Line data Source code
1 : //! An in-memory layer stores recently received key-value pairs.
2 : //!
3 : //! The "in-memory" part of the name is a bit misleading: the actual page versions are
4 : //! held in an ephemeral file, not in memory. The metadata for each page version, i.e.
5 : //! its position in the file, is kept in memory, though.
6 : //!
7 : use crate::assert_u64_eq_usize::{u64_to_usize, U64IsUsize, UsizeIsU64};
8 : use crate::config::PageServerConf;
9 : use crate::context::{PageContentKind, RequestContext, RequestContextBuilder};
10 : use crate::tenant::ephemeral_file::EphemeralFile;
11 : use crate::tenant::storage_layer::{OnDiskValue, OnDiskValueIo};
12 : use crate::tenant::timeline::GetVectoredError;
13 : use crate::virtual_file::owned_buffers_io::io_buf_ext::IoBufExt;
14 : use crate::{l0_flush, page_cache};
15 : use anyhow::Result;
16 : use camino::Utf8PathBuf;
17 : use pageserver_api::key::CompactKey;
18 : use pageserver_api::key::Key;
19 : use pageserver_api::keyspace::KeySpace;
20 : use pageserver_api::models::InMemoryLayerInfo;
21 : use pageserver_api::shard::TenantShardId;
22 : use std::collections::{BTreeMap, HashMap};
23 : use std::sync::{Arc, OnceLock};
24 : use std::time::Instant;
25 : use tracing::*;
26 : use utils::{id::TimelineId, lsn::Lsn, vec_map::VecMap};
27 : use wal_decoder::serialized_batch::{SerializedValueBatch, SerializedValueMeta, ValueMeta};
28 : // avoid binding to Write (conflicts with std::io::Write)
29 : // while being able to use std::fmt::Write's methods
30 : use crate::metrics::TIMELINE_EPHEMERAL_BYTES;
31 : use std::cmp::Ordering;
32 : use std::fmt::Write;
33 : use std::ops::Range;
34 : use std::sync::atomic::Ordering as AtomicOrdering;
35 : use std::sync::atomic::{AtomicU64, AtomicUsize};
36 : use tokio::sync::RwLock;
37 :
38 : use super::{DeltaLayerWriter, PersistentLayerDesc, ValuesReconstructState};
39 :
40 : pub(crate) mod vectored_dio_read;
41 :
42 : #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
43 : pub(crate) struct InMemoryLayerFileId(page_cache::FileId);
44 :
45 : pub struct InMemoryLayer {
46 : conf: &'static PageServerConf,
47 : tenant_shard_id: TenantShardId,
48 : timeline_id: TimelineId,
49 : file_id: InMemoryLayerFileId,
50 :
51 : /// This layer contains all the changes from 'start_lsn'. The
52 : /// start is inclusive.
53 : start_lsn: Lsn,
54 :
55 : /// Frozen layers have an exclusive end LSN.
56 : /// Writes are only allowed when this is `None`.
57 : pub(crate) end_lsn: OnceLock<Lsn>,
58 :
59 : /// Used for traversal path. Cached representation of the in-memory layer after frozen.
60 : frozen_local_path_str: OnceLock<Arc<str>>,
61 :
62 : opened_at: Instant,
63 :
64 : /// The above fields never change, except for `end_lsn`, which is only set once.
65 : /// All other changing parts are in `inner`, and protected by a mutex.
66 : inner: RwLock<InMemoryLayerInner>,
67 :
68 : estimated_in_mem_size: AtomicU64,
69 : }
70 :
71 : impl std::fmt::Debug for InMemoryLayer {
72 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
73 0 : f.debug_struct("InMemoryLayer")
74 0 : .field("start_lsn", &self.start_lsn)
75 0 : .field("end_lsn", &self.end_lsn)
76 0 : .field("inner", &self.inner)
77 0 : .finish()
78 0 : }
79 : }
80 :
81 : pub struct InMemoryLayerInner {
82 : /// All versions of all pages in the layer are kept here. Indexed
83 : /// by block number and LSN. The [`IndexEntry`] is an offset into the
84 : /// ephemeral file where the page version is stored.
85 : index: BTreeMap<CompactKey, VecMap<Lsn, IndexEntry>>,
86 :
87 : /// The values are stored in a serialized format in this file.
88 : /// Each serialized Value is preceded by a 'u32' length field.
89 : /// PerSeg::page_versions map stores offsets into this file.
90 : file: EphemeralFile,
91 :
92 : resource_units: GlobalResourceUnits,
93 : }
94 :
95 : /// Support the same max blob length as blob_io, because ultimately
96 : /// all the InMemoryLayer contents end up being written into a delta layer,
97 : /// using the [`crate::tenant::blob_io`].
98 : const MAX_SUPPORTED_BLOB_LEN: usize = crate::tenant::blob_io::MAX_SUPPORTED_BLOB_LEN;
99 : const MAX_SUPPORTED_BLOB_LEN_BITS: usize = {
100 : let trailing_ones = MAX_SUPPORTED_BLOB_LEN.trailing_ones() as usize;
101 : let leading_zeroes = MAX_SUPPORTED_BLOB_LEN.leading_zeros() as usize;
102 : assert!(trailing_ones + leading_zeroes == std::mem::size_of::<usize>() * 8);
103 : trailing_ones
104 : };
105 :
106 : /// See [`InMemoryLayerInner::index`].
