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// Copyright Materialize, Inc. and contributors. All rights reserved.
//
// Use of this software is governed by the Business Source License
// included in the LICENSE file.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0.
//! Types for the persist crate.
#![warn(missing_docs)]
#![warn(
clippy::cast_possible_truncation,
clippy::cast_precision_loss,
clippy::cast_sign_loss
)]
use bytes::{BufMut, Bytes};
use mz_proto::{RustType, TryFromProtoError};
use proptest_derive::Arbitrary;
use serde::{Deserialize, Serialize};
use uuid::Uuid;
use crate::columnar::Schema2;
pub mod arrow;
pub mod codec_impls;
pub mod columnar;
pub mod parquet;
pub mod part;
pub mod schema;
pub mod stats;
pub mod stats2;
pub mod timestamp;
pub mod txn;
/// Encoding and decoding operations for a type usable as a persisted key or
/// value.
pub trait Codec: Default + Sized + PartialEq + 'static {
/// The type of the associated schema for [Self].
///
/// This is a separate type because Row is not self-describing. For Row, you
/// need a RelationDesc to determine the types of any columns that are
/// Datum::Null.
type Schema: Schema2<Self> + PartialEq;
/// Name of the codec.
///
/// This name is stored for the key and value when a stream is first created
/// and the same key and value codec must be used for that stream afterward.
fn codec_name() -> String;
/// Encode a key or value for permanent storage.
///
/// This must perfectly round-trip Self through [Codec::decode]. If the
/// encode function for this codec ever changes, decode must be able to
/// handle bytes output by all previous versions of encode.
fn encode<B>(&self, buf: &mut B)
where
B: BufMut;
/// Encode a key or value to a Vec.
///
/// This is a convenience function for calling [Self::encode] with a fresh
/// `Vec` each time. Reuse an allocation when performance matters!
fn encode_to_vec(&self) -> Vec<u8> {
let mut buf = vec![];
self.encode(&mut buf);
buf
}
/// Decode a key or value previous encoded with this codec's
/// [Codec::encode].
///
/// This must perfectly round-trip Self through [Codec::encode]. If the
/// encode function for this codec ever changes, decode must be able to
/// handle bytes output by all previous versions of encode.
///
/// It should also gracefully handle data encoded by future versions of
/// encode (likely with an error).
//
// TODO: Mechanically, this could return a ref to the original bytes
// without any copies, see if we can make the types work out for that.
fn decode<'a>(buf: &'a [u8], schema: &Self::Schema) -> Result<Self, String>;
/// A type used with [Self::decode_from] for allocation reuse. Set to `()`
/// if unnecessary.
type Storage: Default;
/// An alternate form of [Self::decode] which enables amortizing allocs.
///
/// First, instead of returning `Self`, it takes `&mut Self` as a parameter,
/// allowing for reuse of the internal `Row`/`SourceData` allocations.
///
/// Second, it adds a `type Storage` to `Codec` and also passes it in as
/// `&mut Option<Self::Storage>`, allowing for reuse of
/// `ProtoRow`/`ProtoSourceData` allocations. If `Some`, this impl may
/// attempt to reuse allocations with it. It may also leave allocations in
/// it for use in future calls to `decode_from`.
///
/// A default implementation is provided for `Codec` impls that can't take
/// advantage of this.
fn decode_from<'a>(
&mut self,
buf: &'a [u8],
_storage: &mut Option<Self::Storage>,
schema: &Self::Schema,
) -> Result<(), String> {
*self = Self::decode(buf, schema)?;
Ok(())
}
/// Checks that the given value matches the provided schema.
///
/// A no-op default implementation is provided for convenience.
fn validate(_val: &Self, _schema: &Self::Schema) -> Result<(), String> {
Ok(())
}
/// Encode a schema for permanent storage.
///
/// This must perfectly round-trip the schema through [Self::decode_schema].
/// If the encode_schema function ever changes, decode_schema must be able
/// to handle bytes output by all previous versions of encode_schema.
///
/// TODO: Move this to instead be a new trait that is required by
/// Self::Schema?
fn encode_schema(schema: &Self::Schema) -> Bytes;
/// Decode a schema previous encoded with this codec's
/// [Self::encode_schema].
///
/// This must perfectly round-trip the schema through [Self::encode_schema].
/// If the encode_schema function ever changes, decode_schema must be able
/// to handle bytes output by all previous versions of encode_schema.
fn decode_schema(buf: &Bytes) -> Self::Schema;
}
/// Encoding and decoding operations for a type usable as a persisted timestamp
/// or diff.
pub trait Codec64: Sized + Clone + 'static {
/// Name of the codec.
