Line data Source code
1 : //!
2 : //! The layer map tracks what layers exist in a timeline.
3 : //!
4 : //! When the timeline is first accessed, the server lists of all layer files
5 : //! in the timelines/<timeline_id> directory, and populates this map with
6 : //! ImageLayer and DeltaLayer structs corresponding to each file. When the first
7 : //! new WAL record is received, we create an InMemoryLayer to hold the incoming
8 : //! records. Now and then, in the checkpoint() function, the in-memory layer is
9 : //! are frozen, and it is split up into new image and delta layers and the
10 : //! corresponding files are written to disk.
11 : //!
12 : //! Design overview:
13 : //!
14 : //! The `search` method of the layer map is on the read critical path, so we've
15 : //! built an efficient data structure for fast reads, stored in `LayerMap::historic`.
16 : //! Other read methods are less critical but still impact performance of background tasks.
17 : //!
18 : //! This data structure relies on a persistent/immutable binary search tree. See the
19 : //! following lecture for an introduction <https://www.youtube.com/watch?v=WqCWghETNDc&t=581s>
20 : //! Summary: A persistent/immutable BST (and persistent data structures in general) allows
21 : //! you to modify the tree in such a way that each modification creates a new "version"
22 : //! of the tree. When you modify it, you get a new version, but all previous versions are
23 : //! still accessible too. So if someone is still holding a reference to an older version,
24 : //! they continue to see the tree as it was then. The persistent BST stores all the
25 : //! different versions in an efficient way.
26 : //!
27 : //! Our persistent BST maintains a map of which layer file "covers" each key. It has only
28 : //! one dimension, the key. See `layer_coverage.rs`. We use the persistent/immutable property
29 : //! to handle the LSN dimension.
30 : //!
31 : //! To build the layer map, we insert each layer to the persistent BST in LSN.start order,
32 : //! starting from the oldest one. After each insertion, we grab a reference to that "version"
33 : //! of the tree, and store it in another tree, a BtreeMap keyed by the LSN. See
34 : //! `historic_layer_coverage.rs`.
35 : //!
36 : //! To search for a particular key-LSN pair, you first look up the right "version" in the
37 : //! BTreeMap. Then you search that version of the BST with the key.
38 : //!
39 : //! The persistent BST keeps all the versions, but there is no way to change the old versions
40 : //! afterwards. We can add layers as long as they have larger LSNs than any previous layer in
41 : //! the map, but if we need to remove a layer, or insert anything with an older LSN, we need
42 : //! to throw away most of the persistent BST and build a new one, starting from the oldest
43 : //! LSN. See [`LayerMap::flush_updates()`].
44 : //!
45 :
46 : mod historic_layer_coverage;
47 : mod layer_coverage;
48 :
49 : use std::collections::{HashMap, VecDeque};
50 : use std::iter::Peekable;
51 : use std::ops::Range;
52 : use std::sync::Arc;
53 :
54 : use anyhow::Result;
55 : use historic_layer_coverage::BufferedHistoricLayerCoverage;
56 : pub use historic_layer_coverage::LayerKey;
57 : use pageserver_api::key::Key;
58 : use pageserver_api::keyspace::{KeySpace, KeySpaceAccum};
59 : use range_set_blaze::{CheckSortedDisjoint, RangeSetBlaze};
60 : use tokio::sync::watch;
61 : use utils::lsn::Lsn;
62 :
63 : use super::storage_layer::{LayerVisibilityHint, PersistentLayerDesc};
64 : use crate::context::RequestContext;
65 : use crate::tenant::storage_layer::{InMemoryLayer, ReadableLayerWeak};
66 :
67 : ///
68 : /// LayerMap tracks what layers exist on a timeline.
69 : ///
70 : pub struct LayerMap {
71 : //
72 : // 'open_layer' holds the current InMemoryLayer that is accepting new
73 : // records. If it is None, 'next_open_layer_at' will be set instead, indicating
74 : // where the start LSN of the next InMemoryLayer that is to be created.
75 : //
76 : pub open_layer: Option<Arc<InMemoryLayer>>,
77 : pub next_open_layer_at: Option<Lsn>,
78 :
79 : ///
80 : /// Frozen layers, if any. Frozen layers are in-memory layers that
81 : /// are no longer added to, but haven't been written out to disk
82 : /// yet. They contain WAL older than the current 'open_layer' or
83 : /// 'next_open_layer_at', but newer than any historic layer.
84 : /// The frozen layers are in order from oldest to newest, so that
85 : /// the newest one is in the 'back' of the VecDeque, and the oldest
86 : /// in the 'front'.
87 : ///
88 : pub frozen_layers: VecDeque<Arc<InMemoryLayer>>,
89 :
90 : /// Index of the historic layers optimized for search
91 : historic: BufferedHistoricLayerCoverage<Arc<PersistentLayerDesc>>,
92 :
93 : /// L0 layers have key range Key::MIN..Key::MAX, and locating them using R-Tree search is very inefficient.
94 : /// So L0 layers are held in l0_delta_layers vector, in addition to the R-tree.
95 : ///
96 : /// NB: make sure to notify `watch_l0_deltas` on changes.
97 : l0_delta_layers: Vec<Arc<PersistentLayerDesc>>,
98 :
99 : /// Notifies about L0 delta layer changes, sending the current number of L0 layers.
100 : watch_l0_deltas: watch::Sender<usize>,
101 : }
102 :
103 : impl Default for LayerMap {
104 920 : fn default() -> Self {
105 920 : Self {
106 920 : open_layer: Default::default(),
107 920 : next_open_layer_at: Default::default(),
108 920 : frozen_layers: Default::default(),
109 920 : historic: Default::default(),
110 920 : l0_delta_layers: Default::default(),
111 920 : watch_l0_deltas: watch::channel(0).0,
112 920 : }
113 920 : }
114 : }
115 :
116 : /// The primary update API for the layer map.
117 : ///
118 : /// Batching historic layer insertions and removals is good for
119 : /// performance and this struct helps us do that correctly.
120 : #[must_use]
121 : pub struct BatchedUpdates<'a> {
122 : // While we hold this exclusive reference to the layer map the type checker
123 : // will prevent us from accidentally reading any unflushed updates.
124 : layer_map: &'a mut LayerMap,
125 : }
126 :
127 : /// Provide ability to batch more updates while hiding the read
128 : /// API so we don't accidentally read without flushing.
129 : impl BatchedUpdates<'_> {
130 : ///
131 : /// Insert an on-disk layer.
132 : ///
133 : // TODO remove the `layer` argument when `mapping` is refactored out of `LayerMap`
134 9808 : pub fn insert_historic(&mut self, layer_desc: PersistentLayerDesc) {
135 9808 : self.layer_map.insert_historic_noflush(layer_desc)
136 9808 : }
137 :
138 : ///
139 : /// Remove an on-disk layer from the map.
140 : ///
141 : /// This should be called when the corresponding file on disk has been deleted.
142 : ///
143 1032 : pub fn remove_historic(&mut self, layer_desc: &PersistentLayerDesc) {
144 1032 : self.layer_map.remove_historic_noflush(layer_desc)
145 1032 : }
146 :
147 : // We will flush on drop anyway, but this method makes it
148 : // more explicit that there is some work being done.
149 : /// Apply all updates
150 3584 : pub fn flush(self) {
151 3584 : // Flush happens on drop
152 3584 : }
153 : }
154 :
155 : // Ideally the flush() method should be called explicitly for more
156 : // controlled execution. But if we forget we'd rather flush on drop
157 : // than panic later or read without flushing.
158 : //
159 : // TODO maybe warn if flush hasn't explicitly been called
160 : impl Drop for BatchedUpdates<'_> {
161 3584 : fn drop(&mut self) {
162 3584 : self.layer_map.flush_updates();
163 3584 : }
164 : }
165 :
166 : /// Return value of LayerMap::search
167 : #[derive(Eq, PartialEq, Debug, Hash)]
168 : pub struct SearchResult {
169 : pub layer: ReadableLayerWeak,
170 : pub lsn_floor: Lsn,
171 : }
172 :
173 : /// Return value of [`LayerMap::range_search`]
174 : ///
175 : /// Contains a mapping from a layer description to a keyspace
176 : /// accumulator that contains all the keys which intersect the layer
177 : /// from the original search space.
178 : #[derive(Debug)]
179 : pub struct RangeSearchResult {
180 : pub found: HashMap<SearchResult, KeySpaceAccum>,
181 : }
182 :
183 : impl RangeSearchResult {
184 1960579 : fn new() -> Self {
185 1960579 : Self {
186 1960579 : found: HashMap::new(),
187 1960579 : }
188 1960579 : }
189 :
190 671368 : fn map_to_in_memory_layer(
191 671368 : in_memory_layer: Option<InMemoryLayerDesc>,
192 671368 : range: Range<Key>,
193 671368 : ) -> RangeSearchResult {
194 671368 : match in_memory_layer {
195 218571 : Some(inmem) => {
196 218571 : let search_result = SearchResult {
197 218571 : lsn_floor: inmem.get_lsn_range().start,
198 218571 : layer: ReadableLayerWeak::InMemoryLayer(inmem),
199 218571 : };
200 218571 :
201 218571 : let mut accum = KeySpaceAccum::new();
202 218571 : accum.add_range(range);
203 218571 : RangeSearchResult {
204 218571 : found: HashMap::from([(search_result, accum)]),
205 218571 : }
206 : }
207 452797 : None => RangeSearchResult::new(),
208 : }
209 671368 : }
210 : }
211 :
212 : /// Collector for results of range search queries on the LayerMap.
213 : /// It should be provided with two iterators for the delta and image coverage
214 : /// that contain all the changes for layers which intersect the range.