107 : ///
108 : /// For memory efficiency, the data is packed into a u64.
109 : ///
110 : /// Layout:
111 : /// - 1 bit: `will_init`
112 : /// - [`MAX_SUPPORTED_BLOB_LEN_BITS`][]: `len`
113 : /// - [`MAX_SUPPORTED_POS_BITS`](IndexEntry::MAX_SUPPORTED_POS_BITS): `pos`
114 : #[derive(Debug, Clone, Copy, PartialEq, Eq)]
115 : pub struct IndexEntry(u64);
116 :
117 : impl IndexEntry {
118 : /// See [`Self::MAX_SUPPORTED_POS`].
119 : const MAX_SUPPORTED_POS_BITS: usize = {
120 : let remainder = 64 - 1 - MAX_SUPPORTED_BLOB_LEN_BITS;
121 : if remainder < 32 {
122 : panic!("pos can be u32 as per type system, support that");
123 : }
124 : remainder
125 : };
126 : /// The maximum supported blob offset that can be represented by [`Self`].
127 : /// See also [`Self::validate_checkpoint_distance`].
128 : const MAX_SUPPORTED_POS: usize = (1 << Self::MAX_SUPPORTED_POS_BITS) - 1;
129 :
130 : // Layout
131 : const WILL_INIT_RANGE: Range<usize> = 0..1;
132 : const LEN_RANGE: Range<usize> =
133 : Self::WILL_INIT_RANGE.end..Self::WILL_INIT_RANGE.end + MAX_SUPPORTED_BLOB_LEN_BITS;
134 : const POS_RANGE: Range<usize> =
135 : Self::LEN_RANGE.end..Self::LEN_RANGE.end + Self::MAX_SUPPORTED_POS_BITS;
136 : const _ASSERT: () = {
137 : if Self::POS_RANGE.end != 64 {
138 : panic!("we don't want undefined bits for our own sanity")
139 : }
140 : };
141 :
142 : /// Fails if and only if the offset or length encoded in `arg` is too large to be represented by [`Self`].
143 : ///
144 : /// The only reason why that can happen in the system is if the [`InMemoryLayer`] grows too long.
145 : /// The [`InMemoryLayer`] size is determined by the checkpoint distance, enforced by [`crate::tenant::Timeline::should_roll`].
146 : ///
147 : /// Thus, to avoid failure of this function, whenever we start up and/or change checkpoint distance,
148 : /// call [`Self::validate_checkpoint_distance`] with the new checkpoint distance value.
149 : ///
150 : /// TODO: this check should happen ideally at config parsing time (and in the request handler when a change to checkpoint distance is requested)
151 : /// When cleaning this up, also look into the s3 max file size check that is performed in delta layer writer.
152 : #[inline(always)]
153 10181460 : fn new(arg: IndexEntryNewArgs) -> anyhow::Result<Self> {
154 10181460 : let IndexEntryNewArgs {
155 10181460 : base_offset,
156 10181460 : batch_offset,
157 10181460 : len,
158 10181460 : will_init,
159 10181460 : } = arg;
160 :
161 10181460 : let pos = base_offset
162 10181460 : .checked_add(batch_offset)
163 10181460 : .ok_or_else(|| anyhow::anyhow!("base_offset + batch_offset overflows u64: base_offset={base_offset} batch_offset={batch_offset}"))?;
164 :
165 10181460 : if pos.into_usize() > Self::MAX_SUPPORTED_POS {
166 16 : anyhow::bail!(
167 16 : "base_offset+batch_offset exceeds the maximum supported value: base_offset={base_offset} batch_offset={batch_offset} (+)={pos} max={max}",
168 16 : max = Self::MAX_SUPPORTED_POS
169 16 : );
170 10181444 : }
171 10181444 :
172 10181444 : if len > MAX_SUPPORTED_BLOB_LEN {
173 4 : anyhow::bail!(
174 4 : "len exceeds the maximum supported length: len={len} max={MAX_SUPPORTED_BLOB_LEN}",
175 4 : );
176 10181440 : }
177 10181440 :
178 10181440 : let mut data: u64 = 0;
179 : use bit_field::BitField;
180 10181440 : data.set_bits(Self::WILL_INIT_RANGE, if will_init { 1 } else { 0 });
181 10181440 : data.set_bits(Self::LEN_RANGE, len.into_u64());
182 10181440 : data.set_bits(Self::POS_RANGE, pos);
183 10181440 :
184 10181440 : Ok(Self(data))
185 10181460 : }
186 :
187 : #[inline(always)]
188 9769451 : fn unpack(&self) -> IndexEntryUnpacked {
189 : use bit_field::BitField;
190 9769451 : IndexEntryUnpacked {
191 9769451 : will_init: self.0.get_bits(Self::WILL_INIT_RANGE) != 0,
192 9769451 : len: self.0.get_bits(Self::LEN_RANGE),
193 9769451 : pos: self.0.get_bits(Self::POS_RANGE),
194 9769451 : }
195 9769451 : }
196 :
197 : /// See [`Self::new`].
