alamb commented on code in PR #16971: URL: https://github.com/apache/datafusion/pull/16971#discussion_r2248531228
########## datafusion/execution/src/cache/cache_unit.rs: ########## @@ -157,9 +158,79 @@ impl CacheAccessor<Path, Arc<Vec<ObjectMeta>>> for DefaultListFilesCache { } } +/// Collected file embedded metadata cache. +/// The metadata for some file is invalided when the file size or last modification time have been +/// changed. +#[derive(Default)] +pub struct DefaultFilesMetadataCache { + metadata: DashMap<Path, (ObjectMeta, Arc<FileMetadata>)>, +} + +impl CacheAccessor<Path, Arc<FileMetadata>> for DefaultFilesMetadataCache { + type Extra = ObjectMeta; + + fn get(&self, _k: &Path) -> Option<Arc<FileMetadata>> { + panic!("get in DefaultFilesMetadataCache is not supported, please use get_with_extra") + } + + fn get_with_extra(&self, k: &Path, e: &Self::Extra) -> Option<Arc<FileMetadata>> { + self.metadata + .get(k) + .map(|s| { + let (extra, metadata) = s.value(); + if extra.size != e.size || extra.last_modified != e.last_modified { + None + } else { + Some(Arc::clone(metadata)) + } + }) + .unwrap_or(None) + } + + fn put(&self, _key: &Path, _value: Arc<FileMetadata>) -> Option<Arc<FileMetadata>> { + panic!("put in DefaultFilesMetadataCache is not supported, please use put_with_extra") Review Comment: > What about using just ObjectMeta as the key, since it already has the path embedded? That is a brilliant idea! > And what about the [get|put]_with_extra methods in this new version, should they also panic! or call get/put and ignore the Extra? I think they should ignore the Extra and call get/put instead -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org