Check relation size for gertpage only in case of error

libs/pageserver_api/src/key.rs

@@ -561,6 +561,21 @@ pub fn rel_block_to_key(rel: RelTag, blknum: BlockNumber) -> Key {
     }
 }
 
+#[inline(always)]
+pub fn key_to_rel_tag(key: Key) -> RelTag {
+    RelTag {
+        spcnode: key.field2,
+        dbnode: key.field3,
+        relnode: key.field4,
+        forknum: key.field5,
+    }
+}
+
+#[inline(always)]
+pub fn key_to_blknum(key: Key) -> BlockNumber {
+    key.field6
+}
+
 #[inline(always)]
 pub fn rel_size_to_key(rel: RelTag) -> Key {
     Key {

pageserver/src/pgdatadir_mapping.rs

@@ -16,9 +16,9 @@ use bytes::{Buf, Bytes, BytesMut};
 use enum_map::Enum;
 use pageserver_api::key::{
     AUX_FILES_KEY, CHECKPOINT_KEY, CONTROLFILE_KEY, CompactKey, DBDIR_KEY, Key, RelDirExists,
-    TWOPHASEDIR_KEY, dbdir_key_range, rel_block_to_key, rel_dir_to_key, rel_key_range,
-    rel_size_to_key, rel_tag_sparse_key, rel_tag_sparse_key_range, relmap_file_key,
-    repl_origin_key, repl_origin_key_range, slru_block_to_key, slru_dir_to_key,
+    TWOPHASEDIR_KEY, dbdir_key_range, key_to_blknum, key_to_rel_tag, rel_block_to_key,
+    rel_dir_to_key, rel_key_range, rel_size_to_key, rel_tag_sparse_key, rel_tag_sparse_key_range,
+    relmap_file_key, repl_origin_key, repl_origin_key_range, slru_block_to_key, slru_dir_to_key,
     slru_segment_key_range, slru_segment_size_to_key, twophase_file_key, twophase_key_range,
 };
 use pageserver_api::keyspace::{KeySpaceRandomAccum, SparseKeySpace};
@@ -259,7 +259,7 @@ impl Timeline {
         let mut result = Vec::with_capacity(pages.len());
         let result_slots = result.spare_capacity_mut();
 
-        let mut keys_slots: HashMap<Key, smallvec::SmallVec<[(usize, RequestContext); 1]>> =
+        let mut keys_slots: HashMap<Key, smallvec::SmallVec<[(usize, Lsn, RequestContext); 1]>> =
             HashMap::with_capacity(pages.len());
 
         let mut req_keyspaces: HashMap<Lsn, KeySpaceRandomAccum> =
@@ -275,43 +275,6 @@ impl Timeline {
                 continue;
             }
 
-            let nblocks = {
-                let ctx = RequestContextBuilder::from(&ctx)
-                    .perf_span(|crnt_perf_span| {
-                        info_span!(
-                            target: PERF_TRACE_TARGET,
-                            parent: crnt_perf_span,
-                            "GET_REL_SIZE",
-                            reltag=%tag,
-                            lsn=%lsn,
-                        )
-                    })
-                    .attached_child();
-
-                match self
-                    .get_rel_size(*tag, Version::Lsn(lsn), &ctx)
-                    .maybe_perf_instrument(&ctx, |crnt_perf_span| crnt_perf_span.clone())
-                    .await
-                {
-                    Ok(nblocks) => nblocks,
-                    Err(err) => {
-                        result_slots[response_slot_idx].write(Err(err));
-                        slots_filled += 1;
-                        continue;
-                    }
-                }
-            };
-
-            if *blknum >= nblocks {
-                debug!(
-                    "read beyond EOF at {} blk {} at {}, size is {}: returning all-zeros page",
-                    tag, blknum, lsn, nblocks
-                );
-                result_slots[response_slot_idx].write(Ok(ZERO_PAGE.clone()));
-                slots_filled += 1;
-                continue;
-            }
-
             let key = rel_block_to_key(*tag, *blknum);
 
             let ctx = RequestContextBuilder::from(&ctx)
@@ -326,7 +289,7 @@ impl Timeline {
                 .attached_child();
 
             let key_slots = keys_slots.entry(key).or_default();
-            key_slots.push((response_slot_idx, ctx));
+            key_slots.push((response_slot_idx, lsn, ctx));
 
             let acc = req_keyspaces.entry(lsn).or_default();
             acc.add_key(key);
@@ -347,42 +310,95 @@ impl Timeline {
             Ok(results) => {
                 for (key, res) in results {
                     let mut key_slots = keys_slots.remove(&key).unwrap().into_iter();
-                    let (first_slot, first_req_ctx) = key_slots.next().unwrap();
 
