Line data Source code
1 : use std::collections::HashMap;
2 : use std::sync::Arc;
3 :
4 : use anyhow::{Context, bail, ensure};
5 : use itertools::Itertools;
6 : use pageserver_api::shard::TenantShardId;
7 : use tracing::trace;
8 : use utils::id::TimelineId;
9 : use utils::lsn::{AtomicLsn, Lsn};
10 :
11 : use super::{ReadableLayer, TimelineWriterState};
12 : use crate::config::PageServerConf;
13 : use crate::context::RequestContext;
14 : use crate::metrics::TimelineMetrics;
15 : use crate::tenant::layer_map::{BatchedUpdates, LayerMap};
16 : use crate::tenant::storage_layer::{
17 : AsLayerDesc, InMemoryLayer, Layer, LayerVisibilityHint, PersistentLayerDesc,
18 : PersistentLayerKey, ReadableLayerWeak, ResidentLayer,
19 : };
20 :
21 : /// Provides semantic APIs to manipulate the layer map.
22 : pub(crate) enum LayerManager {
23 : /// Open as in not shutdown layer manager; we still have in-memory layers and we can manipulate
24 : /// the layers.
25 : Open(OpenLayerManager),
26 : /// Shutdown layer manager where there are no more in-memory layers and persistent layers are
27 : /// read-only.
28 : Closed {
29 : layers: HashMap<PersistentLayerKey, Layer>,
30 : },
31 : }
32 :
33 : impl Default for LayerManager {
34 904 : fn default() -> Self {
35 904 : LayerManager::Open(OpenLayerManager::default())
36 904 : }
37 : }
38 :
39 : impl LayerManager {
40 1694654 : pub(crate) fn upgrade(&self, weak: ReadableLayerWeak) -> ReadableLayer {
41 1694654 : match weak {
42 480442 : ReadableLayerWeak::PersistentLayer(desc) => {
43 480442 : ReadableLayer::PersistentLayer(self.get_from_desc(&desc))
44 : }
45 1214212 : ReadableLayerWeak::InMemoryLayer(desc) => {
46 1214212 : let inmem = self
47 1214212 : .layer_map()
48 1214212 : .expect("no concurrent shutdown")
49 1214212 : .in_memory_layer(&desc);
50 1214212 : ReadableLayer::InMemoryLayer(inmem)
51 : }
52 : }
53 1694654 : }
54 :
55 482342 : pub(crate) fn get_from_key(&self, key: &PersistentLayerKey) -> Layer {
56 482342 : // The assumption for the `expect()` is that all code maintains the following invariant:
57 482342 : // A layer's descriptor is present in the LayerMap => the LayerFileManager contains a layer for the descriptor.
58 482342 : self.try_get_from_key(key)
59 482342 : .with_context(|| format!("get layer from key: {key}"))
60 482342 : .expect("not found")
61 482342 : .clone()
62 482342 : }
63 :
64 482434 : pub(crate) fn try_get_from_key(&self, key: &PersistentLayerKey) -> Option<&Layer> {
65 482434 : self.layers().get(key)
66 482434 : }
67 :
68 482298 : pub(crate) fn get_from_desc(&self, desc: &PersistentLayerDesc) -> Layer {
69 482298 : self.get_from_key(&desc.key())
70 482298 : }
71 :
72 : /// Get an immutable reference to the layer map.
73 : ///
74 : /// We expect users only to be able to get an immutable layer map. If users want to make modifications,
75 : /// they should use the below semantic APIs. This design makes us step closer to immutable storage state.
76 3365907 : pub(crate) fn layer_map(&self) -> Result<&LayerMap, Shutdown> {
77 : use LayerManager::*;
78 3365907 : match self {
79 3365907 : Open(OpenLayerManager { layer_map, .. }) => Ok(layer_map),
80 0 : Closed { .. } => Err(Shutdown),
81 : }
82 3365907 : }
83 :
84 9912 : pub(crate) fn open_mut(&mut self) -> Result<&mut OpenLayerManager, Shutdown> {
85 : use LayerManager::*;
86 :
87 9912 : match self {
88 9912 : Open(open) => Ok(open),
89 0 : Closed { .. } => Err(Shutdown),
90 : }
91 9912 : }
92 :
93 : /// LayerManager shutdown. The in-memory layers do cleanup on drop, so we must drop them in
94 : /// order to allow shutdown to complete.
