mz_persist_types/
arrow.rs

1// Copyright Materialize, Inc. and contributors. All rights reserved.
2//
3// Use of this software is governed by the Business Source License
4// included in the LICENSE file.
5//
6// As of the Change Date specified in that file, in accordance with
7// the Business Source License, use of this software will be governed
8// by the Apache License, Version 2.0.
9
10//! A [protobuf] representation of [Apache Arrow] arrays.
11//!
12//! # Motivation
13//!
14//! Persist can store a small amount of data inline at the consensus layer.
15//! Because we are space constrained, we take particular care to store only the
16//! data that is necessary. Other Arrow serialization formats, e.g. [Parquet]
17//! or [Arrow IPC], include data that we don't need and would be wasteful to
18//! store.
19//!
20//! [protobuf]: https://protobuf.dev/
21//! [Apache Arrow]: https://arrow.apache.org/
22//! [Parquet]: https://parquet.apache.org/docs/
23//! [Arrow IPC]: https://arrow.apache.org/docs/format/Columnar.html#serialization-and-interprocess-communication-ipc
24
25use std::cmp::Ordering;
26use std::fmt::{Debug, Display};
27use std::sync::Arc;
28
29use arrow::array::*;
30use arrow::buffer::{BooleanBuffer, NullBuffer, OffsetBuffer};
31use arrow::datatypes::{ArrowNativeType, DataType, Field, FieldRef, Fields};
32use itertools::Itertools;
33use mz_ore::cast::CastFrom;
34use mz_ore::soft_assert_eq_no_log;
35use mz_proto::{IntoRustIfSome, ProtoType, RustType, TryFromProtoError};
36use prost::Message;
37
38#[allow(missing_docs)]
39mod proto {
40    include!(concat!(env!("OUT_DIR"), "/mz_persist_types.arrow.rs"));
41}
42use crate::arrow::proto::data_type;
43pub use proto::{DataType as ProtoDataType, ProtoArrayData};
44
45/// Extract the list of fields for our recursive datatypes.
46pub fn fields_for_type(data_type: &DataType) -> &[FieldRef] {
47    match data_type {
48        DataType::Struct(fields) => fields,
49        DataType::List(field) => std::slice::from_ref(field),
50        DataType::Map(field, _) => std::slice::from_ref(field),
51        DataType::Null
52        | DataType::Boolean
53        | DataType::Int8
54        | DataType::Int16
55        | DataType::Int32
56        | DataType::Int64
57        | DataType::UInt8
58        | DataType::UInt16
59        | DataType::UInt32
60        | DataType::UInt64
61        | DataType::Float16
62        | DataType::Float32
63        | DataType::Float64
64        | DataType::Timestamp(_, _)
65        | DataType::Date32
66        | DataType::Date64
67        | DataType::Time32(_)
68        | DataType::Time64(_)
69        | DataType::Duration(_)
70        | DataType::Interval(_)
71        | DataType::Binary
72        | DataType::FixedSizeBinary(_)
73        | DataType::LargeBinary
74        | DataType::BinaryView
75        | DataType::Utf8
76        | DataType::LargeUtf8
77        | DataType::Utf8View
78        | DataType::Decimal128(_, _)
79        | DataType::Decimal256(_, _) => &[],
80        DataType::ListView(_)
81        | DataType::FixedSizeList(_, _)
82        | DataType::LargeList(_)
83        | DataType::LargeListView(_)
84        | DataType::Union(_, _)
85        | DataType::Dictionary(_, _)
86        | DataType::RunEndEncoded(_, _) => unimplemented!("not supported"),
87    }
88}
89
90/// Encode the array into proto. If an expected data type is passed, that implies it is
91/// encoded at some higher level, and we omit it from the data.
92fn into_proto_with_type(data: &ArrayData, expected_type: Option<&DataType>) -> ProtoArrayData {
93    let data_type = match expected_type {
94        Some(expected) => {
95            // Equality is recursive, and this function is itself called recursively,
96            // skip the call in production to avoid a quadratic overhead.
97            soft_assert_eq_no_log!(
98                expected,
99                data.data_type(),
100                "actual type should match expected type"
101            );
102            None
103        }
104        None => Some(data.data_type().into_proto()),
105    };
106
107    ProtoArrayData {
108        data_type,
109        length: u64::cast_from(data.len()),
110        offset: u64::cast_from(data.offset()),
111        buffers: data.buffers().iter().map(|b| b.into_proto()).collect(),
112        children: data
113            .child_data()
114            .iter()
115            .zip_eq(fields_for_type(
116                expected_type.unwrap_or_else(|| data.data_type()),
117            ))
118            .map(|(child, expect)| into_proto_with_type(child, Some(expect.data_type())))
119            .collect(),
120        nulls: data.nulls().map(|n| n.inner().into_proto()),
121    }
122}
123
124/// Decode the array data.
125/// If the data type is omitted from the proto, we decode it as the expected type.
