cobble 0.1.1

A flexible embedded key-value storage engine for distributed systems as well as single-node applications.
Documentation
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
use super::Db;
use crate::Config;
use crate::config::PrimaryVolumeOffloadPolicyKind;
use crate::db_state::{DbStateHandle, MultiLSMTreeVersion};
use crate::db_status::DbLifecycle;
use crate::error::{Error, Result};
use crate::file::{
    FileManager, PrimaryOffloadFileRef, RestoreCopyResourceRegistry, TrackedFileId,
    VLOG_FILE_PRIORITY, compare_primary_offload_file_refs, lsm_file_priority_for_level,
};
use crate::lsm::LSMTreeVersion;
use crate::merge_operator::MergeOperatorResolver;
use crate::metrics_manager::MetricsManager;
use crate::metrics_registry;
use crate::snapshot::{
    ManifestSnapshot, build_tree_versions_from_manifest, build_vlog_version_from_manifest,
    list_snapshot_manifest_ids, load_manifest_entry, load_manifest_for_snapshot,
};
use crate::util::{build_commit_short_id, build_version_string, init_logging};
use std::collections::{HashMap, VecDeque};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, Mutex};
use tokio::runtime::Builder;
use tokio::task::JoinSet;

struct RestoreTempResourceRegistry {
    file_manager: Arc<FileManager>,
    temp_copied_file_ids: Mutex<Vec<u64>>,
    finalized: AtomicBool,
}

impl RestoreTempResourceRegistry {
    fn new(file_manager: Arc<FileManager>) -> Self {
        Self {
            file_manager,
            temp_copied_file_ids: Mutex::new(Vec::new()),
            finalized: AtomicBool::new(false),
        }
    }

    fn finalize(&self) {
        self.finalized.store(true, Ordering::SeqCst);
    }
}

impl RestoreCopyResourceRegistry for RestoreTempResourceRegistry {
    fn register_temp_restored_copy(&self, file_id: u64) {
        if self.finalized.load(Ordering::SeqCst) {
            return;
        }
        if let Ok(mut guard) = self.temp_copied_file_ids.lock() {
            guard.push(file_id);
        }
    }
}

impl Drop for RestoreTempResourceRegistry {
    fn drop(&mut self) {
        if self.finalized.load(Ordering::SeqCst) {
            return;
        }
        let copied_ids = self
            .temp_copied_file_ids
            .lock()
            .map(|guard| guard.clone())
            .unwrap_or_default();
        for file_id in copied_ids {
            let _ = self.file_manager.remove_data_file(file_id);
        }
    }
}

fn prepare_manifest_data_files_for_restore(
    file_manager: &Arc<FileManager>,
    manifest: &ManifestSnapshot,
) -> Result<HashMap<u64, Option<u64>>> {
    let refs = ordered_manifest_data_file_refs_for_restore(
        manifest,
        file_manager.options.primary_volume_offload_policy,
    );
    if refs.is_empty() {
        return Ok(HashMap::new());
    }
    if let Some(max_file_id) = refs.iter().map(|item| item.file_id).max() {
        let min_next_file_id = max_file_id.saturating_add(1);
        if file_manager.peek_next_file_id() < min_next_file_id {
            file_manager.set_next_file_id(min_next_file_id);
        }
    }
    let resources = Arc::new(RestoreTempResourceRegistry::new(Arc::clone(file_manager)));
    let registry: Arc<dyn RestoreCopyResourceRegistry + Send + Sync> = resources.clone();
    let file_manager = Arc::clone(file_manager);
    let registry = Arc::clone(&registry);
    let prepared = std::thread::spawn(move || {
        let worker_threads = std::thread::available_parallelism()
            .map(|parallelism| parallelism.get())
            .unwrap_or(1)
            .min(8);
        let runtime = Builder::new_multi_thread()
            .worker_threads(worker_threads)
            .enable_all()
            .build()
            .map_err(|err| Error::IoError(format!("Failed to build restore runtime: {}", err)))?;
        runtime.block_on(run_restore_prepare_jobs(
            file_manager,
            refs,
            registry,
            worker_threads.max(1),
        ))
    })
    .join()
    .map_err(|_| Error::IoError("Restore worker thread panicked".to_string()))??;
    resources.finalize();
    Ok(prepared)
}

