refactor database engine/options; add column descriptors

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/engine/descriptor.rs

@@ -0,0 +1,89 @@
+use conduwuit::utils::string::EMPTY;
+use rocksdb::{
+	DBCompactionPri as CompactionPri, DBCompactionStyle as CompactionStyle,
+	DBCompressionType as CompressionType,
+};
+
+#[derive(Debug, Clone, Copy)]
+pub(crate) enum CacheDisp {
+	Unique,
+	Shared,
+	SharedWith(&'static str),
+}
+
+#[derive(Debug, Clone)]
+pub(crate) struct Descriptor {
+	pub(crate) name: &'static str,
+	pub(crate) cache_disp: CacheDisp,
+	pub(crate) key_size_hint: Option<usize>,
+	pub(crate) val_size_hint: Option<usize>,
+	pub(crate) block_size: usize,
+	pub(crate) index_size: usize,
+	pub(crate) write_size: Option<usize>,
+	pub(crate) cache_size: usize,
+	pub(crate) level_size: u64,
+	pub(crate) level_shape: [i32; 7],
+	pub(crate) file_size: u64,
+	pub(crate) file_shape: [i32; 1],
+	pub(crate) level0_width: i32,
+	pub(crate) merge_width: (i32, i32),
+	pub(crate) ttl: u64,
+	pub(crate) compaction: CompactionStyle,
+	pub(crate) compaction_pri: CompactionPri,
+	pub(crate) compression: CompressionType,
+	pub(crate) compression_level: i32,
+	pub(crate) bottommost_level: Option<i32>,
+	pub(crate) block_index_hashing: bool,
+	pub(crate) cache_shards: u32,
+}
+
+pub(crate) static BASE: Descriptor = Descriptor {
+	name: EMPTY,
+	cache_disp: CacheDisp::Shared,
+	key_size_hint: None,
+	val_size_hint: None,
+	block_size: 1024 * 4,
+	index_size: 1024 * 4,
+	write_size: None,
+	cache_size: 1024 * 1024 * 4,
+	level_size: 1024 * 1024 * 8,
+	level_shape: [1, 1, 1, 3, 7, 15, 31],
+	file_size: 1024 * 1024,
+	file_shape: [2],
+	level0_width: 2,
+	merge_width: (2, 16),
+	ttl: 60 * 60 * 24 * 21,
+	compaction: CompactionStyle::Level,
+	compaction_pri: CompactionPri::MinOverlappingRatio,
+	compression: CompressionType::Zstd,
+	compression_level: 32767,
+	bottommost_level: Some(32767),
+	block_index_hashing: false,
+	cache_shards: 64,
+};
+
+pub(crate) static RANDOM: Descriptor = Descriptor {
+	compaction_pri: CompactionPri::OldestSmallestSeqFirst,
+	..BASE
+};
+
+pub(crate) static SEQUENTIAL: Descriptor = Descriptor {
+	compaction_pri: CompactionPri::OldestLargestSeqFirst,
+	level_size: 1024 * 1024 * 32,
+	file_size: 1024 * 1024 * 2,
+	..BASE
+};
+
+pub(crate) static RANDOM_SMALL: Descriptor = Descriptor {
+	compaction: CompactionStyle::Universal,
+	level_size: 1024 * 512,
+	file_size: 1024 * 128,
+	..RANDOM
+};
+
+pub(crate) static SEQUENTIAL_SMALL: Descriptor = Descriptor {
+	compaction: CompactionStyle::Universal,
+	level_size: 1024 * 1024,
+	file_size: 1024 * 512,
+	..SEQUENTIAL
+};