TLA Line data Source code
1 : //! A DeltaLayer represents a collection of WAL records or page images in a range of
2 : //! LSNs, and in a range of Keys. It is stored on a file on disk.
3 : //!
4 : //! Usually a delta layer only contains differences, in the form of WAL records
5 : //! against a base LSN. However, if a relation extended or a whole new relation
6 : //! is created, there would be no base for the new pages. The entries for them
7 : //! must be page images or WAL records with the 'will_init' flag set, so that
8 : //! they can be replayed without referring to an older page version.
9 : //!
10 : //! The delta files are stored in `timelines/<timeline_id>` directory. Currently,
11 : //! there are no subdirectories, and each delta file is named like this:
12 : //!
13 : //! ```text
14 : //! <key start>-<key end>__<start LSN>-<end LSN>
15 : //! ```
16 : //!
17 : //! For example:
18 : //!
19 : //! ```text
20 : //! 000000067F000032BE0000400000000020B6-000000067F000032BE0000400000000030B6__000000578C6B29-0000000057A50051
21 : //! ```
22 : //!
23 : //! Every delta file consists of three parts: "summary", "index", and
24 : //! "values". The summary is a fixed size header at the beginning of the file,
25 : //! and it contains basic information about the layer, and offsets to the other
26 : //! parts. The "index" is a B-tree, mapping from Key and LSN to an offset in the
27 : //! "values" part. The actual page images and WAL records are stored in the
28 : //! "values" part.
29 : //!
30 : use crate::config::PageServerConf;
31 : use crate::context::{PageContentKind, RequestContext, RequestContextBuilder};
32 : use crate::page_cache::PAGE_SZ;
33 : use crate::repository::{Key, Value, KEY_SIZE};
34 : use crate::tenant::blob_io::BlobWriter;
35 : use crate::tenant::block_io::{BlockBuf, BlockCursor, BlockLease, BlockReader, FileBlockReader};
36 : use crate::tenant::disk_btree::{DiskBtreeBuilder, DiskBtreeReader, VisitDirection};
37 : use crate::tenant::storage_layer::{Layer, ValueReconstructResult, ValueReconstructState};
38 : use crate::tenant::Timeline;
39 : use crate::virtual_file::VirtualFile;
40 : use crate::{walrecord, TEMP_FILE_SUFFIX};
41 : use crate::{DELTA_FILE_MAGIC, STORAGE_FORMAT_VERSION};
42 : use anyhow::{bail, ensure, Context, Result};
43 : use camino::{Utf8Path, Utf8PathBuf};
44 : use pageserver_api::models::LayerAccessKind;
45 : use pageserver_api::shard::TenantShardId;
46 : use rand::{distributions::Alphanumeric, Rng};
47 : use serde::{Deserialize, Serialize};
48 : use std::fs::File;
49 : use std::io::SeekFrom;
50 : use std::ops::Range;
51 : use std::os::unix::fs::FileExt;
52 : use std::sync::Arc;
53 : use tokio::sync::OnceCell;
54 : use tracing::*;
55 :
56 : use utils::{
57 : bin_ser::BeSer,
58 : id::{TenantId, TimelineId},
59 : lsn::Lsn,
60 : };
61 :
62 : use super::{AsLayerDesc, LayerAccessStats, PersistentLayerDesc, ResidentLayer};
63 :
64 : ///
65 : /// Header stored in the beginning of the file
66 : ///
67 : /// After this comes the 'values' part, starting on block 1. After that,
68 : /// the 'index' starts at the block indicated by 'index_start_blk'
69 : ///
70 CBC 14809 : #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
71 : pub struct Summary {
72 : /// Magic value to identify this as a neon delta file. Always DELTA_FILE_MAGIC.
73 : pub magic: u16,
74 : pub format_version: u16,
75 :
76 : pub tenant_id: TenantId,
77 : pub timeline_id: TimelineId,
78 : pub key_range: Range<Key>,
79 : pub lsn_range: Range<Lsn>,
80 :
81 : /// Block number where the 'index' part of the file begins.
82 : pub index_start_blk: u32,
83 : /// Block within the 'index', where the B-tree root page is stored
84 : pub index_root_blk: u32,
85 : }
86 :
87 : impl From<&DeltaLayer> for Summary {
88 UBC 0 : fn from(layer: &DeltaLayer) -> Self {
89 0 : Self::expected(
90 0 : layer.desc.tenant_shard_id.tenant_id,
91 0 : layer.desc.timeline_id,
92 0 : layer.desc.key_range.clone(),
93 0 : layer.desc.lsn_range.clone(),
94 0 : )
95 0 : }
96 : }
97 :
98 : impl Summary {
99 CBC 11055 : pub(super) fn expected(
100 11055 : tenant_id: TenantId,
101 11055 : timeline_id: TimelineId,
102 11055 : keys: Range<Key>,
103 11055 : lsns: Range<Lsn>,
104 11055 : ) -> Self {
105 11055 : Self {
106 11055 : magic: DELTA_FILE_MAGIC,
107 11055 : format_version: STORAGE_FORMAT_VERSION,
108 11055 :
109 11055 : tenant_id,
110 11055 : timeline_id,
111 11055 : key_range: keys,
112 11055 : lsn_range: lsns,
113 11055 :
114 11055 : index_start_blk: 0,
115 11055 : index_root_blk: 0,
116 11055 : }
117 11055 : }
118 : }
119 :
120 : // Flag indicating that this version initialize the page
121 : const WILL_INIT: u64 = 1;
122 :
123 : /// Struct representing reference to BLOB in layers. Reference contains BLOB
124 : /// offset, and for WAL records it also contains `will_init` flag. The flag
125 : /// helps to determine the range of records that needs to be applied, without
126 : /// reading/deserializing records themselves.