async fn run_restore_prepare_jobs(
    file_manager: Arc<FileManager>,
    refs: Vec<RestoreFileRef>,
    registry: Arc<dyn RestoreCopyResourceRegistry + Send + Sync>,
    worker_count: usize,
) -> Result<HashMap<u64, Option<u64>>> {
    let worker_count = worker_count.max(1);
    let queue = Arc::new(Mutex::new(VecDeque::from(refs)));
    let mut join_set = JoinSet::new();
    for _ in 0..worker_count {
        let file_manager = Arc::clone(&file_manager);
        let queue = Arc::clone(&queue);
        let registry = Arc::clone(&registry);
        join_set.spawn_blocking(move || -> Result<Vec<(u64, Option<u64>)>> {
            let mut completed = Vec::new();
            loop {
                let next = {
                    let mut guard = queue.lock().unwrap();
                    guard.pop_front()
                };
                let Some(file) = next else {
                    break;
                };
                let restored = file_manager.register_data_file_for_restore(
                    file.file_id,
                    &file.path,
                    Some(file.size_bytes),
                    Some(Arc::clone(&registry)),
                )?;
                completed.push((file.file_id, restored.snapshot_link_file_id));
            }
            Ok(completed)
        });
    }
    let mut links = HashMap::new();
    while let Some(joined) = join_set.join_next().await {
        let completed = joined
            .map_err(|err| Error::IoError(format!("Restore worker join failed: {}", err)))??;
        for (file_id, snapshot_link_file_id) in completed {
            links.insert(file_id, snapshot_link_file_id);
        }
    }
    Ok(links)
}

#[derive(Clone, Debug)]
struct RestoreFileRef {
    file_id: u64,
    path: String,
    size_bytes: u64,
    priority: u8,
}

fn ordered_manifest_data_file_refs_for_restore(
    manifest: &ManifestSnapshot,
    policy: PrimaryVolumeOffloadPolicyKind,
) -> Vec<RestoreFileRef> {
    let mut refs: HashMap<u64, RestoreFileRef> = HashMap::new();
    for tree_levels in &manifest.tree_levels {
        for level in tree_levels {
            let level_priority = lsm_file_priority_for_level(level.ordinal);
            for file in &level.files {
                let entry = refs.entry(file.file_id).or_insert_with(|| RestoreFileRef {
                    file_id: file.file_id,
                    path: file.path.clone(),
                    size_bytes: file.size as u64,
                    priority: level_priority,
                });
                if file.size as u64 > entry.size_bytes {
                    entry.size_bytes = file.size as u64;
                }
                if level_priority < entry.priority {
                    entry.priority = level_priority;
                }
            }
        }
    }
    for file in &manifest.vlog_files {
        let entry = refs.entry(file.file_id).or_insert_with(|| RestoreFileRef {
            file_id: file.file_id,
            path: file.path.clone(),
            size_bytes: 0,
            priority: VLOG_FILE_PRIORITY,
        });
        entry.priority = entry.priority.min(VLOG_FILE_PRIORITY);
    }
    let mut ordered: Vec<RestoreFileRef> = refs.into_values().collect();
    ordered.sort_by(|left, right| {
        let left_ref = PrimaryOffloadFileRef {
            file_id: left.file_id,
            size_bytes: left.size_bytes,
            priority: left.priority,
        };
        let right_ref = PrimaryOffloadFileRef {
            file_id: right.file_id,
            size_bytes: right.size_bytes,
            priority: right.priority,
        };
        compare_primary_offload_file_refs(policy, &left_ref, &right_ref)
    });
    ordered
}

