garage/src/db/open.rs

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use std::path::PathBuf;
use crate::{Db, Error, Result};
/// List of supported database engine types
///
/// The `enum` holds list of *all* database engines that are are be supported by crate, no matter
/// if relevant feature is enabled or not. It allows us to distinguish between invalid engine
/// and valid engine, whose support is not enabled via feature flag.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Engine {
Lmdb,
Sqlite,
Sled,
}
impl Engine {
/// Return variant name as static `&str`
pub fn as_str(&self) -> &'static str {
match self {
Self::Lmdb => "lmdb",
Self::Sqlite => "sqlite",
Self::Sled => "sled",
}
}
}
impl std::fmt::Display for Engine {
fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
self.as_str().fmt(fmt)
}
}
impl std::str::FromStr for Engine {
type Err = Error;
fn from_str(text: &str) -> Result<Engine> {
match text {
"lmdb" | "heed" => Ok(Self::Lmdb),
"sqlite" | "sqlite3" | "rusqlite" => Ok(Self::Sqlite),
"sled" => Ok(Self::Sled),
kind => Err(Error(
format!(
"Invalid DB engine: {} (options are: lmdb, sled, sqlite)",
kind
)
.into(),
)),
}
}
}
pub struct OpenOpt {
pub fsync: bool,
pub lmdb_map_size: Option<usize>,
pub sled_cache_capacity: usize,
pub sled_flush_every_ms: u64,
}
impl Default for OpenOpt {
fn default() -> Self {
Self {
fsync: false,
lmdb_map_size: None,
sled_cache_capacity: 1024 * 1024 * 1024,
sled_flush_every_ms: 2000,
}
}
}
pub fn open_db(path: &PathBuf, engine: Engine, opt: &OpenOpt) -> Result<Db> {
match engine {
// ---- Sled DB ----
#[cfg(feature = "sled")]
Engine::Sled => {
if opt.fsync {
return Err(Error(
"`metadata_fsync = true` is not supported with the Sled database engine".into(),
));
}
info!("Opening Sled database at: {}", path.display());
let db = crate::sled_adapter::sled::Config::default()
.path(&path)
.cache_capacity(opt.sled_cache_capacity as u64)
.flush_every_ms(Some(opt.sled_flush_every_ms))
.open()?;
Ok(crate::sled_adapter::SledDb::init(db))
}
// ---- Sqlite DB ----
#[cfg(feature = "sqlite")]
Engine::Sqlite => {
info!("Opening Sqlite database at: {}", path.display());
let db = crate::sqlite_adapter::rusqlite::Connection::open(&path)?;
db.pragma_update(None, "journal_mode", "WAL")?;
if opt.fsync {
db.pragma_update(None, "synchronous", "NORMAL")?;
} else {
db.pragma_update(None, "synchronous", "OFF")?;
}
Ok(crate::sqlite_adapter::SqliteDb::init(db))
}
// ---- LMDB DB ----
#[cfg(feature = "lmdb")]
Engine::Lmdb => {
info!("Opening LMDB database at: {}", path.display());
if let Err(e) = std::fs::create_dir_all(&path) {
return Err(Error(
format!("Unable to create LMDB data directory: {}", e).into(),
));
}
let map_size = match opt.lmdb_map_size {
None => crate::lmdb_adapter::recommended_map_size(),
Some(v) => v - (v % 4096),
};
let mut env_builder = heed::EnvOpenOptions::new();
env_builder.max_dbs(100);
env_builder.map_size(map_size);
env_builder.max_readers(2048);
unsafe {
env_builder.flag(crate::lmdb_adapter::heed::flags::Flags::MdbNoMetaSync);
if !opt.fsync {
env_builder.flag(heed::flags::Flags::MdbNoSync);
}
}
match env_builder.open(&path) {
Err(heed::Error::Io(e)) if e.kind() == std::io::ErrorKind::OutOfMemory => {
return Err(Error(
"OutOfMemory error while trying to open LMDB database. This can happen \
if your operating system is not allowing you to use sufficient virtual \
memory address space. Please check that no limit is set (ulimit -v). \
You may also try to set a smaller `lmdb_map_size` configuration parameter. \
On 32-bit machines, you should probably switch to another database engine."
.into(),
))
}
Err(e) => Err(Error(format!("Cannot open LMDB database: {}", e).into())),
Ok(db) => Ok(crate::lmdb_adapter::LmdbDb::init(db)),
}
}
// Pattern is unreachable when all supported DB engines are compiled into binary. The allow
// attribute is added so that we won't have to change this match in case stop building
// support for one or more engines by default.
#[allow(unreachable_patterns)]
engine => Err(Error(
format!("DB engine support not available in this build: {}", engine).into(),
)),
}
}