-                    for (slot, req_ctx) in key_slots {
-                        let clone = match &res {
-                            Ok(buf) => Ok(buf.clone()),
-                            Err(err) => Err(match err {
-                                PageReconstructError::Cancelled => PageReconstructError::Cancelled,
+                    // Try to check if error is caused by access beyond end of relation
+                    match &res {
+                        Err(err) => {
+                            let tag = key_to_rel_tag(key);
+                            let blknum = key_to_blknum(key);
+                            let mut first_error_slot: Option<usize> = None;
+                            for (slot, lsn, req_ctx) in key_slots {
+                                // Check relation size only in case of error
+                                let relsize_ctx = RequestContextBuilder::from(&ctx)
+                                    .perf_span(|crnt_perf_span| {
+                                        info_span!(
+                                         target: PERF_TRACE_TARGET,
+                                         parent: crnt_perf_span,
+                                         "GET_REL_SIZE",
+                                         reltag=%tag,
+                                         lsn=%lsn,
+                                        )
+                                    })
+                                    .attached_child();
 
-                                x @ PageReconstructError::Other(_)
-                                | x @ PageReconstructError::AncestorLsnTimeout(_)
-                                | x @ PageReconstructError::WalRedo(_)
-                                | x @ PageReconstructError::MissingKey(_) => {
-                                    PageReconstructError::Other(anyhow::anyhow!(
-                                        "there was more than one request for this key in the batch, error logged once: {x:?}"
-                                    ))
+                                if let Ok(nblocks) = self
+                                    .get_rel_size(tag, Version::Lsn(lsn), &relsize_ctx)
+                                    .maybe_perf_instrument(&ctx, |crnt_perf_span| {
+                                        crnt_perf_span.clone()
+                                    })
+                                    .await
+                                {
+                                    if blknum >= nblocks {
+                                        debug!(
+                                            "read beyond EOF at {} blk {} at {}, size is {}: returning all-zeros page",
+                                            tag, blknum, lsn, nblocks
+                                        );
+                                        result_slots[slot].write(Ok(ZERO_PAGE.clone()));
+                                        slots_filled += 1;
+                                        continue;
+                                    }
                                 }
-                            }),
-                        };
+                                if first_error_slot.is_none() {
+                                    first_error_slot = Some(slot);
+                                } else {
+                                    let err = match err {
+                                        PageReconstructError::Cancelled => {
+                                            PageReconstructError::Cancelled
+                                        }
 