215 : struct RangeSearchCollector<Iter>
216 : where
217 : Iter: Iterator<Item = (i128, Option<Arc<PersistentLayerDesc>>)>,
218 : {
219 : in_memory_layer: Option<InMemoryLayerDesc>,
220 : delta_coverage: Peekable<Iter>,
221 : image_coverage: Peekable<Iter>,
222 : key_range: Range<Key>,
223 : end_lsn: Lsn,
224 :
225 : current_delta: Option<Arc<PersistentLayerDesc>>,
226 : current_image: Option<Arc<PersistentLayerDesc>>,
227 :
228 : result: RangeSearchResult,
229 : }
230 :
231 : #[derive(Debug)]
232 : enum NextLayerType {
233 : Delta(i128),
234 : Image(i128),
235 : Both(i128),
236 : }
237 :
238 : impl NextLayerType {
239 2997992 : fn next_change_at_key(&self) -> Key {
240 2997992 : match self {
241 305190 : NextLayerType::Delta(at) => Key::from_i128(*at),
242 1206640 : NextLayerType::Image(at) => Key::from_i128(*at),
243 1486162 : NextLayerType::Both(at) => Key::from_i128(*at),
244 : }
245 2997992 : }
246 : }
247 :
248 : impl<Iter> RangeSearchCollector<Iter>
249 : where
250 : Iter: Iterator<Item = (i128, Option<Arc<PersistentLayerDesc>>)>,
251 : {
252 1493618 : fn new(
253 1493618 : key_range: Range<Key>,
254 1493618 : end_lsn: Lsn,
255 1493618 : in_memory_layer: Option<InMemoryLayerDesc>,
256 1493618 : delta_coverage: Iter,
257 1493618 : image_coverage: Iter,
258 1493618 : ) -> Self {
259 1493618 : Self {
260 1493618 : in_memory_layer,
261 1493618 : delta_coverage: delta_coverage.peekable(),
262 1493618 : image_coverage: image_coverage.peekable(),
263 1493618 : key_range,
264 1493618 : end_lsn,
265 1493618 : current_delta: None,
266 1493618 : current_image: None,
267 1493618 : result: RangeSearchResult::new(),
268 1493618 : }
269 1493618 : }
270 :
271 : /// Run the collector. Collection is implemented via a two pointer algorithm.
272 : /// One pointer tracks the start of the current range and the other tracks
273 : /// the beginning of the next range which will overlap with the next change
274 : /// in coverage across both image and delta.
275 1493618 : fn collect(mut self) -> RangeSearchResult {
276 1493618 : let next_layer_type = self.choose_next_layer_type();
277 1484718 : let mut current_range_start = match next_layer_type {
278 : None => {
279 : // No changes for the range
280 8900 : self.pad_range(self.key_range.clone());
281 8900 : return self.result;
282 : }
283 1484718 : Some(layer_type) if self.key_range.end <= layer_type.next_change_at_key() => {
284 0 : // Changes only after the end of the range
285 0 : self.pad_range(self.key_range.clone());
286 0 : return self.result;
287 : }
288 1484718 : Some(layer_type) => {
289 1484718 : // Changes for the range exist.
290 1484718 : let coverage_start = layer_type.next_change_at_key();
291 1484718 : let range_before = self.key_range.start..coverage_start;
292 1484718 : self.pad_range(range_before);
293 1484718 :
294 1484718 : self.advance(&layer_type);
295 1484718 : coverage_start
296 : }
297 : };
298 :
299 2997992 : while current_range_start < self.key_range.end {
300 1513274 : let next_layer_type = self.choose_next_layer_type();
301 1513274 : match next_layer_type {
302 28556 : Some(t) => {
303 28556 : let current_range_end = t.next_change_at_key();
304 28556 : self.add_range(current_range_start..current_range_end);
305 28556 : current_range_start = current_range_end;
306 28556 :
307 28556 : self.advance(&t);
308 28556 : }
309 1484718 : None => {
310 1484718 : self.add_range(current_range_start..self.key_range.end);
311 1484718 : current_range_start = self.key_range.end;
312 1484718 : }
313 : }
314 : }
315 :
316 1484718 : self.result
317 1493618 : }
318 :
319 : /// Map a range which does not intersect any persistent layers to
320 : /// the in-memory layer candidate.
321 1495494 : fn pad_range(&mut self, key_range: Range<Key>) {
322 1495494 : if !key_range.is_empty() {
323 14720 : if let Some(ref inmem) = self.in_memory_layer {
324 6348 : let search_result = SearchResult {
325 6348 : layer: ReadableLayerWeak::InMemoryLayer(inmem.clone()),
326 6348 : lsn_floor: inmem.get_lsn_range().start,
327 6348 : };
328 6348 :
329 6348 : self.result
330 6348 : .found
331 6348 : .entry(search_result)
332 6348 : .or_default()
333 6348 : .add_range(key_range);
334 8372 : }
335 1480774 : }
336 1495494 : }
337 :
338 : /// Select the appropiate layer for the given range and update
339 : /// the collector.
340 1513274 : fn add_range(&mut self, covered_range: Range<Key>) {
341 1513274 : let selected = LayerMap::select_layer(
342 1513274 : self.current_delta.clone(),
343 1513274 : self.current_image.clone(),
344 1513274 : self.in_memory_layer.clone(),
345 1513274 : self.end_lsn,
346 1513274 : );
347 1513274 :
348 1513274 : match selected {
349 1511398 : Some(search_result) => self
350 1511398 : .result
351 1511398 : .found
352 1511398 : .entry(search_result)
353 1511398 : .or_default()
354 1511398 : .add_range(covered_range),
355 1876 : None => self.pad_range(covered_range),
356 : }
357 1513274 : }
358 :
359 : /// Move to the next coverage change.
360 1513274 : fn advance(&mut self, layer_type: &NextLayerType) {
361 1513274 : match layer_type {
362 156015 : NextLayerType::Delta(_) => {
363 156015 : let (_, layer) = self.delta_coverage.next().unwrap();
364 156015 : self.current_delta = layer;
365 156015 : }
366 605134 : NextLayerType::Image(_) => {
367 605134 : let (_, layer) = self.image_coverage.next().unwrap();
368 605134 : self.current_image = layer;
369 605134 : }
370 752125 : NextLayerType::Both(_) => {
371 752125 : let (_, image_layer) = self.image_coverage.next().unwrap();
372 752125 : let (_, delta_layer) = self.delta_coverage.next().unwrap();
373 752125 :
374 752125 : self.current_image = image_layer;
375 752125 : self.current_delta = delta_layer;
376 752125 : }
377 : }
378 1513274 : }
379 :
380 : /// Pick the next coverage change: the one at the lesser key or both if they're alligned.
381 3006892 : fn choose_next_layer_type(&mut self) -> Option<NextLayerType> {
382 3006892 : let next_delta_at = self.delta_coverage.peek().map(|(key, _)| key);
383 3006892 : let next_image_at = self.image_coverage.peek().map(|(key, _)| key);
384 3006892 :
385 3006892 : match (next_delta_at, next_image_at) {
386 1493618 : (None, None) => None,
387 145931 : (Some(next_delta_at), None) => Some(NextLayerType::Delta(*next_delta_at)),
388 603390 : (None, Some(next_image_at)) => Some(NextLayerType::Image(*next_image_at)),
389 763953 : (Some(next_delta_at), Some(next_image_at)) if next_image_at < next_delta_at => {
390 1744 : Some(NextLayerType::Image(*next_image_at))
391 : }
392 762209 : (Some(next_delta_at), Some(next_image_at)) if next_delta_at < next_image_at => {
393 10084 : Some(NextLayerType::Delta(*next_delta_at))
394 : }
395 752125 : (Some(next_delta_at), Some(_)) => Some(NextLayerType::Both(*next_delta_at)),
396 : }
397 3006892 : }
398 : }
399 :
400 : #[derive(Debug, PartialEq, Eq, Clone, Hash)]
401 : pub struct InMemoryLayerDesc {
402 : handle: InMemoryLayerHandle,
403 : lsn_range: Range<Lsn>,
404 : }
405 :
406 : impl InMemoryLayerDesc {
407 2515187 : pub(crate) fn get_lsn_range(&self) -> Range<Lsn> {
408 2515187 : self.lsn_range.clone()
409 2515187 : }
410 : }
411 :
412 : #[derive(Debug, PartialEq, Eq, Clone, Hash)]
413 : enum InMemoryLayerHandle {
414 : Open,
415 : Frozen(usize),
416 : }
417 :
418 : impl LayerMap {
419 : ///
420 : /// Find the latest layer (by lsn.end) that covers the given
421 : /// 'key', with lsn.start < 'end_lsn'.
422 : ///
423 : /// The caller of this function is the page reconstruction
424 : /// algorithm looking for the next relevant delta layer, or
425 : /// the terminal image layer. The caller will pass the lsn_floor
426 : /// value as end_lsn in the next call to search.
427 : ///
428 : /// If there's an image layer exactly below the given end_lsn,
429 : /// search should return that layer regardless if there are
430 : /// overlapping deltas.
431 : ///
432 : /// If the latest layer is a delta and there is an overlapping
433 : /// image with it below, the lsn_floor returned should be right
434 : /// above that image so we don't skip it in the search. Otherwise
435 : /// the lsn_floor returned should be the bottom of the delta layer
436 : /// because we should make as much progress down the lsn axis
437 : /// as possible. It's fine if this way we skip some overlapping
438 : /// deltas, because the delta we returned would contain the same
439 : /// wal content.
440 : ///
441 : /// TODO: This API is convoluted and inefficient. If the caller
442 : /// makes N search calls, we'll end up finding the same latest
443 : /// image layer N times. We should either cache the latest image
444 : /// layer result, or simplify the api to `get_latest_image` and
445 : /// `get_latest_delta`, and only call `get_latest_image` once.
446 : ///
447 287924 : pub fn search(&self, key: Key, end_lsn: Lsn) -> Option<SearchResult> {
448 287924 : let in_memory_layer = self.search_in_memory_layer(end_lsn);
449 :
450 287924 : let version = match self.historic.get().unwrap().get_version(end_lsn.0 - 1) {
451 287924 : Some(version) => version,
452 : None => {
453 0 : return in_memory_layer.map(|desc| SearchResult {
454 0 : lsn_floor: desc.get_lsn_range().start,
455 0 : layer: ReadableLayerWeak::InMemoryLayer(desc),
456 0 : });
457 : }
458 : };
459 :
460 287924 : let latest_delta = version.delta_coverage.query(key.to_i128());
461 287924 : let latest_image = version.image_coverage.query(key.to_i128());
462 287924 :
463 287924 : Self::select_layer(latest_delta, latest_image, in_memory_layer, end_lsn)
464 287924 : }
465 :
466 : /// Select a layer from three potential candidates (in-memory, delta and image layer).
467 : /// The candidates represent the first layer of each type which intersect a key range.
468 : ///
469 : /// Layer types have an in implicit priority (image > delta > in-memory). For instance,
470 : /// if we have the option of reading an LSN range from both an image and a delta, we
471 : /// should read from the image.
