Struct mz_repr::Row

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pub struct Row { /* private fields */ }
Expand description

A packed representation for Datums.

Datum is easy to work with but very space inefficient. A Datum::Int32(42) is laid out in memory like this:

tag: 3 padding: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 data: 0 0 0 42 padding: 0 0 0 0 0 0 0 0 0 0 0 0

For a total of 32 bytes! The second set of padding is needed in case we were to write a 16-byte datum into this location. The first set of padding is needed to align that hypothetical decimal to a 16 bytes boundary.

A Row stores zero or more Datums without any padding. We avoid the need for the first set of padding by only providing access to the Datums via calls to ptr::read_unaligned, which on modern x86 is barely penalized. We avoid the need for the second set of padding by not providing mutable access to the Datum. Instead, Row is append-only.

A Row can be built from a collection of Datums using Row::pack, but it is more efficient to use Row::pack_slice so that a right-sized allocation can be created. If that is not possible, consider using the row buffer pattern: allocate one row, pack into it, and then call Row::clone to receive a copy of that row, leaving behind the original allocation to pack future rows.

Creating a row via Row::pack_slice:

let row = Row::pack_slice(&[Datum::Int32(0), Datum::Int32(1), Datum::Int32(2)]);
assert_eq!(row.unpack(), vec![Datum::Int32(0), Datum::Int32(1), Datum::Int32(2)])

Rows can be unpacked by iterating over them:

let row = Row::pack_slice(&[Datum::Int32(0), Datum::Int32(1), Datum::Int32(2)]);
assert_eq!(row.iter().nth(1).unwrap(), Datum::Int32(1));

If you want random access to the Datums in a Row, use Row::unpack to create a Vec<Datum>

let row = Row::pack_slice(&[Datum::Int32(0), Datum::Int32(1), Datum::Int32(2)]);
let datums = row.unpack();
assert_eq!(datums[1], Datum::Int32(1));

§Performance

Rows are dynamically sized, but up to a fixed size their data is stored in-line. It is best to re-use a Row across multiple Row creation calls, as this avoids the allocations involved in Row::new().

Implementations§

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impl Row

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pub fn decode_from_proto(&mut self, proto: &ProtoRow) -> Result<(), String>

A variant of Row::from_proto that allows for reuse of internal allocs.

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pub fn with_capacity(cap: usize) -> Self

Allocate an empty Row with a pre-allocated capacity.

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pub unsafe fn from_bytes_unchecked(data: &[u8]) -> Self

Creates a new row from supplied bytes.

§Safety

This method relies on data being an appropriate row encoding, and can result in unsafety if this is not the case.

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pub fn packer(&mut self) -> RowPacker<'_>

Constructs a RowPacker that will pack datums into this row’s allocation.

This method clears the existing contents of the row, but retains the allocation.

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pub fn pack<'a, I, D>(iter: I) -> Row
where I: IntoIterator<Item = D>, D: Borrow<Datum<'a>>,

Take some Datums and pack them into a Row.

This method builds a Row by repeatedly increasing the backing allocation. If the contents of the iterator are known ahead of time, consider Row::with_capacity to right-size the allocation first, and then RowPacker::extend to populate it with Datums. This avoids the repeated allocation resizing and copying.

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pub fn pack_using<'a, I, D>(&mut self, iter: I) -> Row
where I: IntoIterator<Item = D>, D: Borrow<Datum<'a>>,

Use self to pack iter, and then clone the result.

This is a convenience method meant to reduce boilerplate around row formation.

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pub fn try_pack<'a, I, D, E>(iter: I) -> Result<Row, E>
where I: IntoIterator<Item = Result<D, E>>, D: Borrow<Datum<'a>>,

Like Row::pack, but the provided iterator is allowed to produce an error, in which case the packing operation is aborted and the error returned.

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pub fn pack_slice<'a>(slice: &[Datum<'a>]) -> Row

Pack a slice of Datums into a Row.

This method has the advantage over pack that it can determine the required allocation before packing the elements, ensuring only one allocation and no redundant copies required.

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pub fn byte_len(&self) -> usize

Returns the total amount of bytes used by this row.

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pub fn byte_capacity(&self) -> usize

Returns the total capacity in bytes used by this row.

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pub fn as_row_ref(&self) -> &RowRef

Extracts a Row slice containing the entire Row.

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pub fn unpack(&self) -> Vec<Datum<'_>>

Unpack self into a Vec<Datum> for efficient random access.

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pub fn unpack_first(&self) -> Datum<'_>

Return the first Datum in self

Panics if the RowRef is empty.

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pub fn iter(&self) -> DatumListIter<'_>

Iterate the Datum elements of the RowRef.