126fn from_proto_with_type(
127    proto: ProtoArrayData,
128    expected_type: Option<&DataType>,
129) -> Result<ArrayData, TryFromProtoError> {
130    let ProtoArrayData {
131        data_type,
132        length,
133        offset,
134        buffers,
135        children,
136        nulls,
137    } = proto;
138    let data_type: Option<DataType> = data_type.into_rust()?;
139    let data_type = match (data_type, expected_type) {
140        (Some(data_type), None) => data_type,
141        (Some(data_type), Some(expected_type)) => {
142            // Equality is recursive, and this function is itself called recursively,
143            // skip the call in production to avoid a quadratic overhead.
144            soft_assert_eq_no_log!(
145                data_type,
146                *expected_type,
147                "expected type should match actual type"
148            );
149            data_type
150        }
151        (None, Some(expected_type)) => expected_type.clone(),
152        (None, None) => {
153            return Err(TryFromProtoError::MissingField(
154                "ProtoArrayData::data_type".to_string(),
155            ));
156        }
157    };
158    let nulls = nulls
159        .map(|n| n.into_rust())
160        .transpose()?
161        .map(NullBuffer::new);
162
163    let mut builder = ArrayDataBuilder::new(data_type.clone())
164        .len(usize::cast_from(length))
165        .offset(usize::cast_from(offset))
166        .nulls(nulls);
167
168    for b in buffers.into_iter().map(|b| b.into_rust()) {
169        builder = builder.add_buffer(b?);
170    }
171    for c in children
172        .into_iter()
173        .zip_eq(fields_for_type(&data_type))
174        .map(|(c, field)| from_proto_with_type(c, Some(field.data_type())))
175    {
176        builder = builder.add_child_data(c?);
177    }
178
179    // Construct the builder which validates all inputs and aligns data.
180    builder
181        .align_buffers(true)
182        .build()
183        .map_err(|e| TryFromProtoError::RowConversionError(e.to_string()))
184}
185
186impl RustType<ProtoArrayData> for arrow::array::ArrayData {
187    fn into_proto(&self) -> ProtoArrayData {
188        into_proto_with_type(self, None)
189    }
190
191    fn from_proto(proto: ProtoArrayData) -> Result<Self, TryFromProtoError> {
192        from_proto_with_type(proto, None)
193    }
194}
195
196impl RustType<proto::DataType> for arrow::datatypes::DataType {
197    fn into_proto(&self) -> proto::DataType {
198        let kind = match self {
199            DataType::Null => proto::data_type::Kind::Null(()),
200            DataType::Boolean => proto::data_type::Kind::Boolean(()),
201            DataType::UInt8 => proto::data_type::Kind::Uint8(()),
202            DataType::UInt16 => proto::data_type::Kind::Uint16(()),
203            DataType::UInt32 => proto::data_type::Kind::Uint32(()),
204            DataType::UInt64 => proto::data_type::Kind::Uint64(()),
205            DataType::Int8 => proto::data_type::Kind::Int8(()),
206            DataType::Int16 => proto::data_type::Kind::Int16(()),
207            DataType::Int32 => proto::data_type::Kind::Int32(()),
208            DataType::Int64 => proto::data_type::Kind::Int64(()),
209            DataType::Float32 => proto::data_type::Kind::Float32(()),
210            DataType::Float64 => proto::data_type::Kind::Float64(()),
211            DataType::Utf8 => proto::data_type::Kind::String(()),
212            DataType::Binary => proto::data_type::Kind::Binary(()),
213            DataType::FixedSizeBinary(size) => proto::data_type::Kind::FixedBinary(*size),
214            DataType::List(inner) => proto::data_type::Kind::List(Box::new(inner.into_proto())),
215            DataType::Map(inner, sorted) => {
216                let map = proto::data_type::Map {
217                    value: Some(Box::new(inner.into_proto())),
218                    sorted: *sorted,
219                };
220                proto::data_type::Kind::Map(Box::new(map))
221            }
222            DataType::Struct(children) => {
223                let children = children.into_iter().map(|f| f.into_proto()).collect();
224                proto::data_type::Kind::Struct(proto::data_type::Struct { children })
225            }
226            other => unimplemented!("unsupported data type {other:?}"),
227        };
228
229        proto::DataType { kind: Some(kind) }
230    }
231
232    fn from_proto(proto: proto::DataType) -> Result<Self, TryFromProtoError> {
233        let data_type = proto
234            .kind
235            .ok_or_else(|| TryFromProtoError::missing_field("kind"))?;
236        let data_type = match data_type {
237            proto::data_type::Kind::Null(()) => DataType::Null,
238            proto::data_type::Kind::Boolean(()) => DataType::Boolean,
239            proto::data_type::Kind::Uint8(()) => DataType::UInt8,