198 480 : pub(crate) const fn validate_checkpoint_distance(
199 480 : checkpoint_distance: u64,
200 480 : ) -> Result<(), &'static str> {
201 480 : if checkpoint_distance > Self::MAX_SUPPORTED_POS as u64 {
202 0 : return Err("exceeds the maximum supported value");
203 480 : }
204 480 : let res = u64_to_usize(checkpoint_distance).checked_add(MAX_SUPPORTED_BLOB_LEN);
205 480 : if res.is_none() {
206 0 : return Err(
207 0 : "checkpoint distance + max supported blob len overflows in-memory addition",
208 0 : );
209 480 : }
210 480 :
211 480 : // NB: it is ok for the result of the addition to be larger than MAX_SUPPORTED_POS
212 480 :
213 480 : Ok(())
214 480 : }
215 :
216 : const _ASSERT_DEFAULT_CHECKPOINT_DISTANCE_IS_VALID: () = {
217 : let res = Self::validate_checkpoint_distance(
218 : pageserver_api::config::tenant_conf_defaults::DEFAULT_CHECKPOINT_DISTANCE,
219 : );
220 : if res.is_err() {
221 : panic!("default checkpoint distance is valid")
222 : }
223 : };
224 : }
225 :
226 : /// Args to [`IndexEntry::new`].
227 : #[derive(Clone, Copy)]
228 : struct IndexEntryNewArgs {
229 : base_offset: u64,
230 : batch_offset: u64,
231 : len: usize,
232 : will_init: bool,
233 : }
234 :
235 : /// Unpacked representation of the bitfielded [`IndexEntry`].
236 : #[derive(Clone, Copy, PartialEq, Eq, Debug)]
237 : struct IndexEntryUnpacked {
238 : will_init: bool,
239 : len: u64,
240 : pos: u64,
241 : }
242 :
243 : impl std::fmt::Debug for InMemoryLayerInner {
244 0 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
245 0 : f.debug_struct("InMemoryLayerInner").finish()
246 0 : }
247 : }
248 :
249 : /// State shared by all in-memory (ephemeral) layers. Updated infrequently during background ticks in Timeline,
250 : /// to minimize contention.
251 : ///
252 : /// This global state is used to implement behaviors that require a global view of the system, e.g.
253 : /// rolling layers proactively to limit the total amount of dirty data.
254 : pub(crate) struct GlobalResources {
255 : // Limit on how high dirty_bytes may grow before we start freezing layers to reduce it.
256 : // Zero means unlimited.
257 : pub(crate) max_dirty_bytes: AtomicU64,
258 : // How many bytes are in all EphemeralFile objects
259 : dirty_bytes: AtomicU64,
260 : // How many layers are contributing to dirty_bytes
261 : dirty_layers: AtomicUsize,
262 : }
263 :
264 : // Per-timeline RAII struct for its contribution to [`GlobalResources`]
265 : struct GlobalResourceUnits {
266 : // How many dirty bytes have I added to the global dirty_bytes: this guard object is responsible
267 : // for decrementing the global counter by this many bytes when dropped.
268 : dirty_bytes: u64,
269 : }
270 :
271 : impl GlobalResourceUnits {
272 : // Hint for the layer append path to update us when the layer size differs from the last
273 : // call to update_size by this much. If we don't reach this threshold, we'll still get
274 : // updated when the Timeline "ticks" in the background.
275 : const MAX_SIZE_DRIFT: u64 = 10 * 1024 * 1024;
276 :
277 2596 : fn new() -> Self {
278 2596 : GLOBAL_RESOURCES
279 2596 : .dirty_layers
280 2596 : .fetch_add(1, AtomicOrdering::Relaxed);
281 2596 : Self { dirty_bytes: 0 }
282 2596 : }
283 :
284 : /// Do not call this frequently: all timelines will write to these same global atomics,
285 : /// so this is a relatively expensive operation. Wait at least a few seconds between calls.
286 : ///
287 : /// Returns the effective layer size limit that should be applied, if any, to keep
288 : /// the total number of dirty bytes below the configured maximum.
289 2368 : fn publish_size(&mut self, size: u64) -> Option<u64> {
290 2368 : let new_global_dirty_bytes = match size.cmp(&self.dirty_bytes) {
291 2348 : Ordering::Equal => GLOBAL_RESOURCES.dirty_bytes.load(AtomicOrdering::Relaxed),
292 : Ordering::Greater => {
293 16 : let delta = size - self.dirty_bytes;
294 16 : let old = GLOBAL_RESOURCES
295 16 : .dirty_bytes
296 16 : .fetch_add(delta, AtomicOrdering::Relaxed);
297 16 : old + delta
298 : }
299 : Ordering::Less => {
300 4 : let delta = self.dirty_bytes - size;
301 4 : let old = GLOBAL_RESOURCES
302 4 : .dirty_bytes
303 4 : .fetch_sub(delta, AtomicOrdering::Relaxed);
304 4 : old - delta
305 : }
306 : };
307 :
308 : // This is a sloppy update: concurrent updates to the counter will race, and the exact
309 : // value of the metric might not be the exact latest value of GLOBAL_RESOURCES::dirty_bytes.
310 : // That's okay: as long as the metric contains some recent value, it doesn't have to always
311 : // be literally the last update.