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pub fn data(&self) -> &[u8]

For debugging only.

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pub fn is_empty(&self) -> bool

True iff there is no data in this RowRef.

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impl Arbitrary for Row

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type Parameters = SizeRange

The type of parameters that arbitrary_with accepts for configuration of the generated Strategy. Parameters must implement Default.
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type Strategy = BoxedStrategy<Row>

The type of Strategy used to generate values of type Self.
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fn arbitrary_with(size: Self::Parameters) -> Self::Strategy

Generates a Strategy for producing arbitrary values of type the implementing type (Self). The strategy is passed the arguments given in args. Read more
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fn arbitrary() -> Self::Strategy

Generates a Strategy for producing arbitrary values of type the implementing type (Self). Read more
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impl AsRef<RowRef> for Row

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fn as_ref(&self) -> &RowRef

Converts this type into a shared reference of the (usually inferred) input type.
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impl Borrow<RowRef> for Row

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fn borrow(&self) -> &RowRef

Immutably borrows from an owned value. Read more
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impl Clone for Row

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Codec for Row

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fn encode<B>(&self, buf: &mut B)
where B: BufMut,

Encodes a row into the permanent storage format.

This perfectly round-trips through Row::decode. It’s guaranteed to be readable by future versions of Materialize through v(TODO: Figure out our policy).

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fn decode(buf: &[u8]) -> Result<Row, String>

Decodes a row from the permanent storage format.

This perfectly round-trips through Row::encode. It can read rows encoded by historical versions of Materialize back to v(TODO: Figure out our policy).

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type Storage = ProtoRow

A type used with Self::decode_from for allocation reuse. Set to () if unnecessary.
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type Schema = RelationDesc

The type of the associated schema for Self. Read more
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fn codec_name() -> String

Name of the codec. Read more
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fn decode_from<'a>( &mut self, buf: &'a [u8], storage: &mut Option<ProtoRow> ) -> Result<(), String>

An alternate form of Self::decode which enables amortizing allocs. Read more
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impl ColumnDecoder<Row> for RowColumnarDecoder

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fn decode(&self, idx: usize, val: &mut Row)

Decode the value at idx into the buffer val. Read more
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fn is_null(&self, idx: usize) -> bool

Returns if the value at idx is null.
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impl ColumnEncoder<Row> for RowColumnarEncoder

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type FinishedColumn = StructArray

Type of column that this encoder returns when finalized.
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fn append(&mut self, val: &Row)

Appends val onto this encoder.
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fn append_null(&mut self)

Appends a null value onto this encoder.
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fn finish(self) -> Self::FinishedColumn

Finish this encoder, returning an immutable column.
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impl Columnation for Row

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type InnerRegion = RowStack

The type of region capable of absorbing allocations owned by the Self type. Note: not allocations of Self, but of the things that it owns.
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impl Debug for Row

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

Debug representation using the internal datums

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impl Default for Row

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fn default() -> Row

Returns the “default value” for a type. Read more
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impl Deref for Row

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type Target = RowRef

The resulting type after dereferencing.
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fn deref(&self) -> &Self::Target

Dereferences the value.
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impl<'de> Deserialize<'de> for Row

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fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>
where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl Display for Row

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

Display representation using the internal datums

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impl FromDatumIter for Row

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fn from_datum_iter<'a, I, D>(&mut self, datum_iter: I) -> Self
where I: IntoIterator<Item = D>, D: Borrow<Datum<'a>>,

Packs into self the given iterator of datums and returns a clone.

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fn try_from_datum_iter<'a, I, D, E>(&mut self, datum_iter: I) -> Result<Self, E>
where I: IntoIterator<Item = Result<D, E>>, D: Borrow<Datum<'a>>,

Packs into self by using the packer’s try_extend method on the given iterator and returns a clone.

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impl Hash for Row

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a> IntoIterator for &'a Row

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type Item = Datum<'a>

The type of the elements being iterated over.
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type IntoIter = DatumListIter<'a>

Which kind of iterator are we turning this into?
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fn into_iter(self) -> DatumListIter<'a>

Creates an iterator from a value. Read more
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impl IntoRowIterator for Row

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type Iter = SingleRowIter

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fn into_row_iter(self) -> Self::Iter

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impl Ord for Row

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

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized + PartialOrd,

Restrict a value to a certain interval. Read more
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impl PartDecoder<Row> for RowDecoder

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fn decode(&self, idx: usize, val: &mut Row)

Decodes the value at the given index. Read more
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impl PartEncoder<Row> for RowEncoder

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fn encode(&mut self, val: &Row)

Encodes the given value into the Part being constructed.
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fn finish(self) -> (usize, Vec<DynColumnMut>)