127 UBC 0 : #[derive(Debug, Serialize, Deserialize, Copy, Clone)]
128 : pub struct BlobRef(pub u64);
129 :
130 : impl BlobRef {
131 CBC 46208731 : pub fn will_init(&self) -> bool {
132 46208731 : (self.0 & WILL_INIT) != 0
133 46208731 : }
134 :
135 79394338 : pub fn pos(&self) -> u64 {
136 79394338 : self.0 >> 1
137 79394338 : }
138 :
139 46500457 : pub fn new(pos: u64, will_init: bool) -> BlobRef {
140 46500457 : let mut blob_ref = pos << 1;
141 46500457 : if will_init {
142 7470345 : blob_ref |= WILL_INIT;
143 39030112 : }
144 46500457 : BlobRef(blob_ref)
145 46500457 : }
146 : }
147 :
148 : pub const DELTA_KEY_SIZE: usize = KEY_SIZE + 8;
149 : struct DeltaKey([u8; DELTA_KEY_SIZE]);
150 :
151 : /// This is the key of the B-tree index stored in the delta layer. It consists
152 : /// of the serialized representation of a Key and LSN.
153 : impl DeltaKey {
154 16792834 : fn from_slice(buf: &[u8]) -> Self {
155 16792834 : let mut bytes: [u8; DELTA_KEY_SIZE] = [0u8; DELTA_KEY_SIZE];
156 16792834 : bytes.copy_from_slice(buf);
157 16792834 : DeltaKey(bytes)
158 16792834 : }
159 :
160 61503217 : fn from_key_lsn(key: &Key, lsn: Lsn) -> Self {
161 61503217 : let mut bytes: [u8; DELTA_KEY_SIZE] = [0u8; DELTA_KEY_SIZE];
162 61503217 : key.write_to_byte_slice(&mut bytes[0..KEY_SIZE]);
163 61503217 : bytes[KEY_SIZE..].copy_from_slice(&u64::to_be_bytes(lsn.0));
164 61503217 : DeltaKey(bytes)
165 61503217 : }
166 :
167 16792834 : fn key(&self) -> Key {
168 16792834 : Key::from_slice(&self.0)
169 16792834 : }
170 :
171 16792834 : fn lsn(&self) -> Lsn {
172 16792834 : Lsn(u64::from_be_bytes(self.0[KEY_SIZE..].try_into().unwrap()))
173 16792834 : }
174 :
175 46608683 : fn extract_lsn_from_buf(buf: &[u8]) -> Lsn {
176 46608683 : let mut lsn_buf = [0u8; 8];
177 46608683 : lsn_buf.copy_from_slice(&buf[KEY_SIZE..]);
178 46608683 : Lsn(u64::from_be_bytes(lsn_buf))
179 46608683 : }
180 : }
181 :
182 : /// This is used only from `pagectl`. Within pageserver, all layers are
183 : /// [`crate::tenant::storage_layer::Layer`], which can hold a [`DeltaLayerInner`].
184 : pub struct DeltaLayer {
185 : path: Utf8PathBuf,
186 : pub desc: PersistentLayerDesc,
187 : access_stats: LayerAccessStats,
188 : inner: OnceCell<Arc<DeltaLayerInner>>,
189 : }
190 :
191 : impl std::fmt::Debug for DeltaLayer {
192 UBC 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
193 0 : use super::RangeDisplayDebug;
194 0 :
195 0 : f.debug_struct("DeltaLayer")
196 0 : .field("key_range", &RangeDisplayDebug(&self.desc.key_range))
197 0 : .field("lsn_range", &self.desc.lsn_range)
198 0 : .field("file_size", &self.desc.file_size)
199 0 : .field("inner", &self.inner)
200 0 : .finish()
201 0 : }
202 : }
203 :
204 : /// `DeltaLayerInner` is the in-memory data structure associated with an on-disk delta
205 : /// file.
206 : pub struct DeltaLayerInner {
207 : // values copied from summary
208 : index_start_blk: u32,
209 : index_root_blk: u32,
210 :
211 : /// Reader object for reading blocks from the file.
212 : file: FileBlockReader,
213 : }
214 :
215 : impl std::fmt::Debug for DeltaLayerInner {
216 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
217 0 : f.debug_struct("DeltaLayerInner")
218 0 : .field("index_start_blk", &self.index_start_blk)
219 0 : .field("index_root_blk", &self.index_root_blk)
220 0 : .finish()
221 0 : }
222 : }
223 :
224 : /// Boilerplate to implement the Layer trait, always use layer_desc for persistent layers.