95 : ///
96 : /// If there was a want to flush in-memory layers, it must have happened earlier.
97 20 : pub(crate) fn shutdown(&mut self, writer_state: &mut Option<TimelineWriterState>) {
98 : use LayerManager::*;
99 20 : match self {
100 : Open(OpenLayerManager {
101 20 : layer_map,
102 20 : layer_fmgr: LayerFileManager(hashmap),
103 20 : }) => {
104 20 : // NB: no need to decrement layer metrics; metrics are removed on timeline shutdown.
105 20 : let open = layer_map.open_layer.take();
106 20 : let frozen = layer_map.frozen_layers.len();
107 20 : let taken_writer_state = writer_state.take();
108 20 : tracing::info!(open = open.is_some(), frozen, "dropped inmemory layers");
109 20 : let layers = std::mem::take(hashmap);
110 20 : *self = Closed { layers };
111 20 : assert_eq!(open.is_some(), taken_writer_state.is_some());
112 : }
113 : Closed { .. } => {
114 0 : tracing::debug!("ignoring multiple shutdowns on layer manager")
115 : }
116 : }
117 20 : }
118 :
119 : /// Sum up the historic layer sizes
120 0 : pub(crate) fn layer_size_sum(&self) -> u64 {
121 0 : self.layers()
122 0 : .values()
123 0 : .map(|l| l.layer_desc().file_size)
124 0 : .sum()
125 0 : }
126 :
127 80 : pub(crate) fn likely_resident_layers(&self) -> impl Iterator<Item = &'_ Layer> + '_ {
128 227 : self.layers().values().filter(|l| l.is_likely_resident())
129 80 : }
130 :
131 0 : pub(crate) fn visible_layers(&self) -> impl Iterator<Item = &'_ Layer> + '_ {
132 0 : self.layers()
133 0 : .values()
134 0 : .filter(|l| l.visibility() == LayerVisibilityHint::Visible)
135 0 : }
136 :
137 616 : pub(crate) fn contains(&self, layer: &Layer) -> bool {
138 616 : self.contains_key(&layer.layer_desc().key())
139 616 : }
140 :
141 820 : pub(crate) fn contains_key(&self, key: &PersistentLayerKey) -> bool {
142 820 : self.layers().contains_key(key)
143 820 : }
144 :
145 0 : pub(crate) fn all_persistent_layers(&self) -> Vec<PersistentLayerKey> {
146 0 : self.layers().keys().cloned().collect_vec()
147 0 : }
148 :
149 483334 : fn layers(&self) -> &HashMap<PersistentLayerKey, Layer> {
150 : use LayerManager::*;
151 483334 : match self {
152 483334 : Open(OpenLayerManager { layer_fmgr, .. }) => &layer_fmgr.0,
153 0 : Closed { layers } => layers,
154 : }
155 483334 : }
156 : }
157 :
158 : #[derive(Default)]
159 : pub(crate) struct OpenLayerManager {
160 : layer_map: LayerMap,
161 : layer_fmgr: LayerFileManager<Layer>,
162 : }
163 :
164 : impl std::fmt::Debug for OpenLayerManager {
165 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
166 0 : f.debug_struct("OpenLayerManager")
167 0 : .field("layer_count", &self.layer_fmgr.0.len())
168 0 : .finish()
169 0 : }
170 : }
171 :
172 : #[derive(Debug, thiserror::Error)]
173 : #[error("layer manager has been shutdown")]
174 : pub(crate) struct Shutdown;
175 :
176 : impl OpenLayerManager {
177 : /// Called from `load_layer_map`. Initialize the layer manager with:
178 : /// 1. all on-disk layers
179 : /// 2. next open layer (with disk disk_consistent_lsn LSN)
180 12 : pub(crate) fn initialize_local_layers(&mut self, layers: Vec<Layer>, next_open_layer_at: Lsn) {
181 12 : let mut updates = self.layer_map.batch_update();
182 44 : for layer in layers {
183 32 : Self::insert_historic_layer(layer, &mut updates, &mut self.layer_fmgr);
184 32 : }
185 12 : updates.flush();
186 12 : self.layer_map.next_open_layer_at = Some(next_open_layer_at);
187 12 : }
188 :
189 : /// Initialize when creating a new timeline, called in `init_empty_layer_map`.