-                        result_slots[slot].write(clone);
-                        // There is no standardized way to express that the batched span followed from N request spans.
-                        // So, abuse the system and mark the request contexts as follows_from the batch span, so we get
-                        // some linkage in our trace viewer. It allows us to answer: which GET_VECTORED did this GET_PAGE wait for.
-                        req_ctx.perf_follows_from(ctx);
-                        slots_filled += 1;
+                                        x @ PageReconstructError::Other(_)
+                                        | x @ PageReconstructError::AncestorLsnTimeout(_)
+                                        | x @ PageReconstructError::WalRedo(_)
+                                        | x @ PageReconstructError::MissingKey(_) => {
+                                            PageReconstructError::Other(anyhow::anyhow!(
+                                                "there was more than one request for this key in the batch, error logged once: {x:?}"
+                                            ))
+                                        }
+                                    };
+                                    result_slots[slot].write(Err(err));
+                                };
+                                // There is no standardized way to express that the batched span followed from N request spans.
+                                // So, abuse the system and mark the request contexts as follows_from the batch span, so we get
+                                // some linkage in our trace viewer. It allows us to answer: which GET_VECTORED did this GET_PAGE wait for.
+                                req_ctx.perf_follows_from(ctx);
+                                slots_filled += 1;
+                            }
+                            if let Some(slot) = first_error_slot {
+                                result_slots[slot].write(res);
+                            }
+                        }
+                        Ok(buf) => {
+                            let (first_slot, _first_lsn, first_req_ctx) = key_slots.next().unwrap();
+
+                            for (slot, _lsn, req_ctx) in key_slots {
+                                result_slots[slot].write(Ok(buf.clone()));
+                                // There is no standardized way to express that the batched span followed from N request spans.
+                                // So, abuse the system and mark the request contexts as follows_from the batch span, so we get
+                                // some linkage in our trace viewer. It allows us to answer: which GET_VECTORED did this GET_PAGE wait for.
+                                req_ctx.perf_follows_from(ctx);
+                                slots_filled += 1;
+                            }
+                            result_slots[first_slot].write(res);
+                            first_req_ctx.perf_follows_from(ctx);
+                            slots_filled += 1;
+                        }
                     }
-
-                    result_slots[first_slot].write(res);
-                    first_req_ctx.perf_follows_from(ctx);
-                    slots_filled += 1;
                 }
             }
             Err(err) => {
                 // this cannot really happen because get_vectored only errors globally on invalid LSN or too large batch size
                 // (We enforce the max batch size outside of this function, in the code that constructs the batch request.)
-                for (slot, req_ctx) in keys_slots.values().flatten() {
+                for (slot, _lsn, req_ctx) in keys_slots.values().flatten() {
                     // this whole `match` is a lot like `From<GetVectoredError> for PageReconstructError`
                     // but without taking ownership of the GetVectoredError
                     let err = match &err {
@@ -488,8 +504,6 @@ impl Timeline {
         let mut buf = version.get(self, key, ctx).await?;
         let nblocks = buf.get_u32_le();
 
-        self.update_cached_rel_size(tag, version.get_lsn(), nblocks);
-
         Ok(nblocks)
     }
 
@@ -1343,32 +1357,6 @@ impl Timeline {
         None
     }
 
-    /// Update cached relation size if there is no more recent update
-    pub fn update_cached_rel_size(&self, tag: RelTag, lsn: Lsn, nblocks: BlockNumber) {
-        let mut rel_size_cache = self.rel_size_cache.write().unwrap();
-
-        if lsn < rel_size_cache.complete_as_of {
-            // Do not cache old values. It's safe to cache the size on read, as long as
-            // the read was at an LSN since we started the WAL ingestion. Reasoning: we
-            // never evict values from the cache, so if the relation size changed after
-            // 'lsn', the new value is already in the cache.
-            return;
-        }
-
-        match rel_size_cache.map.entry(tag) {
-            hash_map::Entry::Occupied(mut entry) => {
-                let cached_lsn = entry.get_mut();
-                if lsn >= cached_lsn.0 {
-                    *cached_lsn = (lsn, nblocks);
-                }
-            }
-            hash_map::Entry::Vacant(entry) => {
-                entry.insert((lsn, nblocks));
-                RELSIZE_CACHE_ENTRIES.inc();
-            }
-        }
-    }
-
     /// Store cached relation size
     pub fn set_cached_rel_size(&self, tag: RelTag, lsn: Lsn, nblocks: BlockNumber) {
         let mut rel_size_cache = self.rel_size_cache.write().unwrap();

pageserver/src/tenant/timeline.rs

@@ -199,11 +199,8 @@ pub struct TimelineResources {
 
 /// The relation size cache caches relation sizes at the end of the timeline. It speeds up WAL
 /// ingestion considerably, because WAL ingestion needs to check on most records if the record
-/// implicitly extends the relation.  At startup, `complete_as_of` is initialized to the current end
-/// of the timeline (disk_consistent_lsn).  It's used on reads of relation sizes to check if the
-/// value can be used to also update the cache, see [`Timeline::update_cached_rel_size`].
+/// implicitly extends the relation.
 pub(crate) struct RelSizeCache {
-    pub(crate) complete_as_of: Lsn,
     pub(crate) map: HashMap<RelTag, (Lsn, BlockNumber)>,
 }
 
@@ -2970,7 +2967,6 @@ impl Timeline {
 
                 last_received_wal: Mutex::new(None),
                 rel_size_cache: RwLock::new(RelSizeCache {
-                    complete_as_of: disk_consistent_lsn,
                     map: HashMap::new(),
                 }),