diff options
Diffstat (limited to 'log_db/src/log_reader_forward.rs')
| -rw-r--r-- | log_db/src/log_reader_forward.rs | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/log_db/src/log_reader_forward.rs b/log_db/src/log_reader_forward.rs index 808d3fa..1b34dfc 100644 --- a/log_db/src/log_reader_forward.rs +++ b/log_db/src/log_reader_forward.rs @@ -31,13 +31,26 @@ impl<'a> ForwardLogReader { } } + debug!("Read 16 bytes from metadata file: {:?}", metadata_entry_buf); + // First u64 is the offset of the record in the data file, second is the length of the record let entry_offset = u64::from_be_bytes(metadata_entry_buf[0..8].try_into().unwrap()); let entry_length = u64::from_be_bytes(metadata_entry_buf[8..16].try_into().unwrap()); - self.data_reader.seek(io::SeekFrom::Start(entry_offset))?; + debug!( + "Read offset {} and length {} from metadata file", + entry_offset, entry_length + ); + + // Use .seek_relative instead of .seek to avoid dropping the BufReader internal buffer when + // the seek distance is small + let seek_distance = entry_offset - self.data_reader.stream_position()?; + self.data_reader.seek_relative(seek_distance as i64)?; + let mut result_buf = vec![0; entry_length as usize]; + debug!("Reading {} bytes from data file", entry_length); self.data_reader.read_exact(&mut result_buf)?; + debug!("Read {} bytes from data file", result_buf.len()); let record = Record::deserialize(&result_buf); Ok(Some(record)) @@ -63,6 +76,7 @@ mod tests { #[test] fn test_forward_log_reader_fixture_db1() { + let _ = env_logger::builder().is_test(true).try_init(); let metadata_path = Path::new(TEST_RESOURCES_DIR).join("test_metadata_1"); let data_path = Path::new(TEST_RESOURCES_DIR).join("test_data_1"); let metadata_file = fs::OpenOptions::new() @@ -82,7 +96,7 @@ mod tests { .next() .expect("Failed to read the first record"); assert!(match first_record.values.as_slice() { - [RecordValue::Bytes(_)] => true, + [RecordValue::Bytes(bytes)] => bytes.len() == 256, _ => false, }); |