LCOV - code coverage report
Current view: top level - pageserver/src/tenant/storage_layer - delta_layer.rs (source / functions) Coverage Total Hit
Test: 2a9d99866121f170b43760bd62e1e2431e597707.info Lines: 84.7 % 1682 1425
Test Date: 2024-09-02 14:10:37 Functions: 71.3 % 167 119

            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", "values", and
      24              : //! "index". 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::{self, FileId, 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::{
      37              :     DiskBtreeBuilder, DiskBtreeIterator, DiskBtreeReader, VisitDirection,
      38              : };
      39              : use crate::tenant::storage_layer::layer::S3_UPLOAD_LIMIT;
      40              : use crate::tenant::timeline::GetVectoredError;
      41              : use crate::tenant::vectored_blob_io::{
      42              :     BlobFlag, MaxVectoredReadBytes, StreamingVectoredReadPlanner, VectoredBlobReader, VectoredRead,
      43              :     VectoredReadCoalesceMode, VectoredReadPlanner,
      44              : };
      45              : use crate::tenant::PageReconstructError;
      46              : use crate::virtual_file::owned_buffers_io::io_buf_ext::{FullSlice, IoBufExt};
      47              : use crate::virtual_file::{self, VirtualFile};
      48              : use crate::{walrecord, TEMP_FILE_SUFFIX};
      49              : use crate::{DELTA_FILE_MAGIC, STORAGE_FORMAT_VERSION};
      50              : use anyhow::{anyhow, bail, ensure, Context, Result};
      51              : use bytes::BytesMut;
      52              : use camino::{Utf8Path, Utf8PathBuf};
      53              : use futures::StreamExt;
      54              : use itertools::Itertools;
      55              : use pageserver_api::keyspace::KeySpace;
      56              : use pageserver_api::models::ImageCompressionAlgorithm;
      57              : use pageserver_api::shard::TenantShardId;
      58              : use rand::{distributions::Alphanumeric, Rng};
      59              : use serde::{Deserialize, Serialize};
      60              : use std::collections::VecDeque;
      61              : use std::fs::File;
      62              : use std::io::SeekFrom;
      63              : use std::ops::Range;
      64              : use std::os::unix::fs::FileExt;
      65              : use std::str::FromStr;
      66              : use std::sync::Arc;
      67              : use tokio::sync::OnceCell;
      68              : use tokio_epoll_uring::IoBuf;
      69              : use tracing::*;
      70              : 
      71              : use utils::{
      72              :     bin_ser::BeSer,
      73              :     id::{TenantId, TimelineId},
      74              :     lsn::Lsn,
      75              : };
      76              : 
      77              : use super::{AsLayerDesc, LayerName, PersistentLayerDesc, ValuesReconstructState};
      78              : 
      79              : ///
      80              : /// Header stored in the beginning of the file
      81              : ///
      82              : /// After this comes the 'values' part, starting on block 1. After that,
      83              : /// the 'index' starts at the block indicated by 'index_start_blk'
      84              : ///
      85         3126 : #[derive(Debug, Serialize, Deserialize, PartialEq, Eq)]
      86              : pub struct Summary {
      87              :     /// Magic value to identify this as a neon delta file. Always DELTA_FILE_MAGIC.
      88              :     pub magic: u16,
      89              :     pub format_version: u16,
      90              : 
      91              :     pub tenant_id: TenantId,
      92              :     pub timeline_id: TimelineId,
      93              :     pub key_range: Range<Key>,
      94              :     pub lsn_range: Range<Lsn>,
      95              : 
      96              :     /// Block number where the 'index' part of the file begins.
      97              :     pub index_start_blk: u32,
      98              :     /// Block within the 'index', where the B-tree root page is stored
      99              :     pub index_root_blk: u32,
     100              : }
     101              : 
     102              : impl From<&DeltaLayer> for Summary {
     103            0 :     fn from(layer: &DeltaLayer) -> Self {
     104            0 :         Self::expected(
     105            0 :             layer.desc.tenant_shard_id.tenant_id,
     106            0 :             layer.desc.timeline_id,
     107            0 :             layer.desc.key_range.clone(),
     108            0 :             layer.desc.lsn_range.clone(),
     109            0 :         )
     110            0 :     }
     111              : }
     112              : 
     113              : impl Summary {
     114         3126 :     pub(super) fn expected(
     115         3126 :         tenant_id: TenantId,
     116         3126 :         timeline_id: TimelineId,
     117         3126 :         keys: Range<Key>,
     118         3126 :         lsns: Range<Lsn>,
     119         3126 :     ) -> Self {
     120         3126 :         Self {
     121         3126 :             magic: DELTA_FILE_MAGIC,
     122         3126 :             format_version: STORAGE_FORMAT_VERSION,
     123         3126 : 
     124         3126 :             tenant_id,
     125         3126 :             timeline_id,
     126         3126 :             key_range: keys,
     127         3126 :             lsn_range: lsns,
     128         3126 : 
     129         3126 :             index_start_blk: 0,
     130         3126 :             index_root_blk: 0,
     131         3126 :         }
     132         3126 :     }
     133              : }
     134              : 
     135              : // Flag indicating that this version initialize the page
     136              : const WILL_INIT: u64 = 1;
     137              : 
     138              : /// Struct representing reference to BLOB in layers. Reference contains BLOB
     139              : /// offset, and for WAL records it also contains `will_init` flag. The flag
     140              : /// helps to determine the range of records that needs to be applied, without
     141              : /// reading/deserializing records themselves.
     142            0 : #[derive(Debug, Serialize, Deserialize, Copy, Clone)]
     143              : pub struct BlobRef(pub u64);
     144              : 
     145              : impl BlobRef {
     146      1533241 :     pub fn will_init(&self) -> bool {
     147      1533241 :         (self.0 & WILL_INIT) != 0
     148      1533241 :     }
     149              : 
     150     20432781 :     pub fn pos(&self) -> u64 {
     151     20432781 :         self.0 >> 1
     152     20432781 :     }
     153              : 
     154     19413306 :     pub fn new(pos: u64, will_init: bool) -> BlobRef {
     155     19413306 :         let mut blob_ref = pos << 1;
     156     19413306 :         if will_init {
     157     19408998 :             blob_ref |= WILL_INIT;
     158     19408998 :         }
     159     19413306 :         BlobRef(blob_ref)
     160     19413306 :     }
     161              : }
     162              : 
     163              : pub const DELTA_KEY_SIZE: usize = KEY_SIZE + 8;
     164              : struct DeltaKey([u8; DELTA_KEY_SIZE]);
     165              : 
     166              : /// This is the key of the B-tree index stored in the delta layer. It consists
     167              : /// of the serialized representation of a Key and LSN.
     168              : impl DeltaKey {
     169      6192594 :     fn from_slice(buf: &[u8]) -> Self {
     170      6192594 :         let mut bytes: [u8; DELTA_KEY_SIZE] = [0u8; DELTA_KEY_SIZE];
     171      6192594 :         bytes.copy_from_slice(buf);
     172      6192594 :         DeltaKey(bytes)
     173      6192594 :     }
     174              : 
     175     20155091 :     fn from_key_lsn(key: &Key, lsn: Lsn) -> Self {
     176     20155091 :         let mut bytes: [u8; DELTA_KEY_SIZE] = [0u8; DELTA_KEY_SIZE];
     177     20155091 :         key.write_to_byte_slice(&mut bytes[0..KEY_SIZE]);
     178     20155091 :         bytes[KEY_SIZE..].copy_from_slice(&u64::to_be_bytes(lsn.0));
     179     20155091 :         DeltaKey(bytes)
     180     20155091 :     }
     181              : 
     182      6192594 :     fn key(&self) -> Key {
     183      6192594 :         Key::from_slice(&self.0)
     184      6192594 :     }
     185              : 
     186      6192594 :     fn lsn(&self) -> Lsn {
     187      6192594 :         Lsn(u64::from_be_bytes(self.0[KEY_SIZE..].try_into().unwrap()))
     188      6192594 :     }
     189              : 
     190      8047893 :     fn extract_lsn_from_buf(buf: &[u8]) -> Lsn {
     191      8047893 :         let mut lsn_buf = [0u8; 8];
     192      8047893 :         lsn_buf.copy_from_slice(&buf[KEY_SIZE..]);
     193      8047893 :         Lsn(u64::from_be_bytes(lsn_buf))
     194      8047893 :     }
     195              : }
     196              : 
     197              : /// This is used only from `pagectl`. Within pageserver, all layers are
     198              : /// [`crate::tenant::storage_layer::Layer`], which can hold a [`DeltaLayerInner`].
     199              : pub struct DeltaLayer {
     200              :     path: Utf8PathBuf,
     201              :     pub desc: PersistentLayerDesc,
     202              :     inner: OnceCell<Arc<DeltaLayerInner>>,
     203              : }
     204              : 
     205              : impl std::fmt::Debug for DeltaLayer {
     206            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     207            0 :         use super::RangeDisplayDebug;
     208            0 : 
     209            0 :         f.debug_struct("DeltaLayer")
     210            0 :             .field("key_range", &RangeDisplayDebug(&self.desc.key_range))
     211            0 :             .field("lsn_range", &self.desc.lsn_range)
     212            0 :             .field("file_size", &self.desc.file_size)
     213            0 :             .field("inner", &self.inner)
     214            0 :             .finish()
     215            0 :     }
     216              : }
     217              : 
     218              : /// `DeltaLayerInner` is the in-memory data structure associated with an on-disk delta
     219              : /// file.
     220              : pub struct DeltaLayerInner {
     221              :     // values copied from summary
     222              :     index_start_blk: u32,
     223              :     index_root_blk: u32,
     224              : 
     225              :     file: VirtualFile,
     226              :     file_id: FileId,
     227              : 
     228              :     #[allow(dead_code)]
     229              :     layer_key_range: Range<Key>,
     230              :     #[allow(dead_code)]
     231              :     layer_lsn_range: Range<Lsn>,
     232              : 
     233              :     max_vectored_read_bytes: Option<MaxVectoredReadBytes>,
     234              : }
     235              : 
     236              : impl DeltaLayerInner {
     237            0 :     pub(crate) fn layer_dbg_info(&self) -> String {
     238            0 :         format!(
     239            0 :             "delta {}..{} {}..{}",
     240            0 :             self.key_range().start,
     241            0 :             self.key_range().end,
     242            0 :             self.lsn_range().start,
     243            0 :             self.lsn_range().end
     244            0 :         )
     245            0 :     }
     246              : }
     247              : 
     248              : impl std::fmt::Debug for DeltaLayerInner {
     249            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     250            0 :         f.debug_struct("DeltaLayerInner")
     251            0 :             .field("index_start_blk", &self.index_start_blk)
     252            0 :             .field("index_root_blk", &self.index_root_blk)
     253            0 :             .finish()
     254            0 :     }
     255              : }
     256              : 
     257              : /// Boilerplate to implement the Layer trait, always use layer_desc for persistent layers.
     258              : impl std::fmt::Display for DeltaLayer {
     259            0 :     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
     260            0 :         write!(f, "{}", self.layer_desc().short_id())
     261            0 :     }
     262              : }
     263              : 
     264              : impl AsLayerDesc for DeltaLayer {
     265            0 :     fn layer_desc(&self) -> &PersistentLayerDesc {
     266            0 :         &self.desc
     267            0 :     }
     268              : }
     269              : 
     270              : impl DeltaLayer {
     271            0 :     pub(crate) async fn dump(&self, verbose: bool, ctx: &RequestContext) -> Result<()> {
     272            0 :         self.desc.dump();
     273            0 : 
     274            0 :         if !verbose {
     275            0 :             return Ok(());
     276            0 :         }
     277              : 
     278            0 :         let inner = self.load(ctx).await?;
     279              : 
     280            0 :         inner.dump(ctx).await
     281            0 :     }
     282              : 
     283         4248 :     fn temp_path_for(
     284         4248 :         conf: &PageServerConf,
     285         4248 :         tenant_shard_id: &TenantShardId,
     286         4248 :         timeline_id: &TimelineId,
     287         4248 :         key_start: Key,
     288         4248 :         lsn_range: &Range<Lsn>,
     289         4248 :     ) -> Utf8PathBuf {
     290         4248 :         let rand_string: String = rand::thread_rng()
     291         4248 :             .sample_iter(&Alphanumeric)
     292         4248 :             .take(8)
     293         4248 :             .map(char::from)
     294         4248 :             .collect();
     295         4248 : 
     296         4248 :         conf.timeline_path(tenant_shard_id, timeline_id)
     297         4248 :             .join(format!(
     298         4248 :                 "{}-XXX__{:016X}-{:016X}.{}.{}",
     299         4248 :                 key_start,
     300         4248 :                 u64::from(lsn_range.start),
     301         4248 :                 u64::from(lsn_range.end),
     302         4248 :                 rand_string,
     303         4248 :                 TEMP_FILE_SUFFIX,
     304         4248 :             ))
     305         4248 :     }
     306              : 
     307              :     ///
     308              :     /// Open the underlying file and read the metadata into memory, if it's
     309              :     /// not loaded already.
     310              :     ///
     311            0 :     async fn load(&self, ctx: &RequestContext) -> Result<&Arc<DeltaLayerInner>> {
     312            0 :         // Quick exit if already loaded
     313            0 :         self.inner
     314            0 :             .get_or_try_init(|| self.load_inner(ctx))
     315            0 :             .await
     316            0 :             .with_context(|| format!("Failed to load delta layer {}", self.path()))
     317            0 :     }
     318              : 
     319            0 :     async fn load_inner(&self, ctx: &RequestContext) -> anyhow::Result<Arc<DeltaLayerInner>> {
     320            0 :         let path = self.path();
     321              : 
     322            0 :         let loaded = DeltaLayerInner::load(&path, None, None, ctx).await?;
     323              : 
     324              :         // not production code
     325            0 :         let actual_layer_name = LayerName::from_str(path.file_name().unwrap()).unwrap();
     326            0 :         let expected_layer_name = self.layer_desc().layer_name();
     327            0 : 
     328            0 :         if actual_layer_name != expected_layer_name {
     329            0 :             println!("warning: filename does not match what is expected from in-file summary");
     330            0 :             println!("actual: {:?}", actual_layer_name.to_string());
     331            0 :             println!("expected: {:?}", expected_layer_name.to_string());
     332            0 :         }
     333              : 
     334            0 :         Ok(Arc::new(loaded))
     335            0 :     }
     336              : 
     337              :     /// Create a DeltaLayer struct representing an existing file on disk.