225 : impl std::fmt::Display for DeltaLayer {
226 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
227 0 : write!(f, "{}", self.layer_desc().short_id())
228 0 : }
229 : }
230 :
231 : impl AsLayerDesc for DeltaLayer {
232 0 : fn layer_desc(&self) -> &PersistentLayerDesc {
233 0 : &self.desc
234 0 : }
235 : }
236 :
237 : impl DeltaLayer {
238 0 : pub(crate) async fn dump(&self, verbose: bool, ctx: &RequestContext) -> Result<()> {
239 0 : self.desc.dump();
240 0 :
241 0 : if !verbose {
242 0 : return Ok(());
243 0 : }
244 :
245 0 : let inner = self.load(LayerAccessKind::Dump, ctx).await?;
246 :
247 0 : inner.dump(ctx).await
248 0 : }
249 :
250 CBC 14815 : fn temp_path_for(
251 14815 : conf: &PageServerConf,
252 14815 : tenant_shard_id: &TenantShardId,
253 14815 : timeline_id: &TimelineId,
254 14815 : key_start: Key,
255 14815 : lsn_range: &Range<Lsn>,
256 14815 : ) -> Utf8PathBuf {
257 14815 : let rand_string: String = rand::thread_rng()
258 14815 : .sample_iter(&Alphanumeric)
259 14815 : .take(8)
260 14815 : .map(char::from)
261 14815 : .collect();
262 14815 :
263 14815 : conf.timeline_path(tenant_shard_id, timeline_id)
264 14815 : .join(format!(
265 14815 : "{}-XXX__{:016X}-{:016X}.{}.{}",
266 14815 : key_start,
267 14815 : u64::from(lsn_range.start),
268 14815 : u64::from(lsn_range.end),
269 14815 : rand_string,
270 14815 : TEMP_FILE_SUFFIX,
271 14815 : ))
272 14815 : }
273 :
274 : ///
275 : /// Open the underlying file and read the metadata into memory, if it's
276 : /// not loaded already.
277 : ///
278 UBC 0 : async fn load(
279 0 : &self,
280 0 : access_kind: LayerAccessKind,
281 0 : ctx: &RequestContext,
282 0 : ) -> Result<&Arc<DeltaLayerInner>> {
283 0 : self.access_stats.record_access(access_kind, ctx);
284 0 : // Quick exit if already loaded
285 0 : self.inner
286 0 : .get_or_try_init(|| self.load_inner(ctx))
287 0 : .await
288 0 : .with_context(|| format!("Failed to load delta layer {}", self.path()))
289 0 : }
290 :
291 0 : async fn load_inner(&self, ctx: &RequestContext) -> Result<Arc<DeltaLayerInner>> {
292 0 : let path = self.path();
293 :
294 0 : let loaded = DeltaLayerInner::load(&path, None, ctx)
295 0 : .await
296 0 : .and_then(|res| res)?;
297 :
298 : // not production code
299 0 : let actual_filename = path.file_name().unwrap().to_owned();
300 0 : let expected_filename = self.layer_desc().filename().file_name();
301 0 :
302 0 : if actual_filename != expected_filename {
303 0 : println!("warning: filename does not match what is expected from in-file summary");
304 0 : println!("actual: {:?}", actual_filename);
305 0 : println!("expected: {:?}", expected_filename);
306 0 : }
307 :
308 0 : Ok(Arc::new(loaded))
309 0 : }
310 :
311 : /// Create a DeltaLayer struct representing an existing file on disk.
312 : ///
313 : /// This variant is only used for debugging purposes, by the 'pagectl' binary.
314 0 : pub fn new_for_path(path: &Utf8Path, file: File) -> Result<Self> {
315 0 : let mut summary_buf = vec![0; PAGE_SZ];
316 0 : file.read_exact_at(&mut summary_buf, 0)?;
317 0 : let summary = Summary::des_prefix(&summary_buf)?;
318 :
319 0 : let metadata = file
320 0 : .metadata()
321 0 : .context("get file metadata to determine size")?;
322 :
323 : // This function is never used for constructing layers in a running pageserver,
324 : // so it does not need an accurate TenantShardId.
325 0 : let tenant_shard_id = TenantShardId::unsharded(summary.tenant_id);
326 0 :
327 0 : Ok(DeltaLayer {
328 0 : path: path.to_path_buf(),
329 0 : desc: PersistentLayerDesc::new_delta(
330 0 : tenant_shard_id,
331 0 : summary.timeline_id,
332 0 : summary.key_range,
333 0 : summary.lsn_range,
334 0 : metadata.len(),
335 0 : ),
336 0 : access_stats: LayerAccessStats::empty_will_record_residence_event_later(),
337 0 : inner: OnceCell::new(),
338 0 : })
339 0 : }
340 :
341 : /// Path to the layer file in pageserver workdir.
342 0 : fn path(&self) -> Utf8PathBuf {
343 0 : self.path.clone()
344 0 : }
345 : }
346 :
347 : /// A builder object for constructing a new delta layer.
348 : ///
349 : /// Usage:
350 : ///
351 : /// 1. Create the DeltaLayerWriter by calling DeltaLayerWriter::new(...)
352 : ///
353 : /// 2. Write the contents by calling `put_value` for every page
354 : /// version to store in the layer.
