Struct re_dataframe::QueryEngine

pub struct QueryEngine<E: StorageEngineLike> {
    pub engine: E,
}

A handle to our user-facing query engine.

Cheap to clone.

See the following methods:

• QueryEngine::schema: get the complete schema of the recording.
• QueryEngine::query: execute a [QueryExpression] on the recording.

Fields

engine: E

Implementations

impl QueryEngine<StorageEngine>

pub fn new(store: ChunkStoreHandle, cache: QueryCacheHandle) -> Self

pub fn from_store(store: ChunkStoreHandle) -> Self

This will automatically instantiate a new empty QueryCache.

pub fn from_rrd_filepath( store_config: &ChunkStoreConfig, path_to_rrd: impl AsRef<Path>, version_policy: VersionPolicy ) -> Result<BTreeMap<StoreId, Self>>

Like [ChunkStore::from_rrd_filepath], but automatically instantiates QueryEngines with new empty QueryCaches.

impl<E: StorageEngineLike + Clone> QueryEngine<E>

pub fn schema(&self) -> Vec<ColumnDescriptor>

Returns the full schema of the store.

This will include a column descriptor for every timeline and every component on every entity that has been written to the store so far.

The order of the columns to guaranteed to be in a specific order:

• first, the time columns in lexical order (frame_nr, log_time, …);
• second, the component columns in lexical order (Color, Radius, ...).

pub fn schema_for_query(&self, query: &QueryExpression) -> Vec<ColumnDescriptor>

Returns the filtered schema for the given [QueryExpression].

The order of the columns is guaranteed to be in a specific order:

• first, the time columns in lexical order (frame_nr, log_time, …);
• second, the component columns in lexical order (Color, Radius, ...).

pub fn query(&self, query: QueryExpression) -> QueryHandle<E>

Starts a new query by instantiating a QueryHandle.

pub fn iter_entity_paths<'a>( &self, filter: &'a EntityPathFilter ) -> impl Iterator<Item = EntityPath> + 'a

Returns an iterator over all the [EntityPath]s present in the database.

Trait Implementations

impl<E: Clone + StorageEngineLike> Clone for QueryEngine<E>

fn clone(&self) -> QueryEngine<E>

Returns a copy of the value.

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

Performs copy-assignment from source.