472 2698862 : fn select_layer(
473 2698862 : delta_layer: Option<Arc<PersistentLayerDesc>>,
474 2698862 : image_layer: Option<Arc<PersistentLayerDesc>>,
475 2698862 : in_memory_layer: Option<InMemoryLayerDesc>,
476 2698862 : end_lsn: Lsn,
477 2698862 : ) -> Option<SearchResult> {
478 2698862 : assert!(delta_layer.as_ref().is_none_or(|l| l.is_delta()));
479 2698862 : assert!(image_layer.as_ref().is_none_or(|l| !l.is_delta()));
480 :
481 2698862 : match (delta_layer, image_layer, in_memory_layer) {
482 23200 : (None, None, None) => None,
483 73656 : (None, Some(image), None) => {
484 73656 : let lsn_floor = image.get_lsn_range().start;
485 73656 : Some(SearchResult {
486 73656 : layer: ReadableLayerWeak::PersistentLayer(image),
487 73656 : lsn_floor,
488 73656 : })
489 : }
490 153627 : (Some(delta), None, None) => {
491 153627 : let lsn_floor = delta.get_lsn_range().start;
492 153627 : Some(SearchResult {
493 153627 : layer: ReadableLayerWeak::PersistentLayer(delta),
494 153627 : lsn_floor,
495 153627 : })
496 : }
497 842861 : (Some(delta), Some(image), None) => {
498 842861 : let img_lsn = image.get_lsn_range().start;
499 842861 : let image_is_newer = image.get_lsn_range().end >= delta.get_lsn_range().end;
500 842861 : let image_exact_match = img_lsn + 1 == end_lsn;
501 842861 : if image_is_newer || image_exact_match {
502 82388 : Some(SearchResult {
503 82388 : layer: ReadableLayerWeak::PersistentLayer(image),
504 82388 : lsn_floor: img_lsn,
505 82388 : })
506 : } else {
507 : // If the delta overlaps with the image in the LSN dimension, do a partial
508 : // up to the image layer.
509 760473 : let lsn_floor =
510 760473 : std::cmp::max(delta.get_lsn_range().start, image.get_lsn_range().start + 1);
511 760473 : Some(SearchResult {
512 760473 : layer: ReadableLayerWeak::PersistentLayer(delta),
513 760473 : lsn_floor,
514 760473 : })
515 : }
516 : }
517 23164 : (None, None, Some(inmem)) => {
518 23164 : let lsn_floor = inmem.get_lsn_range().start;
519 23164 : Some(SearchResult {
520 23164 : layer: ReadableLayerWeak::InMemoryLayer(inmem),
521 23164 : lsn_floor,
522 23164 : })
523 : }
524 685326 : (None, Some(image), Some(inmem)) => {
525 685326 : // If the in-memory layer overlaps with the image in the LSN dimension, do a partial
526 685326 : // up to the image layer.
527 685326 : let img_lsn = image.get_lsn_range().start;
528 685326 : let image_is_newer = image.get_lsn_range().end >= inmem.get_lsn_range().end;
529 685326 : let image_exact_match = img_lsn + 1 == end_lsn;
530 685326 : if image_is_newer || image_exact_match {
531 20 : Some(SearchResult {
532 20 : layer: ReadableLayerWeak::PersistentLayer(image),
533 20 : lsn_floor: img_lsn,
534 20 : })
535 : } else {
536 685306 : let lsn_floor =
537 685306 : std::cmp::max(inmem.get_lsn_range().start, image.get_lsn_range().start + 1);
538 685306 : Some(SearchResult {
539 685306 : layer: ReadableLayerWeak::InMemoryLayer(inmem),
540 685306 : lsn_floor,
541 685306 : })
542 : }
543 : }
544 448244 : (Some(delta), None, Some(inmem)) => {
545 448244 : // Overlaps between delta and in-memory layers are not a valid
546 448244 : // state, but we handle them here for completeness.
547 448244 : let delta_end = delta.get_lsn_range().end;
548 448244 : let delta_is_newer = delta_end >= inmem.get_lsn_range().end;
549 448244 : let delta_exact_match = delta_end == end_lsn;
550 448244 : if delta_is_newer || delta_exact_match {
551 16 : Some(SearchResult {
552 16 : lsn_floor: delta.get_lsn_range().start,
553 16 : layer: ReadableLayerWeak::PersistentLayer(delta),
554 16 : })
555 : } else {
556 : // If the in-memory layer overlaps with the delta in the LSN dimension, do a partial
557 : // up to the delta layer.
558 448228 : let lsn_floor =
559 448228 : std::cmp::max(inmem.get_lsn_range().start, delta.get_lsn_range().end);
560 448228 : Some(SearchResult {
561 448228 : layer: ReadableLayerWeak::InMemoryLayer(inmem),
562 448228 : lsn_floor,
563 448228 : })
564 : }
565 : }
566 448784 : (Some(delta), Some(image), Some(inmem)) => {
567 448784 : // Determine the preferred persistent layer without taking the in-memory layer
568 448784 : // into consideration.
569 448784 : let persistent_res =
570 448784 : Self::select_layer(Some(delta.clone()), Some(image.clone()), None, end_lsn)
571 448784 : .unwrap();
572 448784 : let persistent_l = match persistent_res.layer {
573 448784 : ReadableLayerWeak::PersistentLayer(l) => l,
574 0 : ReadableLayerWeak::InMemoryLayer(_) => unreachable!(),
575 : };
576 :
577 : // Now handle the in-memory layer overlaps.
578 448784 : let inmem_res = if persistent_l.is_delta() {
579 428296 : Self::select_layer(Some(persistent_l), None, Some(inmem.clone()), end_lsn)
580 428296 : .unwrap()
581 : } else {
582 20488 : Self::select_layer(None, Some(persistent_l), Some(inmem.clone()), end_lsn)
583 20488 : .unwrap()
584 : };
585 :
586 448784 : Some(SearchResult {
587 448784 : layer: inmem_res.layer,
588 448784 : // Use the more restrictive LSN floor
589 448784 : lsn_floor: std::cmp::max(persistent_res.lsn_floor, inmem_res.lsn_floor),
590 448784 : })
591 : }
592 : }
593 2698862 : }
594 :
595 2164986 : pub fn range_search(&self, key_range: Range<Key>, end_lsn: Lsn) -> RangeSearchResult {
596 2164986 : let in_memory_layer = self.search_in_memory_layer(end_lsn);
597 :
598 2164986 : let version = match self.historic.get().unwrap().get_version(end_lsn.0 - 1) {
599 1493618 : Some(version) => version,
600 : None => {
601 671368 : return RangeSearchResult::map_to_in_memory_layer(in_memory_layer, key_range);
602 : }
603 : };
604 :
605 1493618 : let raw_range = key_range.start.to_i128()..key_range.end.to_i128();
606 1493618 : let delta_changes = version.delta_coverage.range_overlaps(&raw_range);
607 1493618 : let image_changes = version.image_coverage.range_overlaps(&raw_range);
608 1493618 :
609 1493618 : let collector = RangeSearchCollector::new(
610 1493618 : key_range,
611 1493618 : end_lsn,
612 1493618 : in_memory_layer,
613 1493618 : delta_changes,
614 1493618 : image_changes,
615 1493618 : );
616 1493618 : collector.collect()
617 2164986 : }
618 :
619 : /// Start a batch of updates, applied on drop
620 3584 : pub fn batch_update(&mut self) -> BatchedUpdates<'_> {
621 3584 : BatchedUpdates { layer_map: self }
622 3584 : }
623 :
624 : ///
625 : /// Insert an on-disk layer
626 : ///
627 : /// Helper function for BatchedUpdates::insert_historic
628 : ///
629 : /// TODO(chi): remove L generic so that we do not need to pass layer object.
630 9828 : pub(self) fn insert_historic_noflush(&mut self, layer_desc: PersistentLayerDesc) {
631 9828 : // TODO: See #3869, resulting #4088, attempted fix and repro #4094
632 9828 :
633 9828 : if Self::is_l0(&layer_desc.key_range, layer_desc.is_delta) {
634 1996 : self.l0_delta_layers.push(layer_desc.clone().into());
635 1996 : self.watch_l0_deltas
636 1996 : .send_replace(self.l0_delta_layers.len());
637 7832 : }
638 :
639 9828 : self.historic.insert(
640 9828 : historic_layer_coverage::LayerKey::from(&layer_desc),
641 9828 : layer_desc.into(),
642 9828 : );
643 9828 : }
644 :
645 : ///
646 : /// Remove an on-disk layer from the map.
647 : ///
648 : /// Helper function for BatchedUpdates::remove_historic
649 : ///
650 1032 : pub fn remove_historic_noflush(&mut self, layer_desc: &PersistentLayerDesc) {
651 1032 : self.historic
652 1032 : .remove(historic_layer_coverage::LayerKey::from(layer_desc));
653 1032 : let layer_key = layer_desc.key();
654 1032 : if Self::is_l0(&layer_desc.key_range, layer_desc.is_delta) {
655 808 : let len_before = self.l0_delta_layers.len();
656 808 : let mut l0_delta_layers = std::mem::take(&mut self.l0_delta_layers);
657 11048 : l0_delta_layers.retain(|other| other.key() != layer_key);
658 808 : self.l0_delta_layers = l0_delta_layers;
659 808 : self.watch_l0_deltas
660 808 : .send_replace(self.l0_delta_layers.len());
661 808 : // this assertion is related to use of Arc::ptr_eq in Self::compare_arced_layers,
662 808 : // there's a chance that the comparison fails at runtime due to it comparing (pointer,
663 808 : // vtable) pairs.
664 808 : assert_eq!(
665 808 : self.l0_delta_layers.len(),
666 808 : len_before - 1,
667 0 : "failed to locate removed historic layer from l0_delta_layers"
668 : );
669 224 : }
670 1032 : }
671 :
672 : /// Helper function for BatchedUpdates::drop.
673 3588 : pub(self) fn flush_updates(&mut self) {
674 3588 : self.historic.rebuild();
675 3588 : }
676 :
677 : /// Is there a newer image layer for given key- and LSN-range? Or a set
678 : /// of image layers within the specified lsn range that cover the entire
679 : /// specified key range?
680 : ///
681 : /// This is used for garbage collection, to determine if an old layer can
682 : /// be deleted.
683 16 : pub fn image_layer_exists(&self, key: &Range<Key>, lsn: &Range<Lsn>) -> bool {
684 16 : if key.is_empty() {
685 : // Vacuously true. There's a newer image for all 0 of the kerys in the range.
