value_log/
config.rs

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

value_log/
config.rs