fn apply_restore_snapshot_links(
    tree_versions: &[LSMTreeVersion],
    file_manager: &Arc<FileManager>,
    restored_snapshot_links: &HashMap<u64, Option<u64>>,
) {
    for file in tree_versions
        .iter()
        .flat_map(|version| version.levels.iter())
        .flat_map(|level| level.files.iter())
    {
        if let Some(snapshot_data_file_id) = restored_snapshot_links
            .get(&file.file_id)
            .copied()
            .flatten()
            && snapshot_data_file_id != file.file_id
        {
            file.set_snapshot_data_file(TrackedFileId::new(file_manager, snapshot_data_file_id));
            file_manager.register_snapshot_replica_hint(file.file_id, snapshot_data_file_id);
        }
    }
}

fn can_incremental_snapshot_from_tree_versions(
    tree_versions: &[LSMTreeVersion],
    file_manager: &Arc<FileManager>,
) -> bool {
    tree_versions
        .iter()
        .flat_map(|version| version.levels.iter())
        .flat_map(|level| level.files.iter())
        .all(|file| {
            file.snapshot_data_file_id().is_some()
                || file_manager.is_data_file_on_snapshot_volume(file.file_id)
        })
}

impl Db {
    /// Open a writable database initialized from a snapshot manifest.
    pub fn open_from_snapshot(
        config: Config,
        snapshot_id: u64,
        db_id: impl Into<String>,
    ) -> Result<Self> {
        Self::open_from_snapshot_with_resolver(config, snapshot_id, db_id, None)
    }

    pub fn open_from_snapshot_with_resolver(
        config: Config,
        snapshot_id: u64,
        db_id: impl Into<String>,
        resolver: Option<Arc<dyn MergeOperatorResolver>>,
    ) -> Result<Self> {
        let db_id = db_id.into();
        let config = config.normalize_volume_paths()?;
        init_logging(&config);
        log::info!(
            "cobble=db runtime start version={} build_commit={}",
            build_version_string(),
            build_commit_short_id()
        );
        metrics_registry::init_metrics();
        let metrics_manager = Arc::new(MetricsManager::new(&db_id));
        let hybrid_cache_plan =
            config.resolve_hybrid_cache_volume_plan(config.block_cache_size_bytes()?)?;
        let file_manager_config =
            config.apply_hybrid_cache_primary_partition_with_plan(hybrid_cache_plan.as_ref())?;
        let file_manager =
            FileManager::from_config(&file_manager_config, &db_id, Arc::clone(&metrics_manager))?;
        let file_manager = Arc::new(file_manager);
        let manifest = load_manifest_for_snapshot(&file_manager, snapshot_id)?;
        let schema_manager = Arc::new(crate::schema::SchemaManager::from_manifest(
            &file_manager,
            &manifest,
            config.num_columns,
            resolver,
        )?);
        let restored_snapshot_links =
            prepare_manifest_data_files_for_restore(&file_manager, &manifest)?;
        let max_vlog_file_seq = manifest
            .vlog_files
            .iter()
            .map(|file| file.file_seq as u64)
            .max()
            .unwrap_or(0);
        let restored_seq_id = manifest.seq_id;
        if manifest.bucket_ranges.is_empty() {
            return Err(Error::InvalidState(format!(
                "Snapshot {} manifest missing bucket_ranges",
                snapshot_id
            )));
        }
        let bucket_ranges = manifest.bucket_ranges.clone();
        let lsm_tree_bucket_ranges = if manifest.lsm_tree_bucket_ranges.is_empty() {
            manifest.bucket_ranges.clone()
        } else {
            manifest.lsm_tree_bucket_ranges.clone()
        };
        let active_memtable_data = manifest.active_memtable_data.clone();
        let tree_versions = build_tree_versions_from_manifest(&file_manager, &manifest, false)?;
        apply_restore_snapshot_links(&tree_versions, &file_manager, &restored_snapshot_links);
        let vlog_version = build_vlog_version_from_manifest(&file_manager, &manifest, false)?;
        let can_incremental_base =
            can_incremental_snapshot_from_tree_versions(&tree_versions, &file_manager);
        let multi_lsm_version = MultiLSMTreeVersion::from_bucket_ranges_with_tree_versions(
            config.total_buckets,
            &lsm_tree_bucket_ranges,
            tree_versions.into_iter().map(Arc::new).collect(),
        )?;

