Struct re_log_types::RowId

pub struct RowId(/* private fields */);

A unique ID for a DataRow.

Semantics

RowIds play an important role in how we store, query and garbage collect data.

Storage

RowIds must be unique within a DataStore. This is enforced by the store’s APIs.

This makes it easy to build and maintain secondary indices around RowIds with few to no extraneous state tracking.

Query

Queries (both latest-at & range semantics) will defer to RowId order as a tie-breaker when looking at several rows worth of data that rest at the exact same timestamp.

In pseudo-code:

rr.set_time_sequence("frame", 10)

rr.log("my_entity", point1, row_id=#1)
rr.log("my_entity", point2, row_id=#0)

rr.query("my_entity", at=("frame", 10))  # returns `point1`

Think carefully about your RowIds when logging a lot of data at the same timestamp.

Garbage collection

Garbage collection happens in RowId-order, which roughly means that it happens in the logger’s wall-clock order.

This has very important implications where inserting data far into the past or into the future: think carefully about your RowIds in these cases.

Implementations

impl RowId

pub const ZERO: Self = _

pub const MAX: Self = _

pub fn new() -> Self

Create a new unique RowId based on the current time.

pub fn next(&self) -> Self

Returns the next logical RowId.

Beware: wrong usage can easily lead to conflicts. Prefer RowId::new when unsure.

pub fn incremented_by(&self, n: u64) -> Self

Returns the n-next logical RowId.

This is equivalent to calling RowId::next n times. Wraps the monotonically increasing back to zero on overflow.

Beware: wrong usage can easily lead to conflicts. Prefer RowId::new when unsure.

pub fn nanoseconds_since_epoch(&self) -> u64

When the RowId was created, in nanoseconds since unix epoch.

Methods from Deref<Target = Tuid>

pub fn heap_size_bytes(&self) -> u64

Returns the total size of self on the heap, in bytes.

NOTE: This crate cannot depend on re_types_core, therefore the actual implementation of SizeBytes for Tuid lives in re_types_core and calls this method.

pub const ZERO: Tuid = _

pub const MAX: Tuid = _

pub fn as_u128(&self) -> u128

pub fn nanoseconds_since_epoch(&self) -> u64

Approximate nanoseconds since unix epoch.

The upper 64 bits of the Tuid.

pub fn inc(&self) -> u64

The increment part of the Tuid.

The lower 64 bits of the Tuid.

pub fn next(&self) -> Tuid

Returns the next logical Tuid.

Wraps the monotonically increasing back to zero on overflow.

Beware: wrong usage can easily lead to conflicts. Prefer Tuid::new when unsure.

pub fn incremented_by(&self, n: u64) -> Tuid

Returns the n-next logical Tuid.

This is equivalent to calling Tuid::next n times. Wraps the monotonically increasing back to zero on overflow.

Beware: wrong usage can easily lead to conflicts. Prefer Tuid::new when unsure.

pub fn short_string(&self) -> String

A shortened string representation of the Tuid.

Trait Implementations

impl Clone for RowId

fn clone(&self) -> RowId

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RowId

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for RowId

type Target = Tuid

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for RowId

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'de> Deserialize<'de> for RowId

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for RowId

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> From<&'a RowId> for Cow<'a, RowId>

fn from(value: &'a RowId) -> Self

Converts to this type from the input type.

impl<'a> From<RowId> for Cow<'a, RowId>

fn from(value: RowId) -> Self

Converts to this type from the input type.

impl Hash for RowId

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Loggable for RowId

type Name = ComponentName

fn name() -> Self::Name

The fully-qualified name of this loggable, e.g. rerun.datatypes.Vec2D.

fn arrow_datatype() -> DataType

The underlying arrow2::datatypes::DataType, excluding datatype extensions.

fn to_arrow_opt<'a>( values: impl IntoIterator<Item = Option<impl Into<Cow<'a, Self>>>> ) -> SerializationResult<Box<dyn Array>>

where Self: 'a,

Given an iterator of options of owned or reference values to the current Loggable, serializes them into an Arrow array. The Arrow array’s datatype will match Loggable::arrow_field.

fn to_arrow<'a>( values: impl IntoIterator<Item = impl Into<Cow<'a, Self>>> ) -> SerializationResult<Box<dyn Array>>

Given an iterator of owned or reference values to the current Loggable, serializes them into an Arrow array. The Arrow array’s datatype will match Loggable::arrow_field.

fn from_arrow(array: &dyn Array) -> DeserializationResult<Vec<Self>>

Given an Arrow array, deserializes it into a collection of Loggables.

fn extended_arrow_datatype() -> DataType

The underlying arrow2::datatypes::DataType, including datatype extensions.

fn arrow_field() -> Field

The underlying arrow2::datatypes::Field, including datatype extensions.

fn from_arrow_opt( data: &(dyn Array + 'static) ) -> Result<Vec<Option<Self>>, DeserializationError>

Given an Arrow array, deserializes it into a collection of optional Loggables.

impl Ord for RowId

fn cmp(&self, other: &RowId) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl PartialEq for RowId

fn eq(&self, other: &RowId) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for RowId

fn partial_cmp(&self, other: &RowId) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for RowId

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl SizeBytes for RowId

fn heap_size_bytes(&self) -> u64

Returns the total size of self on the heap, in bytes.

fn is_pod() -> bool

Is Self just plain old data?

fn total_size_bytes(&self) -> u64

Returns the total size of self in bytes, accounting for both stack and heap space.

fn stack_size_bytes(&self) -> u64

Returns the total size of self on the stack, in bytes.

impl Copy for RowId

impl Eq for RowId

impl StructuralPartialEq for RowId