312 2368 : TIMELINE_EPHEMERAL_BYTES.set(new_global_dirty_bytes);
313 2368 :
314 2368 : self.dirty_bytes = size;
315 2368 :
316 2368 : let max_dirty_bytes = GLOBAL_RESOURCES
317 2368 : .max_dirty_bytes
318 2368 : .load(AtomicOrdering::Relaxed);
319 2368 : if max_dirty_bytes > 0 && new_global_dirty_bytes > max_dirty_bytes {
320 : // Set the layer file limit to the average layer size: this implies that all above-average
321 : // sized layers will be elegible for freezing. They will be frozen in the order they
322 : // next enter publish_size.
323 0 : Some(
324 0 : new_global_dirty_bytes
325 0 : / GLOBAL_RESOURCES.dirty_layers.load(AtomicOrdering::Relaxed) as u64,
326 0 : )
327 : } else {
328 2368 : None
329 : }
330 2368 : }
331 :
332 : // Call publish_size if the input size differs from last published size by more than
333 : // the drift limit
334 9608464 : fn maybe_publish_size(&mut self, size: u64) {
335 9608464 : let publish = match size.cmp(&self.dirty_bytes) {
336 0 : Ordering::Equal => false,
337 9608464 : Ordering::Greater => size - self.dirty_bytes > Self::MAX_SIZE_DRIFT,
338 0 : Ordering::Less => self.dirty_bytes - size > Self::MAX_SIZE_DRIFT,
339 : };
340 :
341 9608464 : if publish {
342 16 : self.publish_size(size);
343 9608448 : }
344 9608464 : }
345 : }
346 :
347 : impl Drop for GlobalResourceUnits {
348 2352 : fn drop(&mut self) {
349 2352 : GLOBAL_RESOURCES
350 2352 : .dirty_layers
351 2352 : .fetch_sub(1, AtomicOrdering::Relaxed);
352 2352 :
353 2352 : // Subtract our contribution to the global total dirty bytes
354 2352 : self.publish_size(0);
355 2352 : }
356 : }
357 :
358 : pub(crate) static GLOBAL_RESOURCES: GlobalResources = GlobalResources {
359 : max_dirty_bytes: AtomicU64::new(0),
360 : dirty_bytes: AtomicU64::new(0),
361 : dirty_layers: AtomicUsize::new(0),
362 : };
363 :
364 : impl InMemoryLayer {
365 1213347 : pub(crate) fn file_id(&self) -> InMemoryLayerFileId {
366 1213347 : self.file_id
367 1213347 : }
368 :
369 2348 : pub(crate) fn get_timeline_id(&self) -> TimelineId {
370 2348 : self.timeline_id
371 2348 : }
372 :
373 4696 : pub(crate) fn info(&self) -> InMemoryLayerInfo {
374 4696 : let lsn_start = self.start_lsn;
375 :
376 4696 : if let Some(&lsn_end) = self.end_lsn.get() {
377 4696 : InMemoryLayerInfo::Frozen { lsn_start, lsn_end }
378 : } else {
379 0 : InMemoryLayerInfo::Open { lsn_start }
380 : }
381 4696 : }
382 :
383 4696 : pub(crate) fn try_len(&self) -> Option<u64> {
384 4696 : self.inner.try_read().map(|i| i.file.len()).ok()
385 4696 : }
386 :
387 9608464 : pub(crate) fn assert_writable(&self) {
388 9608464 : assert!(self.end_lsn.get().is_none());
389 9608464 : }
390 :
391 4259800 : pub(crate) fn end_lsn_or_max(&self) -> Lsn {
392 4259800 : self.end_lsn.get().copied().unwrap_or(Lsn::MAX)
393 4259800 : }
394 :
395 4257452 : pub(crate) fn get_lsn_range(&self) -> Range<Lsn> {
396 4257452 : self.start_lsn..self.end_lsn_or_max()
397 4257452 : }
398 :
399 : /// debugging function to print out the contents of the layer
400 : ///
401 : /// this is likely completly unused
402 0 : pub async fn dump(&self, _verbose: bool, _ctx: &RequestContext) -> Result<()> {
403 0 : let end_str = self.end_lsn_or_max();
404 0 :
405 0 : println!(
406 0 : "----- in-memory layer for tli {} LSNs {}-{} ----",
407 0 : self.timeline_id, self.start_lsn, end_str,
408 0 : );
409 0 :
410 0 : Ok(())
411 0 : }
412 :
413 : // Look up the keys in the provided keyspace and update
414 : // the reconstruct state with whatever is found.