240            proto::data_type::Kind::Uint16(()) => DataType::UInt16,
241            proto::data_type::Kind::Uint32(()) => DataType::UInt32,
242            proto::data_type::Kind::Uint64(()) => DataType::UInt64,
243            proto::data_type::Kind::Int8(()) => DataType::Int8,
244            proto::data_type::Kind::Int16(()) => DataType::Int16,
245            proto::data_type::Kind::Int32(()) => DataType::Int32,
246            proto::data_type::Kind::Int64(()) => DataType::Int64,
247            proto::data_type::Kind::Float32(()) => DataType::Float32,
248            proto::data_type::Kind::Float64(()) => DataType::Float64,
249            proto::data_type::Kind::String(()) => DataType::Utf8,
250            proto::data_type::Kind::Binary(()) => DataType::Binary,
251            proto::data_type::Kind::FixedBinary(size) => DataType::FixedSizeBinary(size),
252            proto::data_type::Kind::List(inner) => DataType::List(Arc::new((*inner).into_rust()?)),
253            proto::data_type::Kind::Map(inner) => {
254                let value = inner
255                    .value
256                    .ok_or_else(|| TryFromProtoError::missing_field("map.value"))?;
257                DataType::Map(Arc::new((*value).into_rust()?), inner.sorted)
258            }
259            proto::data_type::Kind::Struct(inner) => {
260                let children: Vec<Field> = inner
261                    .children
262                    .into_iter()
263                    .map(|c| c.into_rust())
264                    .collect::<Result<_, _>>()?;
265                DataType::Struct(Fields::from(children))
266            }
267        };
268
269        Ok(data_type)
270    }
271}
272
273impl RustType<proto::Field> for arrow::datatypes::Field {
274    fn into_proto(&self) -> proto::Field {
275        proto::Field {
276            name: self.name().clone(),
277            nullable: self.is_nullable(),
278            data_type: Some(Box::new(self.data_type().into_proto())),
279        }
280    }
281
282    fn from_proto(proto: proto::Field) -> Result<Self, TryFromProtoError> {
283        let proto::Field {
284            name,
285            nullable,
286            data_type,
287        } = proto;
288        let data_type =
289            data_type.ok_or_else(|| TryFromProtoError::missing_field("field.data_type"))?;
290        let data_type = (*data_type).into_rust()?;
291
292        Ok(Field::new(name, data_type, nullable))
293    }
294}
295
296impl RustType<proto::Buffer> for arrow::buffer::Buffer {
297    fn into_proto(&self) -> proto::Buffer {
298        // Wrapping since arrow's buffer doesn't implement AsRef, though the deref impl exists.
299        #[repr(transparent)]
300        struct BufferWrapper(arrow::buffer::Buffer);
301        impl AsRef<[u8]> for BufferWrapper {
302            fn as_ref(&self) -> &[u8] {
303                &*self.0
304            }
305        }
306        proto::Buffer {
307            data: bytes::Bytes::from_owner(BufferWrapper(self.clone())),
308        }
309    }
310
311    fn from_proto(proto: proto::Buffer) -> Result<Self, TryFromProtoError> {
312        Ok(arrow::buffer::Buffer::from(proto.data))
313    }
314}
315
316impl RustType<proto::BooleanBuffer> for arrow::buffer::BooleanBuffer {
317    fn into_proto(&self) -> proto::BooleanBuffer {
318        proto::BooleanBuffer {
319            buffer: Some(self.sliced().into_proto()),
320            length: u64::cast_from(self.len()),
321        }
322    }
323
324    fn from_proto(proto: proto::BooleanBuffer) -> Result<Self, TryFromProtoError> {
325        let proto::BooleanBuffer { buffer, length } = proto;
326        let buffer = buffer.into_rust_if_some("buffer")?;
327        Ok(BooleanBuffer::new(buffer, 0, usize::cast_from(length)))
328    }
329}
330
331/// Wraps a single arrow array, downcasted to a specific type.
332#[derive(Clone)]
333pub enum ArrayOrd {
334    /// Wraps a `NullArray`.
335    Null(NullArray),
336    /// Wraps a `Bool` array.
337    Bool(BooleanArray),
338    /// Wraps a `Int8` array.
339    Int8(Int8Array),
340    /// Wraps a `Int16` array.
341    Int16(Int16Array),
342    /// Wraps a `Int32` array.
343    Int32(Int32Array),
344    /// Wraps a `Int64` array.
345    Int64(Int64Array),
346    /// Wraps a `UInt8` array.
347    UInt8(UInt8Array),
348    /// Wraps a `UInt16` array.
349    UInt16(UInt16Array),
350    /// Wraps a `UInt32` array.
351    UInt32(UInt32Array),
352    /// Wraps a `UInt64` array.
353    UInt64(UInt64Array),
354    /// Wraps a `Float32` array.
355    Float32(Float32Array),
356    /// Wraps a `Float64` array.
357    Float64(Float64Array),
358    /// Wraps a `String` array.
359    String(StringArray),
360    /// Wraps a `Binary` array.
361    Binary(BinaryArray),
362    /// Wraps a `FixedSizeBinary` array.
363    FixedSizeBinary(FixedSizeBinaryArray),
364    /// Wraps a `List` array.
