feat(index): add file_size_hint for remote blob reader

src/common/base/src/range_read.rs

@@ -36,6 +36,11 @@ pub struct Metadata {
 /// `RangeReader` reads a range of bytes from a source.
 #[async_trait]
 pub trait RangeReader: Send + Unpin {
+    /// Sets the file size hint for the reader.
+    ///
+    /// It's used to optimize the reading process by reducing the number of remote requests.
+    fn with_file_size_hint(&mut self, file_size_hint: u64);
+
     /// Returns the metadata of the source.
     async fn metadata(&mut self) -> io::Result<Metadata>;
 
@@ -70,6 +75,10 @@ pub trait RangeReader: Send + Unpin {
 
 #[async_trait]
 impl<R: ?Sized + RangeReader> RangeReader for &mut R {
+    fn with_file_size_hint(&mut self, file_size_hint: u64) {
+        (*self).with_file_size_hint(file_size_hint)
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
         (*self).metadata().await
     }
@@ -186,6 +195,10 @@ impl<R: RangeReader + 'static> AsyncRead for AsyncReadAdapter<R> {
 
 #[async_trait]
 impl RangeReader for Vec<u8> {
+    fn with_file_size_hint(&mut self, _file_size_hint: u64) {
+        // do nothing
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
         Ok(Metadata {
             content_length: self.len() as u64,
@@ -222,6 +235,10 @@ impl FileReader {
 
 #[async_trait]
 impl RangeReader for FileReader {
+    fn with_file_size_hint(&mut self, _file_size_hint: u64) {
+        // do nothing
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
         Ok(Metadata {
             content_length: self.content_length,

src/mito2/src/sst/file.rs

@@ -146,13 +146,33 @@ pub enum IndexType {
 }
 
 impl FileMeta {
+    /// Returns true if the file has an inverted index
     pub fn inverted_index_available(&self) -> bool {
         self.available_indexes.contains(&IndexType::InvertedIndex)
     }
 
+    /// Returns true if the file has a fulltext index
     pub fn fulltext_index_available(&self) -> bool {
         self.available_indexes.contains(&IndexType::FulltextIndex)
     }
+
+    /// Returns the size of the inverted index file
+    pub fn inverted_index_size(&self) -> Option<u64> {
+        if self.available_indexes.len() == 1 && self.inverted_index_available() {
+            Some(self.index_file_size)
+        } else {
+            None
+        }
+    }
+
+    /// Returns the size of the fulltext index file
+    pub fn fulltext_index_size(&self) -> Option<u64> {
+        if self.available_indexes.len() == 1 && self.fulltext_index_available() {
+            Some(self.index_file_size)
+        } else {
+            None
+        }
+    }
 }
 
 /// Handle to a SST file.

src/mito2/src/sst/index/inverted_index/applier.rs

@@ -113,7 +113,7 @@ impl InvertedIndexApplier {
     }
 
     /// Applies predicates to the provided SST file id and returns the relevant row group ids
-    pub async fn apply(&self, file_id: FileId) -> Result<ApplyOutput> {
+    pub async fn apply(&self, file_id: FileId, file_size_hint: Option<u64>) -> Result<ApplyOutput> {
         let _timer = INDEX_APPLY_ELAPSED
             .with_label_values(&[TYPE_INVERTED_INDEX])
             .start_timer();
@@ -129,8 +129,7 @@ impl InvertedIndexApplier {
                 if let Err(err) = other {
                     warn!(err; "An unexpected error occurred while reading the cached index file. Fallback to remote index file.")
                 }
-
-                self.remote_blob_reader(file_id).await?
+                self.remote_blob_reader(file_id, file_size_hint).await?
             }
         };
 
@@ -181,16 +180,22 @@ impl InvertedIndexApplier {
     }
 
     /// Creates a blob reader from the remote index file.
-    async fn remote_blob_reader(&self, file_id: FileId) -> Result<BlobReader> {
+    async fn remote_blob_reader(
+        &self,
+        file_id: FileId,
+        file_size_hint: Option<u64>,
+    ) -> Result<BlobReader> {
         let puffin_manager = self
             .puffin_manager_factory
             .build(self.store.clone())
             .with_puffin_metadata_cache(self.puffin_metadata_cache.clone());
+
         let file_path = location::index_file_path(&self.region_dir, file_id);
         puffin_manager
             .reader(&file_path)
             .await
             .context(PuffinBuildReaderSnafu)?
+            .with_file_size_hint(file_size_hint)
             .blob(INDEX_BLOB_TYPE)
             .await
             .context(PuffinReadBlobSnafu)?
@@ -250,7 +255,7 @@ mod tests {
             Box::new(mock_index_applier),
             puffin_manager_factory,
         );
-        let output = sst_index_applier.apply(file_id).await.unwrap();
+        let output = sst_index_applier.apply(file_id, None).await.unwrap();
         assert_eq!(
             output,
             ApplyOutput {
@@ -290,7 +295,7 @@ mod tests {
             Box::new(mock_index_applier),
             puffin_manager_factory,
         );
-        let res = sst_index_applier.apply(file_id).await;
+        let res = sst_index_applier.apply(file_id, None).await;
         assert!(format!("{:?}", res.unwrap_err()).contains("Blob not found"));
     }
 }

src/mito2/src/sst/index/inverted_index/creator.rs

@@ -464,7 +464,7 @@ mod tests {
             .unwrap();
             Box::pin(async move {
                 applier
-                    .apply(sst_file_id)
+                    .apply(sst_file_id, None)
                     .await
                     .unwrap()
                     .matched_segment_ids

src/mito2/src/sst/index/store.rs

@@ -68,6 +68,7 @@ impl InstrumentedStore {
             path: path.to_string(),
             read_byte_count,
             read_count,
+            file_size_hint: None,
         })
     }
 
