byteview

An immutable byte slice that may be inlined, and can be partially cloned without heap allocation.

Think of it as a specialized Arc<[u8]> that can be inlined (skip allocation for small values) and no weak count.

byteview was originally designed to speed up deserialization in lsm-tree, allow inlining of small values and reduce memory usage compared to Arc'd slices. Values with a known length can be constructed 2-2.5x faster than using Arc<[u8]>:

Sponsors

<a href="https://sqlsync.dev"> <picture> <source width="240" alt="Orbitinghail" media="(prefers-color-scheme: light)" srcset="https://raw.githubusercontent.com/fjall-rs/fjall-rs.github.io/d22fcb1e6966ce08327ea3bf6cf2ea86a840b071/public/logos/orbitinghail.svg" /> <source width="240" alt="Orbitinghail" media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/fjall-rs/fjall-rs.github.io/d22fcb1e6966ce08327ea3bf6cf2ea86a840b071/public/logos/orbitinghail_dark.svg" /> <img width="240" alt="Orbitinghail" src="https://raw.githubusercontent.com/fjall-rs/fjall-rs.github.io/d22fcb1e6966ce08327ea3bf6cf2ea86a840b071/public/logos/orbitinghail_dark.svg" /> </picture> </a>

Memory usage

Allocating 200M "" (len=0) strings:

| Struct | Memory Usage | |-----------------|--------------| | Arc<[u8]> | 9.6 GB | | tokio::Bytes | 6.4 GB | | ByteView | 4.8 GB |

Allocating 200M "helloworld" (len=10) strings:

| Struct | Memory Usage | |-----------------|--------------| | Arc<[u8]> | 12.8 GB | | tokio::Bytes | 12.8 GB | | ByteView | 4.8 GB |

Allocating 100M "helloworldhelloworld" (len=20) strings:

| Struct | Memory Usage | |-----------------|--------------| | Arc<[u8]> | 6.4 GB | | tokio::Bytes | 6.4 GB | | ByteView | 2.4 GB |

Allocating 50M "helloworldhelloworldhelloworldhelloworld" (len=30) strings:

| Struct | Memory Usage | |-----------------|--------------| | Arc<[u8]> | 4.0 GB | | tokio::Bytes | 4.0 GB | | ByteView | 3.6 GB |

Allocating 500k "helloworld".repeat(1000) (len=10'000) strings:

| Struct | Memory Usage | |-----------------|--------------| | Arc<[u8]> | 5 GB | | tokio::Bytes | 5 GB | | ByteView | 5 GB |

Run fuzz tests

cargo +nightly fuzz run fuzz_target_1