686 0 : return true;
687 16 : }
688 :
689 16 : let version = match self.historic.get().unwrap().get_version(lsn.end.0 - 1) {
690 16 : Some(v) => v,
691 0 : None => return false,
692 : };
693 :
694 16 : let start = key.start.to_i128();
695 16 : let end = key.end.to_i128();
696 16 :
697 20 : let layer_covers = |layer: Option<Arc<PersistentLayerDesc>>| match layer {
698 20 : Some(layer) => layer.get_lsn_range().start >= lsn.start,
699 0 : None => false,
700 20 : };
701 :
702 : // Check the start is covered
703 16 : if !layer_covers(version.image_coverage.query(start)) {
704 12 : return false;
705 4 : }
706 :
707 : // Check after all changes of coverage
708 4 : for (_, change_val) in version.image_coverage.range(start..end) {
709 4 : if !layer_covers(change_val) {
710 0 : return false;
711 4 : }
712 : }
713 :
714 4 : true
715 16 : }
716 :
717 7336 : pub fn iter_historic_layers(&self) -> impl '_ + Iterator<Item = Arc<PersistentLayerDesc>> {
718 7336 : self.historic.iter()
719 7336 : }
720 :
721 : /// Get a ref counted pointer for the first in memory layer that matches the provided predicate.
722 2452910 : pub(crate) fn search_in_memory_layer(&self, below: Lsn) -> Option<InMemoryLayerDesc> {
723 2452910 : let is_below = |l: &Arc<InMemoryLayer>| {
724 1981153 : let start_lsn = l.get_lsn_range().start;
725 1981153 : below > start_lsn
726 1981153 : };
727 :
728 2452910 : if let Some(open) = &self.open_layer {
729 1823441 : if is_below(open) {
730 1208529 : return Some(InMemoryLayerDesc {
731 1208529 : handle: InMemoryLayerHandle::Open,
732 1208529 : lsn_range: open.get_lsn_range(),
733 1208529 : });
734 614912 : }
735 629469 : }
736 :
737 1244381 : self.frozen_layers
738 1244381 : .iter()
739 1244381 : .enumerate()
740 1244381 : .rfind(|(_idx, l)| is_below(l))
741 1244381 : .map(|(idx, l)| InMemoryLayerDesc {
742 156864 : handle: InMemoryLayerHandle::Frozen(idx),
743 156864 : lsn_range: l.get_lsn_range(),
744 1244381 : })
745 2452910 : }
746 :
747 1214349 : pub(crate) fn in_memory_layer(&self, desc: &InMemoryLayerDesc) -> Arc<InMemoryLayer> {
748 1214349 : match desc.handle {
749 1208529 : InMemoryLayerHandle::Open => self.open_layer.as_ref().unwrap().clone(),
750 5820 : InMemoryLayerHandle::Frozen(idx) => self.frozen_layers[idx].clone(),
751 : }
752 1214349 : }
753 :
754 : ///
755 : /// Divide the whole given range of keys into sub-ranges based on the latest
756 : /// image layer that covers each range at the specified lsn (inclusive).
757 : /// This is used when creating new image layers.
758 28 : pub fn image_coverage(
759 28 : &self,
760 28 : key_range: &Range<Key>,
761 28 : lsn: Lsn,
762 28 : ) -> Vec<(Range<Key>, Option<Arc<PersistentLayerDesc>>)> {
763 28 : let version = match self.historic.get().unwrap().get_version(lsn.0) {
764 28 : Some(v) => v,
765 0 : None => return vec![],
766 : };
767 :
768 28 : let start = key_range.start.to_i128();
769 28 : let end = key_range.end.to_i128();
770 28 :
771 28 : // Initialize loop variables
772 28 : let mut coverage: Vec<(Range<Key>, Option<Arc<PersistentLayerDesc>>)> = vec![];
773 28 : let mut current_key = start;
774 28 : let mut current_val = version.image_coverage.query(start);
775 :
776 : // Loop through the change events and push intervals
777 28 : for (change_key, change_val) in version.image_coverage.range(start..end) {
778 0 : let kr = Key::from_i128(current_key)..Key::from_i128(change_key);
779 0 : coverage.push((kr, current_val.take()));
780 0 : current_key = change_key;
781 0 : current_val.clone_from(&change_val);
782 0 : }
783 :
784 : // Add the final interval
785 28 : let kr = Key::from_i128(current_key)..Key::from_i128(end);
786 28 : coverage.push((kr, current_val.take()));
787 28 :
788 28 : coverage
789 28 : }
790 :
791 : /// Check if the key range resembles that of an L0 layer.
792 17119 : pub fn is_l0(key_range: &Range<Key>, is_delta_layer: bool) -> bool {
793 17119 : is_delta_layer && key_range == &(Key::MIN..Key::MAX)
794 17119 : }
795 :
796 : /// This function determines which layers are counted in `count_deltas`:
797 : /// layers that should count towards deciding whether or not to reimage
798 : /// a certain partition range.
799 : ///
800 : /// There are two kinds of layers we currently consider reimage-worthy:
801 : ///
802 : /// Case 1: Non-L0 layers are currently reimage-worthy by default.
803 : /// TODO Some of these layers are very sparse and cover the entire key
804 : /// range. Replacing 256MB of data (or less!) with terabytes of
805 : /// images doesn't seem wise. We need a better heuristic, possibly
806 : /// based on some of these factors:
807 : /// a) whether this layer has any wal in this partition range
808 : /// b) the size of the layer
809 : /// c) the number of images needed to cover it
810 : /// d) the estimated time until we'll have to reimage over it for GC
811 : ///
812 : /// Case 2: Since L0 layers by definition cover the entire key space, we consider
813 : /// them reimage-worthy only when the entire key space can be covered by very few
814 : /// images (currently 1).
815 : /// TODO The optimal number should probably be slightly higher than 1, but to
816 : /// implement that we need to plumb a lot more context into this function
817 : /// than just the current partition_range.
818 0 : pub fn is_reimage_worthy(layer: &PersistentLayerDesc, partition_range: &Range<Key>) -> bool {
819 0 : // Case 1
820 0 : if !Self::is_l0(&layer.key_range, layer.is_delta) {
821 0 : return true;
822 0 : }
823 0 :
824 0 : // Case 2
825 0 : if partition_range == &(Key::MIN..Key::MAX) {
826 0 : return true;
827 0 : }
828 0 :
829 0 : false
830 0 : }
831 :
832 : /// Count the height of the tallest stack of reimage-worthy deltas
833 : /// in this 2d region.
834 : ///
835 : /// If `limit` is provided we don't try to count above that number.
836 : ///
837 : /// This number is used to compute the largest number of deltas that
838 : /// we'll need to visit for any page reconstruction in this region.
839 : /// We use this heuristic to decide whether to create an image layer.
840 28 : pub fn count_deltas(&self, key: &Range<Key>, lsn: &Range<Lsn>, limit: Option<usize>) -> usize {
841 28 : // We get the delta coverage of the region, and for each part of the coverage
842 28 : // we recurse right underneath the delta. The recursion depth is limited by
843 28 : // the largest result this function could return, which is in practice between
844 28 : // 3 and 10 (since we usually try to create an image when the number gets larger).
845 28 :
846 28 : if lsn.is_empty() || key.is_empty() || limit == Some(0) {
847 0 : return 0;
848 28 : }
849 :
850 28 : let version = match self.historic.get().unwrap().get_version(lsn.end.0 - 1) {
851 28 : Some(v) => v,
852 0 : None => return 0,
853 : };
854 :
855 28 : let start = key.start.to_i128();
856 28 : let end = key.end.to_i128();
857 28 :
858 28 : // Initialize loop variables
859 28 : let mut max_stacked_deltas = 0;
860 28 : let mut current_key = start;
861 28 : let mut current_val = version.delta_coverage.query(start);
862 :
863 : // Loop through the delta coverage and recurse on each part
864 28 : for (change_key, change_val) in version.delta_coverage.range(start..end) {
865 : // If there's a relevant delta in this part, add 1 and recurse down
866 0 : if let Some(val) = ¤t_val {
867 0 : if val.get_lsn_range().end > lsn.start {
868 0 : let kr = Key::from_i128(current_key)..Key::from_i128(change_key);
869 0 : let lr = lsn.start..val.get_lsn_range().start;
870 0 : if !kr.is_empty() {
871 0 : let base_count = Self::is_reimage_worthy(val, key) as usize;
872 0 : let new_limit = limit.map(|l| l - base_count);
873 0 : let max_stacked_deltas_underneath = self.count_deltas(&kr, &lr, new_limit);
874 0 : max_stacked_deltas = std::cmp::max(
875 0 : max_stacked_deltas,
876 0 : base_count + max_stacked_deltas_underneath,
877 0 : );
878 0 : }
879 0 : }
880 0 : }
881 :
882 0 : current_key = change_key;
883 0 : current_val.clone_from(&change_val);
884 : }
885 :
886 : // Consider the last part
887 28 : if let Some(val) = ¤t_val {
888 0 : if val.get_lsn_range().end > lsn.start {
889 0 : let kr = Key::from_i128(current_key)..Key::from_i128(end);
890 0 : let lr = lsn.start..val.get_lsn_range().start;
891 0 :
892 0 : if !kr.is_empty() {
893 0 : let base_count = Self::is_reimage_worthy(val, key) as usize;
894 0 : let new_limit = limit.map(|l| l - base_count);
895 0 : let max_stacked_deltas_underneath = self.count_deltas(&kr, &lr, new_limit);
896 0 : max_stacked_deltas = std::cmp::max(
897 0 : max_stacked_deltas,
898 0 : base_count + max_stacked_deltas_underneath,
899 0 : );
900 0 : }
901 0 : }
902 28 : }
903 :
904 28 : max_stacked_deltas
905 28 : }
906 :
907 : /// Return all L0 delta layers
908 3312 : pub fn level0_deltas(&self) -> &Vec<Arc<PersistentLayerDesc>> {
909 3312 : &self.l0_delta_layers
910 3312 : }
911 :
912 : /// Subscribes to L0 delta layer changes, sending the current number of L0 delta layers.