415 1213347 : pub(crate) async fn get_values_reconstruct_data(
416 1213347 : self: &Arc<InMemoryLayer>,
417 1213347 : keyspace: KeySpace,
418 1213347 : end_lsn: Lsn,
419 1213347 : reconstruct_state: &mut ValuesReconstructState,
420 1213347 : ctx: &RequestContext,
421 1213347 : ) -> Result<(), GetVectoredError> {
422 1213347 : let ctx = RequestContextBuilder::extend(ctx)
423 1213347 : .page_content_kind(PageContentKind::InMemoryLayer)
424 1213347 : .build();
425 :
426 1213347 : let inner = self.inner.read().await;
427 :
428 : struct ValueRead {
429 : entry_lsn: Lsn,
430 : read: vectored_dio_read::LogicalRead<Vec<u8>>,
431 : }
432 1213347 : let mut reads: HashMap<Key, Vec<ValueRead>> = HashMap::new();
433 1213347 : let mut ios: HashMap<(Key, Lsn), OnDiskValueIo> = Default::default();
434 1213347 :
435 1213347 : let lsn_range = self.start_lsn..end_lsn;
436 :
437 1213759 : for range in keyspace.ranges.iter() {
438 1213759 : for (key, vec_map) in inner
439 1213759 : .index
440 1213759 : .range(range.start.to_compact()..range.end.to_compact())
441 : {
442 998347 : let key = Key::from_compact(*key);
443 998347 : let slice = vec_map.slice_range(lsn_range.clone());
444 :
445 998347 : for (entry_lsn, index_entry) in slice.iter().rev() {
446 : let IndexEntryUnpacked {
447 998339 : pos,
448 998339 : len,
449 998339 : will_init,
450 998339 : } = index_entry.unpack();
451 998339 :
452 998339 : reads.entry(key).or_default().push(ValueRead {
453 998339 : entry_lsn: *entry_lsn,
454 998339 : read: vectored_dio_read::LogicalRead::new(
455 998339 : pos,
456 998339 : Vec::with_capacity(len as usize),
457 998339 : ),
458 998339 : });
459 998339 :
460 998339 : let io = reconstruct_state.update_key(&key, *entry_lsn, will_init);
461 998339 : ios.insert((key, *entry_lsn), io);
462 998339 :
463 998339 : if will_init {
464 998339 : break;
465 0 : }
466 : }
467 : }
468 : }
469 1213347 : drop(inner); // release the lock before we spawn the IO; if it's serial-mode IO we will deadlock on the read().await below
470 1213347 : let read_from = Arc::clone(self);
471 1213347 : let read_ctx = ctx.attached_child();
472 1213347 : reconstruct_state
473 1213347 : .spawn_io(async move {
474 1213347 : let inner = read_from.inner.read().await;
475 1213347 : let f = vectored_dio_read::execute(
476 1213347 : &inner.file,
477 1213347 : reads
478 1213347 : .iter()
479 1213347 : .flat_map(|(_, value_reads)| value_reads.iter().map(|v| &v.read)),
480 1213347 : &read_ctx,
481 1213347 : );
482 1213347 : send_future::SendFuture::send(f) // https://github.com/rust-lang/rust/issues/96865
483 1213347 : .await;
484 :
485 2211686 : for (key, value_reads) in reads {
486 1996678 : for ValueRead { entry_lsn, read } in value_reads {
487 998339 : let io = ios.remove(&(key, entry_lsn)).expect("sender must exist");
488 998339 : match read.into_result().expect("we run execute() above") {
489 0 : Err(e) => {
490 0 : io.complete(Err(std::io::Error::new(
491 0 : e.kind(),
492 0 : "dio vec read failed",
493 0 : )));
494 0 : }
495 998339 : Ok(value_buf) => {
496 998339 : io.complete(Ok(OnDiskValue::WalRecordOrImage(value_buf.into())));
497 998339 : }
498 : }
499 : }
500 : }
501 :
502 1213347 : assert!(ios.is_empty());
503 :
504 : // Keep layer existent until this IO is done;
505 : // This is kinda forced for InMemoryLayer because we need to inner.read() anyway,
506 : // but it's less obvious for DeltaLayer and ImageLayer. So, keep this explicit
507 : // drop for consistency among all three layer types.
508 1213347 : drop(inner);
509 1213347 : drop(read_from);
510 1213347 : })
511 1213347 : .await;
512 :
513 1213347 : Ok(())
514 1213347 : }
515 : }
516 :
517 4696 : fn inmem_layer_display(mut f: impl Write, start_lsn: Lsn, end_lsn: Lsn) -> std::fmt::Result {
518 4696 : write!(f, "inmem-{:016X}-{:016X}", start_lsn.0, end_lsn.0)
519 4696 : }
520 :
521 2348 : fn inmem_layer_log_display(
522 2348 : mut f: impl Write,
523 2348 : timeline: TimelineId,
524 2348 : start_lsn: Lsn,
525 2348 : end_lsn: Lsn,
526 2348 : ) -> std::fmt::Result {
527 2348 : write!(f, "timeline {} in-memory ", timeline)?;
528 2348 : inmem_layer_display(f, start_lsn, end_lsn)
529 2348 : }
530 :
531 : impl std::fmt::Display for InMemoryLayer {
532 2348 : fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
533 2348 : let end_lsn = self.end_lsn_or_max();
534 2348 : inmem_layer_display(f, self.start_lsn, end_lsn)
535 2348 : }
536 : }
537 :
538 : impl InMemoryLayer {
539 : /// Get layer size.
