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refactor database engine/options; add column descriptors

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Signed-off-by: Jason Volk <jason@zemos.net>
This commit is contained in:
Jason Volk 2025-01-06 14:07:26 +00:00
parent 02f19cf951
commit 6a0f9add0c
21 changed files with 1358 additions and 965 deletions
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74
src/database/map.rs
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@ -6,6 +6,8 @@ mod insert;
mod keys;
mod keys_from;
mod keys_prefix;
mod open;
mod options;
mod remove;
mod rev_keys;
mod rev_keys_from;
@ -28,12 +30,15 @@ use std::{
};
use conduwuit::Result;
use rocksdb::{AsColumnFamilyRef, ColumnFamily, ReadOptions, ReadTier, WriteOptions};
use rocksdb::{AsColumnFamilyRef, ColumnFamily, ReadOptions, WriteOptions};
pub(crate) use self::options::{
cache_read_options_default, iter_options_default, read_options_default, write_options_default,
};
use crate::{watchers::Watchers, Engine};
pub struct Map {
name: String,
name: &'static str,
db: Arc<Engine>,
cf: Arc<ColumnFamily>,
watchers: Watchers,
@ -43,11 +48,11 @@ pub struct Map {
}
impl Map {
pub(crate) fn open(db: &Arc<Engine>, name: &str) -> Result<Arc<Self>> {
pub(crate) fn open(db: &Arc<Engine>, name: &'static str) -> Result<Arc<Self>> {
Ok(Arc::new(Self {
name: name.to_owned(),
name,
db: db.clone(),
cf: open(db, name)?,
cf: open::open(db, name),
watchers: Watchers::default(),
write_options: write_options_default(),
read_options: read_options_default(),
@ -75,7 +80,7 @@ impl Map {
pub fn property(&self, name: &str) -> Result<String> { self.db.property(&self.cf(), name) }
#[inline]
pub fn name(&self) -> &str { &self.name }
pub fn name(&self) -> &str { self.name }
#[inline]
pub(crate) fn db(&self) -> &Arc<Engine> { &self.db }
@ -93,60 +98,3 @@ impl Debug for Map {
impl Display for Map {
fn fmt(&self, out: &mut fmt::Formatter<'_>) -> fmt::Result { write!(out, "{0}", self.name) }
}
fn open(db: &Arc<Engine>, name: &str) -> Result<Arc<ColumnFamily>> {
let bounded_arc = db.open_cf(name)?;
let bounded_ptr = Arc::into_raw(bounded_arc);
let cf_ptr = bounded_ptr.cast::<ColumnFamily>();
// SAFETY: Column family handles out of RocksDB are basic pointers and can
// be invalidated: 1. when the database closes. 2. when the column is dropped or
// closed. rust_rocksdb wraps this for us by storing handles in their own
// `RwLock<BTreeMap>` map and returning an Arc<BoundColumnFamily<'_>>` to
// provide expected safety. Similarly in "single-threaded mode" we would
// receive `&'_ ColumnFamily`.
//
// PROBLEM: We need to hold these handles in a field, otherwise we have to take
// a lock and get them by name from this map for every query, which is what
// conduit was doing, but we're not going to make a query for every query so we
// need to be holding it right. The lifetime parameter on these references makes
// that complicated. If this can be done without polluting the userspace
// with lifetimes on every instance of `Map` then this `unsafe` might not be
// necessary.
//
// SOLUTION: After investigating the underlying types it appears valid to
// Arc-swap `BoundColumnFamily<'_>` for `ColumnFamily`. They have the
// same inner data, the same Drop behavior, Deref, etc. We're just losing the
// lifetime parameter. We should not hold this handle, even in its Arc, after
// closing the database (dropping `Engine`). Since `Arc<Engine>` is a sibling
// member along with this handle in `Map`, that is prevented.
Ok(unsafe {
Arc::increment_strong_count(cf_ptr);
Arc::from_raw(cf_ptr)
})
}
#[inline]
pub(crate) fn iter_options_default() -> ReadOptions {
let mut read_options = read_options_default();
read_options.set_background_purge_on_iterator_cleanup(true);
//read_options.set_pin_data(true);
read_options
}
#[inline]
pub(crate) fn cache_read_options_default() -> ReadOptions {
let mut read_options = read_options_default();
read_options.set_read_tier(ReadTier::BlockCache);
read_options
}
#[inline]
pub(crate) fn read_options_default() -> ReadOptions {
let mut read_options = ReadOptions::default();
read_options.set_total_order_seek(true);
read_options
}
#[inline]
pub(crate) fn write_options_default() -> WriteOptions { WriteOptions::default() }