913 892 : pub fn watch_level0_deltas(&self) -> watch::Receiver<usize> {
914 892 : self.watch_l0_deltas.subscribe()
915 892 : }
916 :
917 : /// debugging function to print out the contents of the layer map
918 : #[allow(unused)]
919 4 : pub async fn dump(&self, verbose: bool, ctx: &RequestContext) -> Result<()> {
920 4 : println!("Begin dump LayerMap");
921 4 :
922 4 : println!("open_layer:");
923 4 : if let Some(open_layer) = &self.open_layer {
924 0 : open_layer.dump(verbose, ctx).await?;
925 4 : }
926 :
927 4 : println!("frozen_layers:");
928 4 : for frozen_layer in self.frozen_layers.iter() {
929 0 : frozen_layer.dump(verbose, ctx).await?;
930 : }
931 :
932 4 : println!("historic_layers:");
933 24 : for desc in self.iter_historic_layers() {
934 24 : desc.dump();
935 24 : }
936 4 : println!("End dump LayerMap");
937 4 : Ok(())
938 4 : }
939 :
940 : /// `read_points` represent the tip of a timeline and any branch points, i.e. the places
941 : /// where we expect to serve reads.
942 : ///
943 : /// This function is O(N) and should be called infrequently. The caller is responsible for
944 : /// looking up and updating the Layer objects for these layer descriptors.
945 476 : pub fn get_visibility(
946 476 : &self,
947 476 : mut read_points: Vec<Lsn>,
948 476 : ) -> (
949 476 : Vec<(Arc<PersistentLayerDesc>, LayerVisibilityHint)>,
950 476 : KeySpace,
951 476 : ) {
952 : // This is like a KeySpace, but this type is intended for efficient unions with image layer ranges, whereas
953 : // KeySpace is intended to be composed statically and iterated over.
954 : struct KeyShadow {
955 : // Map of range start to range end
956 : inner: RangeSetBlaze<i128>,
957 : }
958 :
959 : impl KeyShadow {
960 476 : fn new() -> Self {
961 476 : Self {
962 476 : inner: Default::default(),
963 476 : }
964 476 : }
965 :
966 3204 : fn contains(&self, range: Range<Key>) -> bool {
967 3204 : let range_incl = range.start.to_i128()..=range.end.to_i128() - 1;
968 3204 : self.inner.is_superset(&RangeSetBlaze::from_sorted_disjoint(
969 3204 : CheckSortedDisjoint::from([range_incl]),
970 3204 : ))
971 3204 : }
972 :
973 : /// Add the input range to the keys covered by self.
974 : ///
975 : /// Return true if inserting this range covered some keys that were previously not covered
976 3820 : fn cover(&mut self, insert: Range<Key>) -> bool {
977 3820 : let range_incl = insert.start.to_i128()..=insert.end.to_i128() - 1;
978 3820 : self.inner.ranges_insert(range_incl)
979 3820 : }
980 :
981 484 : fn reset(&mut self) {
982 484 : self.inner = Default::default();
983 484 : }
984 :
985 476 : fn to_keyspace(&self) -> KeySpace {
986 476 : let mut accum = KeySpaceAccum::new();
987 484 : for range_incl in self.inner.ranges() {
988 484 : let range = Range {
989 484 : start: Key::from_i128(*range_incl.start()),
990 484 : end: Key::from_i128(range_incl.end() + 1),
991 484 : };
992 484 : accum.add_range(range)
993 : }
994 :
995 476 : accum.to_keyspace()
996 476 : }
997 : }
998 :
999 : // The 'shadow' will be updated as we sweep through the layers: an image layer subtracts from the shadow,
1000 : // and a ReadPoint
1001 476 : read_points.sort_by_key(|rp| rp.0);
1002 476 : let mut shadow = KeyShadow::new();
1003 :
1004 : // We will interleave all our read points and layers into a sorted collection
1005 : enum Item {
1006 : ReadPoint { lsn: Lsn },
1007 : Layer(Arc<PersistentLayerDesc>),
1008 : }
1009 :
1010 476 : let mut items = Vec::with_capacity(self.historic.len() + read_points.len());
1011 476 : items.extend(self.iter_historic_layers().map(Item::Layer));
1012 476 : items.extend(
1013 476 : read_points
1014 476 : .into_iter()
1015 484 : .map(|rp| Item::ReadPoint { lsn: rp }),
1016 476 : );
1017 476 :
1018 476 : // Ordering: we want to iterate like this:
1019 476 : // 1. Highest LSNs first
1020 476 : // 2. Consider images before deltas if they end at the same LSNs (images cover deltas)
1021 476 : // 3. Consider ReadPoints before image layers if they're at the same LSN (readpoints make that image visible)
1022 127176 : items.sort_by_key(|item| {
1023 127176 : std::cmp::Reverse(match item {
1024 126280 : Item::Layer(layer) => {
1025 126280 : if layer.is_delta() {
1026 59256 : (Lsn(layer.get_lsn_range().end.0 - 1), 0)
1027 : } else {
1028 67024 : (layer.image_layer_lsn(), 1)
1029 : }
1030 : }
1031 896 : Item::ReadPoint { lsn } => (*lsn, 2),
1032 : })
1033 127176 : });
1034 476 :
1035 476 : let mut results = Vec::with_capacity(self.historic.len());
1036 476 :
1037 476 : let mut maybe_covered_deltas: Vec<Arc<PersistentLayerDesc>> = Vec::new();
1038 :
1039 7984 : for item in items {
1040 7508 : let (reached_lsn, is_readpoint) = match &item {
1041 484 : Item::ReadPoint { lsn } => (lsn, true),
1042 7024 : Item::Layer(layer) => (&layer.lsn_range.start, false),
1043 : };
1044 7508 : maybe_covered_deltas.retain(|d| {
1045 212 : if *reached_lsn >= d.lsn_range.start && is_readpoint {
1046 : // We encountered a readpoint within the delta layer: it is visible
1047 :
1048 4 : results.push((d.clone(), LayerVisibilityHint::Visible));
1049 4 : false
1050 208 : } else if *reached_lsn < d.lsn_range.start {
1051 : // We passed the layer's range without encountering a read point: it is not visible
1052 64 : results.push((d.clone(), LayerVisibilityHint::Covered));
1053 64 : false
1054 : } else {
1055 : // We're still in the delta layer: continue iterating
1056 144 : true
1057 : }
1058 7508 : });
1059 7508 :
1060 7508 : match item {
1061 484 : Item::ReadPoint { lsn: _lsn } => {
1062 484 : // TODO: propagate the child timeline's shadow from their own run of this function, so that we don't have
1063 484 : // to assume that the whole key range is visible at the branch point.
1064 484 : shadow.reset();
1065 484 : }
1066 7024 : Item::Layer(layer) => {
1067 7024 : let visibility = if layer.is_delta() {
1068 3204 : if shadow.contains(layer.get_key_range()) {
1069 : // If a layer isn't visible based on current state, we must defer deciding whether
1070 : // it is truly not visible until we have advanced past the delta's range: we might
1071 : // encounter another branch point within this delta layer's LSN range.
1072 76 : maybe_covered_deltas.push(layer);
1073 76 : continue;
1074 : } else {
1075 3128 : LayerVisibilityHint::Visible
1076 : }
1077 : } else {
1078 3820 : let modified = shadow.cover(layer.get_key_range());
1079 3820 : if modified {
1080 : // An image layer in a region which wasn't fully covered yet: this layer is visible, but layers below it will be covered
1081 3748 : LayerVisibilityHint::Visible
1082 : } else {
1083 : // An image layer in a region that was already covered
1084 72 : LayerVisibilityHint::Covered
1085 : }
1086 : };
1087 :
1088 6948 : results.push((layer, visibility));
1089 : }
1090 : }
1091 : }
1092 :
1093 : // Drain any remaining maybe_covered deltas
1094 476 : results.extend(
1095 476 : maybe_covered_deltas
1096 476 : .into_iter()
1097 476 : .map(|d| (d, LayerVisibilityHint::Covered)),
1098 476 : );
1099 476 :
1100 476 : (results, shadow.to_keyspace())
1101 476 : }
1102 : }
1103 :
1104 : #[cfg(test)]
1105 : mod tests {
1106 : use std::collections::HashMap;
1107 : use std::path::PathBuf;
1108 :
1109 : use crate::{
1110 : DEFAULT_PG_VERSION,
1111 : tenant::{harness::TenantHarness, storage_layer::LayerName},
1112 : };
1113 : use pageserver_api::key::DBDIR_KEY;
1114 : use pageserver_api::keyspace::{KeySpace, KeySpaceRandomAccum};
1115 : use utils::id::{TenantId, TimelineId};
1116 : use utils::shard::TenantShardId;
1117 :
1118 : use super::*;
1119 : use crate::tenant::IndexPart;
1120 :
1121 : #[derive(Clone)]
1122 : struct LayerDesc {
1123 : key_range: Range<Key>,
1124 : lsn_range: Range<Lsn>,
1125 : is_delta: bool,
1126 : }
1127 :
1128 4 : fn create_layer_map(layers: Vec<LayerDesc>) -> LayerMap {
1129 4 : let mut layer_map = LayerMap::default();
1130 :
1131 24 : for layer in layers {
1132 20 : layer_map.insert_historic_noflush(PersistentLayerDesc::new_test(
1133 20 : layer.key_range,
1134 20 : layer.lsn_range,
1135 20 : layer.is_delta,
1136 20 : ));
1137 20 : }
1138 :
1139 4 : layer_map.flush_updates();
1140 4 : layer_map
1141 4 : }
1142 :
1143 14164 : fn assert_range_search_result_eq(lhs: RangeSearchResult, rhs: RangeSearchResult) {
1144 14164 : let lhs: HashMap<SearchResult, KeySpace> = lhs
1145 14164 : .found
1146 14164 : .into_iter()
1147 27280 : .map(|(search_result, accum)| (search_result, accum.to_keyspace()))
1148 14164 : .collect();
1149 14164 : let rhs: HashMap<SearchResult, KeySpace> = rhs
1150 14164 : .found
1151 14164 : .into_iter()
1152 27280 : .map(|(search_result, accum)| (search_result, accum.to_keyspace()))
1153 14164 : .collect();
1154 14164 :
1155 14164 : assert_eq!(lhs, rhs);
1156 14164 : }
1157 :
1158 : #[cfg(test)]
1159 14160 : fn brute_force_range_search(
1160 14160 : layer_map: &LayerMap,
1161 14160 : key_range: Range<Key>,
1162 14160 : end_lsn: Lsn,
1163 14160 : ) -> RangeSearchResult {
1164 14160 : let mut range_search_result = RangeSearchResult::new();
1165 14160 :
1166 14160 : let mut key = key_range.start;
1167 302080 : while key != key_range.end {
1168 287920 : let res = layer_map.search(key, end_lsn);
1169 287920 : if let Some(res) = res {
1170 266600 : range_search_result
1171 266600 : .found
1172 266600 : .entry(res)
1173 266600 : .or_default()
1174 266600 : .add_key(key);
1175 266600 : }
1176 :
1177 287920 : key = key.next();
1178 : }
1179 :
1180 14160 : range_search_result
1181 14160 : }
1182 :
1183 : #[test]
1184 4 : fn ranged_search_on_empty_layer_map() {
1185 4 : let layer_map = LayerMap::default();
1186 4 : let range = Key::from_i128(100)..Key::from_i128(200);
1187 4 :
1188 4 : let res = layer_map.range_search(range.clone(), Lsn(100));
1189 4 : assert_range_search_result_eq(res, RangeSearchResult::new());
1190 4 : }
1191 :
1192 : #[tokio::test]
1193 4 : async fn ranged_search() {
1194 4 : let harness = TenantHarness::create("ranged_search").await.unwrap();
1195 4 : let (tenant, ctx) = harness.load().await;
1196 4 : let timeline_id = TimelineId::generate();
1197 4 : // Create the timeline such that the in-memory layers can be written
1198 4 : // to the timeline directory.
