marvinlanhenke commented on code in PR #324: URL: https://github.com/apache/iceberg-rust/pull/324#discussion_r1579919751
########## crates/integrations/datafusion/src/catalog.rs: ########## @@ -0,0 +1,95 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::{any::Any, sync::Arc}; + +use dashmap::DashMap; +use datafusion::catalog::{schema::SchemaProvider, CatalogProvider}; +use futures::future::try_join_all; +use iceberg::{Catalog, NamespaceIdent, Result}; + +use crate::schema::IcebergSchemaProvider; + +/// Provides an interface to manage and access multiple schemas +/// within an Iceberg [`Catalog`]. +/// +/// Acts as a centralized catalog provider that aggregates +/// multiple [`SchemaProvider`], each associated with distinct namespaces. +pub struct IcebergCatalogProvider { + /// A concurrent `HashMap` where keys are namespace names + /// and values are dynamic references to objects implementing the + /// [`SchemaProvider`] trait. + schemas: DashMap<String, Arc<dyn SchemaProvider>>, Review Comment: the datafusion docs provide a link to a reference implementation by [delta-rs](https://github.com/delta-io/delta-rs/blob/951436ecec476ce65b5ed3b58b50fb0846ca7b91/crates/deltalake-core/src/data_catalog/unity/datafusion.rs#L21), that uses a DashMap as well. My understanding based on the [docs](https://docs.rs/datafusion/latest/datafusion/catalog/trait.CatalogProvider.html#implementing-remote-catalogs) is that datafusion might share the `CatalogProvider` on multiple threads inside an Arc; thus concurrently accessing our "cached" schemas, etc.? Perhaps someone else can clarify this? > [...] The pattern that DataFusion itself uses to plan SQL queries is to walk over the query to [find all schema / table references in an async function](https://docs.rs/datafusion/latest/datafusion/execution/context/struct.SessionState.html#method.resolve_table_references), performing required remote catalog in parallel, and then plans the query using that snapshot. -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