540 2596 : pub async fn size(&self) -> Result<u64> {
541 2596 : let inner = self.inner.read().await;
542 2596 : Ok(inner.file.len())
543 2596 : }
544 :
545 2426 : pub fn estimated_in_mem_size(&self) -> u64 {
546 2426 : self.estimated_in_mem_size.load(AtomicOrdering::Relaxed)
547 2426 : }
548 :
549 : /// Create a new, empty, in-memory layer
550 2596 : pub async fn create(
551 2596 : conf: &'static PageServerConf,
552 2596 : timeline_id: TimelineId,
553 2596 : tenant_shard_id: TenantShardId,
554 2596 : start_lsn: Lsn,
555 2596 : gate: &utils::sync::gate::Gate,
556 2596 : ctx: &RequestContext,
557 2596 : ) -> Result<InMemoryLayer> {
558 2596 : trace!("initializing new empty InMemoryLayer for writing on timeline {timeline_id} at {start_lsn}");
559 :
560 2596 : let file = EphemeralFile::create(conf, tenant_shard_id, timeline_id, gate, ctx).await?;
561 2596 : let key = InMemoryLayerFileId(file.page_cache_file_id());
562 2596 :
563 2596 : Ok(InMemoryLayer {
564 2596 : file_id: key,
565 2596 : frozen_local_path_str: OnceLock::new(),
566 2596 : conf,
567 2596 : timeline_id,
568 2596 : tenant_shard_id,
569 2596 : start_lsn,
570 2596 : end_lsn: OnceLock::new(),
571 2596 : opened_at: Instant::now(),
572 2596 : inner: RwLock::new(InMemoryLayerInner {
573 2596 : index: BTreeMap::new(),
574 2596 : file,
575 2596 : resource_units: GlobalResourceUnits::new(),
576 2596 : }),
577 2596 : estimated_in_mem_size: AtomicU64::new(0),
578 2596 : })
579 2596 : }
580 :
581 : /// Write path.
582 : ///
583 : /// Errors are not retryable, the [`InMemoryLayer`] must be discarded, and not be read from.
584 : /// The reason why it's not retryable is that the [`EphemeralFile`] writes are not retryable.
585 : /// TODO: it can be made retryable if we aborted the process on EphemeralFile write errors.
586 9608464 : pub async fn put_batch(
587 9608464 : &self,
588 9608464 : serialized_batch: SerializedValueBatch,
589 9608464 : ctx: &RequestContext,
590 9608464 : ) -> anyhow::Result<()> {
591 9608464 : let mut inner = self.inner.write().await;
592 9608464 : self.assert_writable();
593 9608464 :
594 9608464 : let base_offset = inner.file.len();
595 9608464 :
596 9608464 : let SerializedValueBatch {
597 9608464 : raw,
598 9608464 : metadata,
599 9608464 : max_lsn: _,
600 9608464 : len: _,
601 9608464 : } = serialized_batch;
602 9608464 :
603 9608464 : // Write the batch to the file
604 9608464 : inner.file.write_raw(&raw, ctx).await?;
605 9608464 : let new_size = inner.file.len();
606 9608464 :
607 9608464 : let expected_new_len = base_offset
608 9608464 : .checked_add(raw.len().into_u64())
609 9608464 : // write_raw would error if we were to overflow u64.
610 9608464 : // also IndexEntry and higher levels in
611 9608464 : //the code don't allow the file to grow that large
612 9608464 : .unwrap();
613 9608464 : assert_eq!(new_size, expected_new_len);
614 :
615 : // Update the index with the new entries
616 19789824 : for meta in metadata {
617 : let SerializedValueMeta {
618 10181360 : key,
619 10181360 : lsn,
620 10181360 : batch_offset,
621 10181360 : len,
622 10181360 : will_init,
623 10181360 : } = match meta {
624 10181360 : ValueMeta::Serialized(ser) => ser,
625 : ValueMeta::Observed(_) => {
626 0 : continue;
627 : }
628 : };
629 :
630 : // Add the base_offset to the batch's index entries which are relative to the batch start.
631 10181360 : let index_entry = IndexEntry::new(IndexEntryNewArgs {
632 10181360 : base_offset,
633 10181360 : batch_offset,
634 10181360 : len,
635 10181360 : will_init,
636 10181360 : })?;
637 :
638 10181360 : let vec_map = inner.index.entry(key).or_default();
639 10181360 : let old = vec_map.append_or_update_last(lsn, index_entry).unwrap().0;
640 10181360 : if old.is_some() {
641 : // This should not break anything, but is unexpected: ingestion code aims to filter out
642 : // multiple writes to the same key at the same LSN. This happens in cases where our
643 : // ingenstion code generates some write like an empty page, and we see a write from postgres
644 : // to the same key in the same wal record. If one such write makes it through, we
645 : // index the most recent write, implicitly ignoring the earlier write. We log a warning
646 : // because this case is unexpected, and we would like tests to fail if this happens.
647 0 : warn!("Key {} at {} written twice at same LSN", key, lsn);
648 10181360 : }
649 10181360 : self.estimated_in_mem_size.fetch_add(
650 10181360 : (std::mem::size_of::<CompactKey>()
651 10181360 : + std::mem::size_of::<Lsn>()
652 10181360 : + std::mem::size_of::<IndexEntry>()) as u64,
653 10181360 : AtomicOrdering::Relaxed,
654 10181360 : );
655 : }
656 :
657 9608464 : inner.resource_units.maybe_publish_size(new_size);
658 9608464 :
659 9608464 : Ok(())
660 9608464 : }
661 :
662 9606020 : pub(crate) fn get_opened_at(&self) -> Instant {
663 9606020 : self.opened_at
664 9606020 : }
665 :
666 0 : pub(crate) async fn tick(&self) -> Option<u64> {
667 0 : let mut inner = self.inner.write().await;
668 0 : let size = inner.file.len();
669 0 : inner.resource_units.publish_size(size)
670 0 : }
671 :
672 4 : pub(crate) async fn put_tombstones(&self, _key_ranges: &[(Range<Key>, Lsn)]) -> Result<()> {
673 4 : // TODO: Currently, we just leak the storage for any deleted keys
674 4 : Ok(())
675 4 : }
676 :
677 : /// Records the end_lsn for non-dropped layers.