1199 4 : tenant
1200 4 : .create_test_timeline(timeline_id, Lsn(0x10), DEFAULT_PG_VERSION, &ctx)
1201 4 : .await
1202 4 : .unwrap();
1203 4 :
1204 4 : let gate = utils::sync::gate::Gate::default();
1205 4 : let add_in_memory_layer = async |layer_map: &mut LayerMap, lsn_range: Range<Lsn>| {
1206 4 : let layer = InMemoryLayer::create(
1207 4 : harness.conf,
1208 4 : timeline_id,
1209 4 : harness.tenant_shard_id,
1210 4 : lsn_range.start,
1211 4 : &gate,
1212 4 : &ctx,
1213 4 : )
1214 4 : .await
1215 4 : .unwrap();
1216 4 :
1217 4 : layer.freeze(lsn_range.end).await;
1218 4 :
1219 4 : layer_map.frozen_layers.push_back(Arc::new(layer));
1220 4 : };
1221 4 :
1222 4 : let in_memory_layer_configurations = [
1223 4 : vec![],
1224 4 : // Overlaps with the top-most image
1225 4 : vec![Lsn(35)..Lsn(50)],
1226 4 : ];
1227 4 :
1228 4 : let layers = vec![
1229 4 : LayerDesc {
1230 4 : key_range: Key::from_i128(15)..Key::from_i128(50),
1231 4 : lsn_range: Lsn(5)..Lsn(6),
1232 4 : is_delta: false,
1233 4 : },
1234 4 : LayerDesc {
1235 4 : key_range: Key::from_i128(10)..Key::from_i128(20),
1236 4 : lsn_range: Lsn(5)..Lsn(20),
1237 4 : is_delta: true,
1238 4 : },
1239 4 : LayerDesc {
1240 4 : key_range: Key::from_i128(15)..Key::from_i128(25),
1241 4 : lsn_range: Lsn(20)..Lsn(30),
1242 4 : is_delta: true,
1243 4 : },
1244 4 : LayerDesc {
1245 4 : key_range: Key::from_i128(35)..Key::from_i128(40),
1246 4 : lsn_range: Lsn(25)..Lsn(35),
1247 4 : is_delta: true,
1248 4 : },
1249 4 : LayerDesc {
1250 4 : key_range: Key::from_i128(35)..Key::from_i128(40),
1251 4 : lsn_range: Lsn(40)..Lsn(41),
1252 4 : is_delta: false,
1253 4 : },
1254 4 : ];
1255 4 :
1256 4 : let mut layer_map = create_layer_map(layers.clone());
1257 12 : for in_memory_layers in in_memory_layer_configurations {
1258 12 : for in_mem_layer_range in in_memory_layers {
1259 4 : add_in_memory_layer(&mut layer_map, in_mem_layer_range).await;
1260 4 : }
1261 4 :
1262 488 : for start in 0..60 {
1263 14160 : for end in (start + 1)..60 {
1264 14160 : let range = Key::from_i128(start)..Key::from_i128(end);
1265 14160 : let result = layer_map.range_search(range.clone(), Lsn(100));
1266 14160 : let expected = brute_force_range_search(&layer_map, range, Lsn(100));
1267 14160 :
1268 14160 : eprintln!("{start}..{end}: {result:?}");
1269 14160 :
1270 14160 : assert_range_search_result_eq(result, expected);
1271 14160 : }
1272 4 : }
1273 4 : }
1274 4 : }
1275 :
1276 : #[test]
1277 4 : fn layer_visibility_basic() {
1278 4 : // A simple synthetic input, as a smoke test.
1279 4 : let tenant_shard_id = TenantShardId::unsharded(TenantId::generate());
1280 4 : let timeline_id = TimelineId::generate();
1281 4 : let mut layer_map = LayerMap::default();
1282 4 : let mut updates = layer_map.batch_update();
1283 :
1284 : const FAKE_LAYER_SIZE: u64 = 1024;
1285 :
1286 4 : let inject_delta = |updates: &mut BatchedUpdates,
1287 : key_start: i128,
1288 : key_end: i128,
1289 : lsn_start: u64,
1290 28 : lsn_end: u64| {
1291 28 : let desc = PersistentLayerDesc::new_delta(
1292 28 : tenant_shard_id,
1293 28 : timeline_id,
1294 28 : Range {
1295 28 : start: Key::from_i128(key_start),
1296 28 : end: Key::from_i128(key_end),
1297 28 : },
1298 28 : Range {
1299 28 : start: Lsn(lsn_start),
1300 28 : end: Lsn(lsn_end),
1301 28 : },
1302 28 : 1024,
1303 28 : );
1304 28 : updates.insert_historic(desc.clone());
1305 28 : desc
1306 28 : };
1307 :
1308 4 : let inject_image =
1309 24 : |updates: &mut BatchedUpdates, key_start: i128, key_end: i128, lsn: u64| {
1310 24 : let desc = PersistentLayerDesc::new_img(
1311 24 : tenant_shard_id,
1312 24 : timeline_id,
1313 24 : Range {
1314 24 : start: Key::from_i128(key_start),
1315 24 : end: Key::from_i128(key_end),
1316 24 : },
1317 24 : Lsn(lsn),
1318 24 : FAKE_LAYER_SIZE,
1319 24 : );
1320 24 : updates.insert_historic(desc.clone());
1321 24 : desc
1322 24 : };
1323 :
1324 : //
1325 : // Construct our scenario: the following lines go in backward-LSN order, constructing the various scenarios
1326 : // we expect to handle. You can follow these examples through in the same order as they would be processed
1327 : // by the function under test.
1328 : //
1329 :
1330 4 : let mut read_points = vec![Lsn(1000)];
1331 4 :
1332 4 : // A delta ahead of any image layer
1333 4 : let ahead_layer = inject_delta(&mut updates, 10, 20, 101, 110);
1334 4 :
1335 4 : // An image layer is visible and covers some layers beneath itself
1336 4 : let visible_covering_img = inject_image(&mut updates, 5, 25, 99);
1337 4 :
1338 4 : // A delta layer covered by the image layer: should be covered
1339 4 : let covered_delta = inject_delta(&mut updates, 10, 20, 90, 100);
1340 4 :
1341 4 : // A delta layer partially covered by an image layer: should be visible
1342 4 : let partially_covered_delta = inject_delta(&mut updates, 1, 7, 90, 100);
1343 4 :
1344 4 : // A delta layer not covered by an image layer: should be visible
1345 4 : let not_covered_delta = inject_delta(&mut updates, 1, 4, 90, 100);
1346 4 :
1347 4 : // An image layer covered by the image layer above: should be covered
1348 4 : let covered_image = inject_image(&mut updates, 10, 20, 89);
1349 4 :
1350 4 : // An image layer partially covered by an image layer: should be visible
1351 4 : let partially_covered_image = inject_image(&mut updates, 1, 7, 89);
1352 4 :
1353 4 : // An image layer not covered by an image layer: should be visible
1354 4 : let not_covered_image = inject_image(&mut updates, 1, 4, 89);
1355 4 :
1356 4 : // A read point: this will make subsequent layers below here visible, even if there are
1357 4 : // more recent layers covering them.