355 : ///
356 : /// 3. Call `finish`.
357 : ///
358 : struct DeltaLayerWriterInner {
359 : conf: &'static PageServerConf,
360 : pub path: Utf8PathBuf,
361 : timeline_id: TimelineId,
362 : tenant_shard_id: TenantShardId,
363 :
364 : key_start: Key,
365 : lsn_range: Range<Lsn>,
366 :
367 : tree: DiskBtreeBuilder<BlockBuf, DELTA_KEY_SIZE>,
368 :
369 : blob_writer: BlobWriter<true>,
370 : }
371 :
372 : impl DeltaLayerWriterInner {
373 : ///
374 : /// Start building a new delta layer.
375 : ///
376 CBC 14815 : async fn new(
377 14815 : conf: &'static PageServerConf,
378 14815 : timeline_id: TimelineId,
379 14815 : tenant_shard_id: TenantShardId,
380 14815 : key_start: Key,
381 14815 : lsn_range: Range<Lsn>,
382 14815 : ) -> anyhow::Result<Self> {
383 14815 : // Create the file initially with a temporary filename. We don't know
384 14815 : // the end key yet, so we cannot form the final filename yet. We will
385 14815 : // rename it when we're done.
386 14815 : //
387 14815 : // Note: This overwrites any existing file. There shouldn't be any.
388 14815 : // FIXME: throw an error instead?
389 14815 : let path =
390 14815 : DeltaLayer::temp_path_for(conf, &tenant_shard_id, &timeline_id, key_start, &lsn_range);
391 :
392 14815 : let mut file = VirtualFile::create(&path).await?;
393 : // make room for the header block
394 14815 : file.seek(SeekFrom::Start(PAGE_SZ as u64)).await?;
395 14815 : let blob_writer = BlobWriter::new(file, PAGE_SZ as u64);
396 14815 :
397 14815 : // Initialize the b-tree index builder
398 14815 : let block_buf = BlockBuf::new();
399 14815 : let tree_builder = DiskBtreeBuilder::new(block_buf);
400 14815 :
401 14815 : Ok(Self {
402 14815 : conf,
403 14815 : path,
404 14815 : timeline_id,
405 14815 : tenant_shard_id,
406 14815 : key_start,
407 14815 : lsn_range,
408 14815 : tree: tree_builder,
409 14815 : blob_writer,
410 14815 : })
411 14815 : }
412 :
413 : ///
414 : /// Append a key-value pair to the file.
415 : ///
416 : /// The values must be appended in key, lsn order.
417 : ///
418 16392780 : async fn put_value(&mut self, key: Key, lsn: Lsn, val: Value) -> anyhow::Result<()> {
419 16392780 : self.put_value_bytes(key, lsn, &Value::ser(&val)?, val.will_init())
420 UBC 0 : .await
421 CBC 16392780 : }
422 :
423 46500457 : async fn put_value_bytes(
424 46500457 : &mut self,
425 46500457 : key: Key,
426 46500457 : lsn: Lsn,
427 46500457 : val: &[u8],
428 46500457 : will_init: bool,
429 46500485 : ) -> anyhow::Result<()> {
430 46500485 : assert!(self.lsn_range.start <= lsn);
431 :
432 46500485 : let off = self.blob_writer.write_blob(val).await?;
433 :
434 46500485 : let blob_ref = BlobRef::new(off, will_init);
435 46500485 :
436 46500485 : let delta_key = DeltaKey::from_key_lsn(&key, lsn);
437 46500485 : self.tree.append(&delta_key.0, blob_ref.0)?;
438 :
439 46500485 : Ok(())
440 46500485 : }
441 :
442 1757221 : fn size(&self) -> u64 {
443 1757221 : self.blob_writer.size() + self.tree.borrow_writer().size()
444 1757221 : }
445 :
446 : ///
447 : /// Finish writing the delta layer.