365    List(Option<NullBuffer>, OffsetBuffer<i32>, Box<ArrayOrd>),
366    /// Wraps a `Struct` array.
367    Struct(Option<NullBuffer>, Vec<ArrayOrd>),
368}
369
370impl ArrayOrd {
371    /// Downcast the provided array to a specific type in our enum.
372    pub fn new(array: &dyn Array) -> Self {
373        match array.data_type() {
374            DataType::Null => ArrayOrd::Null(NullArray::from(array.to_data())),
375            DataType::Boolean => ArrayOrd::Bool(array.as_boolean().clone()),
376            DataType::Int8 => ArrayOrd::Int8(array.as_primitive().clone()),
377            DataType::Int16 => ArrayOrd::Int16(array.as_primitive().clone()),
378            DataType::Int32 => ArrayOrd::Int32(array.as_primitive().clone()),
379            DataType::Int64 => ArrayOrd::Int64(array.as_primitive().clone()),
380            DataType::UInt8 => ArrayOrd::UInt8(array.as_primitive().clone()),
381            DataType::UInt16 => ArrayOrd::UInt16(array.as_primitive().clone()),
382            DataType::UInt32 => ArrayOrd::UInt32(array.as_primitive().clone()),
383            DataType::UInt64 => ArrayOrd::UInt64(array.as_primitive().clone()),
384            DataType::Float32 => ArrayOrd::Float32(array.as_primitive().clone()),
385            DataType::Float64 => ArrayOrd::Float64(array.as_primitive().clone()),
386            DataType::Binary => ArrayOrd::Binary(array.as_binary().clone()),
387            DataType::Utf8 => ArrayOrd::String(array.as_string().clone()),
388            DataType::FixedSizeBinary(_) => {
389                ArrayOrd::FixedSizeBinary(array.as_fixed_size_binary().clone())
390            }
391            DataType::List(_) => {
392                let list_array = array.as_list();
393                ArrayOrd::List(
394                    list_array.nulls().cloned(),
395                    list_array.offsets().clone(),
396                    Box::new(ArrayOrd::new(list_array.values())),
397                )
398            }
399            DataType::Struct(_) => {
400                let struct_array = array.as_struct();
401                let nulls = array.nulls().cloned();
402                let columns: Vec<_> = struct_array
403                    .columns()
404                    .iter()
405                    .map(|a| ArrayOrd::new(a))
406                    .collect();
407                ArrayOrd::Struct(nulls, columns)
408            }
409            data_type => unimplemented!("array type {data_type:?} not yet supported"),
410        }
411    }
412
413    /// Returns the rough amount of space required for the data in this array in bytes.
414    /// (Not counting nulls, dictionary encoding, or other space optimizations.)
415    pub fn goodbytes(&self) -> usize {
416        match self {
417            ArrayOrd::Null(_) => 0,
418            // This is, strictly speaking, wrong - but consistent with `ArrayIdx::goodbytes`,
419            // which counts one byte per bool.
420            ArrayOrd::Bool(b) => b.len(),
421            ArrayOrd::Int8(a) => a.values().inner().len(),
422            ArrayOrd::Int16(a) => a.values().inner().len(),
423            ArrayOrd::Int32(a) => a.values().inner().len(),
424            ArrayOrd::Int64(a) => a.values().inner().len(),
425            ArrayOrd::UInt8(a) => a.values().inner().len(),
426            ArrayOrd::UInt16(a) => a.values().inner().len(),
427            ArrayOrd::UInt32(a) => a.values().inner().len(),
428            ArrayOrd::UInt64(a) => a.values().inner().len(),
429            ArrayOrd::Float32(a) => a.values().inner().len(),
430            ArrayOrd::Float64(a) => a.values().inner().len(),
431            ArrayOrd::String(a) => a.values().len(),
432            ArrayOrd::Binary(a) => a.values().len(),
433            ArrayOrd::FixedSizeBinary(a) => a.values().len(),
434            ArrayOrd::List(_, _, nested) => nested.goodbytes(),
435            ArrayOrd::Struct(_, nested) => nested.iter().map(|a| a.goodbytes()).sum(),
436        }
437    }
438
439    /// Return a struct representing the value at a particular index in this array.