     338              :     ///
     339              :     /// This variant is only used for debugging purposes, by the 'pagectl' binary.
     340            0 :     pub fn new_for_path(path: &Utf8Path, file: File) -> Result<Self> {
     341            0 :         let mut summary_buf = vec![0; PAGE_SZ];
     342            0 :         file.read_exact_at(&mut summary_buf, 0)?;
     343            0 :         let summary = Summary::des_prefix(&summary_buf)?;
     344              : 
     345            0 :         let metadata = file
     346            0 :             .metadata()
     347            0 :             .context("get file metadata to determine size")?;
     348              : 
     349              :         // This function is never used for constructing layers in a running pageserver,
     350              :         // so it does not need an accurate TenantShardId.
     351            0 :         let tenant_shard_id = TenantShardId::unsharded(summary.tenant_id);
     352            0 : 
     353            0 :         Ok(DeltaLayer {
     354            0 :             path: path.to_path_buf(),
     355            0 :             desc: PersistentLayerDesc::new_delta(
     356            0 :                 tenant_shard_id,
     357            0 :                 summary.timeline_id,
     358            0 :                 summary.key_range,
     359            0 :                 summary.lsn_range,
     360            0 :                 metadata.len(),
     361            0 :             ),
     362            0 :             inner: OnceCell::new(),
     363            0 :         })
     364            0 :     }
     365              : 
     366              :     /// Path to the layer file in pageserver workdir.
     367            0 :     fn path(&self) -> Utf8PathBuf {
     368            0 :         self.path.clone()
     369            0 :     }
     370              : }
     371              : 
     372              : /// A builder object for constructing a new delta layer.
     373              : ///
     374              : /// Usage:
     375              : ///
     376              : /// 1. Create the DeltaLayerWriter by calling DeltaLayerWriter::new(...)
     377              : ///
     378              : /// 2. Write the contents by calling `put_value` for every page
     379              : ///    version to store in the layer.
     380              : ///
     381              : /// 3. Call `finish`.
     382              : ///
     383              : struct DeltaLayerWriterInner {
     384              :     pub path: Utf8PathBuf,
     385              :     timeline_id: TimelineId,
     386              :     tenant_shard_id: TenantShardId,
     387              : 
     388              :     key_start: Key,
     389              :     lsn_range: Range<Lsn>,
     390              : 
     391              :     tree: DiskBtreeBuilder<BlockBuf, DELTA_KEY_SIZE>,
     392              : 
     393              :     blob_writer: BlobWriter<true>,
     394              : 
     395              :     // Number of key-lsns in the layer.
     396              :     num_keys: usize,
     397              : }
     398              : 
     399              : impl DeltaLayerWriterInner {
     400              :     ///
     401              :     /// Start building a new delta layer.
     402              :     ///
     403         4248 :     async fn new(
     404         4248 :         conf: &'static PageServerConf,
     405         4248 :         timeline_id: TimelineId,
     406         4248 :         tenant_shard_id: TenantShardId,
     407         4248 :         key_start: Key,
     408         4248 :         lsn_range: Range<Lsn>,
     409         4248 :         ctx: &RequestContext,
     410         4248 :     ) -> anyhow::Result<Self> {
     411         4248 :         // Create the file initially with a temporary filename. We don't know
     412         4248 :         // the end key yet, so we cannot form the final filename yet. We will
     413         4248 :         // rename it when we're done.
     414         4248 :         //
     415         4248 :         // Note: This overwrites any existing file. There shouldn't be any.
     416         4248 :         // FIXME: throw an error instead?
     417         4248 :         let path =
     418         4248 :             DeltaLayer::temp_path_for(conf, &tenant_shard_id, &timeline_id, key_start, &lsn_range);
     419              : 
     420         4248 :         let mut file = VirtualFile::create(&path, ctx).await?;
     421              :         // make room for the header block
     422         4248 :         file.seek(SeekFrom::Start(PAGE_SZ as u64)).await?;
     423         4248 :         let blob_writer = BlobWriter::new(file, PAGE_SZ as u64);
     424         4248 : 
     425         4248 :         // Initialize the b-tree index builder
     426         4248 :         let block_buf = BlockBuf::new();
     427         4248 :         let tree_builder = DiskBtreeBuilder::new(block_buf);
     428         4248 : 
     429         4248 :         Ok(Self {
     430         4248 :             path,
     431         4248 :             timeline_id,
     432         4248 :             tenant_shard_id,
     433         4248 :             key_start,
     434         4248 :             lsn_range,
     435         4248 :             tree: tree_builder,
     436         4248 :             blob_writer,
     437         4248 :             num_keys: 0,
     438         4248 :         })
     439         4248 :     }
     440              : 
     441              :     ///
     442              :     /// Append a key-value pair to the file.
     443              :     ///
     444              :     /// The values must be appended in key, lsn order.
     445              :     ///
     446      6253014 :     async fn put_value(
     447      6253014 :         &mut self,
     448      6253014 :         key: Key,
     449      6253014 :         lsn: Lsn,
     450      6253014 :         val: Value,
     451      6253014 :         ctx: &RequestContext,
     452      6253014 :     ) -> anyhow::Result<()> {
     453      6253014 :         let (_, res) = self
     454      6253014 :             .put_value_bytes(
     455      6253014 :                 key,
     456      6253014 :                 lsn,
     457      6253014 :                 Value::ser(&val)?.slice_len(),
     458      6253014 :                 val.will_init(),
     459      6253014 :                 ctx,
     460              :             )
     461         5924 :             .await;
     462      6253014 :         res
     463      6253014 :     }
     464              : 
     465     19412994 :     async fn put_value_bytes<Buf>(
     466     19412994 :         &mut self,
     467     19412994 :         key: Key,
     468     19412994 :         lsn: Lsn,
     469     19412994 :         val: FullSlice<Buf>,
     470     19412994 :         will_init: bool,
     471     19412994 :         ctx: &RequestContext,
     472     19412994 :     ) -> (FullSlice<Buf>, anyhow::Result<()>)
     473     19412994 :     where
     474     19412994 :         Buf: IoBuf + Send,
     475     19412994 :     {
     476     19412994 :         assert!(
     477     19412994 :             self.lsn_range.start <= lsn,
     478            0 :             "lsn_start={}, lsn={}",
     479              :             self.lsn_range.start,
     480              :             lsn
     481              :         );
     482              :         // We don't want to use compression in delta layer creation
     483     19412994 :         let compression = ImageCompressionAlgorithm::Disabled;
     484     19412994 :         let (val, res) = self
     485     19412994 :             .blob_writer
     486     19412994 :             .write_blob_maybe_compressed(val, ctx, compression)
     487        14767 :             .await;
     488     19412994 :         let off = match res {
     489     19412994 :             Ok((off, _)) => off,
     490            0 :             Err(e) => return (val, Err(anyhow::anyhow!(e))),
     491              :         };
     492              : 
     493     19412994 :         let blob_ref = BlobRef::new(off, will_init);
     494     19412994 : 
     495     19412994 :         let delta_key = DeltaKey::from_key_lsn(&key, lsn);
     496     19412994 :         let res = self.tree.append(&delta_key.0, blob_ref.0);
     497     19412994 : 
     498     19412994 :         self.num_keys += 1;
     499     19412994 : 
     500     19412994 :         (val, res.map_err(|e| anyhow::anyhow!(e)))
     501     19412994 :     }
     502              : 
     503      6071916 :     fn size(&self) -> u64 {
     504      6071916 :         self.blob_writer.size() + self.tree.borrow_writer().size()
     505      6071916 :     }
     506              : 
     507              :     ///
     508              :     /// Finish writing the delta layer.
     509              :     ///
     510         4200 :     async fn finish(
     511         4200 :         self,
     512         4200 :         key_end: Key,
     513         4200 :         ctx: &RequestContext,
     514         4200 :     ) -> anyhow::Result<(PersistentLayerDesc, Utf8PathBuf)> {
     515         4200 :         let temp_path = self.path.clone();
     516        29006 :         let result = self.finish0(key_end, ctx).await;
     517         4200 :         if result.is_err() {
     518            0 :             tracing::info!(%temp_path, "cleaning up temporary file after error during writing");
     519            0 :             if let Err(e) = std::fs::remove_file(&temp_path) {
     520            0 :                 tracing::warn!(error=%e, %temp_path, "error cleaning up temporary layer file after error during writing");
     521            0 :             }
     522         4200 :         }
     523         4200 :         result
     524         4200 :     }
     525              : 
     526         4200 :     async fn finish0(
     527         4200 :         self,
     528         4200 :         key_end: Key,
     529         4200 :         ctx: &RequestContext,
     530         4200 :     ) -> anyhow::Result<(PersistentLayerDesc, Utf8PathBuf)> {
     531         4200 :         let index_start_blk =
     532         4200 :             ((self.blob_writer.size() + PAGE_SZ as u64 - 1) / PAGE_SZ as u64) as u32;
     533              : 
     534         4200 :         let mut file = self.blob_writer.into_inner(ctx).await?;
     535              : 
     536              :         // Write out the index
     537         4200 :         let (index_root_blk, block_buf) = self.tree.finish()?;
     538         4200 :         file.seek(SeekFrom::Start(index_start_blk as u64 * PAGE_SZ as u64))
     539            0 :             .await?;
     540        45051 :         for buf in block_buf.blocks {
     541        40851 :             let (_buf, res) = file.write_all(buf.slice_len(), ctx).await;
     542        40851 :             res?;
     543              :         }
     544         4200 :         assert!(self.lsn_range.start < self.lsn_range.end);
     545              :         // Fill in the summary on blk 0
     546         4200 :         let summary = Summary {
     547         4200 :             magic: DELTA_FILE_MAGIC,
     548         4200 :             format_version: STORAGE_FORMAT_VERSION,
     549         4200 :             tenant_id: self.tenant_shard_id.tenant_id,
     550         4200 :             timeline_id: self.timeline_id,
     551         4200 :             key_range: self.key_start..key_end,
     552         4200 :             lsn_range: self.lsn_range.clone(),
     553         4200 :             index_start_blk,
     554         4200 :             index_root_blk,
     555         4200 :         };
     556         4200 : 
     557         4200 :         let mut buf = Vec::with_capacity(PAGE_SZ);
     558         4200 :         // TODO: could use smallvec here but it's a pain with Slice<T>
     559         4200 :         Summary::ser_into(&summary, &mut buf)?;
     560         4200 :         file.seek(SeekFrom::Start(0)).await?;
     561         4200 :         let (_buf, res) = file.write_all(buf.slice_len(), ctx).await;
     562         4200 :         res?;
     563              : 
     564         4200 :         let metadata = file
     565         4200 :             .metadata()
     566         2100 :             .await
     567         4200 :             .context("get file metadata to determine size")?;
     568              : 
     569              :         // 5GB limit for objects without multipart upload (which we don't want to use)
     570              :         // Make it a little bit below to account for differing GB units
     571              :         // https://docs.aws.amazon.com/AmazonS3/latest/userguide/upload-objects.html
     572         4200 :         ensure!(
     573         4200 :             metadata.len() <= S3_UPLOAD_LIMIT,
     574            0 :             "Created delta layer file at {} of size {} above limit {S3_UPLOAD_LIMIT}!",
     575            0 :             file.path,
     576            0 :             metadata.len()
     577              :         );
     578              : 
     579              :         // Note: Because we opened the file in write-only mode, we cannot
     580              :         // reuse the same VirtualFile for reading later. That's why we don't
     581              :         // set inner.file here. The first read will have to re-open it.
     582              : 
     583         4200 :         let desc = PersistentLayerDesc::new_delta(
     584         4200 :             self.tenant_shard_id,
     585         4200 :             self.timeline_id,
     586         4200 :             self.key_start..key_end,
     587         4200 :             self.lsn_range.clone(),
     588         4200 :             metadata.len(),
     589         4200 :         );
     590         4200 : 
     591         4200 :         // fsync the file
     592         4200 :         file.sync_all().await?;
     593              : 
     594         4200 :         trace!("created delta layer {}", self.path);
     595              : 
     596         4200 :         Ok((desc, self.path))
     597         4200 :     }
     598              : }
     599              : 
     600              : /// A builder object for constructing a new delta layer.
     601              : ///
     602              : /// Usage:
     603              : ///
     604              : /// 1. Create the DeltaLayerWriter by calling DeltaLayerWriter::new(...)
     605              : ///
     606              : /// 2. Write the contents by calling `put_value` for every page
     607              : ///    version to store in the layer.
     608              : ///
     609              : /// 3. Call `finish`.
     610              : ///
     611              : /// # Note
     612              : ///
     613              : /// As described in <https://github.com/neondatabase/neon/issues/2650>, it's
     614              : /// possible for the writer to drop before `finish` is actually called. So this
     615              : /// could lead to odd temporary files in the directory, exhausting file system.
     616              : /// This structure wraps `DeltaLayerWriterInner` and also contains `Drop`
     617              : /// implementation that cleans up the temporary file in failure. It's not
     618              : /// possible to do this directly in `DeltaLayerWriterInner` since `finish` moves
     619              : /// out some fields, making it impossible to implement `Drop`.
