pub enum ParallelStrategy {
None,
Columns,
RowGroups,
Prefiltered,
Auto,
}
Available on crate feature
parquet
only.Variants§
None
Don’t parallelize
Columns
Parallelize over the columns
RowGroups
Parallelize over the row groups
Prefiltered
First evaluates the pushed-down predicates in parallel and determines a mask of which rows to read. Then, it parallelizes over both the columns and the row groups while filtering out rows that do not need to be read. This can provide significant speedups for large files (i.e. many row-groups) with a predicate that filters clustered rows or filters heavily. In other cases, this may slow down the scan compared other strategies.
If no predicate is given, this falls back to back to ParallelStrategy::Auto
.
Auto
Automatically determine over which unit to parallelize This will choose the most occurring unit.
Trait Implementations§
Source§impl Clone for ParallelStrategy
impl Clone for ParallelStrategy
Source§fn clone(&self) -> ParallelStrategy
fn clone(&self) -> ParallelStrategy
Returns a copy of the value. Read more
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source
. Read moreSource§impl Debug for ParallelStrategy
impl Debug for ParallelStrategy
Source§impl Default for ParallelStrategy
impl Default for ParallelStrategy
Source§fn default() -> ParallelStrategy
fn default() -> ParallelStrategy
Returns the “default value” for a type. Read more
Source§impl<'de> Deserialize<'de> for ParallelStrategy
impl<'de> Deserialize<'de> for ParallelStrategy
Source§fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where
__D: Deserializer<'de>,
fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>where
__D: Deserializer<'de>,
Deserialize this value from the given Serde deserializer. Read more
Source§impl Hash for ParallelStrategy
impl Hash for ParallelStrategy
Source§impl PartialEq for ParallelStrategy
impl PartialEq for ParallelStrategy
Source§impl Serialize for ParallelStrategy
impl Serialize for ParallelStrategy
impl Copy for ParallelStrategy
impl Eq for ParallelStrategy
impl StructuralPartialEq for ParallelStrategy
Auto Trait Implementations§
impl Freeze for ParallelStrategy
impl RefUnwindSafe for ParallelStrategy
impl Send for ParallelStrategy
impl Sync for ParallelStrategy
impl Unpin for ParallelStrategy
impl UnwindSafe for ParallelStrategy
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§unsafe fn clone_to_uninit(&self, dst: *mut T)
unsafe fn clone_to_uninit(&self, dst: *mut T)
🔬This is a nightly-only experimental API. (
clone_to_uninit
)§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Compare self to
key
and return true
if they are equal.§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Checks if this value is equivalent to the given key. Read more
§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
Converts
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more