440    pub fn at(&self, idx: usize) -> ArrayIdx<'_> {
441        ArrayIdx { idx, array: self }
442    }
443}
444
445impl Debug for ArrayOrd {
446    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
447        struct DebugType<'a>(&'a ArrayOrd);
448
449        impl Debug for DebugType<'_> {
450            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
451                match self.0 {
452                    ArrayOrd::Null(_) => write!(f, "Null"),
453                    ArrayOrd::Bool(_) => write!(f, "Bool"),
454                    ArrayOrd::Int8(_) => write!(f, "Int8"),
455                    ArrayOrd::Int16(_) => write!(f, "Int16"),
456                    ArrayOrd::Int32(_) => write!(f, "Int32"),
457                    ArrayOrd::Int64(_) => write!(f, "Int64"),
458                    ArrayOrd::UInt8(_) => write!(f, "UInt8"),
459                    ArrayOrd::UInt16(_) => write!(f, "UInt16"),
460                    ArrayOrd::UInt32(_) => write!(f, "UInt32"),
461                    ArrayOrd::UInt64(_) => write!(f, "UInt64"),
462                    ArrayOrd::Float32(_) => write!(f, "Float32"),
463                    ArrayOrd::Float64(_) => write!(f, "Float64"),
464                    ArrayOrd::String(_) => write!(f, "String"),
465                    ArrayOrd::Binary(_) => write!(f, "Binary"),
466                    ArrayOrd::FixedSizeBinary(a) => f
467                        .debug_tuple("FixedSizeBinary")
468                        .field(&a.value_length())
469                        .finish(),
470                    ArrayOrd::List(_, _, nested) => f.debug_tuple("List").field(&*nested).finish(),
471                    ArrayOrd::Struct(_, fields) => {
472                        let mut tuple = f.debug_tuple("Struct");
473                        for field in fields {
474                            tuple.field(field);
475                        }
476                        tuple.finish()
477                    }
478                }
479            }
480        }
481
482        f.debug_struct("ArrayOrd")
483            .field("type", &DebugType(self))
484            .field("goodbytes", &self.goodbytes())
485            .finish()
486    }
487}
488
489/// A struct representing a particular entry in a particular array. Most useful for its `Ord`
490/// implementation, which can compare entire rows across similarly-typed arrays.
491///
492/// It is an error to compare indices from arrays with different types, with one exception:
493/// it is valid to compare two `StructArray`s, one of which is a prefix of the other...
494/// in which case we'll compare the values on that subset of the fields, and the shorter
495/// of the two structs will compare less if they're otherwise equal.
496#[derive(Clone, Copy, Debug)]
497pub struct ArrayIdx<'a> {
498    /// An index into a particular array.
499    pub idx: usize,
500    /// The particular array.
501    pub array: &'a ArrayOrd,
502}
503
504impl Display for ArrayIdx<'_> {
505    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
506        match self.array {
507            ArrayOrd::Null(_) => write!(f, "null"),
508            ArrayOrd::Bool(a) => write!(f, "{}", a.value(self.idx)),
509            ArrayOrd::Int8(a) => write!(f, "{}", a.value(self.idx)),
510            ArrayOrd::Int16(a) => write!(f, "{}", a.value(self.idx)),
511            ArrayOrd::Int32(a) => write!(f, "{}", a.value(self.idx)),
512            ArrayOrd::Int64(a) => write!(f, "{}", a.value(self.idx)),
513            ArrayOrd::UInt8(a) => write!(f, "{}", a.value(self.idx)),
514            ArrayOrd::UInt16(a) => write!(f, "{}", a.value(self.idx)),
515            ArrayOrd::UInt32(a) => write!(f, "{}", a.value(self.idx)),
516            ArrayOrd::UInt64(a) => write!(f, "{}", a.value(self.idx)),
517            ArrayOrd::Float32(a) => write!(f, "{}", a.value(self.idx)),
518            ArrayOrd::Float64(a) => write!(f, "{}", a.value(self.idx)),
519            ArrayOrd::String(a) => write!(f, "{}", a.value(self.idx)),
520            ArrayOrd::Binary(a) => {
521                for byte in a.value(self.idx) {
522                    write!(f, "{:02x}", byte)?;
523                }
524                Ok(())
525            }
526            ArrayOrd::FixedSizeBinary(a) => {
527                for byte in a.value(self.idx) {
528                    write!(f, "{:02x}", byte)?;
529                }
530                Ok(())
531            }
532            ArrayOrd::List(_, offsets, nested) => {
533                write!(
534                    f,
535                    "[{}]",
536                    mz_ore::str::separated(", ", list_range(offsets, nested, self.idx))
537                )
538            }
539            ArrayOrd::Struct(_, nested) => write!(
540                f,
541                "{{{}}}",
542                mz_ore::str::separated(", ", nested.iter().map(|f| f.at(self.idx)))
543            ),
544        }
545    }
546}
547
548#[inline]
549fn list_range<'a>(
550    offsets: &OffsetBuffer<i32>,
551    values: &'a ArrayOrd,
552    idx: usize,
553) -> impl Iterator<Item = ArrayIdx<'a>> + Clone {
554    let offsets = offsets.inner();
555    let from = offsets[idx].as_usize();
556    let to = offsets[idx + 1].as_usize();
557    (from..to).map(|i| values.at(i))
558}
559
560impl<'a> ArrayIdx<'a> {
561    /// Returns the rough amount of space required for this entry in bytes.
562    /// (Not counting nulls, dictionary encoding, or other space optimizations.)