     620              : ///
     621              : #[must_use]
     622              : pub struct DeltaLayerWriter {
     623              :     inner: Option<DeltaLayerWriterInner>,
     624              : }
     625              : 
     626              : impl DeltaLayerWriter {
     627              :     ///
     628              :     /// Start building a new delta layer.
     629              :     ///
     630         4248 :     pub async fn new(
     631         4248 :         conf: &'static PageServerConf,
     632         4248 :         timeline_id: TimelineId,
     633         4248 :         tenant_shard_id: TenantShardId,
     634         4248 :         key_start: Key,
     635         4248 :         lsn_range: Range<Lsn>,
     636         4248 :         ctx: &RequestContext,
     637         4248 :     ) -> anyhow::Result<Self> {
     638         4248 :         Ok(Self {
     639         4248 :             inner: Some(
     640         4248 :                 DeltaLayerWriterInner::new(
     641         4248 :                     conf,
     642         4248 :                     timeline_id,
     643         4248 :                     tenant_shard_id,
     644         4248 :                     key_start,
     645         4248 :                     lsn_range,
     646         4248 :                     ctx,
     647         4248 :                 )
     648         2159 :                 .await?,
     649              :             ),
     650              :         })
     651         4248 :     }
     652              : 
     653              :     ///
     654              :     /// Append a key-value pair to the file.
     655              :     ///
     656              :     /// The values must be appended in key, lsn order.
     657              :     ///
     658      6253014 :     pub async fn put_value(
     659      6253014 :         &mut self,
     660      6253014 :         key: Key,
     661      6253014 :         lsn: Lsn,
     662      6253014 :         val: Value,
     663      6253014 :         ctx: &RequestContext,
     664      6253014 :     ) -> anyhow::Result<()> {
     665      6253014 :         self.inner
     666      6253014 :             .as_mut()
     667      6253014 :             .unwrap()
     668      6253014 :             .put_value(key, lsn, val, ctx)
     669         5924 :             .await
     670      6253014 :     }
     671              : 
     672     13159980 :     pub async fn put_value_bytes<Buf>(
     673     13159980 :         &mut self,
     674     13159980 :         key: Key,
     675     13159980 :         lsn: Lsn,
     676     13159980 :         val: FullSlice<Buf>,
     677     13159980 :         will_init: bool,
     678     13159980 :         ctx: &RequestContext,
     679     13159980 :     ) -> (FullSlice<Buf>, anyhow::Result<()>)
     680     13159980 :     where
     681     13159980 :         Buf: IoBuf + Send,
     682     13159980 :     {
     683     13159980 :         self.inner
     684     13159980 :             .as_mut()
     685     13159980 :             .unwrap()
     686     13159980 :             .put_value_bytes(key, lsn, val, will_init, ctx)
     687         8843 :             .await
     688     13159980 :     }
     689              : 
     690      6071916 :     pub fn size(&self) -> u64 {
     691      6071916 :         self.inner.as_ref().unwrap().size()
     692      6071916 :     }
     693              : 
     694              :     ///
     695              :     /// Finish writing the delta layer.
     696              :     ///
     697         4200 :     pub(crate) async fn finish(
     698         4200 :         mut self,
     699         4200 :         key_end: Key,
     700         4200 :         ctx: &RequestContext,
     701         4200 :     ) -> anyhow::Result<(PersistentLayerDesc, Utf8PathBuf)> {
     702        29006 :         self.inner.take().unwrap().finish(key_end, ctx).await
     703         4200 :     }
     704              : 
     705        36498 :     pub(crate) fn num_keys(&self) -> usize {
     706        36498 :         self.inner.as_ref().unwrap().num_keys
     707        36498 :     }
     708              : 
     709        45252 :     pub(crate) fn estimated_size(&self) -> u64 {
     710        45252 :         let inner = self.inner.as_ref().unwrap();
     711        45252 :         inner.blob_writer.size() + inner.tree.borrow_writer().size() + PAGE_SZ as u64
     712        45252 :     }
     713              : }
     714              : 
     715              : impl Drop for DeltaLayerWriter {
     716         4248 :     fn drop(&mut self) {
     717         4248 :         if let Some(inner) = self.inner.take() {
     718           48 :             // We want to remove the virtual file here, so it's fine to not
     719           48 :             // having completely flushed unwritten data.
     720           48 :             let vfile = inner.blob_writer.into_inner_no_flush();
     721           48 :             vfile.remove();
     722         4200 :         }
     723         4248 :     }
     724              : }
     725              : 
     726            0 : #[derive(thiserror::Error, Debug)]
     727              : pub enum RewriteSummaryError {
     728              :     #[error("magic mismatch")]
     729              :     MagicMismatch,
     730              :     #[error(transparent)]
     731              :     Other(#[from] anyhow::Error),
     732              : }
     733              : 
     734              : impl From<std::io::Error> for RewriteSummaryError {
     735            0 :     fn from(e: std::io::Error) -> Self {
     736            0 :         Self::Other(anyhow::anyhow!(e))
     737            0 :     }
     738              : }
     739              : 
     740              : impl DeltaLayer {
     741            0 :     pub async fn rewrite_summary<F>(
     742            0 :         path: &Utf8Path,
     743            0 :         rewrite: F,
     744            0 :         ctx: &RequestContext,
     745            0 :     ) -> Result<(), RewriteSummaryError>
     746            0 :     where
     747            0 :         F: Fn(Summary) -> Summary,
     748            0 :     {
     749            0 :         let mut file = VirtualFile::open_with_options(
     750            0 :             path,
     751            0 :             virtual_file::OpenOptions::new().read(true).write(true),
     752            0 :             ctx,
     753            0 :         )
     754            0 :         .await
     755            0 :         .with_context(|| format!("Failed to open file '{}'", path))?;
     756            0 :         let file_id = page_cache::next_file_id();
     757            0 :         let block_reader = FileBlockReader::new(&file, file_id);
     758            0 :         let summary_blk = block_reader.read_blk(0, ctx).await?;
     759            0 :         let actual_summary = Summary::des_prefix(summary_blk.as_ref()).context("deserialize")?;
     760            0 :         if actual_summary.magic != DELTA_FILE_MAGIC {
     761            0 :             return Err(RewriteSummaryError::MagicMismatch);
     762            0 :         }
     763            0 : 
     764            0 :         let new_summary = rewrite(actual_summary);
     765            0 : 
     766            0 :         let mut buf = Vec::with_capacity(PAGE_SZ);
     767            0 :         // TODO: could use smallvec here, but it's a pain with Slice<T>
     768            0 :         Summary::ser_into(&new_summary, &mut buf).context("serialize")?;
     769            0 :         file.seek(SeekFrom::Start(0)).await?;
     770            0 :         let (_buf, res) = file.write_all(buf.slice_len(), ctx).await;
     771            0 :         res?;
     772            0 :         Ok(())
     773            0 :     }
     774              : }
     775              : 
     776              : impl DeltaLayerInner {
     777         1422 :     pub(crate) fn key_range(&self) -> &Range<Key> {
     778         1422 :         &self.layer_key_range
     779         1422 :     }
     780              : 
     781         1422 :     pub(crate) fn lsn_range(&self) -> &Range<Lsn> {
     782         1422 :         &self.layer_lsn_range
     783         1422 :     }
     784              : 
     785         3126 :     pub(super) async fn load(
     786         3126 :         path: &Utf8Path,
     787         3126 :         summary: Option<Summary>,
     788         3126 :         max_vectored_read_bytes: Option<MaxVectoredReadBytes>,
     789         3126 :         ctx: &RequestContext,
     790         3126 :     ) -> anyhow::Result<Self> {
     791         3126 :         let file = VirtualFile::open(path, ctx)
     792         1563 :             .await
     793         3126 :             .context("open layer file")?;
     794              : 
     795         3126 :         let file_id = page_cache::next_file_id();
     796         3126 : 
     797         3126 :         let block_reader = FileBlockReader::new(&file, file_id);
     798              : 
     799         3126 :         let summary_blk = block_reader
     800         3126 :             .read_blk(0, ctx)
     801         1579 :             .await
     802         3126 :             .context("read first block")?;
     803              : 
     804              :         // TODO: this should be an assertion instead; see ImageLayerInner::load
     805         3126 :         let actual_summary =
     806         3126 :             Summary::des_prefix(summary_blk.as_ref()).context("deserialize first block")?;
     807              : 
     808         3126 :         if let Some(mut expected_summary) = summary {
     809              :             // production code path
     810         3126 :             expected_summary.index_start_blk = actual_summary.index_start_blk;
     811         3126 :             expected_summary.index_root_blk = actual_summary.index_root_blk;
     812         3126 :             // mask out the timeline_id, but still require the layers to be from the same tenant
     813         3126 :             expected_summary.timeline_id = actual_summary.timeline_id;
     814         3126 : 
     815         3126 :             if actual_summary != expected_summary {
     816            0 :                 bail!(
     817            0 :                     "in-file summary does not match expected summary. actual = {:?} expected = {:?}",
     818            0 :                     actual_summary,
     819            0 :                     expected_summary
     820            0 :                 );
     821         3126 :             }
     822            0 :         }
     823              : 
     824         3126 :         Ok(DeltaLayerInner {
     825         3126 :             file,
     826         3126 :             file_id,
     827         3126 :             index_start_blk: actual_summary.index_start_blk,
     828         3126 :             index_root_blk: actual_summary.index_root_blk,
     829         3126 :             max_vectored_read_bytes,
     830         3126 :             layer_key_range: actual_summary.key_range,
     831         3126 :             layer_lsn_range: actual_summary.lsn_range,
     832         3126 :         })
     833         3126 :     }
     834              : 
     835              :     // Look up the keys in the provided keyspace and update
     836              :     // the reconstruct state with whatever is found.
     837              :     //
     838              :     // If the key is cached, go no further than the cached Lsn.
     839              :     //
     840              :     // Currently, the index is visited for each range, but this
     841              :     // can be further optimised to visit the index only once.
     842       614615 :     pub(super) async fn get_values_reconstruct_data(
     843       614615 :         &self,
     844       614615 :         keyspace: KeySpace,
     845       614615 :         lsn_range: Range<Lsn>,
     846       614615 :         reconstruct_state: &mut ValuesReconstructState,
     847       614615 :         ctx: &RequestContext,
     848       614615 :     ) -> Result<(), GetVectoredError> {
     849       614615 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
     850       614615 :         let index_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
     851       614615 :             self.index_start_blk,
     852       614615 :             self.index_root_blk,
     853       614615 :             block_reader,
     854       614615 :         );
     855       614615 : 
     856       614615 :         let planner = VectoredReadPlanner::new(
     857       614615 :             self.max_vectored_read_bytes
     858       614615 :                 .expect("Layer is loaded with max vectored bytes config")
     859       614615 :                 .0
     860       614615 :                 .into(),
     861       614615 :         );
     862       614615 : 
     863       614615 :         let data_end_offset = self.index_start_offset();
     864              : 
     865       614615 :         let reads = Self::plan_reads(
     866       614615 :             &keyspace,
     867       614615 :             lsn_range.clone(),
     868       614615 :             data_end_offset,
     869       614615 :             index_reader,
     870       614615 :             planner,
     871       614615 :             reconstruct_state,
     872       614615 :             ctx,
     873       614615 :         )
     874        61968 :         .await
     875       614615 :         .map_err(GetVectoredError::Other)?;
     876              : 
     877       614615 :         self.do_reads_and_update_state(reads, reconstruct_state, ctx)
     878       205224 :             .await;
     879              : 
     880       614615 :         reconstruct_state.on_lsn_advanced(&keyspace, lsn_range.start);
     881       614615 : 
     882       614615 :         Ok(())
     883       614615 :     }
     884              : 
     885              :     /// Load all key-values in the delta layer, should be replaced by an iterator-based interface in the future.
     886            0 :     pub(super) async fn load_key_values(
     887            0 :         &self,
     888            0 :         ctx: &RequestContext,
     889            0 :     ) -> anyhow::Result<Vec<(Key, Lsn, Value)>> {
     890            0 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
     891            0 :         let index_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
     892            0 :             self.index_start_blk,
     893            0 :             self.index_root_blk,
     894            0 :             block_reader,
     895            0 :         );
     896            0 :         let mut result = Vec::new();
     897            0 :         let mut stream =
     898            0 :             Box::pin(self.stream_index_forwards(index_reader, &[0; DELTA_KEY_SIZE], ctx));
     899            0 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
     900            0 :         let cursor = block_reader.block_cursor();
     901            0 :         let mut buf = Vec::new();
     902            0 :         while let Some(item) = stream.next().await {
     903            0 :             let (key, lsn, pos) = item?;
     904              :             // TODO: dedup code with get_reconstruct_value
     905              :             // TODO: ctx handling and sharding
     906            0 :             cursor
     907            0 :                 .read_blob_into_buf(pos.pos(), &mut buf, ctx)
     908            0 :                 .await
     909            0 :                 .with_context(|| {
     910            0 :                     format!("Failed to read blob from virtual file {}", self.file.path)
     911            0 :                 })?;
     912            0 :             let val = Value::des(&buf).with_context(|| {
     913            0 :                 format!(
     914            0 :                     "Failed to deserialize file blob from virtual file {}",
     915            0 :                     self.file.path
     916            0 :                 )
     917            0 :             })?;
     918            0 :             result.push((key, lsn, val));
     919              :         }
     920            0 :         Ok(result)
     921            0 :     }
     922              : 
     923       615221 :     async fn plan_reads<Reader>(
     924       615221 :         keyspace: &KeySpace,
     925       615221 :         lsn_range: Range<Lsn>,
     926       615221 :         data_end_offset: u64,
     927       615221 :         index_reader: DiskBtreeReader<Reader, DELTA_KEY_SIZE>,
     928       615221 :         mut planner: VectoredReadPlanner,
     929       615221 :         reconstruct_state: &mut ValuesReconstructState,
     930       615221 :         ctx: &RequestContext,
     931       615221 :     ) -> anyhow::Result<Vec<VectoredRead>>
     932       615221 :     where
     933       615221 :         Reader: BlockReader + Clone,
     934       615221 :     {
     935       615221 :         let ctx = RequestContextBuilder::extend(ctx)
     936       615221 :             .page_content_kind(PageContentKind::DeltaLayerBtreeNode)
     937       615221 :             .build();
     938              : 
     939       741995 :         for range in keyspace.ranges.iter() {
     940       741995 :             let mut range_end_handled = false;
     941       741995 : 
     942       741995 :             let start_key = DeltaKey::from_key_lsn(&range.start, lsn_range.start);
     943       741995 :             let index_stream = index_reader.clone().into_stream(&start_key.0, &ctx);
     944       741995 :             let mut index_stream = std::pin::pin!(index_stream);
     945              : 
     946      1779079 :             while let Some(index_entry) = index_stream.next().await {
     947      1752215 :                 let (raw_key, value) = index_entry?;
     948      1752215 :                 let key = Key::from_slice(&raw_key[..KEY_SIZE]);
     949      1752215 :                 let lsn = DeltaKey::extract_lsn_from_buf(&raw_key);
     950      1752215 :                 let blob_ref = BlobRef(value);
     951      1752215 : 
     952      1752215 :                 // Lsns are not monotonically increasing across keys, so we don't assert on them.