Consumes self returning the columns that were written to.
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impl PartialEq for Row

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

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

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

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl RustType<ProtoRow> for Row

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fn into_proto(&self) -> ProtoRow

Convert a Self into a Proto value.
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fn from_proto(proto: ProtoRow) -> Result<Self, TryFromProtoError>

Consume and convert a Proto back into a Self value. Read more
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impl Schema<Row> for RelationDesc

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type Encoder = RowEncoder

The associated PartEncoder implementor.
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type Decoder = RowDecoder

The associated PartDecoder implementor.
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fn columns(&self) -> DynStructCfg

Returns the name and types of the columns in this type.
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fn decoder(&self, part: ColumnsRef) -> Result<Self::Decoder, String>

Returns a Self::Decoder for the given columns.
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fn encoder<'a>(&self, part: ColumnsMut) -> Result<Self::Encoder, String>

Returns a Self::Encoder for the given columns.
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impl Schema2<Row> for RelationDesc

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type ArrowColumn = StructArray

The type of column we decode from, and encoder will finish into.
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type Decoder = RowColumnarDecoder

Type that is able to decode values of T from Self::ArrowColumn.
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type Encoder = RowColumnarEncoder

Type that is able to encoder values of T.
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fn decoder(&self, col: Self::ArrowColumn) -> Result<Self::Decoder, Error>

Returns a type that is able to decode instances of T from the provider column.
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fn encoder(&self) -> Result<Self::Encoder, Error>

Returns a type that can encode values of T.
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impl Serialize for Row

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

Serialize this value into the given Serde serializer. Read more
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impl ToDatumIter for Row

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type DatumIter<'a> = DatumListIter<'a>

Datum iterator for Row.

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fn to_datum_iter<'a>(&'a self) -> Self::DatumIter<'a>

Borrows self and gets an iterator from it.

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impl TryFrom<&ProtoRow> for Row

TODO: remove this in favor of RustType::from_proto.

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type Error = String

The type returned in the event of a conversion error.
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fn try_from(x: &ProtoRow) -> Result<Self, Self::Error>

Performs the conversion.
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impl Eq for Row

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impl StructuralPartialEq for Row

Auto Trait Implementations§

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impl Freeze for Row

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impl RefUnwindSafe for Row

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impl Send for Row

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impl Sync for Row

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impl Unpin for Row

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impl UnwindSafe for Row

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T, U> CastInto<U> for T
where U: CastFrom<T>,

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fn cast_into(self) -> U

Performs the cast.
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impl<Q, K> Comparable<K> for Q
where Q: Ord + ?Sized, K: Borrow<Q> + ?Sized,

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fn compare(&self, key: &K) -> Ordering

Compare self to key and return their ordering.
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FromRef<T> for T
where T: Clone,

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fn from_ref(input: &T) -> T

Converts to this type from a reference to the input type.
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impl<T> FutureExt for T

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fn with_context(self, otel_cx: Context) -> WithContext<Self>

Attaches the provided Context to this type, returning a WithContext wrapper. Read more
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fn with_current_context(self) -> WithContext<Self>

Attaches the current Context to this type, returning a WithContext wrapper. Read more
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impl<T> Hashable for T
where T: Hash,

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type Output = u64

The type of the output value.
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fn hashed(&self) -> u64

A well-distributed integer derived from the data.
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> IntoRequest<T> for T

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fn into_request(self) -> Request<T>

Wrap the input message T in a tonic::Request
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impl<T, U> OverrideFrom<Option<&T>> for U
where U: OverrideFrom<T>,

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fn override_from(self, layer: &Option<&T>) -> U

Override the configuration represented by Self with values from the given layer.
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> PreferredContainer for T
where T: Ord + Clone + 'static,

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type Container = Vec<T>

The preferred container for the type.
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impl<T> ProgressEventTimestamp for T
where T: Data + Debug + Any,

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fn as_any(&self) -> &(dyn Any + 'static)

Upcasts this ProgressEventTimestamp to Any. Read more
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fn type_name(&self) -> &'static str

Returns the name of the concrete type of this object. Read more
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impl<P, R> ProtoType<R> for P
where R: RustType<P>,

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<'a, S, T> Semigroup<&'a S> for T
where T: Semigroup<S>,

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fn plus_equals(&mut self, rhs: &&'a S)

The method of std::ops::AddAssign, for types that do not implement AddAssign.
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for T
where T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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where V: MultiLane<T>,

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fn vzip(self) -> V

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where S: Into<Dispatch>,

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where T: Send + Sync + Any + Serialize + for<'a> Deserialize<'a> + 'static,

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