Struct RegionMetadata

pub struct RegionMetadata {
    pub schema: SchemaRef,
    time_index: ColumnId,
    id_to_index: HashMap<ColumnId, usize>,
    pub column_metadatas: Vec<ColumnMetadata>,
    pub primary_key: Vec<ColumnId>,
    pub region_id: RegionId,
    pub schema_version: u64,
}

General static metadata of a region.

This struct implements Serialize and Deserialize traits. To build a RegionMetadata object, use RegionMetadataBuilder.

class RegionMetadata { +RegionId region_id +SchemaRef schema +Vec<ColumnMetadata> column_metadatas +Vec<ColumnId> primary_key } class Schema class ColumnMetadata { +ColumnSchema column_schema +SemanticTyle semantic_type +ColumnId column_id } class SemanticType RegionMetadata o-- Schema RegionMetadata o-- ColumnMetadata ColumnMetadata o-- SemanticType

Fields

schema: SchemaRef

Latest schema constructed from column_metadatas.

time_index: ColumnId

Id of the time index column.

id_to_index: HashMap<ColumnId, usize>

Map column id to column’s index in column_metadatas.

column_metadatas: Vec<ColumnMetadata>

Columns in the region. Has the same order as columns in schema.

primary_key: Vec<ColumnId>

Maintains an ordered list of primary keys

region_id: RegionId

Immutable and unique id of a region.

schema_version: u64

Current version of the region schema.

The version starts from 0. Altering the schema bumps the version.

Implementations

impl RegionMetadata

pub fn from_json(s: &str) -> Result<Self>

Decode the metadata from a JSON str.

pub fn to_json(&self) -> Result<String>

Encode the metadata to a JSON string.

pub fn column_by_id(&self, column_id: ColumnId) -> Option<&ColumnMetadata>

Find column by id.

pub fn column_index_by_id(&self, column_id: ColumnId) -> Option<usize>

Find column index by id.

pub fn column_index_by_name(&self, column_name: &str) -> Option<usize>

Find column index by name.

pub fn time_index_column(&self) -> &ColumnMetadata

Returns the time index column

Panics

Panics if the time index column id is invalid.

pub fn time_index_field(&self) -> FieldRef

Returns the arrow field of the time index column.

pub fn column_by_name(&self, name: &str) -> Option<&ColumnMetadata>

Finds a column by name.

pub fn primary_key_columns(&self) -> impl Iterator<Item = &ColumnMetadata>

Returns all primary key columns.

pub fn field_columns(&self) -> impl Iterator<Item = &ColumnMetadata>

Returns all field columns before projection.

Use with caution. On read path where might have projection, this method can return columns that not present in data batch.

pub fn primary_key_index(&self, column_id: ColumnId) -> Option<usize>

Returns a column’s index in primary key if it is a primary key column.

This does a linear search.

pub fn project(&self, projection: &[ColumnId]) -> Result<RegionMetadata>

Project the metadata to a new one using specified column ids.

RegionId and schema version are preserved.

pub fn inverted_indexed_column_ids<'a>( &self, ignore_column_ids: impl Iterator<Item = &'a ColumnId>, ) -> HashSet<ColumnId>

Gets the column ids to be indexed by inverted index.

If there is no column with inverted index key, it will use primary key columns.

fn validate(&self) -> Result<()>

Checks whether the metadata is valid.

fn validate_column_metadata(column_metadata: &ColumnMetadata) -> Result<()>

Checks whether it is a valid column.

Trait Implementations

impl Clone for RegionMetadata

fn clone(&self) -> RegionMetadata

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RegionMetadata

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for RegionMetadata

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for RegionMetadata

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Serialize for RegionMetadata

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for RegionMetadata

impl StructuralPartialEq for RegionMetadata