448 : ///
449 14809 : async fn finish(self, key_end: Key, timeline: &Arc<Timeline>) -> anyhow::Result<ResidentLayer> {
450 14809 : let index_start_blk =
451 14809 : ((self.blob_writer.size() + PAGE_SZ as u64 - 1) / PAGE_SZ as u64) as u32;
452 :
453 14809 : let mut file = self.blob_writer.into_inner().await?;
454 :
455 : // Write out the index
456 14809 : let (index_root_blk, block_buf) = self.tree.finish()?;
457 14809 : file.seek(SeekFrom::Start(index_start_blk as u64 * PAGE_SZ as u64))
458 UBC 0 : .await?;
459 CBC 113612 : for buf in block_buf.blocks {
460 98803 : file.write_all(buf.as_ref()).await?;
461 : }
462 14809 : assert!(self.lsn_range.start < self.lsn_range.end);
463 : // Fill in the summary on blk 0
464 14809 : let summary = Summary {
465 14809 : magic: DELTA_FILE_MAGIC,
466 14809 : format_version: STORAGE_FORMAT_VERSION,
467 14809 : tenant_id: self.tenant_shard_id.tenant_id,
468 14809 : timeline_id: self.timeline_id,
469 14809 : key_range: self.key_start..key_end,
470 14809 : lsn_range: self.lsn_range.clone(),
471 14809 : index_start_blk,
472 14809 : index_root_blk,
473 14809 : };
474 14809 :
475 14809 : let mut buf = smallvec::SmallVec::<[u8; PAGE_SZ]>::new();
476 14809 : Summary::ser_into(&summary, &mut buf)?;
477 14809 : if buf.spilled() {
478 : // This is bad as we only have one free block for the summary
479 UBC 0 : warn!(
480 0 : "Used more than one page size for summary buffer: {}",
481 0 : buf.len()
482 0 : );
483 CBC 14809 : }
484 14809 : file.seek(SeekFrom::Start(0)).await?;
485 14809 : file.write_all(&buf).await?;
486 :
487 14809 : let metadata = file
488 14809 : .metadata()
489 UBC 0 : .await
490 CBC 14809 : .context("get file metadata to determine size")?;
491 :
492 : // 5GB limit for objects without multipart upload (which we don't want to use)
493 : // Make it a little bit below to account for differing GB units
494 : // https://docs.aws.amazon.com/AmazonS3/latest/userguide/upload-objects.html
495 : const S3_UPLOAD_LIMIT: u64 = 4_500_000_000;
496 : ensure!(
497 14809 : metadata.len() <= S3_UPLOAD_LIMIT,
498 UBC 0 : "Created delta layer file at {} of size {} above limit {S3_UPLOAD_LIMIT}!",
499 0 : file.path,
500 0 : metadata.len()
501 : );
502 :
503 : // Note: Because we opened the file in write-only mode, we cannot
504 : // reuse the same VirtualFile for reading later. That's why we don't
505 : // set inner.file here. The first read will have to re-open it.
506 :
507 CBC 14809 : let desc = PersistentLayerDesc::new_delta(
508 14809 : self.tenant_shard_id,
509 14809 : self.timeline_id,
510 14809 : self.key_start..key_end,
511 14809 : self.lsn_range.clone(),
512 14809 : metadata.len(),
513 14809 : );
514 14809 :
515 14809 : // fsync the file
516 14809 : file.sync_all().await?;
517 :
518 14809 : let layer = Layer::finish_creating(self.conf, timeline, desc, &self.path)?;
519 :
520 UBC 0 : trace!("created delta layer {}", layer.local_path());
521 :
522 CBC 14809 : Ok(layer)
523 14809 : }
524 : }
525 :
526 : /// A builder object for constructing a new delta layer.
527 : ///
528 : /// Usage:
529 : ///
530 : /// 1. Create the DeltaLayerWriter by calling DeltaLayerWriter::new(...)
531 : ///
532 : /// 2. Write the contents by calling `put_value` for every page
533 : /// version to store in the layer.
534 : ///
535 : /// 3. Call `finish`.
536 : ///
537 : /// # Note
538 : ///
539 : /// As described in <https://github.com/neondatabase/neon/issues/2650>, it's
540 : /// possible for the writer to drop before `finish` is actually called. So this
541 : /// could lead to odd temporary files in the directory, exhausting file system.
542 : /// This structure wraps `DeltaLayerWriterInner` and also contains `Drop`
543 : /// implementation that cleans up the temporary file in failure. It's not
544 : /// possible to do this directly in `DeltaLayerWriterInner` since `finish` moves
545 : /// out some fields, making it impossible to implement `Drop`.
546 : ///
547 : #[must_use]
548 : pub struct DeltaLayerWriter {
549 : inner: Option<DeltaLayerWriterInner>,
550 : }
551 :
552 : impl DeltaLayerWriter {
553 : ///
554 : /// Start building a new delta layer.
555 : ///
556 14815 : pub async fn new(
557 14815 : conf: &'static PageServerConf,
558 14815 : timeline_id: TimelineId,
559 14815 : tenant_shard_id: TenantShardId,
560 14815 : key_start: Key,
561 14815 : lsn_range: Range<Lsn>,
562 14815 : ) -> anyhow::Result<Self> {
563 14815 : Ok(Self {
564 14815 : inner: Some(
565 14815 : DeltaLayerWriterInner::new(
566 14815 : conf,
567 14815 : timeline_id,
568 14815 : tenant_shard_id,
569 14815 : key_start,
570 14815 : lsn_range,
571 14815 : )
572 UBC 0 : .await?,
573 : ),
574 : })
575 CBC 14815 : }
576 :
577 : ///
578 : /// Append a key-value pair to the file.
579 : ///
580 : /// The values must be appended in key, lsn order.
581 : ///
582 16392780 : pub async fn put_value(&mut self, key: Key, lsn: Lsn, val: Value) -> anyhow::Result<()> {
583 16392780 : self.inner.as_mut().unwrap().put_value(key, lsn, val).await
584 16392780 : }
585 :
586 30107691 : pub async fn put_value_bytes(
587 30107691 : &mut self,
588 30107691 : key: Key,
589 30107691 : lsn: Lsn,
590 30107691 : val: &[u8],
591 30107691 : will_init: bool,
592 30107705 : ) -> anyhow::Result<()> {
593 30107705 : self.inner
594 30107705 : .as_mut()
595 30107705 : .unwrap()
596 30107705 : .put_value_bytes(key, lsn, val, will_init)
597 UBC 0 : .await
598 CBC 30107705 : }
599 :
600 1757221 : pub fn size(&self) -> u64 {
601 1757221 : self.inner.as_ref().unwrap().size()
602 1757221 : }
603 :
604 : ///
605 : /// Finish writing the delta layer.