     953      1752215 :                 assert!(key >= range.start);
     954              : 
     955      1752215 :                 let outside_lsn_range = !lsn_range.contains(&lsn);
     956      1752215 :                 let below_cached_lsn = reconstruct_state.get_cached_lsn(&key) >= Some(lsn);
     957              : 
     958      1752215 :                 let flag = {
     959      1752215 :                     if outside_lsn_range || below_cached_lsn {
     960       218974 :                         BlobFlag::Ignore
     961      1533241 :                     } else if blob_ref.will_init() {
     962      1358287 :                         BlobFlag::ReplaceAll
     963              :                     } else {
     964              :                         // Usual path: add blob to the read
     965       174954 :                         BlobFlag::None
     966              :                     }
     967              :                 };
     968              : 
     969      1752215 :                 if key >= range.end || (key.next() == range.end && lsn >= lsn_range.end) {
     970       715131 :                     planner.handle_range_end(blob_ref.pos());
     971       715131 :                     range_end_handled = true;
     972       715131 :                     break;
     973      1037084 :                 } else {
     974      1037084 :                     planner.handle(key, lsn, blob_ref.pos(), flag);
     975      1037084 :                 }
     976              :             }
     977              : 
     978       741995 :             if !range_end_handled {
     979        26864 :                 tracing::debug!("Handling range end fallback at {}", data_end_offset);
     980        26864 :                 planner.handle_range_end(data_end_offset);
     981       715131 :             }
     982              :         }
     983              : 
     984       615221 :         Ok(planner.finish())
     985       615221 :     }
     986              : 
     987       615215 :     fn get_min_read_buffer_size(
     988       615215 :         planned_reads: &[VectoredRead],
     989       615215 :         read_size_soft_max: usize,
     990       615215 :     ) -> usize {
     991       615215 :         let Some(largest_read) = planned_reads.iter().max_by_key(|read| read.size()) else {
     992       248696 :             return read_size_soft_max;
     993              :         };
     994              : 
     995       366519 :         let largest_read_size = largest_read.size();
     996       366519 :         if largest_read_size > read_size_soft_max {
     997              :             // If the read is oversized, it should only contain one key.
     998          600 :             let offenders = largest_read
     999          600 :                 .blobs_at
    1000          600 :                 .as_slice()
    1001          600 :                 .iter()
    1002          600 :                 .map(|(_, blob_meta)| format!("{}@{}", blob_meta.key, blob_meta.lsn))
    1003          600 :                 .join(", ");
    1004          600 :             tracing::warn!(
    1005            0 :                 "Oversized vectored read ({} > {}) for keys {}",
    1006              :                 largest_read_size,
    1007              :                 read_size_soft_max,
    1008              :                 offenders
    1009              :             );
    1010       365919 :         }
    1011              : 
    1012       366519 :         largest_read_size
    1013       615215 :     }
    1014              : 
    1015       614615 :     async fn do_reads_and_update_state(
    1016       614615 :         &self,
    1017       614615 :         reads: Vec<VectoredRead>,
    1018       614615 :         reconstruct_state: &mut ValuesReconstructState,
    1019       614615 :         ctx: &RequestContext,
    1020       614615 :     ) {
    1021       614615 :         let vectored_blob_reader = VectoredBlobReader::new(&self.file);
    1022       614615 :         let mut ignore_key_with_err = None;
    1023       614615 : 
    1024       614615 :         let max_vectored_read_bytes = self
    1025       614615 :             .max_vectored_read_bytes
    1026       614615 :             .expect("Layer is loaded with max vectored bytes config")
    1027       614615 :             .0
    1028       614615 :             .into();
    1029       614615 :         let buf_size = Self::get_min_read_buffer_size(&reads, max_vectored_read_bytes);
    1030       614615 :         let mut buf = Some(BytesMut::with_capacity(buf_size));
    1031              : 
    1032              :         // Note that reads are processed in reverse order (from highest key+lsn).
    1033              :         // This is the order that `ReconstructState` requires such that it can
    1034              :         // track when a key is done.
    1035       614615 :         for read in reads.into_iter().rev() {
    1036       403662 :             let res = vectored_blob_reader
    1037       403662 :                 .read_blobs(&read, buf.take().expect("Should have a buffer"), ctx)
    1038       205224 :                 .await;
    1039              : 
    1040       403662 :             let blobs_buf = match res {
    1041       403662 :                 Ok(blobs_buf) => blobs_buf,
    1042            0 :                 Err(err) => {
    1043            0 :                     let kind = err.kind();
    1044            0 :                     for (_, blob_meta) in read.blobs_at.as_slice() {
    1045            0 :                         reconstruct_state.on_key_error(
    1046            0 :                             blob_meta.key,
    1047            0 :                             PageReconstructError::Other(anyhow!(
    1048            0 :                                 "Failed to read blobs from virtual file {}: {}",
    1049            0 :                                 self.file.path,
    1050            0 :                                 kind
    1051            0 :                             )),
    1052            0 :                         );
    1053            0 :                     }
    1054              : 
    1055              :                     // We have "lost" the buffer since the lower level IO api
    1056              :                     // doesn't return the buffer on error. Allocate a new one.
    1057            0 :                     buf = Some(BytesMut::with_capacity(buf_size));
    1058            0 : 
    1059            0 :                     continue;
    1060              :                 }
    1061              :             };
    1062              : 
    1063       449933 :             for meta in blobs_buf.blobs.iter().rev() {
    1064       449933 :                 if Some(meta.meta.key) == ignore_key_with_err {
    1065            0 :                     continue;
    1066       449933 :                 }
    1067       449933 : 
    1068       449933 :                 let value = Value::des(&blobs_buf.buf[meta.start..meta.end]);
    1069       449933 :                 let value = match value {
    1070       449933 :                     Ok(v) => v,
    1071            0 :                     Err(e) => {
    1072            0 :                         reconstruct_state.on_key_error(
    1073            0 :                             meta.meta.key,
    1074            0 :                             PageReconstructError::Other(anyhow!(e).context(format!(
    1075            0 :                                 "Failed to deserialize blob from virtual file {}",
    1076            0 :                                 self.file.path,
    1077            0 :                             ))),
    1078            0 :                         );
    1079            0 : 
    1080            0 :                         ignore_key_with_err = Some(meta.meta.key);
    1081            0 :                         continue;
    1082              :                     }
    1083              :                 };
    1084              : 
    1085              :                 // Invariant: once a key reaches [`ValueReconstructSituation::Complete`]
    1086              :                 // state, no further updates shall be made to it. The call below will
    1087              :                 // panic if the invariant is violated.
    1088       449933 :                 reconstruct_state.update_key(&meta.meta.key, meta.meta.lsn, value);
    1089              :             }
    1090              : 
    1091       403662 :             buf = Some(blobs_buf.buf);
    1092              :         }
    1093       614615 :     }
    1094              : 
    1095         1218 :     pub(super) async fn load_keys<'a>(
    1096         1218 :         &'a self,
    1097         1218 :         ctx: &RequestContext,
    1098         1218 :     ) -> Result<Vec<DeltaEntry<'a>>> {
    1099         1218 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
    1100         1218 :         let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    1101         1218 :             self.index_start_blk,
    1102         1218 :             self.index_root_blk,
    1103         1218 :             block_reader,
    1104         1218 :         );
    1105         1218 : 
    1106         1218 :         let mut all_keys: Vec<DeltaEntry<'_>> = Vec::new();
    1107         1218 : 
    1108         1218 :         tree_reader
    1109         1218 :             .visit(
    1110         1218 :                 &[0u8; DELTA_KEY_SIZE],
    1111         1218 :                 VisitDirection::Forwards,
    1112      6192138 :                 |key, value| {
    1113      6192138 :                     let delta_key = DeltaKey::from_slice(key);
    1114      6192138 :                     let val_ref = ValueRef {
    1115      6192138 :                         blob_ref: BlobRef(value),
    1116      6192138 :                         layer: self,
    1117      6192138 :                     };
    1118      6192138 :                     let pos = BlobRef(value).pos();
    1119      6192138 :                     if let Some(last) = all_keys.last_mut() {
    1120      6190920 :                         // subtract offset of the current and last entries to get the size
    1121      6190920 :                         // of the value associated with this (key, lsn) tuple
    1122      6190920 :                         let first_pos = last.size;
    1123      6190920 :                         last.size = pos - first_pos;
    1124      6190920 :                     }
    1125      6192138 :                     let entry = DeltaEntry {
    1126      6192138 :                         key: delta_key.key(),
    1127      6192138 :                         lsn: delta_key.lsn(),
    1128      6192138 :                         size: pos,
    1129      6192138 :                         val: val_ref,
    1130      6192138 :                     };
    1131      6192138 :                     all_keys.push(entry);
    1132      6192138 :                     true
    1133      6192138 :                 },
    1134         1218 :                 &RequestContextBuilder::extend(ctx)
    1135         1218 :                     .page_content_kind(PageContentKind::DeltaLayerBtreeNode)
    1136         1218 :                     .build(),
    1137         1218 :             )
    1138         6357 :             .await?;
    1139         1218 :         if let Some(last) = all_keys.last_mut() {
    1140         1218 :             // Last key occupies all space till end of value storage,
    1141         1218 :             // which corresponds to beginning of the index
    1142         1218 :             last.size = self.index_start_offset() - last.size;
    1143         1218 :         }
    1144         1218 :         Ok(all_keys)
    1145         1218 :     }
    1146              : 
    1147              :     /// Using the given writer, write out a version which has the earlier Lsns than `until`.
    1148              :     ///
    1149              :     /// Return the amount of key value records pushed to the writer.
