From b44d3fc796484a50cd6854f20c9b46e5fddedc9d Mon Sep 17 00:00:00 2001 From: Alex Date: Wed, 8 Jun 2022 10:01:44 +0200 Subject: Abstract database behind generic interface and implement alternative drivers (#322) - [x] Design interface - [x] Implement Sled backend - [x] Re-implement the SledCountedTree hack ~~on Sled backend~~ on all backends (i.e. over the abstraction) - [x] Convert Garage code to use generic interface - [x] Proof-read converted Garage code - [ ] Test everything well - [x] Implement sqlite backend - [x] Implement LMDB backend - [ ] (Implement Persy backend?) - [ ] (Implement other backends? (like RocksDB, ...)) - [x] Implement backend choice in config file and garage server module - [x] Add CLI for converting between DB formats - Exploit the new interface to put more things in transactions - [x] `.updated()` trigger on Garage tables Fix #284 **Bugs** - [x] When exporting sqlite, trees iterate empty?? - [x] LMDB doesn't work **Known issues for various back-ends** - Sled: - Eats all my RAM and also all my disk space - `.len()` has to traverse the whole table - Is actually quite slow on some operations - And is actually pretty bad code... - Sqlite: - Requires a lock to be taken on all operations. The lock is also taken when iterating on a table with `.iter()`, and the lock isn't released until the iterator is dropped. This means that we must be VERY carefull to not do anything else inside a `.iter()` loop or else we will have a deadlock! Most such cases have been eliminated from the Garage codebase, but there might still be some that remain. If your Garage-over-Sqlite seems to hang/freeze, this is the reason. - (adapter uses a bunch of unsafe code) - Heed (LMDB): - Not suited for 32-bit machines as it has to map the whole DB in memory. - (adpater uses a tiny bit of unsafe code) **My recommendation:** avoid 32-bit machines and use LMDB as much as possible. **Converting databases** is actually quite easy. For example from Sled to LMDB: ```bash cd src/db cargo run --features cli --bin convert -- -i path/to/garage/meta/db -a sled -o path/to/garage/meta/db.lmdb -b lmdb ``` Then, just add this to your `config.toml`: ```toml db_engine = "lmdb" ``` Co-authored-by: Alex Auvolat Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/322 Co-authored-by: Alex Co-committed-by: Alex --- src/db/bin/convert.rs | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 src/db/bin/convert.rs (limited to 'src/db/bin') diff --git a/src/db/bin/convert.rs b/src/db/bin/convert.rs new file mode 100644 index 00000000..9e45e61f --- /dev/null +++ b/src/db/bin/convert.rs @@ -0,0 +1,76 @@ +use std::path::PathBuf; + +use garage_db::*; + +use clap::Parser; + +/// K2V command line interface +#[derive(Parser, Debug)] +#[clap(author, version, about, long_about = None)] +struct Args { + /// Input DB path + #[clap(short = 'i')] + input_path: PathBuf, + /// Input DB engine + #[clap(short = 'a')] + input_engine: String, + + /// Output DB path + #[clap(short = 'o')] + output_path: PathBuf, + /// Output DB engine + #[clap(short = 'b')] + output_engine: String, +} + +fn main() { + let args = Args::parse(); + pretty_env_logger::init(); + + match do_conversion(args) { + Ok(()) => println!("Success!"), + Err(e) => eprintln!("Error: {}", e), + } +} + +fn do_conversion(args: Args) -> Result<()> { + let input = open_db(args.input_path, args.input_engine)?; + let output = open_db(args.output_path, args.output_engine)?; + output.import(&input)?; + Ok(()) +} + +fn open_db(path: PathBuf, engine: String) -> Result { + match engine.as_str() { + "sled" => { + let db = sled_adapter::sled::Config::default().path(&path).open()?; + Ok(sled_adapter::SledDb::init(db)) + } + "sqlite" | "sqlite3" | "rusqlite" => { + let db = sqlite_adapter::rusqlite::Connection::open(&path)?; + Ok(sqlite_adapter::SqliteDb::init(db)) + } + "lmdb" | "heed" => { + std::fs::create_dir_all(&path).map_err(|e| { + Error(format!("Unable to create LMDB data directory: {}", e).into()) + })?; + + let map_size = if u32::MAX as usize == usize::MAX { + eprintln!( + "LMDB is not recommended on 32-bit systems, database size will be limited" + ); + 1usize << 30 // 1GB for 32-bit systems + } else { + 1usize << 40 // 1TB for 64-bit systems + }; + + let db = lmdb_adapter::heed::EnvOpenOptions::new() + .max_dbs(100) + .map_size(map_size) + .open(&path) + .unwrap(); + Ok(lmdb_adapter::LmdbDb::init(db)) + } + e => Err(Error(format!("Invalid DB engine: {}", e).into())), + } +} -- cgit v1.2.3 From 138e13071be37d873344cd03e316c87ff8057ea0 Mon Sep 17 00:00:00 2001 From: Alex Auvolat Date: Thu, 9 Jun 2022 14:55:20 +0200 Subject: Fix garage_db build on 32-bit systems --- src/db/bin/convert.rs | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'src/db/bin') diff --git a/src/db/bin/convert.rs b/src/db/bin/convert.rs index 9e45e61f..bbde2048 100644 --- a/src/db/bin/convert.rs +++ b/src/db/bin/convert.rs @@ -55,14 +55,7 @@ fn open_db(path: PathBuf, engine: String) -> Result { Error(format!("Unable to create LMDB data directory: {}", e).into()) })?; - let map_size = if u32::MAX as usize == usize::MAX { - eprintln!( - "LMDB is not recommended on 32-bit systems, database size will be limited" - ); - 1usize << 30 // 1GB for 32-bit systems - } else { - 1usize << 40 // 1TB for 64-bit systems - }; + let map_size = lmdb_adapter::recommended_map_size(); let db = lmdb_adapter::heed::EnvOpenOptions::new() .max_dbs(100) -- cgit v1.2.3