606 : ///
607 14809 : pub(crate) async fn finish(
608 14809 : mut self,
609 14809 : key_end: Key,
610 14809 : timeline: &Arc<Timeline>,
611 14809 : ) -> anyhow::Result<ResidentLayer> {
612 14809 : self.inner.take().unwrap().finish(key_end, timeline).await
613 14809 : }
614 : }
615 :
616 : impl Drop for DeltaLayerWriter {
617 14809 : fn drop(&mut self) {
618 14809 : if let Some(inner) = self.inner.take() {
619 UBC 0 : // We want to remove the virtual file here, so it's fine to not
620 0 : // having completely flushed unwritten data.
621 0 : let vfile = inner.blob_writer.into_inner_no_flush();
622 0 : vfile.remove();
623 CBC 14809 : }
624 14809 : }
625 : }
626 :
627 UBC 0 : #[derive(thiserror::Error, Debug)]
628 : pub enum RewriteSummaryError {
629 : #[error("magic mismatch")]
630 : MagicMismatch,
631 : #[error(transparent)]
632 : Other(#[from] anyhow::Error),
633 : }
634 :
635 : impl From<std::io::Error> for RewriteSummaryError {
636 0 : fn from(e: std::io::Error) -> Self {
637 0 : Self::Other(anyhow::anyhow!(e))
638 0 : }
639 : }
640 :
641 : impl DeltaLayer {
642 0 : pub async fn rewrite_summary<F>(
643 0 : path: &Utf8Path,
644 0 : rewrite: F,
645 0 : ctx: &RequestContext,
646 0 : ) -> Result<(), RewriteSummaryError>
647 0 : where
648 0 : F: Fn(Summary) -> Summary,
649 0 : {
650 0 : let file = VirtualFile::open_with_options(
651 0 : path,
652 0 : &*std::fs::OpenOptions::new().read(true).write(true),
653 0 : )
654 0 : .await
655 0 : .with_context(|| format!("Failed to open file '{}'", path))?;
656 0 : let file = FileBlockReader::new(file);
657 0 : let summary_blk = file.read_blk(0, ctx).await?;
658 0 : let actual_summary = Summary::des_prefix(summary_blk.as_ref()).context("deserialize")?;
659 0 : let mut file = file.file;
660 0 : if actual_summary.magic != DELTA_FILE_MAGIC {
661 0 : return Err(RewriteSummaryError::MagicMismatch);
662 0 : }
663 0 :
664 0 : let new_summary = rewrite(actual_summary);
665 0 :
666 0 : let mut buf = smallvec::SmallVec::<[u8; PAGE_SZ]>::new();
667 0 : Summary::ser_into(&new_summary, &mut buf).context("serialize")?;
668 0 : if buf.spilled() {
669 : // The code in DeltaLayerWriterInner just warn!()s for this.
670 : // It should probably error out as well.
671 0 : return Err(RewriteSummaryError::Other(anyhow::anyhow!(
672 0 : "Used more than one page size for summary buffer: {}",
673 0 : buf.len()
674 0 : )));
675 0 : }
676 0 : file.seek(SeekFrom::Start(0)).await?;
677 0 : file.write_all(&buf).await?;
678 0 : Ok(())
679 0 : }
680 : }
681 :
682 : impl DeltaLayerInner {
683 : /// Returns nested result following Result<Result<_, OpErr>, Critical>:
684 : /// - inner has the success or transient failure
685 : /// - outer has the permanent failure
686 CBC 11055 : pub(super) async fn load(
687 11055 : path: &Utf8Path,
688 11055 : summary: Option<Summary>,
689 11055 : ctx: &RequestContext,
690 11055 : ) -> Result<Result<Self, anyhow::Error>, anyhow::Error> {
691 11055 : let file = match VirtualFile::open(path).await {
692 11055 : Ok(file) => file,
693 UBC 0 : Err(e) => return Ok(Err(anyhow::Error::new(e).context("open layer file"))),
694 : };
695 CBC 11055 : let file = FileBlockReader::new(file);
696 :
697 11055 : let summary_blk = match file.read_blk(0, ctx).await {
698 11055 : Ok(blk) => blk,
699 UBC 0 : Err(e) => return Ok(Err(anyhow::Error::new(e).context("read first block"))),
700 : };
701 :
702 : // TODO: this should be an assertion instead; see ImageLayerInner::load
703 CBC 11055 : let actual_summary =
704 11055 : Summary::des_prefix(summary_blk.as_ref()).context("deserialize first block")?;
705 :
706 11055 : if let Some(mut expected_summary) = summary {
707 : // production code path
708 11055 : expected_summary.index_start_blk = actual_summary.index_start_blk;
709 11055 : expected_summary.index_root_blk = actual_summary.index_root_blk;
710 11055 : if actual_summary != expected_summary {
711 1 : bail!(
712 1 : "in-file summary does not match expected summary. actual = {:?} expected = {:?}",
713 1 : actual_summary,
714 1 : expected_summary
715 1 : );
716 11054 : }
717 UBC 0 : }
718 :
719 CBC 11054 : Ok(Ok(DeltaLayerInner {
720 11054 : file,
721 11054 : index_start_blk: actual_summary.index_start_blk,
722 11054 : index_root_blk: actual_summary.index_root_blk,
723 11054 : }))
724 11055 : }
725 :
726 15002760 : pub(super) async fn get_value_reconstruct_data(
727 15002760 : &self,
728 15002760 : key: Key,
729 15002760 : lsn_range: Range<Lsn>,
730 15002760 : reconstruct_state: &mut ValueReconstructState,
731 15002760 : ctx: &RequestContext,
732 15002767 : ) -> anyhow::Result<ValueReconstructResult> {
733 15002767 : let mut need_image = true;
734 15002767 : // Scan the page versions backwards, starting from `lsn`.
