forked from Deuxfleurs/garage
Alex
b44d3fc796
- [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 <alex@adnab.me> Reviewed-on: Deuxfleurs/garage#322 Co-authored-by: Alex <alex@adnab.me> Co-committed-by: Alex <alex@adnab.me>
77 lines
1.7 KiB
Rust
77 lines
1.7 KiB
Rust
use serde::{Deserialize, Serialize};
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use std::sync::Arc;
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use garage_db as db;
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use garage_util::data::*;
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use garage_table::crdt::Crdt;
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use garage_table::*;
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use garage_block::manager::*;
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#[derive(PartialEq, Clone, Debug, Serialize, Deserialize)]
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pub struct BlockRef {
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/// Hash (blake2 sum) of the block, used as partition key
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pub block: Hash,
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/// Id of the Version for the object containing this block, used as sorting key
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pub version: Uuid,
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// Keep track of deleted status
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/// Is the Version that contains this block deleted
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pub deleted: crdt::Bool,
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}
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impl Entry<Hash, Uuid> for BlockRef {
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fn partition_key(&self) -> &Hash {
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&self.block
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}
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fn sort_key(&self) -> &Uuid {
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&self.version
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}
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fn is_tombstone(&self) -> bool {
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self.deleted.get()
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}
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}
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impl Crdt for BlockRef {
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fn merge(&mut self, other: &Self) {
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self.deleted.merge(&other.deleted);
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}
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}
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pub struct BlockRefTable {
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pub block_manager: Arc<BlockManager>,
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}
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impl TableSchema for BlockRefTable {
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const TABLE_NAME: &'static str = "block_ref";
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type P = Hash;
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type S = Uuid;
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type E = BlockRef;
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type Filter = DeletedFilter;
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fn updated(
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&self,
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tx: &mut db::Transaction,
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old: Option<&Self::E>,
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new: Option<&Self::E>,
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) -> db::TxOpResult<()> {
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let block = old.or(new).unwrap().block;
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let was_before = old.map(|x| !x.deleted.get()).unwrap_or(false);
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let is_after = new.map(|x| !x.deleted.get()).unwrap_or(false);
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if is_after && !was_before {
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self.block_manager.block_incref(tx, block)?;
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}
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if was_before && !is_after {
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self.block_manager.block_decref(tx, block)?;
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}
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Ok(())
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}
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fn matches_filter(entry: &Self::E, filter: &Self::Filter) -> bool {
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filter.apply(entry.deleted.get())
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}
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}
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