563    pub fn goodbytes(&self) -> usize {
564        match self.array {
565            ArrayOrd::Null(_) => 0,
566            ArrayOrd::Bool(_) => size_of::<bool>(),
567            ArrayOrd::Int8(_) => size_of::<i8>(),
568            ArrayOrd::Int16(_) => size_of::<i16>(),
569            ArrayOrd::Int32(_) => size_of::<i32>(),
570            ArrayOrd::Int64(_) => size_of::<i64>(),
571            ArrayOrd::UInt8(_) => size_of::<u8>(),
572            ArrayOrd::UInt16(_) => size_of::<u16>(),
573            ArrayOrd::UInt32(_) => size_of::<u32>(),
574            ArrayOrd::UInt64(_) => size_of::<u64>(),
575            ArrayOrd::Float32(_) => size_of::<f32>(),
576            ArrayOrd::Float64(_) => size_of::<f64>(),
577            ArrayOrd::String(a) => a.value(self.idx).len(),
578            ArrayOrd::Binary(a) => a.value(self.idx).len(),
579            ArrayOrd::FixedSizeBinary(a) => a.value_length().as_usize(),
580            ArrayOrd::List(_, offsets, nested) => {
581                // Range over the list, summing up the bytes for each entry.
582                list_range(offsets, nested, self.idx)
583                    .map(|a| a.goodbytes())
584                    .sum()
585            }
586            ArrayOrd::Struct(_, nested) => nested.iter().map(|a| a.at(self.idx).goodbytes()).sum(),
587        }
588    }
589}
590
591impl<'a> Ord for ArrayIdx<'a> {
592    fn cmp(&self, other: &Self) -> Ordering {
593        #[inline]
594        fn is_null(buffer: &Option<NullBuffer>, idx: usize) -> bool {
595            buffer.as_ref().map_or(false, |b| b.is_null(idx))
596        }
597        #[inline]
598        fn cmp<A: ArrayAccessor>(
599            left: A,
600            left_idx: usize,
601            right: A,
602            right_idx: usize,
603            cmp: fn(&A::Item, &A::Item) -> Ordering,
604        ) -> Ordering {
605            // NB: nulls sort last, conveniently matching psql / mz_repr
606            match (left.is_null(left_idx), right.is_null(right_idx)) {
607                (false, true) => Ordering::Less,
608                (true, true) => Ordering::Equal,
609                (true, false) => Ordering::Greater,
610                (false, false) => cmp(&left.value(left_idx), &right.value(right_idx)),
611            }
612        }
613        match (&self.array, &other.array) {
614            (ArrayOrd::Null(s), ArrayOrd::Null(o)) => {
615                debug_assert!(
616                    self.idx < s.len() && other.idx < o.len(),
617                    "null array indices in bounds"
618                );
619                Ordering::Equal
620            }
621            // For arrays with "simple" value types, we fetch and compare the underlying values directly.
622            (ArrayOrd::Bool(s), ArrayOrd::Bool(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
623            (ArrayOrd::Int8(s), ArrayOrd::Int8(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
624            (ArrayOrd::Int16(s), ArrayOrd::Int16(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
625            (ArrayOrd::Int32(s), ArrayOrd::Int32(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
626            (ArrayOrd::Int64(s), ArrayOrd::Int64(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
627            (ArrayOrd::UInt8(s), ArrayOrd::UInt8(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
628            (ArrayOrd::UInt16(s), ArrayOrd::UInt16(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
629            (ArrayOrd::UInt32(s), ArrayOrd::UInt32(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
630            (ArrayOrd::UInt64(s), ArrayOrd::UInt64(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
631            (ArrayOrd::Float32(s), ArrayOrd::Float32(o)) => {
632                cmp(s, self.idx, o, other.idx, f32::total_cmp)
633            }
634            (ArrayOrd::Float64(s), ArrayOrd::Float64(o)) => {
635                cmp(s, self.idx, o, other.idx, f64::total_cmp)
636            }
637            (ArrayOrd::String(s), ArrayOrd::String(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
638            (ArrayOrd::Binary(s), ArrayOrd::Binary(o)) => cmp(s, self.idx, o, other.idx, Ord::cmp),
639            (ArrayOrd::FixedSizeBinary(s), ArrayOrd::FixedSizeBinary(o)) => {
640                cmp(s, self.idx, o, other.idx, Ord::cmp)
641            }
642            // For lists, we generate an iterator for each side that ranges over the correct
643            // indices into the value buffer, then compare them lexicographically.
644            (
645                ArrayOrd::List(s_nulls, s_offset, s_values),
646                ArrayOrd::List(o_nulls, o_offset, o_values),
647            ) => match (is_null(s_nulls, self.idx), is_null(o_nulls, other.idx)) {
648                (false, true) => Ordering::Less,
649                (true, true) => Ordering::Equal,
650                (true, false) => Ordering::Greater,
651                (false, false) => list_range(s_offset, s_values, self.idx)
652                    .cmp(list_range(o_offset, o_values, other.idx)),
653            },
654            // For structs, we iterate over the same index in each field for each input,
655            // comparing them lexicographically in order.