1358 4 : read_points.push(Lsn(80));
1359 4 :
1360 4 : // A delta layer covered by an earlier image layer, but visible to a readpoint below that covering layer
1361 4 : let covered_delta_below_read_point = inject_delta(&mut updates, 10, 20, 70, 79);
1362 4 :
1363 4 : // A delta layer whose end LSN is covered, but where a read point is present partway through its LSN range:
1364 4 : // the read point should make it visible, even though its end LSN is covered
1365 4 : let covering_img_between_read_points = inject_image(&mut updates, 10, 20, 69);
1366 4 : let covered_delta_between_read_points = inject_delta(&mut updates, 10, 15, 67, 69);
1367 4 : read_points.push(Lsn(65));
1368 4 : let covered_delta_intersects_read_point = inject_delta(&mut updates, 15, 20, 60, 69);
1369 4 :
1370 4 : let visible_img_after_last_read_point = inject_image(&mut updates, 10, 20, 65);
1371 4 :
1372 4 : updates.flush();
1373 4 :
1374 4 : let (layer_visibilities, shadow) = layer_map.get_visibility(read_points);
1375 4 : let layer_visibilities = layer_visibilities.into_iter().collect::<HashMap<_, _>>();
1376 4 :
1377 4 : assert_eq!(
1378 4 : layer_visibilities.get(&ahead_layer),
1379 4 : Some(&LayerVisibilityHint::Visible)
1380 4 : );
1381 4 : assert_eq!(
1382 4 : layer_visibilities.get(&visible_covering_img),
1383 4 : Some(&LayerVisibilityHint::Visible)
1384 4 : );
1385 4 : assert_eq!(
1386 4 : layer_visibilities.get(&covered_delta),
1387 4 : Some(&LayerVisibilityHint::Covered)
1388 4 : );
1389 4 : assert_eq!(
1390 4 : layer_visibilities.get(&partially_covered_delta),
1391 4 : Some(&LayerVisibilityHint::Visible)
1392 4 : );
1393 4 : assert_eq!(
1394 4 : layer_visibilities.get(¬_covered_delta),
1395 4 : Some(&LayerVisibilityHint::Visible)
1396 4 : );
1397 4 : assert_eq!(
1398 4 : layer_visibilities.get(&covered_image),
1399 4 : Some(&LayerVisibilityHint::Covered)
1400 4 : );
1401 4 : assert_eq!(
1402 4 : layer_visibilities.get(&partially_covered_image),
1403 4 : Some(&LayerVisibilityHint::Visible)
1404 4 : );
1405 4 : assert_eq!(
1406 4 : layer_visibilities.get(¬_covered_image),
1407 4 : Some(&LayerVisibilityHint::Visible)
1408 4 : );
1409 4 : assert_eq!(
1410 4 : layer_visibilities.get(&covered_delta_below_read_point),
1411 4 : Some(&LayerVisibilityHint::Visible)
1412 4 : );
1413 4 : assert_eq!(
1414 4 : layer_visibilities.get(&covering_img_between_read_points),
1415 4 : Some(&LayerVisibilityHint::Visible)
1416 4 : );
1417 4 : assert_eq!(
1418 4 : layer_visibilities.get(&covered_delta_between_read_points),
1419 4 : Some(&LayerVisibilityHint::Covered)
1420 4 : );
1421 4 : assert_eq!(
1422 4 : layer_visibilities.get(&covered_delta_intersects_read_point),
1423 4 : Some(&LayerVisibilityHint::Visible)
1424 4 : );
1425 4 : assert_eq!(
1426 4 : layer_visibilities.get(&visible_img_after_last_read_point),
1427 4 : Some(&LayerVisibilityHint::Visible)
1428 4 : );
1429 :
1430 : // Shadow should include all the images below the last read point
1431 4 : let expected_shadow = KeySpace {
1432 4 : ranges: vec![Key::from_i128(10)..Key::from_i128(20)],
1433 4 : };
1434 4 : assert_eq!(shadow, expected_shadow);
1435 4 : }
1436 :
1437 4 : fn fixture_path(relative: &str) -> PathBuf {
1438 4 : PathBuf::from(env!("CARGO_MANIFEST_DIR")).join(relative)
1439 4 : }
1440 :
1441 : #[test]
1442 4 : fn layer_visibility_realistic() {
1443 4 : // Load a large example layermap
1444 4 : let index_raw = std::fs::read_to_string(fixture_path(
1445 4 : "test_data/indices/mixed_workload/index_part.json",
1446 4 : ))
1447 4 : .unwrap();
1448 4 : let index: IndexPart = serde_json::from_str::<IndexPart>(&index_raw).unwrap();
1449 4 :
1450 4 : let tenant_id = TenantId::generate();
1451 4 : let tenant_shard_id = TenantShardId::unsharded(tenant_id);
1452 4 : let timeline_id = TimelineId::generate();
1453 4 :
1454 4 : let mut layer_map = LayerMap::default();
1455 4 : let mut updates = layer_map.batch_update();
1456 6260 : for (layer_name, layer_metadata) in index.layer_metadata {
1457 6256 : let layer_desc = match layer_name {
1458 3208 : LayerName::Image(layer_name) => PersistentLayerDesc {
1459 3208 : key_range: layer_name.key_range.clone(),
1460 3208 : lsn_range: layer_name.lsn_as_range(),
1461 3208 : tenant_shard_id,
1462 3208 : timeline_id,
1463 3208 : is_delta: false,
1464 3208 : file_size: layer_metadata.file_size,
1465 3208 : },
1466 3048 : LayerName::Delta(layer_name) => PersistentLayerDesc {
1467 3048 : key_range: layer_name.key_range,
1468 3048 : lsn_range: layer_name.lsn_range,
1469 3048 : tenant_shard_id,
1470 3048 : timeline_id,
1471 3048 : is_delta: true,
1472 3048 : file_size: layer_metadata.file_size,
1473 3048 : },
1474 : };
1475 6256 : updates.insert_historic(layer_desc);
1476 : }
1477 4 : updates.flush();
1478 4 :
1479 4 : let read_points = vec![index.metadata.disk_consistent_lsn()];
1480 4 : let (layer_visibilities, shadow) = layer_map.get_visibility(read_points);
1481 6260 : for (layer_desc, visibility) in &layer_visibilities {
1482 6256 : tracing::info!("{layer_desc:?}: {visibility:?}");
1483 6256 : eprintln!("{layer_desc:?}: {visibility:?}");
1484 : }
1485 :
1486 : // The shadow should be non-empty, since there were some image layers
1487 4 : assert!(!shadow.ranges.is_empty());
1488 :
1489 : // At least some layers should be marked covered
1490 4 : assert!(
1491 4 : layer_visibilities
1492 4 : .iter()
1493 76 : .any(|i| matches!(i.1, LayerVisibilityHint::Covered))
1494 4 : );
1495 :
1496 4 : let layer_visibilities = layer_visibilities.into_iter().collect::<HashMap<_, _>>();
1497 :
1498 : // Brute force validation: a layer should be marked covered if and only if there are image layers above it in LSN order which cover it
1499 6260 : for (layer_desc, visible) in &layer_visibilities {
1500 6256 : let mut coverage = KeySpaceRandomAccum::new();
1501 6256 : let mut covered_by = Vec::new();
1502 :
1503 9784384 : for other_layer in layer_map.iter_historic_layers() {
1504 9784384 : if &other_layer == layer_desc {
1505 6256 : continue;
1506 9778128 : }
1507 9778128 : if !other_layer.is_delta()
1508 5014104 : && other_layer.image_layer_lsn() >= Lsn(layer_desc.get_lsn_range().end.0 - 1)
1509 2527024 : && other_layer.key_range.start <= layer_desc.key_range.end
1510 930608 : && layer_desc.key_range.start <= other_layer.key_range.end
1511 171292 : {
1512 171292 : coverage.add_range(other_layer.get_key_range());
1513 171292 : covered_by.push((*other_layer).clone());
1514 9606836 : }
1515 : }
1516 6256 : let coverage = coverage.to_keyspace();
1517 :
1518 6256 : let expect_visible = if coverage.ranges.len() == 1
1519 1512 : && coverage.contains(&layer_desc.key_range.start)
1520 68 : && coverage.contains(&Key::from_i128(layer_desc.key_range.end.to_i128() - 1))
1521 : {
1522 40 : LayerVisibilityHint::Covered
1523 : } else {
1524 6216 : LayerVisibilityHint::Visible
1525 : };
1526 :
1527 6256 : if expect_visible != *visible {
1528 0 : eprintln!(
1529 0 : "Layer {}..{} @ {}..{} (delta={}) is {visible:?}, should be {expect_visible:?}",
1530 0 : layer_desc.key_range.start,
1531 0 : layer_desc.key_range.end,
1532 0 : layer_desc.lsn_range.start,
1533 0 : layer_desc.lsn_range.end,
1534 0 : layer_desc.is_delta()
1535 0 : );
1536 0 : if expect_visible == LayerVisibilityHint::Covered {
1537 0 : eprintln!("Covered by:");
1538 0 : for other in covered_by {
1539 0 : eprintln!(
1540 0 : " {}..{} @ {}",
1541 0 : other.get_key_range().start,
1542 0 : other.get_key_range().end,
1543 0 : other.image_layer_lsn()
1544 0 : );
1545 0 : }
1546 0 : if let Some(range) = coverage.ranges.first() {
1547 0 : eprintln!(
1548 0 : "Total coverage from contributing layers: {}..{}",
1549 0 : range.start, range.end
1550 0 : );
1551 0 : } else {
1552 0 : eprintln!(
1553 0 : "Total coverage from contributing layers: {:?}",
1554 0 : coverage.ranges
1555 0 : );
1556 0 : }
1557 0 : }
1558 6256 : }
1559 6256 : assert_eq!(expect_visible, *visible);
1560 : }
1561 :
1562 : // Sanity: the layer that holds latest data for the DBDIR key should always be visible
1563 : // (just using this key as a key that will always exist for any layermap fixture)
1564 4 : let dbdir_layer = {
1565 4 : let readable_layer = layer_map
1566 4 : .search(DBDIR_KEY, index.metadata.disk_consistent_lsn())
1567 4 : .unwrap();
1568 4 :
1569 4 : match readable_layer.layer {
1570 4 : ReadableLayerWeak::PersistentLayer(desc) => desc,
1571 0 : ReadableLayerWeak::InMemoryLayer(_) => unreachable!(""),
1572 : }
1573 : };
1574 4 : assert!(matches!(
1575 4 : layer_visibilities.get(&dbdir_layer).unwrap(),
1576 : LayerVisibilityHint::Visible
1577 : ));
1578 4 : }
1579 : }
1580 :
1581 : #[cfg(test)]
1582 : mod select_layer_tests {
1583 : use super::*;
1584 :
1585 68 : fn create_persistent_layer(
1586 68 : start_lsn: u64,
1587 68 : end_lsn: u64,
1588 68 : is_delta: bool,
1589 68 : ) -> Arc<PersistentLayerDesc> {
1590 68 : if !is_delta {
1591 32 : assert_eq!(end_lsn, start_lsn + 1);
1592 36 : }
1593 :
1594 68 : Arc::new(PersistentLayerDesc::new_test(
1595 68 : Key::MIN..Key::MAX,
1596 68 : Lsn(start_lsn)..Lsn(end_lsn),
1597 68 : is_delta,
1598 68 : ))
1599 68 : }
1600 :
1601 24 : fn create_inmem_layer(start_lsn: u64, end_lsn: u64) -> InMemoryLayerDesc {
1602 24 : InMemoryLayerDesc {
1603 24 : handle: InMemoryLayerHandle::Open,
1604 24 : lsn_range: Lsn(start_lsn)..Lsn(end_lsn),
1605 24 : }
1606 24 : }
1607 :
