yjshen commented on a change in pull request #1010: URL: https://github.com/apache/arrow-datafusion/pull/1010#discussion_r714511626
########## File path: datafusion/src/datasource/file_format/mod.rs ########## @@ -0,0 +1,192 @@ +// 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. + +//! Module containing helper methods for the various file formats + +pub mod avro; +pub mod csv; +pub mod json; +pub mod parquet; + +use std::pin::Pin; +use std::sync::Arc; + +use crate::arrow::datatypes::SchemaRef; +use crate::datasource::{create_max_min_accs, get_col_stats}; +use crate::error::Result; +use crate::logical_plan::Expr; +use crate::physical_plan::{Accumulator, ExecutionPlan, Statistics}; + +use async_trait::async_trait; +use futures::Stream; + +/// A stream of String that can be used accross await calls +pub type StringStream = Pin<Box<dyn Stream<Item = String> + Send + Sync>>; + +/// Convert a vector into a stream +pub fn string_stream(strings: Vec<String>) -> StringStream { + Box::pin(futures::stream::iter(strings)) +} + +/// This trait abstracts all the file format specific implementations +/// from the `TableProvider`. This helps code re-utilization accross +/// providers that support the the same file formats. +#[async_trait] +pub trait FileFormat: Send + Sync { + /// Open the files at the paths provided by iterator and infer the + /// common schema + async fn infer_schema(&self, paths: StringStream) -> Result<SchemaRef>; + + /// Open the file at the given path and infer its statistics + async fn infer_stats(&self, path: &str) -> Result<Statistics>; + + /// Take a list of files and convert it to the appropriate executor + /// according to this file format. + /// TODO group params into TableDescription(schema,files,stats) and + /// ScanOptions(projection,batch_size,filters) to avoid too_many_arguments + #[allow(clippy::too_many_arguments)] + async fn create_executor( Review comment: The name `executor` seems vague to me. Since it creates a scan physical plan, can we name it more precisely? ########## File path: datafusion/src/datasource/listing.rs ########## @@ -0,0 +1,297 @@ +// 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. + +//! A table that uses the `ObjectStore` listing capability +//! to get the list of files to process. + +use std::{any::Any, sync::Arc}; + +use arrow::datatypes::{DataType, Field, Schema, SchemaRef}; +use async_trait::async_trait; +use futures::{StreamExt, TryStreamExt}; + +use crate::{ + datasource::file_format::{self, PartitionedFile}, + error::Result, + logical_plan::Expr, + physical_plan::{common, ExecutionPlan, Statistics}, +}; + +use super::{ + datasource::TableProviderFilterPushDown, file_format::FileFormat, TableProvider, +}; + +/// Options for creating a `ListingTable` +pub struct ListingOptions { + /// A suffix on which files should be filtered (leave empty to + /// keep all files on the path) + pub file_extension: String, + /// The file format + pub format: Arc<dyn FileFormat>, + /// The expected partition column names. + /// For example `Vec["a", "b"]` means that the two first levels of + /// partitioning expected should be named "a" and "b": + /// - If there is a third level of partitioning it will be ignored. + /// - Files that don't follow this partitioning will be ignored. Review comment: Regarding the comments here, we haven't think about how to deal with default partition semantics yet. I.e while inserting a table with a partition column values NULL, how do we deal with a=20210922/b=NULL/1.parquet? how to differentiate if the NULL is a valid string value or it denotes none exists? I recall Hive have `__HIVE_DEFAULT_PARTITION__` for this purpose. ########## File path: datafusion/src/datasource/file_format/mod.rs ########## @@ -0,0 +1,192 @@ +// 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. + +//! Module containing helper methods for the various file formats + +pub mod avro; +pub mod csv; +pub mod json; +pub mod parquet; + +use std::pin::Pin; +use std::sync::Arc; + +use crate::arrow::datatypes::SchemaRef; +use crate::datasource::{create_max_min_accs, get_col_stats}; +use crate::error::Result; +use crate::logical_plan::Expr; +use crate::physical_plan::{Accumulator, ExecutionPlan, Statistics}; + +use async_trait::async_trait; +use futures::Stream; + +/// A stream of String that can be used accross await calls +pub type StringStream = Pin<Box<dyn Stream<Item = String> + Send + Sync>>; + +/// Convert a vector into a stream +pub fn string_stream(strings: Vec<String>) -> StringStream { + Box::pin(futures::stream::iter(strings)) +} + +/// This trait abstracts all the file format specific implementations +/// from the `TableProvider`. This helps code re-utilization accross +/// providers that support the the same file formats. +#[async_trait] +pub trait FileFormat: Send + Sync { + /// Open the files at the paths provided by iterator and infer the + /// common schema + async fn infer_schema(&self, paths: StringStream) -> Result<SchemaRef>; Review comment: Maybe `FileMetaStream` as arguments instead? ########## File path: datafusion/src/datasource/listing.rs ########## @@ -0,0 +1,297 @@ +// 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. + +//! A table that uses the `ObjectStore` listing capability +//! to get the list of files to process. + +use std::{any::Any, sync::Arc}; + +use arrow::datatypes::{DataType, Field, Schema, SchemaRef}; +use async_trait::async_trait; +use futures::{StreamExt, TryStreamExt}; + +use crate::{ + datasource::file_format::{self, PartitionedFile}, + error::Result, + logical_plan::Expr, + physical_plan::{common, ExecutionPlan, Statistics}, +}; + +use super::{ + datasource::TableProviderFilterPushDown, file_format::FileFormat, TableProvider, +}; + +/// Options for creating a `ListingTable` +pub struct ListingOptions { + /// A suffix on which files should be filtered (leave empty to + /// keep all files on the path) + pub file_extension: String, + /// The file format + pub format: Arc<dyn FileFormat>, + /// The expected partition column names. + /// For example `Vec["a", "b"]` means that the two first levels of + /// partitioning expected should be named "a" and "b": + /// - If there is a third level of partitioning it will be ignored. + /// - Files that don't follow this partitioning will be ignored. + /// Note that only `DataType::Utf8` is supported for the column type. + /// TODO implement case where partitions.len() > 0 + pub partitions: Vec<String>, Review comment: Does it make sense to have `partitions` a schema instead of `Vec<String>`, and introduce a cast if needed from path string to its `partition_values` or `Vec<ScalarValue>`? -- This is an automated message from the Apache Git Service. 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