656            (ArrayOrd::Struct(s_nulls, s_cols), ArrayOrd::Struct(o_nulls, o_cols)) => {
657                match (is_null(s_nulls, self.idx), is_null(o_nulls, other.idx)) {
658                    (false, true) => Ordering::Less,
659                    (true, true) => Ordering::Equal,
660                    (true, false) => Ordering::Greater,
661                    (false, false) => {
662                        let s = s_cols.iter().map(|array| array.at(self.idx));
663                        let o = o_cols.iter().map(|array| array.at(other.idx));
664                        s.cmp(o)
665                    }
666                }
667            }
668            (a, b) => panic!("array types did not match! {a:?} vs. {b:?}",),
669        }
670    }
671}
672
673impl<'a> PartialOrd for ArrayIdx<'a> {
674    fn partial_cmp(&self, other: &ArrayIdx) -> Option<Ordering> {
675        Some(self.cmp(other))
676    }
677}
678
679impl<'a> PartialEq for ArrayIdx<'a> {
680    fn eq(&self, other: &ArrayIdx) -> bool {
681        self.cmp(other) == Ordering::Equal
682    }
683}
684
685impl<'a> Eq for ArrayIdx<'a> {}
686
687/// An array with precisely one entry, for use as a lower bound.
688#[derive(Debug, Clone)]
689pub struct ArrayBound {
690    raw: ArrayRef,
691    ord: ArrayOrd,
692    index: usize,
693}
694
695impl PartialEq for ArrayBound {
696    fn eq(&self, other: &Self) -> bool {
697        self.get().eq(&other.get())
698    }
699}
700
701impl Eq for ArrayBound {}
702
703impl ArrayBound {
704    /// Create a new `ArrayBound` for this array, with the bound at the provided index.
705    pub fn new(array: ArrayRef, index: usize) -> Self {
706        Self {
707            ord: ArrayOrd::new(array.as_ref()),
708            raw: array,
709            index,
710        }
711    }
712
713    /// Get the value of the bound.
714    pub fn get(&self) -> ArrayIdx<'_> {
715        self.ord.at(self.index)
716    }
717
718    /// Convert to an array-data proto, respecting a maximum data size. The resulting proto will
719    /// decode to a single-row array, such that `ArrayBound::new(decoded, 0).get() <= self.get()`,
720    /// which makes it suitable as a lower bound.
721    pub fn to_proto_lower(&self, max_len: usize) -> Option<ProtoArrayData> {
722        // Use `take` instead of slice to make sure we encode just the relevant row to proto,
723        // instead of some larger buffer with an offset.
724        let indices = UInt64Array::from_value(u64::usize_as(self.index), 1);
725        let taken = arrow::compute::take(self.raw.as_ref(), &indices, None).ok()?;
726        let array_data = taken.into_data();
727
728        let mut proto = array_data.into_proto();
729        let original_len = proto.encoded_len();
730        if original_len <= max_len {
731            return Some(proto);
732        }
733
734        let mut data_type = proto.data_type.take()?;
735        maybe_trim_proto(&mut data_type, &mut proto, max_len);
736        proto.data_type = Some(data_type);
737
738        if cfg!(debug_assertions) {
739            let array: ArrayData = proto
740                .clone()
741                .into_rust()
742                .expect("trimmed array data can still be decoded");
743            assert_eq!(array.len(), 1);
744            let new_bound = Self::new(make_array(array), 0);
745            assert!(
746                new_bound.get() <= self.get(),
747                "trimmed bound should be comparable to and no larger than the original data"
748            )
749        }
750
751        if proto.encoded_len() <= max_len {
752            Some(proto)
753        } else {
754            None
755        }
756    }
757}
758
759/// Makes a best effort to shrink the proto while preserving the ordering.
760/// (The proto might not be smaller after this method is called, but it should always
761/// be a valid lower bound.)
762///
763/// Note that we pass in the data type and the array data separately, since we only keep
764/// type info at the top level. If a caller does have a top-level `ArrayData` instance,
765/// they should take that type and pass it in separately.
766fn maybe_trim_proto(data_type: &mut proto::DataType, body: &mut ProtoArrayData, max_len: usize) {
767    assert!(body.data_type.is_none(), "expected separate data type");
768    // TODO: consider adding cases for strings and byte arrays
769    let encoded_len = data_type.encoded_len() + body.encoded_len();
770    match &mut data_type.kind {
771        Some(data_type::Kind::Struct(data_type::Struct { children: fields })) => {
772            // Pop off fields one by one, keeping an estimate of the encoded length.
773            let mut struct_len = encoded_len;
774            while struct_len > max_len {
775                let Some(mut child) = body.children.pop() else {
776                    break;
777                };
778                let Some(mut field) = fields.pop() else { break };
779
780                struct_len -= field.encoded_len() + child.encoded_len();
781                if let Some(remaining_len) = max_len.checked_sub(struct_len) {
782                    // We're under budget after removing this field! See if we can
783                    // shrink it to fit, but exit the loop regardless.