    1150           30 :     pub(super) async fn copy_prefix(
    1151           30 :         &self,
    1152           30 :         writer: &mut DeltaLayerWriter,
    1153           30 :         until: Lsn,
    1154           30 :         ctx: &RequestContext,
    1155           30 :     ) -> anyhow::Result<usize> {
    1156           30 :         use crate::tenant::vectored_blob_io::{
    1157           30 :             BlobMeta, VectoredReadBuilder, VectoredReadExtended,
    1158           30 :         };
    1159           30 :         use futures::stream::TryStreamExt;
    1160           30 : 
    1161           30 :         #[derive(Debug)]
    1162           30 :         enum Item {
    1163           30 :             Actual(Key, Lsn, BlobRef),
    1164           30 :             Sentinel,
    1165           30 :         }
    1166           30 : 
    1167           30 :         impl From<Item> for Option<(Key, Lsn, BlobRef)> {
    1168          210 :             fn from(value: Item) -> Self {
    1169          210 :                 match value {
    1170          180 :                     Item::Actual(key, lsn, blob) => Some((key, lsn, blob)),
    1171           30 :                     Item::Sentinel => None,
    1172           30 :                 }
    1173          210 :             }
    1174           30 :         }
    1175           30 : 
    1176           30 :         impl Item {
    1177          210 :             fn offset(&self) -> Option<BlobRef> {
    1178          210 :                 match self {
    1179          180 :                     Item::Actual(_, _, blob) => Some(*blob),
    1180           30 :                     Item::Sentinel => None,
    1181           30 :                 }
    1182          210 :             }
    1183           30 : 
    1184          210 :             fn is_last(&self) -> bool {
    1185          210 :                 matches!(self, Item::Sentinel)
    1186          210 :             }
    1187           30 :         }
    1188           30 : 
    1189           30 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
    1190           30 :         let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    1191           30 :             self.index_start_blk,
    1192           30 :             self.index_root_blk,
    1193           30 :             block_reader,
    1194           30 :         );
    1195           30 : 
    1196           30 :         let stream = self.stream_index_forwards(tree_reader, &[0u8; DELTA_KEY_SIZE], ctx);
    1197          180 :         let stream = stream.map_ok(|(key, lsn, pos)| Item::Actual(key, lsn, pos));
    1198           30 :         // put in a sentinel value for getting the end offset for last item, and not having to
    1199           30 :         // repeat the whole read part
    1200           30 :         let stream = stream.chain(futures::stream::once(futures::future::ready(Ok(
    1201           30 :             Item::Sentinel,
    1202           30 :         ))));
    1203           30 :         let mut stream = std::pin::pin!(stream);
    1204           30 : 
    1205           30 :         let mut prev: Option<(Key, Lsn, BlobRef)> = None;
    1206           30 : 
    1207           30 :         let mut read_builder: Option<VectoredReadBuilder> = None;
    1208           30 :         let read_mode = VectoredReadCoalesceMode::get();
    1209           30 : 
    1210           30 :         let max_read_size = self
    1211           30 :             .max_vectored_read_bytes
    1212           30 :             .map(|x| x.0.get())
    1213           30 :             .unwrap_or(8192);
    1214           30 : 
    1215           30 :         let mut buffer = Some(BytesMut::with_capacity(max_read_size));
    1216           30 : 
    1217           30 :         // FIXME: buffering of DeltaLayerWriter
    1218           30 :         let mut per_blob_copy = Vec::new();
    1219           30 : 
    1220           30 :         let mut records = 0;
    1221              : 
    1222          240 :         while let Some(item) = stream.try_next().await? {
    1223          210 :             tracing::debug!(?item, "popped");
    1224          210 :             let offset = item
    1225          210 :                 .offset()
    1226          210 :                 .unwrap_or(BlobRef::new(self.index_start_offset(), false));
    1227              : 
    1228          210 :             let actionable = if let Some((key, lsn, start_offset)) = prev.take() {
    1229          180 :                 let end_offset = offset;
    1230          180 : 
    1231          180 :                 Some((BlobMeta { key, lsn }, start_offset..end_offset))
    1232              :             } else {
    1233           30 :                 None
    1234              :             };
    1235              : 
    1236          210 :             let is_last = item.is_last();
    1237          210 : 
    1238          210 :             prev = Option::from(item);
    1239          210 : 
    1240          210 :             let actionable = actionable.filter(|x| x.0.lsn < until);
    1241              : 
    1242          210 :             let builder = if let Some((meta, offsets)) = actionable {
    1243              :                 // extend or create a new builder
    1244           96 :                 if read_builder
    1245           96 :                     .as_mut()
    1246           96 :                     .map(|x| x.extend(offsets.start.pos(), offsets.end.pos(), meta))
    1247           96 :                     .unwrap_or(VectoredReadExtended::No)
    1248           96 :                     == VectoredReadExtended::Yes
    1249              :                 {
    1250           48 :                     None
    1251              :                 } else {
    1252           48 :                     read_builder.replace(VectoredReadBuilder::new(
    1253           48 :                         offsets.start.pos(),
    1254           48 :                         offsets.end.pos(),
    1255           48 :                         meta,
    1256           48 :                         max_read_size,
    1257           48 :                         read_mode,
    1258           48 :                     ))
    1259              :                 }
    1260              :             } else {
    1261              :                 // nothing to do, except perhaps flush any existing for the last element
    1262          114 :                 None
    1263              :             };
    1264              : 
    1265              :             // flush the possible older builder and also the new one if the item was the last one
    1266          210 :             let builders = builder.into_iter();
    1267          210 :             let builders = if is_last {
    1268           30 :                 builders.chain(read_builder.take())
    1269              :             } else {
    1270          180 :                 builders.chain(None)
    1271              :             };
    1272              : 
    1273          258 :             for builder in builders {
    1274           48 :                 let read = builder.build();
    1275           48 : 
    1276           48 :                 let reader = VectoredBlobReader::new(&self.file);
    1277           48 : 
    1278           48 :                 let mut buf = buffer.take().unwrap();
    1279           48 : 
    1280           48 :                 buf.clear();
    1281           48 :                 buf.reserve(read.size());
    1282           48 :                 let res = reader.read_blobs(&read, buf, ctx).await?;
    1283              : 
    1284          144 :                 for blob in res.blobs {
    1285           96 :                     let key = blob.meta.key;
    1286           96 :                     let lsn = blob.meta.lsn;
    1287           96 :                     let data = &res.buf[blob.start..blob.end];
    1288           96 : 
    1289           96 :                     #[cfg(debug_assertions)]
    1290           96 :                     Value::des(data)
    1291           96 :                         .with_context(|| {
    1292            0 :                             format!(
    1293            0 :                                 "blob failed to deserialize for {}@{}, {}..{}: {:?}",
    1294            0 :                                 blob.meta.key,
    1295            0 :                                 blob.meta.lsn,
    1296            0 :                                 blob.start,
    1297            0 :                                 blob.end,
    1298            0 :                                 utils::Hex(data)
    1299            0 :                             )
    1300           96 :                         })
    1301           96 :                         .unwrap();
    1302           96 : 
    1303           96 :                     // is it an image or will_init walrecord?
    1304           96 :                     // FIXME: this could be handled by threading the BlobRef to the
    1305           96 :                     // VectoredReadBuilder
    1306           96 :                     let will_init = crate::repository::ValueBytes::will_init(data)
    1307           96 :                         .inspect_err(|_e| {
    1308            0 :                             #[cfg(feature = "testing")]
    1309            0 :                             tracing::error!(data=?utils::Hex(data), err=?_e, %key, %lsn, "failed to parse will_init out of serialized value");
    1310           96 :                         })
    1311           96 :                         .unwrap_or(false);
    1312           96 : 
    1313           96 :                     per_blob_copy.clear();
    1314           96 :                     per_blob_copy.extend_from_slice(data);
    1315              : 
    1316           96 :                     let (tmp, res) = writer
    1317           96 :                         .put_value_bytes(
    1318           96 :                             key,
    1319           96 :                             lsn,
    1320           96 :                             std::mem::take(&mut per_blob_copy).slice_len(),
    1321           96 :                             will_init,
    1322           96 :                             ctx,
    1323           96 :                         )
    1324           12 :                         .await;
    1325           96 :                     per_blob_copy = tmp.into_raw_slice().into_inner();
    1326           96 : 
    1327           96 :                     res?;
    1328              : 
    1329           96 :                     records += 1;
    1330              :                 }
    1331              : 
    1332           48 :                 buffer = Some(res.buf);
    1333              :             }
    1334              :         }
    1335              : 
    1336           30 :         assert!(
    1337           30 :             read_builder.is_none(),
    1338            0 :             "with the sentinel above loop should had handled all"
    1339              :         );
    1340              : 
    1341           30 :         Ok(records)
    1342           30 :     }
    1343              : 
    1344           12 :     pub(super) async fn dump(&self, ctx: &RequestContext) -> anyhow::Result<()> {
    1345           12 :         println!(
    1346           12 :             "index_start_blk: {}, root {}",
    1347           12 :             self.index_start_blk, self.index_root_blk
    1348           12 :         );
    1349           12 : 
    1350           12 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
    1351           12 :         let tree_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    1352           12 :             self.index_start_blk,
    1353           12 :             self.index_root_blk,
    1354           12 :             block_reader,
    1355           12 :         );
    1356           12 : 
    1357           12 :         tree_reader.dump().await?;
    1358              : 
    1359           12 :         let keys = self.load_keys(ctx).await?;
    1360              : 
    1361           24 :         async fn dump_blob(val: &ValueRef<'_>, ctx: &RequestContext) -> anyhow::Result<String> {
    1362           24 :             let buf = val.load_raw(ctx).await?;
    1363           24 :             let val = Value::des(&buf)?;
    1364           24 :             let desc = match val {
    1365           24 :                 Value::Image(img) => {
    1366           24 :                     format!(" img {} bytes", img.len())
    1367              :                 }
    1368            0 :                 Value::WalRecord(rec) => {
    1369            0 :                     let wal_desc = walrecord::describe_wal_record(&rec)?;
    1370            0 :                     format!(
    1371            0 :                         " rec {} bytes will_init: {} {}",
    1372            0 :                         buf.len(),
    1373            0 :                         rec.will_init(),
    1374            0 :                         wal_desc
    1375            0 :                     )
    1376              :                 }
    1377              :             };
    1378           24 :             Ok(desc)
    1379           24 :         }
    1380              : 
    1381           36 :         for entry in keys {
    1382           24 :             let DeltaEntry { key, lsn, val, .. } = entry;
    1383           24 :             let desc = match dump_blob(&val, ctx).await {
    1384           24 :                 Ok(desc) => desc,
    1385            0 :                 Err(err) => {
    1386            0 :                     format!("ERROR: {err}")
    1387              :                 }
    1388              :             };
    1389           24 :             println!("  key {key} at {lsn}: {desc}");
    1390           24 : 
    1391           24 :             // Print more details about CHECKPOINT records. Would be nice to print details
    1392           24 :             // of many other record types too, but these are particularly interesting, as
    1393           24 :             // have a lot of special processing for them in walingest.rs.
    1394           24 :             use pageserver_api::key::CHECKPOINT_KEY;
    1395           24 :             use postgres_ffi::CheckPoint;
    1396           24 :             if key == CHECKPOINT_KEY {
    1397            0 :                 let val = val.load(ctx).await?;
    1398            0 :                 match val {
    1399            0 :                     Value::Image(img) => {
    1400            0 :                         let checkpoint = CheckPoint::decode(&img)?;
    1401            0 :                         println!("   CHECKPOINT: {:?}", checkpoint);
    1402              :                     }
    1403            0 :                     Value::WalRecord(_rec) => {
    1404            0 :                         println!("   unexpected walrecord value for checkpoint key");
    1405            0 :                     }
    1406              :                 }
    1407           24 :             }
    1408              :         }
    1409              : 
    1410           12 :         Ok(())
    1411           12 :     }
    1412              : 
    1413           90 :     fn stream_index_forwards<'a, R>(
    1414           90 :         &'a self,
    1415           90 :         reader: DiskBtreeReader<R, DELTA_KEY_SIZE>,
    1416           90 :         start: &'a [u8; DELTA_KEY_SIZE],
    1417           90 :         ctx: &'a RequestContext,
    1418           90 :     ) -> impl futures::stream::Stream<
    1419           90 :         Item = Result<(Key, Lsn, BlobRef), crate::tenant::disk_btree::DiskBtreeError>,
    1420           90 :     > + 'a
    1421           90 :     where
    1422           90 :         R: BlockReader + 'a,
    1423           90 :     {
    1424           90 :         use futures::stream::TryStreamExt;
    1425           90 :         let stream = reader.into_stream(start, ctx);
    1426          456 :         stream.map_ok(|(key, value)| {
    1427          456 :             let key = DeltaKey::from_slice(&key);
    1428          456 :             let (key, lsn) = (key.key(), key.lsn());
    1429          456 :             let offset = BlobRef(value);
    1430          456 : 
    1431          456 :             (key, lsn, offset)
    1432          456 :         })
    1433           90 :     }
    1434              : 
    1435              :     /// The file offset to the first block of index.
    1436              :     ///
    1437              :     /// The file structure is summary, values, and index. We often need this for the size of last blob.
    1438       617549 :     fn index_start_offset(&self) -> u64 {
    1439       617549 :         let offset = self.index_start_blk as u64 * PAGE_SZ as u64;
    1440       617549 :         let bref = BlobRef(offset);
    1441       617549 :         tracing::debug!(
    1442              :             index_start_blk = self.index_start_blk,
    1443              :             offset,
    1444            0 :             pos = bref.pos(),
    1445            0 :             "index_start_offset"
    1446              :         );
    1447       617549 :         offset
    1448       617549 :     }
    1449              : 
    1450         1590 :     pub(crate) fn iter<'a>(&'a self, ctx: &'a RequestContext) -> DeltaLayerIterator<'a> {
    1451         1590 :         let block_reader = FileBlockReader::new(&self.file, self.file_id);
    1452         1590 :         let tree_reader =
    1453         1590 :             DiskBtreeReader::new(self.index_start_blk, self.index_root_blk, block_reader);
    1454         1590 :         DeltaLayerIterator {
    1455         1590 :             delta_layer: self,
    1456         1590 :             ctx,
    1457         1590 :             index_iter: tree_reader.iter(&[0; DELTA_KEY_SIZE], ctx),
    1458         1590 :             key_values_batch: std::collections::VecDeque::new(),
    1459         1590 :             is_end: false,
    1460         1590 :             planner: StreamingVectoredReadPlanner::new(
    1461         1590 :                 1024 * 8192, // The default value. Unit tests might use a different value. 1024 * 8K = 8MB buffer.