678 : /// `end_lsn` is exclusive
679 2348 : pub async fn freeze(&self, end_lsn: Lsn) {
680 2348 : assert!(
681 2348 : self.start_lsn < end_lsn,
682 0 : "{} >= {}",
683 : self.start_lsn,
684 : end_lsn
685 : );
686 2348 : self.end_lsn.set(end_lsn).expect("end_lsn set only once");
687 2348 :
688 2348 : self.frozen_local_path_str
689 2348 : .set({
690 2348 : let mut buf = String::new();
691 2348 : inmem_layer_log_display(&mut buf, self.get_timeline_id(), self.start_lsn, end_lsn)
692 2348 : .unwrap();
693 2348 : buf.into()
694 2348 : })
695 2348 : .expect("frozen_local_path_str set only once");
696 :
697 : #[cfg(debug_assertions)]
698 : {
699 2348 : let inner = self.inner.write().await;
700 8511946 : for vec_map in inner.index.values() {
701 8773880 : for (lsn, _) in vec_map.as_slice() {
702 8773880 : assert!(*lsn < end_lsn);
703 : }
704 : }
705 : }
706 2348 : }
707 :
708 : /// Write this frozen in-memory layer to disk. If `key_range` is set, the delta
709 : /// layer will only contain the key range the user specifies, and may return `None`
710 : /// if there are no matching keys.
711 : ///
712 : /// Returns a new delta layer with all the same data as this in-memory layer
713 1936 : pub async fn write_to_disk(
714 1936 : &self,
715 1936 : ctx: &RequestContext,
716 1936 : key_range: Option<Range<Key>>,
717 1936 : l0_flush_global_state: &l0_flush::Inner,
718 1936 : ) -> Result<Option<(PersistentLayerDesc, Utf8PathBuf)>> {
719 : // Grab the lock in read-mode. We hold it over the I/O, but because this
720 : // layer is not writeable anymore, no one should be trying to acquire the
721 : // write lock on it, so we shouldn't block anyone. There's one exception
722 : // though: another thread might have grabbed a reference to this layer
723 : // in `get_layer_for_write' just before the checkpointer called
724 : // `freeze`, and then `write_to_disk` on it. When the thread gets the
725 : // lock, it will see that it's not writeable anymore and retry, but it
726 : // would have to wait until we release it. That race condition is very
727 : // rare though, so we just accept the potential latency hit for now.
728 1936 : let inner = self.inner.read().await;
729 :
730 : use l0_flush::Inner;
731 1936 : let _concurrency_permit = match l0_flush_global_state {
732 1936 : Inner::Direct { semaphore, .. } => Some(semaphore.acquire().await),
733 : };
734 :
735 1936 : let end_lsn = *self.end_lsn.get().unwrap();
736 :
737 1936 : let key_count = if let Some(key_range) = key_range {
738 0 : let key_range = key_range.start.to_compact()..key_range.end.to_compact();
739 0 :
740 0 : inner
741 0 : .index
742 0 : .iter()
743 0 : .filter(|(k, _)| key_range.contains(k))
744 0 : .count()
745 : } else {
746 1936 : inner.index.len()
747 : };
748 1936 : if key_count == 0 {
749 0 : return Ok(None);
750 1936 : }
751 :
752 1936 : let mut delta_layer_writer = DeltaLayerWriter::new(
753 1936 : self.conf,
754 1936 : self.timeline_id,
755 1936 : self.tenant_shard_id,
756 1936 : Key::MIN,
757 1936 : self.start_lsn..end_lsn,
758 1936 : ctx,
759 1936 : )
760 1936 : .await?;
761 :
762 1936 : match l0_flush_global_state {
763 : l0_flush::Inner::Direct { .. } => {
764 1936 : let file_contents = inner.file.load_to_io_buf(ctx).await?;
765 1936 : let file_contents = file_contents.freeze();
766 :
767 8509098 : for (key, vec_map) in inner.index.iter() {
768 : // Write all page versions
769 8771032 : for (lsn, entry) in vec_map
770 8509098 : .as_slice()
771 8509098 : .iter()
772 8771032 : .map(|(lsn, entry)| (lsn, entry.unpack()))
773 : {
774 : let IndexEntryUnpacked {
775 8771032 : pos,
776 8771032 : len,
777 8771032 : will_init,
778 8771032 : } = entry;
779 8771032 : let buf = file_contents.slice(pos as usize..(pos + len) as usize);
780 8771032 : let (_buf, res) = delta_layer_writer
781 8771032 : .put_value_bytes(
782 8771032 : Key::from_compact(*key),
783 8771032 : *lsn,
784 8771032 : buf.slice_len(),
785 8771032 : will_init,
786 8771032 : ctx,
787 8771032 : )
788 8771032 : .await;
789 8771032 : res?;
790 : }
791 : }
792 : }
793 : }
794 :
795 : // MAX is used here because we identify L0 layers by full key range
796 1936 : let (desc, path) = delta_layer_writer.finish(Key::MAX, ctx).await?;
797 :
798 : // Hold the permit until all the IO is done, including the fsync in `delta_layer_writer.finish()``.