        let db_state = Arc::new(DbStateHandle::new());
        let db_lifecycle = Arc::new(DbLifecycle::new_initializing());
        db_state.store(crate::db_state::DbState {
            seq_id: restored_seq_id,
            bucket_ranges: bucket_ranges.clone(),
            multi_lsm_version,
            vlog_version,
            active: None,
            immutables: VecDeque::new(),
            suggested_base_snapshot_id: can_incremental_base.then_some(snapshot_id),
        });
        let db = Self::open_with_state(
            config,
            file_manager,
            db_state,
            Arc::clone(&db_lifecycle),
            db_id,
            bucket_ranges,
            max_vlog_file_seq.saturating_add(1).min(u32::MAX as u64) as u32,
            hybrid_cache_plan,
            metrics_manager,
            schema_manager,
        )?;
        db.restore_active_memtable_snapshot_to_l0(&active_memtable_data)?;
        db.memtable_manager.open()?;
        db.db_lifecycle.mark_open()?;
        Ok(db)
    }

    /// Resume a writable database from an existing folder by loading all snapshot manifests.
    pub fn resume(config: Config, db_id: impl Into<String>) -> Result<Self> {
        Self::resume_with_resolver(config, db_id, None)
    }

    pub fn resume_with_resolver(
        config: Config,
        db_id: impl Into<String>,
        resolver: Option<Arc<dyn MergeOperatorResolver>>,
    ) -> Result<Self> {
        let db_id = db_id.into();
        let config = config.normalize_volume_paths()?;
        init_logging(&config);
        log::info!(
            "Cobble db ({}, Rev:{}) start.",
            build_version_string(),
            build_commit_short_id()
        );
        metrics_registry::init_metrics();
        let metrics_manager = Arc::new(MetricsManager::new(&db_id));
        let hybrid_cache_plan =
            config.resolve_hybrid_cache_volume_plan(config.block_cache_size_bytes()?)?;
        let file_manager_config =
            config.apply_hybrid_cache_primary_partition_with_plan(hybrid_cache_plan.as_ref())?;
        let file_manager =
            FileManager::from_config(&file_manager_config, &db_id, Arc::clone(&metrics_manager))?;
        let file_manager = Arc::new(file_manager);
        let snapshot_ids = list_snapshot_manifest_ids(&file_manager)?;
        if snapshot_ids.is_empty() {
            return Err(Error::IoError(format!(
                "No snapshot manifests found for db {}",
                db_id
            )));
        }