    1462         1590 :                 1024,        // The default value. Unit tests might use a different value
    1463         1590 :             ),
    1464         1590 :         }
    1465         1590 :     }
    1466              : }
    1467              : 
    1468              : /// A set of data associated with a delta layer key and its value
    1469              : pub struct DeltaEntry<'a> {
    1470              :     pub key: Key,
    1471              :     pub lsn: Lsn,
    1472              :     /// Size of the stored value
    1473              :     pub size: u64,
    1474              :     /// Reference to the on-disk value
    1475              :     pub val: ValueRef<'a>,
    1476              : }
    1477              : 
    1478              : /// Reference to an on-disk value
    1479              : pub struct ValueRef<'a> {
    1480              :     blob_ref: BlobRef,
    1481              :     layer: &'a DeltaLayerInner,
    1482              : }
    1483              : 
    1484              : impl<'a> ValueRef<'a> {
    1485              :     /// Loads the value from disk
    1486      6192114 :     pub async fn load(&self, ctx: &RequestContext) -> Result<Value> {
    1487      6192114 :         let buf = self.load_raw(ctx).await?;
    1488      6192114 :         let val = Value::des(&buf)?;
    1489      6192114 :         Ok(val)
    1490      6192114 :     }
    1491              : 
    1492      6192138 :     async fn load_raw(&self, ctx: &RequestContext) -> Result<Vec<u8>> {
    1493      6192138 :         let reader = BlockCursor::new(crate::tenant::block_io::BlockReaderRef::Adapter(Adapter(
    1494      6192138 :             self.layer,
    1495      6192138 :         )));
    1496      6192138 :         let buf = reader.read_blob(self.blob_ref.pos(), ctx).await?;
    1497      6192138 :         Ok(buf)
    1498      6192138 :     }
    1499              : }
    1500              : 
    1501              : pub(crate) struct Adapter<T>(T);
    1502              : 
    1503              : impl<T: AsRef<DeltaLayerInner>> Adapter<T> {
    1504      6249006 :     pub(crate) async fn read_blk(
    1505      6249006 :         &self,
    1506      6249006 :         blknum: u32,
    1507      6249006 :         ctx: &RequestContext,
    1508      6249006 :     ) -> Result<BlockLease, std::io::Error> {
    1509      6249006 :         let block_reader = FileBlockReader::new(&self.0.as_ref().file, self.0.as_ref().file_id);
    1510      6249006 :         block_reader.read_blk(blknum, ctx).await
    1511      6249006 :     }
    1512              : }
    1513              : 
    1514              : impl AsRef<DeltaLayerInner> for DeltaLayerInner {
    1515     12498012 :     fn as_ref(&self) -> &DeltaLayerInner {
    1516     12498012 :         self
    1517     12498012 :     }
    1518              : }
    1519              : 
    1520              : impl<'a> pageserver_compaction::interface::CompactionDeltaEntry<'a, Key> for DeltaEntry<'a> {
    1521            0 :     fn key(&self) -> Key {
    1522            0 :         self.key
    1523            0 :     }
    1524            0 :     fn lsn(&self) -> Lsn {
    1525            0 :         self.lsn
    1526            0 :     }
    1527            0 :     fn size(&self) -> u64 {
    1528            0 :         self.size
    1529            0 :     }
    1530              : }
    1531              : 
    1532              : pub struct DeltaLayerIterator<'a> {
    1533              :     delta_layer: &'a DeltaLayerInner,
    1534              :     ctx: &'a RequestContext,
    1535              :     planner: StreamingVectoredReadPlanner,
    1536              :     index_iter: DiskBtreeIterator<'a>,
    1537              :     key_values_batch: VecDeque<(Key, Lsn, Value)>,
    1538              :     is_end: bool,
    1539              : }
    1540              : 
    1541              : impl<'a> DeltaLayerIterator<'a> {
    1542            0 :     pub(crate) fn layer_dbg_info(&self) -> String {
    1543            0 :         self.delta_layer.layer_dbg_info()
    1544            0 :     }
    1545              : 
    1546              :     /// Retrieve a batch of key-value pairs into the iterator buffer.
    1547        63800 :     async fn next_batch(&mut self) -> anyhow::Result<()> {
    1548        63800 :         assert!(self.key_values_batch.is_empty());
    1549        63800 :         assert!(!self.is_end);
    1550              : 
    1551        63800 :         let plan = loop {
    1552      6297184 :             if let Some(res) = self.index_iter.next().await {
    1553      6295678 :                 let (raw_key, value) = res?;
    1554      6295678 :                 let key = Key::from_slice(&raw_key[..KEY_SIZE]);
    1555      6295678 :                 let lsn = DeltaKey::extract_lsn_from_buf(&raw_key);
    1556      6295678 :                 let blob_ref = BlobRef(value);
    1557      6295678 :                 let offset = blob_ref.pos();
    1558      6295678 :                 if let Some(batch_plan) = self.planner.handle(key, lsn, offset) {
    1559        62294 :                     break batch_plan;
    1560      6233384 :                 }
    1561              :             } else {
    1562         1506 :                 self.is_end = true;
    1563         1506 :                 let data_end_offset = self.delta_layer.index_start_offset();
    1564         1506 :                 if let Some(item) = self.planner.handle_range_end(data_end_offset) {
    1565         1506 :                     break item;
    1566              :                 } else {
    1567            0 :                     return Ok(()); // TODO: test empty iterator
    1568              :                 }
    1569              :             }
    1570              :         };
    1571        63800 :         let vectored_blob_reader = VectoredBlobReader::new(&self.delta_layer.file);
    1572        63800 :         let mut next_batch = std::collections::VecDeque::new();
    1573        63800 :         let buf_size = plan.size();
    1574        63800 :         let buf = BytesMut::with_capacity(buf_size);
    1575        63800 :         let blobs_buf = vectored_blob_reader
    1576        63800 :             .read_blobs(&plan, buf, self.ctx)
    1577        32572 :             .await?;
    1578        63800 :         let frozen_buf = blobs_buf.buf.freeze();
    1579      6295594 :         for meta in blobs_buf.blobs.iter() {
    1580      6295594 :             let value = Value::des(&frozen_buf[meta.start..meta.end])?;
    1581      6295594 :             next_batch.push_back((meta.meta.key, meta.meta.lsn, value));
    1582              :         }
    1583        63800 :         self.key_values_batch = next_batch;
    1584        63800 :         Ok(())
    1585        63800 :     }
    1586              : 
    1587      6297714 :     pub async fn next(&mut self) -> anyhow::Result<Option<(Key, Lsn, Value)>> {
    1588      6297714 :         if self.key_values_batch.is_empty() {
    1589        66476 :             if self.is_end {
    1590         2928 :                 return Ok(None);
    1591        63548 :             }
    1592        63548 :             self.next_batch().await?;
    1593      6231238 :         }
    1594      6294786 :         Ok(Some(
    1595      6294786 :             self.key_values_batch
    1596      6294786 :                 .pop_front()
    1597      6294786 :                 .expect("should not be empty"),
    1598      6294786 :         ))
    1599      6297714 :     }
    1600              : }
    1601              : 
    1602              : #[cfg(test)]
    1603              : pub(crate) mod test {
    1604              :     use std::collections::BTreeMap;
    1605              : 
    1606              :     use itertools::MinMaxResult;
    1607              :     use rand::prelude::{SeedableRng, SliceRandom, StdRng};
    1608              :     use rand::RngCore;
    1609              : 
    1610              :     use super::*;
    1611              :     use crate::repository::Value;
    1612              :     use crate::tenant::harness::TIMELINE_ID;
    1613              :     use crate::tenant::storage_layer::{Layer, ResidentLayer};
    1614              :     use crate::tenant::vectored_blob_io::StreamingVectoredReadPlanner;
    1615              :     use crate::tenant::{Tenant, Timeline};
    1616              :     use crate::{
    1617              :         context::DownloadBehavior,
    1618              :         task_mgr::TaskKind,
    1619              :         tenant::{disk_btree::tests::TestDisk, harness::TenantHarness},
    1620              :         DEFAULT_PG_VERSION,
    1621              :     };
    1622              :     use bytes::Bytes;
    1623              : 
    1624              :     /// Construct an index for a fictional delta layer and and then
    1625              :     /// traverse in order to plan vectored reads for a query. Finally,
    1626              :     /// verify that the traversal fed the right index key and value
    1627              :     /// pairs into the planner.
    1628              :     #[tokio::test]
    1629            6 :     async fn test_delta_layer_index_traversal() {
    1630            6 :         let base_key = Key {
    1631            6 :             field1: 0,
    1632            6 :             field2: 1663,
    1633            6 :             field3: 12972,
    1634            6 :             field4: 16396,
    1635            6 :             field5: 0,
    1636            6 :             field6: 246080,
    1637            6 :         };
    1638            6 : 
    1639            6 :         // Populate the index with some entries
    1640            6 :         let entries: BTreeMap<Key, Vec<Lsn>> = BTreeMap::from([
    1641            6 :             (base_key, vec![Lsn(1), Lsn(5), Lsn(25), Lsn(26), Lsn(28)]),
    1642            6 :             (base_key.add(1), vec![Lsn(2), Lsn(5), Lsn(10), Lsn(50)]),
    1643            6 :             (base_key.add(2), vec![Lsn(2), Lsn(5), Lsn(10), Lsn(50)]),
    1644            6 :             (base_key.add(5), vec![Lsn(10), Lsn(15), Lsn(16), Lsn(20)]),
    1645            6 :         ]);
    1646            6 : 
    1647            6 :         let mut disk = TestDisk::default();
    1648            6 :         let mut writer = DiskBtreeBuilder::<_, DELTA_KEY_SIZE>::new(&mut disk);
    1649            6 : 
    1650            6 :         let mut disk_offset = 0;
    1651           30 :         for (key, lsns) in &entries {
    1652          126 :             for lsn in lsns {
    1653          102 :                 let index_key = DeltaKey::from_key_lsn(key, *lsn);
    1654          102 :                 let blob_ref = BlobRef::new(disk_offset, false);
    1655          102 :                 writer
    1656          102 :                     .append(&index_key.0, blob_ref.0)
    1657          102 :                     .expect("In memory disk append should never fail");
    1658          102 : 
    1659          102 :                 disk_offset += 1;
    1660          102 :             }
    1661            6 :         }
    1662            6 : 
    1663            6 :         // Prepare all the arguments for the call into `plan_reads` below
    1664            6 :         let (root_offset, _writer) = writer
    1665            6 :             .finish()
    1666            6 :             .expect("In memory disk finish should never fail");
    1667            6 :         let reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(0, root_offset, disk);
    1668            6 :         let planner = VectoredReadPlanner::new(100);
    1669            6 :         let mut reconstruct_state = ValuesReconstructState::new();
    1670            6 :         let ctx = RequestContext::new(TaskKind::UnitTest, DownloadBehavior::Error);
    1671            6 : 
    1672            6 :         let keyspace = KeySpace {
    1673            6 :             ranges: vec![
    1674            6 :                 base_key..base_key.add(3),
    1675            6 :                 base_key.add(3)..base_key.add(100),
    1676            6 :             ],
    1677            6 :         };
    1678            6 :         let lsn_range = Lsn(2)..Lsn(40);
    1679            6 : 
    1680            6 :         // Plan and validate
    1681            6 :         let vectored_reads = DeltaLayerInner::plan_reads(
    1682            6 :             &keyspace,
    1683            6 :             lsn_range.clone(),
    1684            6 :             disk_offset,
    1685            6 :             reader,
    1686            6 :             planner,
    1687            6 :             &mut reconstruct_state,
    1688            6 :             &ctx,
    1689            6 :         )
    1690            6 :         .await
    1691            6 :         .expect("Read planning should not fail");
    1692            6 : 
    1693            6 :         validate(keyspace, lsn_range, vectored_reads, entries);
    1694            6 :     }
    1695              : 
    1696            6 :     fn validate(
    1697            6 :         keyspace: KeySpace,
    1698            6 :         lsn_range: Range<Lsn>,
    1699            6 :         vectored_reads: Vec<VectoredRead>,
    1700            6 :         index_entries: BTreeMap<Key, Vec<Lsn>>,
    1701            6 :     ) {
    1702            6 :         #[derive(Debug, PartialEq, Eq)]
    1703            6 :         struct BlobSpec {
    1704            6 :             key: Key,
    1705            6 :             lsn: Lsn,
    1706            6 :             at: u64,
    1707            6 :         }
    1708            6 : 
    1709            6 :         let mut planned_blobs = Vec::new();
    1710           46 :         for read in vectored_reads {
    1711           84 :             for (at, meta) in read.blobs_at.as_slice() {
    1712           84 :                 planned_blobs.push(BlobSpec {
    1713           84 :                     key: meta.key,
    1714           84 :                     lsn: meta.lsn,
    1715           84 :                     at: *at,
    1716           84 :                 });
    1717           84 :             }
    1718              :         }
    1719              : 
    1720            6 :         let mut expected_blobs = Vec::new();
    1721            6 :         let mut disk_offset = 0;
    1722           30 :         for (key, lsns) in index_entries {
    1723          126 :             for lsn in lsns {
    1724          126 :                 let key_included = keyspace.ranges.iter().any(|range| range.contains(&key));
    1725          102 :                 let lsn_included = lsn_range.contains(&lsn);
    1726          102 : 
    1727          102 :                 if key_included && lsn_included {
    1728           84 :                     expected_blobs.push(BlobSpec {
    1729           84 :                         key,
    1730           84 :                         lsn,
    1731           84 :                         at: disk_offset,
    1732           84 :                     });
    1733           84 :                 }
    1734              : 
    1735          102 :                 disk_offset += 1;
    1736              :             }
    1737              :         }
    1738              : 
    1739            6 :         assert_eq!(planned_blobs, expected_blobs);
    1740            6 :     }
    1741              : 
    1742              :     mod constants {
    1743              :         use utils::lsn::Lsn;
    1744              : 
    1745              :         /// Offset used by all lsns in this test
    1746              :         pub(super) const LSN_OFFSET: Lsn = Lsn(0x08);
    1747              :         /// Number of unique keys including in the test data
    1748              :         pub(super) const KEY_COUNT: u8 = 60;
    1749              :         /// Max number of different lsns for each key
    1750              :         pub(super) const MAX_ENTRIES_PER_KEY: u8 = 20;
    1751              :         /// Possible value sizes for each key along with a probability weight
    1752              :         pub(super) const VALUE_SIZES: [(usize, u8); 3] = [(100, 2), (1024, 2), (1024 * 1024, 1)];
    1753              :         /// Probability that there will be a gap between the current key and the next one (33.3%)
    1754              :         pub(super) const KEY_GAP_CHANGES: [(bool, u8); 2] = [(true, 1), (false, 2)];
    1755              :         /// The minimum size of a key range in all the generated reads