///
/// This name is stored for the timestamp and diff when a stream is first
/// created and the same timestamp and diff codec must be used for that
/// stream afterward.
fn codec_name() -> String;
/// Encode a timestamp or diff for permanent storage.
///
/// This must perfectly round-trip Self through [Codec64::decode]. If the
/// encode function for this codec ever changes, decode must be able to
/// handle bytes output by all previous versions of encode.
fn encode(&self) -> [u8; 8];
/// Decode a timestamp or diff previous encoded with this codec's
/// [Codec64::encode].
///
/// This must perfectly round-trip Self through [Codec64::encode]. If the
/// encode function for this codec ever changes, decode must be able to
/// handle bytes output by all previous versions of encode.
fn decode(buf: [u8; 8]) -> Self;
}
/// A location in s3, other cloud storage, or otherwise "durable storage" used
/// by persist.
///
/// This structure can be durably written down or transmitted for use by other
/// processes. This location can contain any number of persist shards.
#[derive(Arbitrary, Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Deserialize, Serialize)]
pub struct PersistLocation {
/// Uri string that identifies the blob store.
pub blob_uri: String,
/// Uri string that identifies the consensus system.
pub consensus_uri: String,
}
impl PersistLocation {
/// Returns a PersistLocation indicating in-mem blob and consensus.
pub fn new_in_mem() -> Self {
PersistLocation {
blob_uri: "mem://".to_owned(),
consensus_uri: "mem://".to_owned(),
}
}
}
/// An opaque identifier for a persist durable TVC (aka shard).
///
/// The [std::string::ToString::to_string] format of this may be stored durably
/// or otherwise used as an interchange format. It can be parsed back using
/// [str::parse] or [std::str::FromStr::from_str].
#[derive(
Arbitrary, Clone, Copy, Default, PartialEq, Eq, Hash, PartialOrd, Ord, Serialize, Deserialize,
)]
#[serde(try_from = "String", into = "String")]
pub struct ShardId([u8; 16]);
impl std::fmt::Display for ShardId {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "s{}", Uuid::from_bytes(self.0))
}
}
impl std::fmt::Debug for ShardId {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "ShardId({})", Uuid::from_bytes(self.0))
}
}
impl std::str::FromStr for ShardId {
type Err = String;
fn from_str(s: &str) -> Result<Self, Self::Err> {
let uuid_encoded = match s.strip_prefix('s') {
Some(x) => x,
None => return Err(format!("invalid ShardId {}: incorrect prefix", s)),
};
let uuid = Uuid::parse_str(uuid_encoded)
.map_err(|err| format!("invalid ShardId {}: {}", s, err))?;
Ok(ShardId(*uuid.as_bytes()))
}
}
impl From<ShardId> for String {
fn from(shard_id: ShardId) -> Self {
shard_id.to_string()
}
}
impl TryFrom<String> for ShardId {
type Error = String;
fn try_from(s: String) -> Result<Self, Self::Error> {
s.parse()
}
}
impl ShardId {
/// Returns a random [ShardId] that is reasonably likely to have never been
/// generated before.
pub fn new() -> Self {
ShardId(Uuid::new_v4().as_bytes().to_owned())
}
}
impl RustType<String> for ShardId {
fn into_proto(&self) -> String {
self.to_string()
}
fn from_proto(proto: String) -> Result<Self, TryFromProtoError> {
match proto.parse() {
Ok(x) => Ok(x),
Err(_) => Err(TryFromProtoError::InvalidShardId(proto)),
}
}
}
/// An opaque fencing token used in compare_and_downgrade_since.
pub trait Opaque: PartialEq + Clone + Sized + 'static {
/// The value of the opaque token when no compare_and_downgrade_since calls
/// have yet been successful.
fn initial() -> Self;
}
/// Advance a timestamp by the least amount possible such that
/// `ts.less_than(ts.step_forward())` is true.
///
/// TODO: Unify this with repr's TimestampManipulation. Or, ideally, get rid of
/// it entirely by making txn-wal methods take an `advance_to` argument.
pub trait StepForward {
/// Advance a timestamp by the least amount possible such that
/// `ts.less_than(ts.step_forward())` is true. Panic if unable to do so.
fn step_forward(&self) -> Self;
}
impl StepForward for u64 {
fn step_forward(&self) -> Self {
self.checked_add(1).unwrap()
}
}