        let mut loaded = Vec::with_capacity(snapshot_ids.len());
        let mut loaded_by_id = HashMap::new();
        for snapshot_id in snapshot_ids {
            let entry = load_manifest_entry(&file_manager, snapshot_id, &loaded_by_id)?;
            loaded_by_id.insert(snapshot_id, entry.clone());
            loaded.push(entry);
        }
        let latest = loaded.last().ok_or_else(|| {
            Error::IoError(format!("No snapshot manifests found for db {}", db_id))
        })?;
        let manifest = latest.manifest.clone();
        if manifest.bucket_ranges.is_empty() {
            return Err(Error::InvalidState(format!(
                "Snapshot {} manifest missing bucket_ranges",
                latest.snapshot_id
            )));
        }
        let restored_snapshot_links =
            prepare_manifest_data_files_for_restore(&file_manager, &manifest)?;
        let bucket_ranges = manifest.bucket_ranges.clone();
        let lsm_tree_bucket_ranges = if manifest.lsm_tree_bucket_ranges.is_empty() {
            manifest.bucket_ranges.clone()
        } else {
            manifest.lsm_tree_bucket_ranges.clone()
        };
        let active_memtable_data = manifest.active_memtable_data.clone();
        let schema_manager = Arc::new(crate::schema::SchemaManager::from_manifests(
            &file_manager,
            loaded.iter().map(|entry| &entry.manifest),
            config.num_columns,
            resolver,
        )?);
        let max_vlog_file_seq = manifest
            .vlog_files
            .iter()
            .map(|file| file.file_seq as u64)
            .max()
            .unwrap_or(0);
        let restored_seq_id = latest.manifest.seq_id;
        let tree_versions = build_tree_versions_from_manifest(&file_manager, &manifest, false)?;
        apply_restore_snapshot_links(&tree_versions, &file_manager, &restored_snapshot_links);
        let vlog_version = build_vlog_version_from_manifest(&file_manager, &manifest, false)?;
        let can_incremental_base =
            can_incremental_snapshot_from_tree_versions(&tree_versions, &file_manager);
        let multi_lsm_version = MultiLSMTreeVersion::from_bucket_ranges_with_tree_versions(
            config.total_buckets,
            &lsm_tree_bucket_ranges,
            tree_versions.into_iter().map(Arc::new).collect(),
        )?;
        let db_state = Arc::new(DbStateHandle::new());
        let db_lifecycle = Arc::new(DbLifecycle::new_initializing());
        db_state.store(crate::db_state::DbState {
            seq_id: restored_seq_id,
            bucket_ranges: bucket_ranges.clone(),
            multi_lsm_version,
            vlog_version,
            active: None,
            immutables: VecDeque::new(),
            suggested_base_snapshot_id: can_incremental_base.then_some(latest.snapshot_id),
        });
        let db = Self::open_with_state(
            config,
            file_manager,
            db_state,
            Arc::clone(&db_lifecycle),
            db_id,
            bucket_ranges,
            max_vlog_file_seq.saturating_add(1).min(u32::MAX as u64) as u32,
            hybrid_cache_plan,
            metrics_manager,
            schema_manager,
        )?;
        db.take_over_snapshot_chain(&loaded)?;
        db.restore_active_memtable_snapshot_to_l0(&active_memtable_data)?;
        db.memtable_manager.open()?;
        db.db_lifecycle.mark_open()?;
        Ok(db)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn ids(refs: Vec<RestoreFileRef>) -> Vec<u64> {
        refs.into_iter().map(|item| item.file_id).collect()
    }

    #[test]
    fn restore_ref_order_priority_policy() {
        let mut refs = vec![
            RestoreFileRef {
                file_id: 3,
                path: "a".to_string(),
                size_bytes: 100,
                priority: 10,
            },
            RestoreFileRef {
                file_id: 1,
                path: "b".to_string(),
                size_bytes: 200,
                priority: 2,
            },
            RestoreFileRef {
                file_id: 2,
                path: "c".to_string(),
                size_bytes: 50,
                priority: 2,
            },
        ];
        refs.sort_by(|left, right| {
            compare_primary_offload_file_refs(
                PrimaryVolumeOffloadPolicyKind::Priority,
                &PrimaryOffloadFileRef {
                    file_id: left.file_id,
                    size_bytes: left.size_bytes,
                    priority: left.priority,
                },
                &PrimaryOffloadFileRef {
                    file_id: right.file_id,
                    size_bytes: right.size_bytes,
                    priority: right.priority,
                },
            )
        });
        assert_eq!(ids(refs), vec![1, 2, 3]);
    }

    #[test]
    fn restore_ref_order_largest_file_policy() {
        let mut refs = vec![
            RestoreFileRef {
                file_id: 3,
                path: "a".to_string(),
                size_bytes: 100,
                priority: 10,
            },
            RestoreFileRef {
                file_id: 1,
                path: "b".to_string(),
                size_bytes: 200,
                priority: 2,
            },
            RestoreFileRef {
                file_id: 2,
                path: "c".to_string(),
                size_bytes: 200,
                priority: 8,
            },
        ];
        refs.sort_by(|left, right| {
            compare_primary_offload_file_refs(
                PrimaryVolumeOffloadPolicyKind::LargestFile,
                &PrimaryOffloadFileRef {
                    file_id: left.file_id,
                    size_bytes: left.size_bytes,
                    priority: left.priority,
                },
                &PrimaryOffloadFileRef {
                    file_id: right.file_id,
                    size_bytes: right.size_bytes,
                    priority: right.priority,
                },
            )
        });
        assert_eq!(ids(refs), vec![1, 2, 3]);
    }
}