190 892 : pub(crate) fn initialize_empty(&mut self, next_open_layer_at: Lsn) {
191 892 : self.layer_map.next_open_layer_at = Some(next_open_layer_at);
192 892 : }
193 :
194 : /// Open a new writable layer to append data if there is no open layer, otherwise return the
195 : /// current open layer, called within `get_layer_for_write`.
196 2604 : pub(crate) async fn get_layer_for_write(
197 2604 : &mut self,
198 2604 : lsn: Lsn,
199 2604 : conf: &'static PageServerConf,
200 2604 : timeline_id: TimelineId,
201 2604 : tenant_shard_id: TenantShardId,
202 2604 : gate: &utils::sync::gate::Gate,
203 2604 : ctx: &RequestContext,
204 2604 : ) -> anyhow::Result<Arc<InMemoryLayer>> {
205 2604 : ensure!(lsn.is_aligned());
206 :
207 : // Do we have a layer open for writing already?
208 2604 : let layer = if let Some(open_layer) = &self.layer_map.open_layer {
209 0 : if open_layer.get_lsn_range().start > lsn {
210 0 : bail!(
211 0 : "unexpected open layer in the future: open layers starts at {}, write lsn {}",
212 0 : open_layer.get_lsn_range().start,
213 0 : lsn
214 0 : );
215 0 : }
216 0 :
217 0 : Arc::clone(open_layer)
218 : } else {
219 : // No writeable layer yet. Create one.
220 2604 : let start_lsn = self
221 2604 : .layer_map
222 2604 : .next_open_layer_at
223 2604 : .context("No next open layer found")?;
224 :
225 2604 : trace!(
226 0 : "creating in-memory layer at {}/{} for record at {}",
227 : timeline_id, start_lsn, lsn
228 : );
229 :
230 2604 : let new_layer =
231 2604 : InMemoryLayer::create(conf, timeline_id, tenant_shard_id, start_lsn, gate, ctx)
232 2604 : .await?;
233 2604 : let layer = Arc::new(new_layer);
234 2604 :
235 2604 : self.layer_map.open_layer = Some(layer.clone());
236 2604 : self.layer_map.next_open_layer_at = None;
237 2604 :
238 2604 : layer
239 : };
240 :
241 2604 : Ok(layer)
242 2604 : }
243 :
244 : /// Tries to freeze an open layer and also manages clearing the TimelineWriterState.
245 : ///
246 : /// Returns true if anything was frozen.
247 2412 : pub(super) async fn try_freeze_in_memory_layer(
248 2412 : &mut self,
249 2412 : lsn: Lsn,
250 2412 : last_freeze_at: &AtomicLsn,
251 2412 : write_lock: &mut tokio::sync::MutexGuard<'_, Option<TimelineWriterState>>,
252 2412 : metrics: &TimelineMetrics,
253 2412 : ) -> bool {
254 2412 : let Lsn(last_record_lsn) = lsn;
255 2412 : let end_lsn = Lsn(last_record_lsn + 1);
256 :
257 2412 : let froze = if let Some(open_layer) = &self.layer_map.open_layer {
258 2356 : let open_layer_rc = Arc::clone(open_layer);
259 2356 : open_layer.freeze(end_lsn).await;
260 :
261 : // Increment the frozen layer metrics. This is decremented in `finish_flush_l0_layer()`.
262 : // TODO: It would be nicer to do this via `InMemoryLayer::drop()`, but it requires a
263 : // reference to the timeline metrics. Other methods use a metrics borrow as well.
264 2356 : metrics.inc_frozen_layer(open_layer);
265 2356 :
266 2356 : // The layer is no longer open, update the layer map to reflect this.
267 2356 : // We will replace it with on-disk historics below.