    1756              :         pub(super) const MIN_RANGE_SIZE: i128 = 10;
    1757              :         /// The number of ranges included in each vectored read
    1758              :         pub(super) const RANGES_COUNT: u8 = 2;
    1759              :         /// The number of vectored reads performed
    1760              :         pub(super) const READS_COUNT: u8 = 100;
    1761              :         /// Soft max size of a vectored read. Will be violated if we have to read keys
    1762              :         /// with values larger than the limit
    1763              :         pub(super) const MAX_VECTORED_READ_BYTES: usize = 64 * 1024;
    1764              :     }
    1765              : 
    1766              :     struct Entry {
    1767              :         key: Key,
    1768              :         lsn: Lsn,
    1769              :         value: Vec<u8>,
    1770              :     }
    1771              : 
    1772            6 :     fn generate_entries(rng: &mut StdRng) -> Vec<Entry> {
    1773            6 :         let mut current_key = Key::MIN;
    1774            6 : 
    1775            6 :         let mut entries = Vec::new();
    1776          366 :         for _ in 0..constants::KEY_COUNT {
    1777          360 :             let count = rng.gen_range(1..constants::MAX_ENTRIES_PER_KEY);
    1778          360 :             let mut lsns_iter =
    1779         6780 :                 std::iter::successors(Some(Lsn(constants::LSN_OFFSET.0 + 0x08)), |lsn| {
    1780         6780 :                     Some(Lsn(lsn.0 + 0x08))
    1781         6780 :                 });
    1782          360 :             let mut lsns = Vec::new();
    1783         7140 :             while lsns.len() < count as usize {
    1784         6780 :                 let take = rng.gen_bool(0.5);
    1785         6780 :                 let lsn = lsns_iter.next().unwrap();
    1786         6780 :                 if take {
    1787         3336 :                     lsns.push(lsn);
    1788         3444 :                 }
    1789              :             }
    1790              : 
    1791         3696 :             for lsn in lsns {
    1792         3336 :                 let size = constants::VALUE_SIZES
    1793        10008 :                     .choose_weighted(rng, |item| item.1)
    1794         3336 :                     .unwrap()
    1795         3336 :                     .0;
    1796         3336 :                 let mut buf = vec![0; size];
    1797         3336 :                 rng.fill_bytes(&mut buf);
    1798         3336 : 
    1799         3336 :                 entries.push(Entry {
    1800         3336 :                     key: current_key,
    1801         3336 :                     lsn,
    1802         3336 :                     value: buf,
    1803         3336 :                 })
    1804              :             }
    1805              : 
    1806          360 :             let gap = constants::KEY_GAP_CHANGES
    1807          720 :                 .choose_weighted(rng, |item| item.1)
    1808          360 :                 .unwrap()
    1809          360 :                 .0;
    1810          360 :             if gap {
    1811          114 :                 current_key = current_key.add(2);
    1812          246 :             } else {
    1813          246 :                 current_key = current_key.add(1);
    1814          246 :             }
    1815              :         }
    1816              : 
    1817            6 :         entries
    1818            6 :     }
    1819              : 
    1820              :     struct EntriesMeta {
    1821              :         key_range: Range<Key>,
    1822              :         lsn_range: Range<Lsn>,
    1823              :         index: BTreeMap<(Key, Lsn), Vec<u8>>,
    1824              :     }
    1825              : 
    1826            6 :     fn get_entries_meta(entries: &[Entry]) -> EntriesMeta {
    1827         3336 :         let key_range = match entries.iter().minmax_by_key(|e| e.key) {
    1828            6 :             MinMaxResult::MinMax(min, max) => min.key..max.key.next(),
    1829            0 :             _ => panic!("More than one entry is always expected"),
    1830              :         };
    1831              : 
    1832         3336 :         let lsn_range = match entries.iter().minmax_by_key(|e| e.lsn) {
    1833            6 :             MinMaxResult::MinMax(min, max) => min.lsn..Lsn(max.lsn.0 + 1),
    1834            0 :             _ => panic!("More than one entry is always expected"),
    1835              :         };
    1836              : 
    1837            6 :         let mut index = BTreeMap::new();
    1838         3336 :         for entry in entries.iter() {
    1839         3336 :             index.insert((entry.key, entry.lsn), entry.value.clone());
    1840         3336 :         }
    1841              : 
    1842            6 :         EntriesMeta {
    1843            6 :             key_range,
    1844            6 :             lsn_range,
    1845            6 :             index,
    1846            6 :         }
    1847            6 :     }
    1848              : 
    1849          600 :     fn pick_random_keyspace(rng: &mut StdRng, key_range: &Range<Key>) -> KeySpace {
    1850          600 :         let start = key_range.start.to_i128();
    1851          600 :         let end = key_range.end.to_i128();
    1852          600 : 
    1853          600 :         let mut keyspace = KeySpace::default();
    1854              : 
    1855         1800 :         for _ in 0..constants::RANGES_COUNT {
    1856         1200 :             let mut range: Option<Range<Key>> = Option::default();
    1857         3732 :             while range.is_none() || keyspace.overlaps(range.as_ref().unwrap()) {
    1858         2532 :                 let range_start = rng.gen_range(start..end);
    1859         2532 :                 let range_end_offset = range_start + constants::MIN_RANGE_SIZE;
    1860         2532 :                 if range_end_offset >= end {
    1861          300 :                     range = Some(Key::from_i128(range_start)..Key::from_i128(end));
    1862         2232 :                 } else {
    1863         2232 :                     let range_end = rng.gen_range((range_start + constants::MIN_RANGE_SIZE)..end);
    1864         2232 :                     range = Some(Key::from_i128(range_start)..Key::from_i128(range_end));
    1865         2232 :                 }
    1866              :             }
    1867         1200 :             keyspace.ranges.push(range.unwrap());
    1868              :         }
    1869              : 
    1870          600 :         keyspace
    1871          600 :     }
    1872              : 
    1873              :     #[tokio::test]
    1874            6 :     async fn test_delta_layer_vectored_read_end_to_end() -> anyhow::Result<()> {
    1875            6 :         let harness = TenantHarness::create("test_delta_layer_oversized_vectored_read").await?;
    1876           24 :         let (tenant, ctx) = harness.load().await;
    1877            6 : 
    1878            6 :         let timeline_id = TimelineId::generate();
    1879            6 :         let timeline = tenant
    1880            6 :             .create_test_timeline(timeline_id, constants::LSN_OFFSET, DEFAULT_PG_VERSION, &ctx)
    1881           12 :             .await?;
    1882            6 : 
    1883            6 :         tracing::info!("Generating test data ...");
    1884            6 : 
    1885            6 :         let rng = &mut StdRng::seed_from_u64(0);
    1886            6 :         let entries = generate_entries(rng);
    1887            6 :         let entries_meta = get_entries_meta(&entries);
    1888            6 : 
    1889            6 :         tracing::info!("Done generating {} entries", entries.len());
    1890            6 : 
    1891            6 :         tracing::info!("Writing test data to delta layer ...");
    1892            6 :         let mut writer = DeltaLayerWriter::new(
    1893            6 :             harness.conf,
    1894            6 :             timeline_id,
    1895            6 :             harness.tenant_shard_id,
    1896            6 :             entries_meta.key_range.start,
    1897            6 :             entries_meta.lsn_range.clone(),
    1898            6 :             &ctx,
    1899            6 :         )
    1900            6 :         .await?;
    1901            6 : 
    1902         3342 :         for entry in entries {
    1903         3336 :             let (_, res) = writer
    1904         3336 :                 .put_value_bytes(entry.key, entry.lsn, entry.value.slice_len(), false, &ctx)
    1905          645 :                 .await;
    1906         3336 :             res?;
    1907            6 :         }
    1908            6 : 
    1909           15 :         let (desc, path) = writer.finish(entries_meta.key_range.end, &ctx).await?;
    1910            6 :         let resident = Layer::finish_creating(harness.conf, &timeline, desc, &path)?;
    1911            6 : 
    1912            6 :         let inner = resident.get_as_delta(&ctx).await?;
    1913            6 : 
    1914            6 :         let file_size = inner.file.metadata().await?.len();
    1915            6 :         tracing::info!(
    1916            6 :             "Done writing test data to delta layer. Resulting file size is: {}",
    1917            6 :             file_size
    1918            6 :         );
    1919            6 : 
    1920          606 :         for i in 0..constants::READS_COUNT {
    1921          600 :             tracing::info!("Doing vectored read {}/{}", i + 1, constants::READS_COUNT);
    1922            6 : 
    1923          600 :             let block_reader = FileBlockReader::new(&inner.file, inner.file_id);
    1924          600 :             let index_reader = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    1925          600 :                 inner.index_start_blk,
    1926          600 :                 inner.index_root_blk,
    1927          600 :                 block_reader,
    1928          600 :             );
    1929          600 : 
    1930          600 :             let planner = VectoredReadPlanner::new(constants::MAX_VECTORED_READ_BYTES);
    1931          600 :             let mut reconstruct_state = ValuesReconstructState::new();
    1932          600 :             let keyspace = pick_random_keyspace(rng, &entries_meta.key_range);
    1933          600 :             let data_end_offset = inner.index_start_blk as u64 * PAGE_SZ as u64;
    1934            6 : 
    1935          600 :             let vectored_reads = DeltaLayerInner::plan_reads(
    1936          600 :                 &keyspace,
    1937          600 :                 entries_meta.lsn_range.clone(),
    1938          600 :                 data_end_offset,
    1939          600 :                 index_reader,
    1940          600 :                 planner,
    1941          600 :                 &mut reconstruct_state,
    1942          600 :                 &ctx,
    1943          600 :             )
    1944           12 :             .await?;
    1945            6 : 
    1946          600 :             let vectored_blob_reader = VectoredBlobReader::new(&inner.file);
    1947          600 :             let buf_size = DeltaLayerInner::get_min_read_buffer_size(
    1948          600 :                 &vectored_reads,
    1949          600 :                 constants::MAX_VECTORED_READ_BYTES,
    1950          600 :             );
    1951          600 :             let mut buf = Some(BytesMut::with_capacity(buf_size));
    1952            6 : 
    1953        59772 :             for read in vectored_reads {
    1954        59172 :                 let blobs_buf = vectored_blob_reader
    1955        59172 :                     .read_blobs(&read, buf.take().expect("Should have a buffer"), &ctx)
    1956        30048 :                     .await?;
    1957       171912 :                 for meta in blobs_buf.blobs.iter() {
    1958       171912 :                     let value = &blobs_buf.buf[meta.start..meta.end];
    1959       171912 :                     assert_eq!(value, entries_meta.index[&(meta.meta.key, meta.meta.lsn)]);
    1960            6 :                 }
    1961            6 : 
    1962        59172 :                 buf = Some(blobs_buf.buf);
    1963            6 :             }
    1964            6 :         }
    1965            6 : 
    1966            6 :         Ok(())
    1967            6 :     }
    1968              : 
    1969              :     #[tokio::test]
    1970            6 :     async fn copy_delta_prefix_smoke() {
    1971            6 :         use crate::walrecord::NeonWalRecord;
    1972            6 :         use bytes::Bytes;
    1973            6 : 
    1974            6 :         let h = crate::tenant::harness::TenantHarness::create("truncate_delta_smoke")
    1975            6 :             .await
    1976            6 :             .unwrap();
    1977           24 :         let (tenant, ctx) = h.load().await;
    1978            6 :         let ctx = &ctx;
    1979            6 :         let timeline = tenant
    1980            6 :             .create_test_timeline(TimelineId::generate(), Lsn(0x10), 14, ctx)
    1981           12 :             .await
    1982            6 :             .unwrap();
    1983            6 : 
    1984            6 :         let initdb_layer = timeline
    1985            6 :             .layers
    1986            6 :             .read()
    1987            6 :             .await
    1988            6 :             .likely_resident_layers()
    1989            6 :             .next()
    1990            6 :             .cloned()
    1991            6 :             .unwrap();
    1992            6 : 
    1993            6 :         {
    1994            6 :             let mut writer = timeline.writer().await;
    1995            6 : 
    1996            6 :             let data = [
    1997            6 :                 (0x20, 12, Value::Image(Bytes::from_static(b"foobar"))),
    1998            6 :                 (
    1999            6 :                     0x30,
    2000            6 :                     12,
    2001            6 :                     Value::WalRecord(NeonWalRecord::Postgres {
    2002            6 :                         will_init: false,
    2003            6 :                         rec: Bytes::from_static(b"1"),
    2004            6 :                     }),
    2005            6 :                 ),
    2006            6 :                 (
    2007            6 :                     0x40,
    2008            6 :                     12,
    2009            6 :                     Value::WalRecord(NeonWalRecord::Postgres {
    2010            6 :                         will_init: true,
    2011            6 :                         rec: Bytes::from_static(b"2"),
    2012            6 :                     }),
    2013            6 :                 ),
    2014            6 :                 // build an oversized value so we cannot extend and existing read over
    2015            6 :                 // this
    2016            6 :                 (
    2017            6 :                     0x50,
    2018            6 :                     12,
    2019            6 :                     Value::WalRecord(NeonWalRecord::Postgres {
    2020            6 :                         will_init: true,
    2021            6 :                         rec: {
    2022            6 :                             let mut buf =
    2023            6 :                                 vec![0u8; tenant.conf.max_vectored_read_bytes.0.get() + 1024];
    2024            6 :                             buf.iter_mut()
    2025            6 :                                 .enumerate()
    2026       792576 :                                 .for_each(|(i, slot)| *slot = (i % 256) as u8);
    2027            6 :                             Bytes::from(buf)
    2028            6 :                         },
    2029            6 :                     }),
    2030            6 :                 ),
    2031            6 :                 // because the oversized read cannot be extended further, we are sure to exercise the
    2032            6 :                 // builder created on the last round with this:
    2033            6 :                 (
    2034            6 :                     0x60,
    2035            6 :                     12,
    2036            6 :                     Value::WalRecord(NeonWalRecord::Postgres {
