1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
// Copyright (c) 2024-present, fjall-rs
// This source code is licensed under both the Apache 2.0 and MIT License
// (found in the LICENSE-* files in the repository)
use crate::{blob_cache::BlobCache, compression::Compressor};
use std::sync::Arc;
/// Value log configuration
pub struct Config<C: Compressor + Clone> {
/// Target size of vLog segments
pub(crate) segment_size_bytes: u64,
/// Blob cache to use
pub(crate) blob_cache: Arc<BlobCache>,
/// Compression to use
pub(crate) compression: C,
}
impl<C: Compressor + Clone + Default> Default for Config<C> {
fn default() -> Self {
Self {
segment_size_bytes: /* 256 MiB */ 256 * 1_024 * 1_024,
blob_cache: Arc::new(BlobCache::with_capacity_bytes(
/* 16 MiB */ 16 * 1_024 * 1_024,
)),
compression: C::default(),
}
}
}
impl<C: Compressor + Clone> Config<C> {
/// Sets the compression & decompression scheme.
#[must_use]
pub fn compression(mut self, compressor: C) -> Self {
self.compression = compressor;
self
}
/// Sets the blob cache.
///
/// You can create a global [`BlobCache`] and share it between multiple
/// value logs to cap global cache memory usage.
///
/// Defaults to a blob cache with 16 MiB of capacity *per value log*.
#[must_use]
pub fn blob_cache(mut self, blob_cache: Arc<BlobCache>) -> Self {
self.blob_cache = blob_cache;
self
}
/// Sets the maximum size of value log segments.
///
/// This heavily influences space amplification, as
/// space reclamation works on a per-segment basis.
///
/// Like `blob_file_size` in `RocksDB`.
///
/// Default = 256 MiB
#[must_use]
pub fn segment_size_bytes(mut self, bytes: u64) -> Self {
self.segment_size_bytes = bytes;
self
}
}