268 2356 : self.layer_map.frozen_layers.push_back(open_layer_rc);
269 2356 : self.layer_map.open_layer = None;
270 2356 : self.layer_map.next_open_layer_at = Some(end_lsn);
271 2356 :
272 2356 : true
273 : } else {
274 56 : false
275 : };
276 :
277 : // Even if there was no layer to freeze, advance last_freeze_at to last_record_lsn+1: this
278 : // accounts for regions in the LSN range where we might have ingested no data due to sharding.
279 2412 : last_freeze_at.store(end_lsn);
280 2412 :
281 2412 : // the writer state must no longer have a reference to the frozen layer
282 2412 : let taken = write_lock.take();
283 2412 : assert_eq!(
284 2412 : froze,
285 2412 : taken.is_some(),
286 0 : "should only had frozen a layer when TimelineWriterState existed"
287 : );
288 :
289 2412 : froze
290 2412 : }
291 :
292 : /// Add image layers to the layer map, called from [`super::Timeline::create_image_layers`].
293 1148 : pub(crate) fn track_new_image_layers(
294 1148 : &mut self,
295 1148 : image_layers: &[ResidentLayer],
296 1148 : metrics: &TimelineMetrics,
297 1148 : ) {
298 1148 : let mut updates = self.layer_map.batch_update();
299 1644 : for layer in image_layers {
300 496 : Self::insert_historic_layer(layer.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
301 496 :
302 496 : // record these here instead of Layer::finish_creating because otherwise partial
303 496 : // failure with create_image_layers would balloon up the physical size gauge. downside
304 496 : // is that all layers need to be created before metrics are updated.
305 496 : metrics.record_new_file_metrics(layer.layer_desc().file_size);
306 496 : }
307 1148 : updates.flush();
308 1148 : }
309 :
310 : /// Flush a frozen layer and add the written delta layer to the layer map.
311 2356 : pub(crate) fn finish_flush_l0_layer(
312 2356 : &mut self,
313 2356 : delta_layer: Option<&ResidentLayer>,
314 2356 : frozen_layer_for_check: &Arc<InMemoryLayer>,
315 2356 : metrics: &TimelineMetrics,
316 2356 : ) {
317 2356 : let inmem = self
318 2356 : .layer_map
319 2356 : .frozen_layers
320 2356 : .pop_front()
321 2356 : .expect("there must be a inmem layer to flush");
322 2356 : metrics.dec_frozen_layer(&inmem);
323 2356 :
324 2356 : // Only one task may call this function at a time (for this
325 2356 : // timeline). If two tasks tried to flush the same frozen
326 2356 : // layer to disk at the same time, that would not work.
327 2356 : assert_eq!(Arc::as_ptr(&inmem), Arc::as_ptr(frozen_layer_for_check));
328 :
329 2356 : if let Some(l) = delta_layer {
330 1936 : let mut updates = self.layer_map.batch_update();
331 1936 : Self::insert_historic_layer(l.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
332 1936 : metrics.record_new_file_metrics(l.layer_desc().file_size);
333 1936 : updates.flush();
334 1936 : }
335 2356 : }
336 :
337 : /// Called when compaction is completed.
338 56 : pub(crate) fn finish_compact_l0(
339 56 : &mut self,
340 56 : compact_from: &[Layer],
341 56 : compact_to: &[ResidentLayer],
342 56 : metrics: &TimelineMetrics,
343 56 : ) {
344 56 : let mut updates = self.layer_map.batch_update();
345 672 : for l in compact_to {
346 616 : Self::insert_historic_layer(l.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
347 616 : metrics.record_new_file_metrics(l.layer_desc().file_size);
348 616 : }
349 860 : for l in compact_from {
350 804 : Self::delete_historic_layer(l, &mut updates, &mut self.layer_fmgr);
351 804 : }
352 56 : updates.flush();
353 56 : }
354 :
355 : /// Called when a GC-compaction is completed.
356 96 : pub(crate) fn finish_gc_compaction(
357 96 : &mut self,
358 96 : compact_from: &[Layer],
359 96 : compact_to: &[ResidentLayer],
360 96 : metrics: &TimelineMetrics,
361 96 : ) {
362 96 : // gc-compaction could contain layer rewrites. We need to delete the old layers and insert the new ones.