1608 : #[test]
1609 4 : fn test_select_layer_empty() {
1610 4 : assert!(LayerMap::select_layer(None, None, None, Lsn(100)).is_none());
1611 4 : }
1612 :
1613 : #[test]
1614 4 : fn test_select_layer_only_delta() {
1615 4 : let delta = create_persistent_layer(10, 20, true);
1616 4 : let result = LayerMap::select_layer(Some(delta.clone()), None, None, Lsn(100)).unwrap();
1617 4 :
1618 4 : assert_eq!(result.lsn_floor, Lsn(10));
1619 4 : assert!(
1620 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1621 : );
1622 4 : }
1623 :
1624 : #[test]
1625 4 : fn test_select_layer_only_image() {
1626 4 : let image = create_persistent_layer(10, 11, false);
1627 4 : let result = LayerMap::select_layer(None, Some(image.clone()), None, Lsn(100)).unwrap();
1628 4 :
1629 4 : assert_eq!(result.lsn_floor, Lsn(10));
1630 4 : assert!(
1631 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1632 : );
1633 4 : }
1634 :
1635 : #[test]
1636 4 : fn test_select_layer_only_inmem() {
1637 4 : let inmem = create_inmem_layer(10, 20);
1638 4 : let result = LayerMap::select_layer(None, None, Some(inmem.clone()), Lsn(100)).unwrap();
1639 4 :
1640 4 : assert_eq!(result.lsn_floor, Lsn(10));
1641 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1642 4 : }
1643 :
1644 : #[test]
1645 4 : fn test_select_layer_image_inside_delta() {
1646 4 : let delta = create_persistent_layer(10, 20, true);
1647 4 : let image = create_persistent_layer(15, 16, false);
1648 4 :
1649 4 : let result =
1650 4 : LayerMap::select_layer(Some(delta.clone()), Some(image.clone()), None, Lsn(100))
1651 4 : .unwrap();
1652 4 :
1653 4 : assert_eq!(result.lsn_floor, Lsn(16));
1654 4 : assert!(
1655 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1656 : );
1657 :
1658 4 : let result = LayerMap::select_layer(
1659 4 : Some(delta.clone()),
1660 4 : Some(image.clone()),
1661 4 : None,
1662 4 : result.lsn_floor,
1663 4 : )
1664 4 : .unwrap();
1665 4 :
1666 4 : assert_eq!(result.lsn_floor, Lsn(15));
1667 4 : assert!(
1668 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1669 : );
1670 4 : }
1671 :
1672 : #[test]
1673 4 : fn test_select_layer_newer_image() {
1674 4 : let delta = create_persistent_layer(10, 20, true);
1675 4 : let image = create_persistent_layer(25, 26, false);
1676 4 :
1677 4 : let result =
1678 4 : LayerMap::select_layer(Some(delta.clone()), Some(image.clone()), None, Lsn(30))
1679 4 : .unwrap();
1680 4 :
1681 4 : assert_eq!(result.lsn_floor, Lsn(25));
1682 4 : assert!(
1683 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1684 : );
1685 :
1686 4 : let result =
1687 4 : LayerMap::select_layer(Some(delta.clone()), None, None, result.lsn_floor).unwrap();
1688 4 :
1689 4 : assert_eq!(result.lsn_floor, Lsn(10));
1690 4 : assert!(
1691 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1692 : );
1693 4 : }
1694 :
1695 : #[test]
1696 4 : fn test_select_layer_delta_with_older_image() {
1697 4 : let delta = create_persistent_layer(15, 25, true);
1698 4 : let image = create_persistent_layer(10, 11, false);
1699 4 :
1700 4 : let result =
1701 4 : LayerMap::select_layer(Some(delta.clone()), Some(image.clone()), None, Lsn(30))
1702 4 : .unwrap();
1703 4 :
1704 4 : assert_eq!(result.lsn_floor, Lsn(15));
1705 4 : assert!(
1706 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1707 : );
1708 :
1709 4 : let result =
1710 4 : LayerMap::select_layer(None, Some(image.clone()), None, result.lsn_floor).unwrap();
1711 4 :
1712 4 : assert_eq!(result.lsn_floor, Lsn(10));
1713 4 : assert!(
1714 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1715 : );
1716 4 : }
1717 :
1718 : #[test]
1719 4 : fn test_select_layer_image_inside_inmem() {
1720 4 : let image = create_persistent_layer(15, 16, false);
1721 4 : let inmem = create_inmem_layer(10, 25);
1722 4 :
1723 4 : let result =
1724 4 : LayerMap::select_layer(None, Some(image.clone()), Some(inmem.clone()), Lsn(30))
1725 4 : .unwrap();
1726 4 :
1727 4 : assert_eq!(result.lsn_floor, Lsn(16));
1728 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1729 :
1730 4 : let result = LayerMap::select_layer(
1731 4 : None,
1732 4 : Some(image.clone()),
1733 4 : Some(inmem.clone()),
1734 4 : result.lsn_floor,
1735 4 : )
1736 4 : .unwrap();
1737 4 :
1738 4 : assert_eq!(result.lsn_floor, Lsn(15));
1739 4 : assert!(
1740 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1741 : );
1742 :
1743 4 : let result =
1744 4 : LayerMap::select_layer(None, None, Some(inmem.clone()), result.lsn_floor).unwrap();
1745 4 : assert_eq!(result.lsn_floor, Lsn(10));
1746 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1747 4 : }
1748 :
1749 : #[test]
1750 4 : fn test_select_layer_delta_inside_inmem() {
1751 4 : let delta_top = create_persistent_layer(15, 20, true);
1752 4 : let delta_bottom = create_persistent_layer(10, 15, true);
1753 4 : let inmem = create_inmem_layer(15, 25);
1754 4 :
1755 4 : let result =
1756 4 : LayerMap::select_layer(Some(delta_top.clone()), None, Some(inmem.clone()), Lsn(30))
1757 4 : .unwrap();
1758 4 :
1759 4 : assert_eq!(result.lsn_floor, Lsn(20));
1760 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1761 :
1762 4 : let result = LayerMap::select_layer(
1763 4 : Some(delta_top.clone()),
1764 4 : None,
1765 4 : Some(inmem.clone()),
1766 4 : result.lsn_floor,
1767 4 : )
1768 4 : .unwrap();
1769 4 :
1770 4 : assert_eq!(result.lsn_floor, Lsn(15));
1771 4 : assert!(
1772 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta_top))
1773 : );
1774 :
1775 4 : let result = LayerMap::select_layer(
1776 4 : Some(delta_bottom.clone()),
1777 4 : None,
1778 4 : Some(inmem.clone()),
1779 4 : result.lsn_floor,
1780 4 : )
1781 4 : .unwrap();
1782 4 : assert_eq!(result.lsn_floor, Lsn(10));
1783 4 : assert!(
1784 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta_bottom))
1785 : );
1786 4 : }
1787 :
1788 : #[test]
1789 4 : fn test_select_layer_all_overlap_1() {
1790 4 : let inmem = create_inmem_layer(10, 30);
1791 4 : let delta = create_persistent_layer(15, 25, true);
1792 4 : let image = create_persistent_layer(20, 21, false);
1793 4 :
1794 4 : let result = LayerMap::select_layer(
1795 4 : Some(delta.clone()),
1796 4 : Some(image.clone()),
1797 4 : Some(inmem.clone()),
1798 4 : Lsn(50),
1799 4 : )
1800 4 : .unwrap();
1801 4 :
1802 4 : assert_eq!(result.lsn_floor, Lsn(25));
1803 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1804 :
1805 4 : let result = LayerMap::select_layer(
1806 4 : Some(delta.clone()),
1807 4 : Some(image.clone()),
1808 4 : Some(inmem.clone()),
1809 4 : result.lsn_floor,
1810 4 : )
1811 4 : .unwrap();
1812 4 :
1813 4 : assert_eq!(result.lsn_floor, Lsn(21));
1814 4 : assert!(
1815 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1816 : );
1817 :
1818 4 : let result = LayerMap::select_layer(
1819 4 : Some(delta.clone()),
1820 4 : Some(image.clone()),
1821 4 : Some(inmem.clone()),
1822 4 : result.lsn_floor,
1823 4 : )
1824 4 : .unwrap();
1825 4 :
1826 4 : assert_eq!(result.lsn_floor, Lsn(20));
1827 4 : assert!(
1828 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1829 : );
1830 4 : }
1831 :
1832 : #[test]
1833 4 : fn test_select_layer_all_overlap_2() {
1834 4 : let inmem = create_inmem_layer(20, 30);
1835 4 : let delta = create_persistent_layer(10, 40, true);
1836 4 : let image = create_persistent_layer(25, 26, false);
1837 4 :
1838 4 : let result = LayerMap::select_layer(
1839 4 : Some(delta.clone()),
1840 4 : Some(image.clone()),
1841 4 : Some(inmem.clone()),
1842 4 : Lsn(50),
1843 4 : )
1844 4 : .unwrap();
1845 4 :
1846 4 : assert_eq!(result.lsn_floor, Lsn(26));
1847 4 : assert!(
1848 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1849 : );
1850 :
1851 4 : let result = LayerMap::select_layer(
1852 4 : Some(delta.clone()),
1853 4 : Some(image.clone()),
1854 4 : Some(inmem.clone()),
1855 4 : result.lsn_floor,
1856 4 : )
1857 4 : .unwrap();
1858 4 :
1859 4 : assert_eq!(result.lsn_floor, Lsn(25));
1860 4 : assert!(
1861 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1862 : );
1863 4 : }
1864 :
1865 : #[test]
1866 4 : fn test_select_layer_all_overlap_3() {
1867 4 : let inmem = create_inmem_layer(30, 40);
1868 4 : let delta = create_persistent_layer(10, 30, true);
1869 4 : let image = create_persistent_layer(20, 21, false);
1870 4 :
1871 4 : let result = LayerMap::select_layer(
1872 4 : Some(delta.clone()),
1873 4 : Some(image.clone()),
1874 4 : Some(inmem.clone()),
1875 4 : Lsn(50),
1876 4 : )
1877 4 : .unwrap();
1878 4 :
1879 4 : assert_eq!(result.lsn_floor, Lsn(30));
1880 4 : assert!(matches!(result.layer, ReadableLayerWeak::InMemoryLayer(l) if l == inmem));
1881 :
1882 4 : let result = LayerMap::select_layer(
1883 4 : Some(delta.clone()),
1884 4 : Some(image.clone()),
1885 4 : None,
1886 4 : result.lsn_floor,
1887 4 : )
1888 4 : .unwrap();
1889 4 :
1890 4 : assert_eq!(result.lsn_floor, Lsn(21));
1891 4 : assert!(
1892 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &delta))
1893 : );
1894 :
1895 4 : let result = LayerMap::select_layer(
1896 4 : Some(delta.clone()),
1897 4 : Some(image.clone()),
1898 4 : None,
1899 4 : result.lsn_floor,
1900 4 : )
1901 4 : .unwrap();
1902 4 :
1903 4 : assert_eq!(result.lsn_floor, Lsn(20));
1904 4 : assert!(
1905 4 : matches!(result.layer, ReadableLayerWeak::PersistentLayer(l) if Arc::ptr_eq(&l, &image))
1906 : );
1907 4 : }
1908 : }
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