735 15002767 : let file = &self.file;
736 15002767 : let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
737 15002767 : self.index_start_blk,
738 15002767 : self.index_root_blk,
739 15002767 : file,
740 15002767 : );
741 15002767 : let search_key = DeltaKey::from_key_lsn(&key, Lsn(lsn_range.end.0 - 1));
742 15002767 :
743 15002767 : let mut offsets: Vec<(Lsn, u64)> = Vec::new();
744 15002767 :
745 15002767 : tree_reader
746 15002767 : .visit(
747 15002767 : &search_key.0,
748 15002767 : VisitDirection::Backwards,
749 49738948 : |key, value| {
750 49738948 : let blob_ref = BlobRef(value);
751 49738948 : if key[..KEY_SIZE] != search_key.0[..KEY_SIZE] {
752 3130263 : return false;
753 46608685 : }
754 46608685 : let entry_lsn = DeltaKey::extract_lsn_from_buf(key);
755 46608685 : if entry_lsn < lsn_range.start {
756 399952 : return false;
757 46208733 : }
758 46208733 : offsets.push((entry_lsn, blob_ref.pos()));
759 46208733 :
760 46208733 : !blob_ref.will_init()
761 49738948 : },
762 15002767 : &RequestContextBuilder::extend(ctx)
763 15002767 : .page_content_kind(PageContentKind::DeltaLayerBtreeNode)
764 15002767 : .build(),
765 15002767 : )
766 183313 : .await?;
767 :
768 15002764 : let ctx = &RequestContextBuilder::extend(ctx)
769 15002764 : .page_content_kind(PageContentKind::DeltaLayerValue)
770 15002764 : .build();
771 15002764 :
772 15002764 : // Ok, 'offsets' now contains the offsets of all the entries we need to read
773 15002764 : let cursor = file.block_cursor();
774 15002764 : let mut buf = Vec::new();
775 58518894 : for (entry_lsn, pos) in offsets {
776 46207958 : cursor
777 46207958 : .read_blob_into_buf(pos, &mut buf, ctx)
778 667285 : .await
779 46207957 : .with_context(|| {
780 UBC 0 : format!("Failed to read blob from virtual file {}", file.file.path)
781 CBC 46207957 : })?;
782 46207957 : let val = Value::des(&buf).with_context(|| {
783 UBC 0 : format!(
784 0 : "Failed to deserialize file blob from virtual file {}",
785 0 : file.file.path
786 0 : )
787 CBC 46207957 : })?;
788 46207957 : match val {
789 1493998 : Value::Image(img) => {
790 1493998 : reconstruct_state.img = Some((entry_lsn, img));
791 1493998 : need_image = false;
792 1493998 : break;
793 : }
794 44713959 : Value::WalRecord(rec) => {
795 44713959 : let will_init = rec.will_init();
796 44713959 : reconstruct_state.records.push((entry_lsn, rec));
797 44713959 : if will_init {
798 : // This WAL record initializes the page, so no need to go further back
799 1197829 : need_image = false;
800 1197829 : break;
801 43516130 : }
802 : }
803 : }
804 : }
805 :
806 : // If an older page image is needed to reconstruct the page, let the
807 : // caller know.