    2037            6 :                         will_init: true,
    2038            6 :                         rec: Bytes::from_static(b"3"),
    2039            6 :                     }),
    2040            6 :                 ),
    2041            6 :                 (
    2042            6 :                     0x60,
    2043            6 :                     9,
    2044            6 :                     Value::Image(Bytes::from_static(b"something for a different key")),
    2045            6 :                 ),
    2046            6 :             ];
    2047            6 : 
    2048            6 :             let mut last_lsn = None;
    2049            6 : 
    2050           42 :             for (lsn, key, value) in data {
    2051           36 :                 let key = Key::from_i128(key);
    2052           36 :                 writer.put(key, Lsn(lsn), &value, ctx).await.unwrap();
    2053           36 :                 last_lsn = Some(lsn);
    2054            6 :             }
    2055            6 : 
    2056            6 :             writer.finish_write(Lsn(last_lsn.unwrap()));
    2057            6 :         }
    2058            6 :         timeline.freeze_and_flush().await.unwrap();
    2059            6 : 
    2060            6 :         let new_layer = timeline
    2061            6 :             .layers
    2062            6 :             .read()
    2063            6 :             .await
    2064            6 :             .likely_resident_layers()
    2065            9 :             .find(|&x| x != &initdb_layer)
    2066            6 :             .cloned()
    2067            6 :             .unwrap();
    2068            6 : 
    2069            6 :         // create a copy for the timeline, so we don't overwrite the file
    2070            6 :         let branch = tenant
    2071            6 :             .branch_timeline_test(&timeline, TimelineId::generate(), None, ctx)
    2072            6 :             .await
    2073            6 :             .unwrap();
    2074            6 : 
    2075            6 :         assert_eq!(branch.get_ancestor_lsn(), Lsn(0x60));
    2076            6 : 
    2077            6 :         // truncating at 0x61 gives us a full copy, otherwise just go backwards until there's just
    2078            6 :         // a single key
    2079            6 : 
    2080           36 :         for truncate_at in [0x61, 0x51, 0x41, 0x31, 0x21] {
    2081           30 :             let truncate_at = Lsn(truncate_at);
    2082            6 : 
    2083           30 :             let mut writer = DeltaLayerWriter::new(
    2084           30 :                 tenant.conf,
    2085           30 :                 branch.timeline_id,
    2086           30 :                 tenant.tenant_shard_id,
    2087           30 :                 Key::MIN,
    2088           30 :                 Lsn(0x11)..truncate_at,
    2089           30 :                 ctx,
    2090           30 :             )
    2091           15 :             .await
    2092           30 :             .unwrap();
    2093            6 : 
    2094           30 :             let new_layer = new_layer.download_and_keep_resident().await.unwrap();
    2095           30 : 
    2096           30 :             new_layer
    2097           30 :                 .copy_delta_prefix(&mut writer, truncate_at, ctx)
    2098           45 :                 .await
    2099           30 :                 .unwrap();
    2100            6 : 
    2101           72 :             let (desc, path) = writer.finish(Key::MAX, ctx).await.unwrap();
    2102           30 :             let copied_layer = Layer::finish_creating(tenant.conf, &branch, desc, &path).unwrap();
    2103           30 : 
    2104           30 :             copied_layer.get_as_delta(ctx).await.unwrap();
    2105           30 : 
    2106           30 :             assert_keys_and_values_eq(
    2107           30 :                 new_layer.get_as_delta(ctx).await.unwrap(),
    2108           30 :                 copied_layer.get_as_delta(ctx).await.unwrap(),
    2109           30 :                 truncate_at,
    2110           30 :                 ctx,
    2111            6 :             )
    2112          158 :             .await;
    2113            6 :         }
    2114            6 :     }
    2115              : 
    2116           30 :     async fn assert_keys_and_values_eq(
    2117           30 :         source: &DeltaLayerInner,
    2118           30 :         truncated: &DeltaLayerInner,
    2119           30 :         truncated_at: Lsn,
    2120           30 :         ctx: &RequestContext,
    2121           30 :     ) {
    2122           30 :         use futures::future::ready;
    2123           30 :         use futures::stream::TryStreamExt;
    2124           30 : 
    2125           30 :         let start_key = [0u8; DELTA_KEY_SIZE];
    2126           30 : 
    2127           30 :         let source_reader = FileBlockReader::new(&source.file, source.file_id);
    2128           30 :         let source_tree = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    2129           30 :             source.index_start_blk,
    2130           30 :             source.index_root_blk,
    2131           30 :             &source_reader,
    2132           30 :         );
    2133           30 :         let source_stream = source.stream_index_forwards(source_tree, &start_key, ctx);
    2134          180 :         let source_stream = source_stream.filter(|res| match res {
    2135          180 :             Ok((_, lsn, _)) => ready(lsn < &truncated_at),
    2136            0 :             _ => ready(true),
    2137          180 :         });
    2138           30 :         let mut source_stream = std::pin::pin!(source_stream);
    2139           30 : 
    2140           30 :         let truncated_reader = FileBlockReader::new(&truncated.file, truncated.file_id);
    2141           30 :         let truncated_tree = DiskBtreeReader::<_, DELTA_KEY_SIZE>::new(
    2142           30 :             truncated.index_start_blk,
    2143           30 :             truncated.index_root_blk,
    2144           30 :             &truncated_reader,
    2145           30 :         );
    2146           30 :         let truncated_stream = truncated.stream_index_forwards(truncated_tree, &start_key, ctx);
    2147           30 :         let mut truncated_stream = std::pin::pin!(truncated_stream);
    2148           30 : 
    2149           30 :         let mut scratch_left = Vec::new();
    2150           30 :         let mut scratch_right = Vec::new();
    2151              : 
    2152              :         loop {
    2153          126 :             let (src, truncated) = (source_stream.try_next(), truncated_stream.try_next());
    2154          126 :             let (src, truncated) = tokio::try_join!(src, truncated).unwrap();
    2155          126 : 
    2156          126 :             if src.is_none() {
    2157           30 :                 assert!(truncated.is_none());
    2158           30 :                 break;
    2159           96 :             }
    2160           96 : 
    2161           96 :             let (src, truncated) = (src.unwrap(), truncated.unwrap());
    2162           96 : 
    2163           96 :             // because we've filtered the source with Lsn, we should always have the same keys from both.
    2164           96 :             assert_eq!(src.0, truncated.0);
    2165           96 :             assert_eq!(src.1, truncated.1);
    2166              : 
    2167              :             // if this is needed for something else, just drop this assert.
    2168           96 :             assert!(
    2169           96 :                 src.2.pos() >= truncated.2.pos(),
    2170            0 :                 "value position should not go backwards {} vs. {}",
    2171            0 :                 src.2.pos(),
    2172            0 :                 truncated.2.pos()
    2173              :             );
    2174              : 
    2175           96 :             scratch_left.clear();
    2176           96 :             let src_cursor = source_reader.block_cursor();
    2177           96 :             let left = src_cursor.read_blob_into_buf(src.2.pos(), &mut scratch_left, ctx);
    2178           96 :             scratch_right.clear();
    2179           96 :             let trunc_cursor = truncated_reader.block_cursor();
    2180           96 :             let right = trunc_cursor.read_blob_into_buf(truncated.2.pos(), &mut scratch_right, ctx);
    2181              : 
    2182           96 :             tokio::try_join!(left, right).unwrap();
    2183           96 : 
    2184           96 :             assert_eq!(utils::Hex(&scratch_left), utils::Hex(&scratch_right));
    2185              :         }
    2186           30 :     }
    2187              : 
    2188        54078 :     pub(crate) fn sort_delta(
    2189        54078 :         (k1, l1, _): &(Key, Lsn, Value),
    2190        54078 :         (k2, l2, _): &(Key, Lsn, Value),
    2191        54078 :     ) -> std::cmp::Ordering {
    2192        54078 :         (k1, l1).cmp(&(k2, l2))
    2193        54078 :     }
    2194              : 
    2195          282 :     pub(crate) fn sort_delta_value(
    2196          282 :         (k1, l1, v1): &(Key, Lsn, Value),
    2197          282 :         (k2, l2, v2): &(Key, Lsn, Value),
    2198          282 :     ) -> std::cmp::Ordering {
    2199          282 :         let order_1 = if v1.is_image() { 0 } else { 1 };
    2200          282 :         let order_2 = if v2.is_image() { 0 } else { 1 };
    2201          282 :         (k1, l1, order_1).cmp(&(k2, l2, order_2))
    2202          282 :     }
    2203              : 
    2204           60 :     pub(crate) async fn produce_delta_layer(
    2205           60 :         tenant: &Tenant,
    2206           60 :         tline: &Arc<Timeline>,
    2207           60 :         mut deltas: Vec<(Key, Lsn, Value)>,
    2208           60 :         ctx: &RequestContext,
    2209           60 :     ) -> anyhow::Result<ResidentLayer> {
    2210           60 :         deltas.sort_by(sort_delta);
    2211           60 :         let (key_start, _, _) = deltas.first().unwrap();
    2212           60 :         let (key_max, _, _) = deltas.last().unwrap();
    2213        24120 :         let lsn_min = deltas.iter().map(|(_, lsn, _)| lsn).min().unwrap();
    2214        24120 :         let lsn_max = deltas.iter().map(|(_, lsn, _)| lsn).max().unwrap();
    2215           60 :         let lsn_end = Lsn(lsn_max.0 + 1);
    2216           60 :         let mut writer = DeltaLayerWriter::new(
    2217           60 :             tenant.conf,
    2218           60 :             tline.timeline_id,
    2219           60 :             tenant.tenant_shard_id,
    2220           60 :             *key_start,
    2221           60 :             (*lsn_min)..lsn_end,
    2222           60 :             ctx,
    2223           60 :         )
    2224           30 :         .await?;
    2225           60 :         let key_end = key_max.next();
    2226              : 
    2227        24180 :         for (key, lsn, value) in deltas {
    2228        24120 :             writer.put_value(key, lsn, value, ctx).await?;
    2229              :         }
    2230              : 
    2231          174 :         let (desc, path) = writer.finish(key_end, ctx).await?;
    2232           60 :         let delta_layer = Layer::finish_creating(tenant.conf, tline, desc, &path)?;
    2233              : 
    2234           60 :         Ok::<_, anyhow::Error>(delta_layer)
    2235           60 :     }
    2236              : 
    2237           84 :     async fn assert_delta_iter_equal(
    2238           84 :         delta_iter: &mut DeltaLayerIterator<'_>,
    2239           84 :         expect: &[(Key, Lsn, Value)],
    2240           84 :     ) {
    2241           84 :         let mut expect_iter = expect.iter();
    2242              :         loop {
    2243        84084 :             let o1 = delta_iter.next().await.unwrap();
    2244        84084 :             let o2 = expect_iter.next();
    2245        84084 :             assert_eq!(o1.is_some(), o2.is_some());
    2246        84084 :             if o1.is_none() && o2.is_none() {
    2247           84 :                 break;
    2248        84000 :             }
    2249        84000 :             let (k1, l1, v1) = o1.unwrap();
    2250        84000 :             let (k2, l2, v2) = o2.unwrap();
    2251        84000 :             assert_eq!(&k1, k2);
    2252        84000 :             assert_eq!(l1, *l2);
    2253        84000 :             assert_eq!(&v1, v2);
    2254              :         }
    2255           84 :     }
    2256              : 
    2257              :     #[tokio::test]
    2258            6 :     async fn delta_layer_iterator() {
    2259            6 :         let harness = TenantHarness::create("delta_layer_iterator").await.unwrap();
    2260           24 :         let (tenant, ctx) = harness.load().await;
    2261            6 : 
    2262            6 :         let tline = tenant
    2263            6 :             .create_test_timeline(TIMELINE_ID, Lsn(0x10), DEFAULT_PG_VERSION, &ctx)
    2264           12 :             .await
    2265            6 :             .unwrap();
    2266            6 : 
    2267         6000 :         fn get_key(id: u32) -> Key {
    2268         6000 :             let mut key = Key::from_hex("000000000033333333444444445500000000").unwrap();
    2269         6000 :             key.field6 = id;
    2270         6000 :             key
    2271         6000 :         }
    2272            6 :         const N: usize = 1000;
    2273            6 :         let test_deltas = (0..N)
    2274         6000 :             .map(|idx| {
    2275         6000 :                 (
    2276         6000 :                     get_key(idx as u32 / 10),
    2277         6000 :                     Lsn(0x10 * ((idx as u64) % 10 + 1)),
    2278         6000 :                     Value::Image(Bytes::from(format!("img{idx:05}"))),
    2279         6000 :                 )
    2280         6000 :             })
    2281            6 :             .collect_vec();
    2282            6 :         let resident_layer = produce_delta_layer(&tenant, &tline, test_deltas.clone(), &ctx)
    2283           24 :             .await
    2284            6 :             .unwrap();
    2285            6 :         let delta_layer = resident_layer.get_as_delta(&ctx).await.unwrap();
    2286           18 :         for max_read_size in [1, 1024] {
    2287           96 :             for batch_size in [1, 2, 4, 8, 3, 7, 13] {
    2288           84 :                 println!("running with batch_size={batch_size} max_read_size={max_read_size}");
    2289           84 :                 // Test if the batch size is correctly determined
    2290           84 :                 let mut iter = delta_layer.iter(&ctx);
    2291           84 :                 iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
    2292           84 :                 let mut num_items = 0;
    2293          336 :                 for _ in 0..3 {
    2294          252 :                     iter.next_batch().await.unwrap();
    2295          252 :                     num_items += iter.key_values_batch.len();
    2296          252 :                     if max_read_size == 1 {
    2297            6 :                         // every key should be a batch b/c the value is larger than max_read_size
    2298          126 :                         assert_eq!(iter.key_values_batch.len(), 1);
    2299            6 :                     } else {
    2300          126 :                         assert!(iter.key_values_batch.len() <= batch_size);
    2301            6 :                     }
    2302          252 :                     if num_items >= N {
    2303            6 :                         break;
    2304          252 :                     }
    2305          252 :                     iter.key_values_batch.clear();
    2306            6 :                 }
    2307            6 :                 // Test if the result is correct
    2308           84 :                 let mut iter = delta_layer.iter(&ctx);
    2309           84 :                 iter.planner = StreamingVectoredReadPlanner::new(max_read_size, batch_size);
    2310        28803 :                 assert_delta_iter_equal(&mut iter, &test_deltas).await;
    2311            6 :             }
    2312            6 :         }
    2313            6 :     }
    2314              : }
        

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