799 : //
800 : // If we didn't and our caller drops this future, tokio-epoll-uring would extend the lifetime of
801 : // the `file_contents: Vec<u8>` until the IO is done, but not the permit's lifetime.
802 : // Thus, we'd have more concurrenct `Vec<u8>` in existence than the semaphore allows.
803 : //
804 : // We hold across the fsync so that on ext4 mounted with data=ordered, all the kernel page cache pages
805 : // we dirtied when writing to the filesystem have been flushed and marked !dirty.
806 1936 : drop(_concurrency_permit);
807 1936 :
808 1936 : Ok(Some((desc, path)))
809 1936 : }
810 : }
811 :
812 : #[cfg(test)]
813 : mod tests {
814 : use super::*;
815 :
816 : #[test]
817 4 : fn test_index_entry() {
818 : const MAX_SUPPORTED_POS: usize = IndexEntry::MAX_SUPPORTED_POS;
819 : use IndexEntryNewArgs as Args;
820 : use IndexEntryUnpacked as Unpacked;
821 :
822 80 : let roundtrip = |args, expect: Unpacked| {
823 80 : let res = IndexEntry::new(args).expect("this tests expects no errors");
824 80 : let IndexEntryUnpacked {
825 80 : will_init,
826 80 : len,
827 80 : pos,
828 80 : } = res.unpack();
829 80 : assert_eq!(will_init, expect.will_init);
830 80 : assert_eq!(len, expect.len);
831 80 : assert_eq!(pos, expect.pos);
832 80 : };
833 :
834 : // basic roundtrip
835 12 : for pos in [0, MAX_SUPPORTED_POS] {
836 24 : for len in [0, MAX_SUPPORTED_BLOB_LEN] {
837 48 : for will_init in [true, false] {
838 32 : let expect = Unpacked {
839 32 : will_init,
840 32 : len: len.into_u64(),
841 32 : pos: pos.into_u64(),
842 32 : };
843 32 : roundtrip(
844 32 : Args {
845 32 : will_init,
846 32 : base_offset: pos.into_u64(),
847 32 : batch_offset: 0,
848 32 : len,
849 32 : },
850 32 : expect,
851 32 : );
852 32 : roundtrip(
853 32 : Args {
854 32 : will_init,
855 32 : base_offset: 0,
856 32 : batch_offset: pos.into_u64(),
857 32 : len,
858 32 : },
859 32 : expect,
860 32 : );
861 32 : }
862 : }
863 : }
864 :
865 : // too-large len
866 4 : let too_large = Args {
867 4 : will_init: false,
868 4 : len: MAX_SUPPORTED_BLOB_LEN + 1,
869 4 : base_offset: 0,
870 4 : batch_offset: 0,
871 4 : };
872 4 : assert!(IndexEntry::new(too_large).is_err());
873 :
874 : // too-large pos
875 : {
876 4 : let too_large = Args {
877 4 : will_init: false,
878 4 : len: 0,
879 4 : base_offset: MAX_SUPPORTED_POS.into_u64() + 1,
880 4 : batch_offset: 0,
881 4 : };
882 4 : assert!(IndexEntry::new(too_large).is_err());
883 4 : let too_large = Args {
884 4 : will_init: false,
885 4 : len: 0,
886 4 : base_offset: 0,
887 4 : batch_offset: MAX_SUPPORTED_POS.into_u64() + 1,
888 4 : };
889 4 : assert!(IndexEntry::new(too_large).is_err());
890 : }
891 :
892 : // too large (base_offset + batch_offset)
893 : {
894 4 : let too_large = Args {
895 4 : will_init: false,
896 4 : len: 0,
897 4 : base_offset: MAX_SUPPORTED_POS.into_u64(),
898 4 : batch_offset: 1,
899 4 : };
900 4 : assert!(IndexEntry::new(too_large).is_err());
901 4 : let too_large = Args {
902 4 : will_init: false,
903 4 : len: 0,
904 4 : base_offset: MAX_SUPPORTED_POS.into_u64() - 1,
905 4 : batch_offset: MAX_SUPPORTED_POS.into_u64() - 1,
906 4 : };
907 4 : assert!(IndexEntry::new(too_large).is_err());
908 : }
909 :
910 : // valid special cases
911 : // - area past the max supported pos that is accessible by len
912 12 : for len in [1, MAX_SUPPORTED_BLOB_LEN] {
913 8 : roundtrip(
914 8 : Args {
915 8 : will_init: false,
916 8 : len,
917 8 : base_offset: MAX_SUPPORTED_POS.into_u64(),
918 8 : batch_offset: 0,
919 8 : },
920 8 : Unpacked {
921 8 : will_init: false,
922 8 : len: len as u64,
923 8 : pos: MAX_SUPPORTED_POS.into_u64(),
924 8 : },
925 8 : );
926 8 : roundtrip(
927 8 : Args {
928 8 : will_init: false,
929 8 : len,
930 8 : base_offset: 0,
931 8 : batch_offset: MAX_SUPPORTED_POS.into_u64(),
932 8 : },
933 8 : Unpacked {
934 8 : will_init: false,
935 8 : len: len as u64,
936 8 : pos: MAX_SUPPORTED_POS.into_u64(),
937 8 : },
938 8 : );
939 8 : }
940 4 : }
941 : }
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