808 15002763 : if need_image {
809 12310936 : Ok(ValueReconstructResult::Continue)
810 : } else {
811 2691827 : Ok(ValueReconstructResult::Complete)
812 : }
813 15002763 : }
814 :
815 3672 : pub(super) async fn load_keys<'a>(
816 3672 : &'a self,
817 3672 : ctx: &RequestContext,
818 3672 : ) -> Result<Vec<DeltaEntry<'a>>> {
819 3672 : let file = &self.file;
820 3672 :
821 3672 : let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
822 3672 : self.index_start_blk,
823 3672 : self.index_root_blk,
824 3672 : file,
825 3672 : );
826 3672 :
827 3672 : let mut all_keys: Vec<DeltaEntry<'_>> = Vec::new();
828 3672 :
829 3672 : tree_reader
830 3672 : .visit(
831 3672 : &[0u8; DELTA_KEY_SIZE],
832 3672 : VisitDirection::Forwards,
833 16792834 : |key, value| {
834 16792834 : let delta_key = DeltaKey::from_slice(key);
835 16792834 : let val_ref = ValueRef {
836 16792834 : blob_ref: BlobRef(value),
837 16792834 : reader: BlockCursor::new(crate::tenant::block_io::BlockReaderRef::Adapter(
838 16792834 : Adapter(self),
839 16792834 : )),
840 16792834 : };
841 16792834 : let pos = BlobRef(value).pos();
842 16792834 : if let Some(last) = all_keys.last_mut() {
843 16789162 : // subtract offset of the current and last entries to get the size
844 16789162 : // of the value associated with this (key, lsn) tuple
845 16789162 : let first_pos = last.size;
846 16789162 : last.size = pos - first_pos;
847 16789162 : }
848 16792834 : let entry = DeltaEntry {
849 16792834 : key: delta_key.key(),
850 16792834 : lsn: delta_key.lsn(),
851 16792834 : size: pos,
852 16792834 : val: val_ref,
853 16792834 : };
854 16792834 : all_keys.push(entry);
855 16792834 : true
856 16792834 : },
857 3672 : &RequestContextBuilder::extend(ctx)
858 3672 : .page_content_kind(PageContentKind::DeltaLayerBtreeNode)
859 3672 : .build(),
860 3672 : )
861 1000 : .await?;
862 3672 : if let Some(last) = all_keys.last_mut() {
863 3672 : // Last key occupies all space till end of value storage,
864 3672 : // which corresponds to beginning of the index
865 3672 : last.size = self.index_start_blk as u64 * PAGE_SZ as u64 - last.size;
866 3672 : }
867 3672 : Ok(all_keys)
868 3672 : }
869 :
870 2 : pub(super) async fn dump(&self, ctx: &RequestContext) -> anyhow::Result<()> {
871 2 : println!(
872 2 : "index_start_blk: {}, root {}",
873 2 : self.index_start_blk, self.index_root_blk
874 2 : );
875 2 :
876 2 : let file = &self.file;
877 2 : let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
878 2 : self.index_start_blk,
879 2 : self.index_root_blk,
880 2 : file,
881 2 : );
882 2 :
883 2 : tree_reader.dump().await?;
884 :
885 2 : let keys = self.load_keys(ctx).await?;
886 :
887 4 : async fn dump_blob(val: ValueRef<'_>, ctx: &RequestContext) -> anyhow::Result<String> {
888 4 : let buf = val.reader.read_blob(val.blob_ref.pos(), ctx).await?;
889 4 : let val = Value::des(&buf)?;
890 4 : let desc = match val {
891 4 : Value::Image(img) => {
892 4 : format!(" img {} bytes", img.len())
893 : }
894 UBC 0 : Value::WalRecord(rec) => {
895 0 : let wal_desc = walrecord::describe_wal_record(&rec)?;
896 0 : format!(
897 0 : " rec {} bytes will_init: {} {}",
898 0 : buf.len(),
899 0 : rec.will_init(),
900 0 : wal_desc
901 0 : )
902 : }
903 : };
904 CBC 4 : Ok(desc)
905 4 : }
906 :
907 6 : for entry in keys {
908 4 : let DeltaEntry { key, lsn, val, .. } = entry;
909 4 : let desc = match dump_blob(val, ctx).await {
910 4 : Ok(desc) => desc,
911 UBC 0 : Err(err) => {
912 0 : format!("ERROR: {err}")
913 : }
914 : };
915 CBC 4 : println!(" key {key} at {lsn}: {desc}");
916 : }
917 :
918 2 : Ok(())
919 2 : }
920 : }
921 :
922 : /// A set of data associated with a delta layer key and its value
923 : pub struct DeltaEntry<'a> {
924 : pub key: Key,
925 : pub lsn: Lsn,
926 : /// Size of the stored value
927 : pub size: u64,
928 : /// Reference to the on-disk value
929 : pub val: ValueRef<'a>,
930 : }
931 :
932 : /// Reference to an on-disk value
933 : pub struct ValueRef<'a> {
934 : blob_ref: BlobRef,
935 : reader: BlockCursor<'a>,
936 : }
937 :
938 : impl<'a> ValueRef<'a> {
939 : /// Loads the value from disk
940 16392783 : pub async fn load(&self, ctx: &RequestContext) -> Result<Value> {
941 : // theoretically we *could* record an access time for each, but it does not really matter
942 16392783 : let buf = self.reader.read_blob(self.blob_ref.pos(), ctx).await?;
943 16392780 : let val = Value::des(&buf)?;
944 16392780 : Ok(val)
945 16392780 : }
946 : }
947 :
948 : pub(crate) struct Adapter<T>(T);
949 :
950 : impl<T: AsRef<DeltaLayerInner>> Adapter<T> {
951 17643804 : pub(crate) async fn read_blk(
952 17643804 : &self,
953 17643804 : blknum: u32,
954 17643804 : ctx: &RequestContext,
955 17643804 : ) -> Result<BlockLease, std::io::Error> {
956 17643804 : self.0.as_ref().file.read_blk(blknum, ctx).await
957 17643802 : }
958 : }
959 :
960 : impl AsRef<DeltaLayerInner> for DeltaLayerInner {
961 17643788 : fn as_ref(&self) -> &DeltaLayerInner {
962 17643788 : self
963 17643788 : }
964 : }
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