363 96 :
364 96 : // Match the old layers with the new layers
365 96 : let mut add_layers = HashMap::new();
366 96 : let mut rewrite_layers = HashMap::new();
367 96 : let mut drop_layers = HashMap::new();
368 304 : for layer in compact_from {
369 208 : drop_layers.insert(layer.layer_desc().key(), layer.clone());
370 208 : }
371 204 : for layer in compact_to {
372 108 : if let Some(old_layer) = drop_layers.remove(&layer.layer_desc().key()) {
373 0 : rewrite_layers.insert(layer.layer_desc().key(), (old_layer.clone(), layer.clone()));
374 108 : } else {
375 108 : add_layers.insert(layer.layer_desc().key(), layer.clone());
376 108 : }
377 : }
378 96 : let add_layers = add_layers.values().cloned().collect::<Vec<_>>();
379 96 : let drop_layers = drop_layers.values().cloned().collect::<Vec<_>>();
380 96 : let rewrite_layers = rewrite_layers.values().cloned().collect::<Vec<_>>();
381 96 :
382 96 : self.rewrite_layers_inner(&rewrite_layers, &drop_layers, &add_layers, metrics);
383 96 : }
384 :
385 : /// Called post-compaction when some previous generation image layers were trimmed.
386 0 : pub fn rewrite_layers(
387 0 : &mut self,
388 0 : rewrite_layers: &[(Layer, ResidentLayer)],
389 0 : drop_layers: &[Layer],
390 0 : metrics: &TimelineMetrics,
391 0 : ) {
392 0 : self.rewrite_layers_inner(rewrite_layers, drop_layers, &[], metrics);
393 0 : }
394 :
395 96 : fn rewrite_layers_inner(
396 96 : &mut self,
397 96 : rewrite_layers: &[(Layer, ResidentLayer)],
398 96 : drop_layers: &[Layer],
399 96 : add_layers: &[ResidentLayer],
400 96 : metrics: &TimelineMetrics,
401 96 : ) {
402 96 : let mut updates = self.layer_map.batch_update();
403 96 : for (old_layer, new_layer) in rewrite_layers {
404 0 : debug_assert_eq!(
405 0 : old_layer.layer_desc().key_range,
406 0 : new_layer.layer_desc().key_range
407 : );
408 0 : debug_assert_eq!(
409 0 : old_layer.layer_desc().lsn_range,
410 0 : new_layer.layer_desc().lsn_range
411 : );
412 :
413 : // Transfer visibility hint from old to new layer, since the new layer covers the same key space. This is not guaranteed to
414 : // be accurate (as the new layer may cover a different subset of the key range), but is a sensible default, and prevents
415 : // always marking rewritten layers as visible.
416 0 : new_layer.as_ref().set_visibility(old_layer.visibility());
417 0 :
418 0 : // Safety: we may never rewrite the same file in-place. Callers are responsible
419 0 : // for ensuring that they only rewrite layers after something changes the path,
420 0 : // such as an increment in the generation number.
421 0 : assert_ne!(old_layer.local_path(), new_layer.local_path());
422 :
423 0 : Self::delete_historic_layer(old_layer, &mut updates, &mut self.layer_fmgr);
424 0 :
425 0 : Self::insert_historic_layer(
426 0 : new_layer.as_ref().clone(),
427 0 : &mut updates,
428 0 : &mut self.layer_fmgr,
429 0 : );
430 0 :
431 0 : metrics.record_new_file_metrics(new_layer.layer_desc().file_size);
432 : }
433 304 : for l in drop_layers {
434 208 : Self::delete_historic_layer(l, &mut updates, &mut self.layer_fmgr);
435 208 : }
436 204 : for l in add_layers {
437 108 : Self::insert_historic_layer(l.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
438 108 : metrics.record_new_file_metrics(l.layer_desc().file_size);
439 108 : }
440 96 : updates.flush();
441 96 : }
442 :
443 : /// Called when garbage collect has selected the layers to be removed.