@@ -262,15 +263,27 @@ pub(crate) struct InstrumentedRangeReader<'a> {
     path: String,
     read_byte_count: &'a IntCounter,
     read_count: &'a IntCounter,
+    file_size_hint: Option<u64>,
 }
 
 #[async_trait]
 impl RangeReader for InstrumentedRangeReader<'_> {
+    fn with_file_size_hint(&mut self, file_size_hint: u64) {
+        self.file_size_hint = Some(file_size_hint);
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
-        let stat = self.store.stat(&self.path).await?;
-        Ok(Metadata {
-            content_length: stat.content_length(),
-        })
+        match self.file_size_hint {
+            Some(file_size_hint) => Ok(Metadata {
+                content_length: file_size_hint,
+            }),
+            None => {
+                let stat = self.store.stat(&self.path).await?;
+                Ok(Metadata {
+                    content_length: stat.content_length(),
+                })
+            }
+        }
     }
 
     async fn read(&mut self, range: Range<u64>) -> io::Result<Bytes> {

src/mito2/src/sst/parquet/reader.rs

@@ -475,8 +475,11 @@ impl ParquetReaderBuilder {
         if !self.file_handle.meta_ref().inverted_index_available() {
             return false;
         }
-
-        let apply_output = match index_applier.apply(self.file_handle.file_id()).await {
+        let file_size_hint = self.file_handle.meta_ref().inverted_index_size();
+        let apply_output = match index_applier
+            .apply(self.file_handle.file_id(), file_size_hint)
+            .await
+        {
             Ok(output) => output,
             Err(err) => {
                 if cfg!(any(test, feature = "test")) {

src/puffin/src/partial_reader/async.rs

@@ -23,6 +23,10 @@ use crate::partial_reader::PartialReader;
 
 #[async_trait]
 impl<R: RangeReader> RangeReader for PartialReader<R> {
+    fn with_file_size_hint(&mut self, _file_size_hint: u64) {
+        // do nothing
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
         Ok(Metadata {
             content_length: self.size,

src/puffin/src/puffin_manager.rs

@@ -73,11 +73,12 @@ pub struct PutOptions {
 
 /// The `PuffinReader` trait provides methods for reading blobs and directories from a Puffin file.
 #[async_trait]
-#[auto_impl::auto_impl(Arc)]
 pub trait PuffinReader {
     type Blob: BlobGuard;
     type Dir: DirGuard;
 
+    fn with_file_size_hint(self, file_size_hint: Option<u64>) -> Self;
+
     /// Reads a blob from the Puffin file.
     ///
     /// The returned `BlobGuard` is used to access the blob data.

src/puffin/src/puffin_manager/fs_puffin_manager/reader.rs

@@ -43,6 +43,9 @@ pub struct FsPuffinReader<S, F> {
     /// The name of the puffin file.
     puffin_file_name: String,
 
+    /// The file size hint.
+    file_size_hint: Option<u64>,
+
     /// The stager.
     stager: S,
 
@@ -62,6 +65,7 @@ impl<S, F> FsPuffinReader<S, F> {
     ) -> Self {
         Self {
             puffin_file_name,
+            file_size_hint: None,
             stager,
             puffin_file_accessor,
             puffin_file_metadata_cache,
@@ -78,11 +82,19 @@ where
     type Blob = Either<RandomReadBlob<F>, S::Blob>;
     type Dir = S::Dir;
 
+    fn with_file_size_hint(mut self, file_size_hint: Option<u64>) -> Self {
+        self.file_size_hint = file_size_hint;
+        self
+    }
+
     async fn blob(&self, key: &str) -> Result<Self::Blob> {
-        let reader = self
+        let mut reader = self
             .puffin_file_accessor
             .reader(&self.puffin_file_name)
             .await?;
+        if let Some(file_size_hint) = self.file_size_hint {
+            reader.with_file_size_hint(file_size_hint);
+        }
         let mut file = PuffinFileReader::new(reader);
 
         let metadata = self.get_puffin_file_metadata(&mut file).await?;
@@ -303,6 +315,13 @@ where
     A: RangeReader,
     B: RangeReader,
 {
+    fn with_file_size_hint(&mut self, file_size_hint: u64) {
+        match self {
+            Either::L(a) => a.with_file_size_hint(file_size_hint),
+            Either::R(b) => b.with_file_size_hint(file_size_hint),
+        }
+    }
+
     async fn metadata(&mut self) -> io::Result<Metadata> {
         match self {
             Either::L(a) => a.metadata().await,