across application or SDK restarts. E.g. implementations MUST NOT use UUIDs as values for this attribute.

Implementations MAY achieve these goals by following a <otel.component.type>/<instance-counter> pattern, e.g. batching_span_processor/0. Hereby otel.component.type refers to the corresponding attribute value of the component.

The value of instance-counter MAY be automatically assigned by the component and uniqueness within the enclosing SDK instance MUST be guaranteed. For example, <instance-counter> MAY be implemented by using a monotonically increasing counter (starting with 0), which is incremented every time an instance of the given component type is started.

With this implementation, for example the first Batching Span Processor would have batching_span_processor/0 as otel.component.name, the second one batching_span_processor/1 and so on. These values will therefore be reused in the case of an application restart.

[3] otel.component.type: If none of the standardized values apply, implementations SHOULD use the language-defined name of the type. E.g. for Java the fully qualified classname SHOULD be used in this case.

error.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`_OTHER`	A fallback error value to be used when the instrumentation doesn't define a custom value.

otel.component.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
`batching_log_processor`	The builtin SDK batching log record processor
`batching_span_processor`	The builtin SDK batching span processor
`otlp_grpc_log_exporter`	OTLP log record exporter over gRPC with protobuf serialization
`otlp_grpc_metric_exporter`	OTLP metric exporter over gRPC with protobuf serialization
`otlp_grpc_span_exporter`	OTLP span exporter over gRPC with protobuf serialization
`otlp_http_json_log_exporter`	OTLP log record exporter over HTTP with JSON serialization
`otlp_http_json_metric_exporter`	OTLP metric exporter over HTTP with JSON serialization
`otlp_http_json_span_exporter`	OTLP span exporter over HTTP with JSON serialization
`otlp_http_log_exporter`	OTLP log record exporter over HTTP with protobuf serialization
`otlp_http_metric_exporter`	OTLP metric exporter over HTTP with protobuf serialization
`otlp_http_span_exporter`	OTLP span exporter over HTTP with protobuf serialization
`periodic_metric_reader`	The builtin SDK periodically exporting metric reader
`prometheus_http_text_metric_exporter`	Prometheus metric exporter over HTTP with the default text-based format
`simple_log_processor`	The builtin SDK simple log record processor
`simple_span_processor`	The builtin SDK simple span processor
`zipkin_http_span_exporter`	Zipkin span exporter over HTTP

Metric: `otel.sdk.exporter.log.inflight`

This metric is recommended.

Name	Instrument Type	Unit (UCUM)	Description	Stability	Entity Associations
`otel.sdk.exporter.log.inflight`	UpDownCounter	`{log_record}`	The number of log records which were passed to the exporter, but that have not been exported yet (neither successful, nor failed). [1]

[1]: For successful exports, error.type MUST NOT be set. For failed exports, error.type MUST contain the failure cause.

Attribute	Type	Description	Examples	Requirement Level
`otel.component.name`	string	A name uniquely identifying the instance of the OpenTelemetry component within its containing SDK instance. [1]	`otlp_grpc_span_exporter/0`; `custom-name`	`Recommended`
`otel.component.type`	string	A name identifying the type of the OpenTelemetry component. [2]	`batching_span_processor`; `com.example.MySpanExporter`	`Recommended`
`server.address`	string	Server domain name if available without reverse DNS lookup; otherwise, IP address or Unix domain socket name. [3]	`example.com`; `10.1.2.80`; `/tmp/my.sock`	`Recommended` when applicable
`server.port`	int	Server port number. [4]	`80`; `8080`; `443`	`Recommended` when applicable