444 16 : pub(crate) fn finish_gc_timeline(&mut self, gc_layers: &[Layer]) {
445 16 : let mut updates = self.layer_map.batch_update();
446 36 : for doomed_layer in gc_layers {
447 20 : Self::delete_historic_layer(doomed_layer, &mut updates, &mut self.layer_fmgr);
448 20 : }
449 16 : updates.flush()
450 16 : }
451 :
452 : #[cfg(test)]
453 312 : pub(crate) fn force_insert_layer(&mut self, layer: ResidentLayer) {
454 312 : let mut updates = self.layer_map.batch_update();
455 312 : Self::insert_historic_layer(layer.as_ref().clone(), &mut updates, &mut self.layer_fmgr);
456 312 : updates.flush()
457 312 : }
458 :
459 : /// Helper function to insert a layer into the layer map and file manager.
460 3500 : fn insert_historic_layer(
461 3500 : layer: Layer,
462 3500 : updates: &mut BatchedUpdates<'_>,
463 3500 : mapping: &mut LayerFileManager<Layer>,
464 3500 : ) {
465 3500 : updates.insert_historic(layer.layer_desc().clone());
466 3500 : mapping.insert(layer);
467 3500 : }
468 :
469 : /// Removes the layer from local FS (if present) and from memory.
470 : /// Remote storage is not affected by this operation.
471 1032 : fn delete_historic_layer(
472 1032 : // we cannot remove layers otherwise, since gc and compaction will race
473 1032 : layer: &Layer,
474 1032 : updates: &mut BatchedUpdates<'_>,
475 1032 : mapping: &mut LayerFileManager<Layer>,
476 1032 : ) {
477 1032 : let desc = layer.layer_desc();
478 1032 :
479 1032 : // TODO Removing from the bottom of the layer map is expensive.
480 1032 : // Maybe instead discard all layer map historic versions that
481 1032 : // won't be needed for page reconstruction for this timeline,
482 1032 : // and mark what we can't delete yet as deleted from the layer
483 1032 : // map index without actually rebuilding the index.
484 1032 : updates.remove_historic(desc);
485 1032 : mapping.remove(layer);
486 1032 : layer.delete_on_drop();
487 1032 : }
488 :
489 : #[cfg(test)]
490 8 : pub(crate) fn force_insert_in_memory_layer(&mut self, layer: Arc<InMemoryLayer>) {
491 : use pageserver_api::models::InMemoryLayerInfo;
492 :
493 8 : match layer.info() {
494 : InMemoryLayerInfo::Open { .. } => {
495 4 : assert!(self.layer_map.open_layer.is_none());
496 4 : self.layer_map.open_layer = Some(layer);
497 : }
498 4 : InMemoryLayerInfo::Frozen { lsn_start, .. } => {
499 4 : if let Some(last) = self.layer_map.frozen_layers.back() {
500 0 : assert!(last.get_lsn_range().end <= lsn_start);
501 4 : }
502 :
503 4 : self.layer_map.frozen_layers.push_back(layer);
504 : }
505 : }
506 8 : }
507 : }
508 :
509 : pub(crate) struct LayerFileManager<T>(HashMap<PersistentLayerKey, T>);
510 :
511 : impl<T> Default for LayerFileManager<T> {
512 904 : fn default() -> Self {
513 904 : Self(HashMap::default())
514 904 : }
515 : }
516 :
517 : impl<T: AsLayerDesc + Clone> LayerFileManager<T> {
518 3500 : pub(crate) fn insert(&mut self, layer: T) {
519 3500 : let present = self.0.insert(layer.layer_desc().key(), layer.clone());
520 3500 : if present.is_some() && cfg!(debug_assertions) {
521 0 : panic!("overwriting a layer: {:?}", layer.layer_desc())
522 3500 : }
523 3500 : }
524 :
525 1032 : pub(crate) fn remove(&mut self, layer: &T) {
526 1032 : let present = self.0.remove(&layer.layer_desc().key());
527 1032 : if present.is_none() && cfg!(debug_assertions) {
528 0 : panic!(
529 0 : "removing layer that is not present in layer mapping: {:?}",
530 0 : layer.layer_desc()
531 0 : )
532 1032 : }
533 1032 : }
534 : }
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