784                    let Some(field_type) = field.data_type.as_mut() else {
785                        break;
786                    };
787                    maybe_trim_proto(field_type, &mut child, remaining_len);
788                    if field.encoded_len() + child.encoded_len() <= remaining_len {
789                        fields.push(field);
790                        body.children.push(child);
791                    }
792                    break;
793                }
794            }
795        }
796        _ => {}
797    };
798}
799
800#[cfg(test)]
801mod tests {
802    use crate::arrow::{ArrayBound, ArrayOrd};
803    use arrow::array::{
804        ArrayRef, AsArray, BooleanArray, StringArray, StructArray, UInt64Array, make_array,
805    };
806    use arrow::datatypes::{DataType, Field, Fields};
807    use mz_ore::assert_none;
808    use mz_proto::ProtoType;
809    use std::sync::Arc;
810
811    #[mz_ore::test]
812    fn trim_proto() {
813        let nested_fields: Fields = vec![Field::new("a", DataType::UInt64, true)].into();
814        let array: ArrayRef = Arc::new(StructArray::new(
815            vec![
816                Field::new("a", DataType::UInt64, true),
817                Field::new("b", DataType::Utf8, true),
818                Field::new_struct("c", nested_fields.clone(), true),
819            ]
820            .into(),
821            vec![
822                Arc::new(UInt64Array::from_iter_values([1])),
823                Arc::new(StringArray::from_iter_values(["large".repeat(50)])),
824                Arc::new(StructArray::new_null(nested_fields, 1)),
825            ],
826            None,
827        ));
828        let bound = ArrayBound::new(array, 0);
829
830        assert_none!(bound.to_proto_lower(0));
831        assert_none!(bound.to_proto_lower(1));
832
833        let proto = bound
834            .to_proto_lower(100)
835            .expect("can fit something in less than 100 bytes");
836        let array = make_array(proto.into_rust().expect("valid proto"));
837        assert_eq!(
838            array.as_struct().column_names().as_slice(),
839            &["a"],
840            "only the first column should fit"
841        );
842
843        let proto = bound
844            .to_proto_lower(1000)
845            .expect("can fit everything in less than 1000 bytes");
846        let array = make_array(proto.into_rust().expect("valid proto"));
847        assert_eq!(
848            array.as_struct().column_names().as_slice(),
849            &["a", "b", "c"],
850            "all columns should fit"
851        )
852    }
853
854    #[mz_ore::test]
855    fn struct_ord() {
856        let prefix = StructArray::new(
857            vec![Field::new("a", DataType::UInt64, true)].into(),
858            vec![Arc::new(UInt64Array::from_iter_values([1, 3, 5]))],
859            None,
860        );
861        let full = StructArray::new(
862            vec![
863                Field::new("a", DataType::UInt64, true),
864                Field::new("b", DataType::Utf8, true),
865            ]
866            .into(),
867            vec![
868                Arc::new(UInt64Array::from_iter_values([2, 3, 4])),
869                Arc::new(StringArray::from_iter_values(["a", "b", "c"])),
870            ],
871            None,
872        );
873        let prefix_ord = ArrayOrd::new(&prefix);
874        let full_ord = ArrayOrd::new(&full);
875
876        // Comparison works as normal over the shared columns... but when those columns are identical,
877        // the shorter struct is always smaller.
878        assert!(prefix_ord.at(0) < full_ord.at(0), "(1) < (2, 'a')");
879        assert!(prefix_ord.at(1) < full_ord.at(1), "(3) < (3, 'b')");
880        assert!(prefix_ord.at(2) > full_ord.at(2), "(5) < (4, 'c')");
881    }
882
883    #[mz_ore::test]
884    #[should_panic(expected = "array types did not match")]
885    fn struct_ord_incompat() {
886        // This test is descriptive, not prescriptive: we declare it is an error to compare
887        // structs like this, but not what the result of comparing them is.
888        let string = StructArray::new(
889            vec![
890                Field::new("a", DataType::UInt64, true),
891                Field::new("b", DataType::Utf8, true),
892            ]
893            .into(),
894            vec![
895                Arc::new(UInt64Array::from_iter_values([1])),
896                Arc::new(StringArray::from_iter_values(["a"])),
897            ],
898            None,
899        );
900        let boolean = StructArray::new(
901            vec![
902                Field::new("a", DataType::UInt64, true),
903                Field::new("b", DataType::Boolean, true),
904            ]
905            .into(),
906            vec![
907                Arc::new(UInt64Array::from_iter_values([1])),
908                Arc::new(BooleanArray::from_iter([Some(true)])),
909            ],
910            None,
911        );
912        let string_ord = ArrayOrd::new(&string);
913        let bool_ord = ArrayOrd::new(&boolean);
914
915        // Despite the matching first column, this will panic with a type mismatch.
916        assert!(string_ord.at(0) < bool_ord.at(0));
917    }
918}
mz_persist_types/arrow.rs

mz_persist_types/
arrow.rs
