liurenjie1024 commented on code in PR #129: URL: https://github.com/apache/iceberg-rust/pull/129#discussion_r1441250114
########## crates/iceberg/src/scan.rs: ########## @@ -0,0 +1,616 @@ +// 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. + +//! Table scan api. + +use crate::io::FileIO; +use crate::spec::{ + DataContentType, ManifestContentType, ManifestEntry, ManifestEntryRef, SchemaRef, SnapshotRef, + TableMetadataRef, INITIAL_SEQUENCE_NUMBER, +}; +use crate::table::Table; +use crate::{Error, ErrorKind}; +use arrow_array::RecordBatch; +use futures::stream::{iter, BoxStream}; +use futures::StreamExt; + +/// Builder to create table scan. +pub struct TableScanBuilder<'a> { + table: &'a Table, + // Empty column names means to select all columns + column_names: Vec<String>, + snapshot_id: Option<i64>, +} + +impl<'a> TableScanBuilder<'a> { + pub fn new(table: &'a Table) -> Self { + Self { + table, + column_names: vec![], + snapshot_id: None, + } + } + + /// Select all columns. + pub fn select_all(mut self) -> Self { + self.column_names.clear(); + self + } + + /// Select some columns of the table. + pub fn select(mut self, column_names: impl IntoIterator<Item = impl ToString>) -> Self { + self.column_names = column_names + .into_iter() + .map(|item| item.to_string()) + .collect(); + self + } + + /// Set the snapshot to scan. When not set, it uses current snapshot. + pub fn snapshot_id(mut self, snapshot_id: i64) -> Self { + self.snapshot_id = Some(snapshot_id); + self + } + + /// Build the table scan. + pub fn build(self) -> crate::Result<TableScan> { + let snapshot = match self.snapshot_id { + Some(snapshot_id) => self + .table + .metadata() + .snapshot_by_id(snapshot_id) + .ok_or_else(|| { + Error::new( + ErrorKind::DataInvalid, + format!("Snapshot with id {} not found", snapshot_id), + ) + })? + .clone(), + None => self + .table + .metadata() + .current_snapshot() + .ok_or_else(|| { + Error::new( + ErrorKind::FeatureUnsupported, + "Can't scan table without snapshots", + ) + })? + .clone(), + }; + + let schema = snapshot.schema(self.table.metadata())?; + + // Check that all column names exist in the schema. + if !self.column_names.is_empty() { + for column_name in &self.column_names { + if schema.field_by_name(column_name).is_none() { + return Err(Error::new( + ErrorKind::DataInvalid, + format!("Column {} not found in table.", column_name), + )); + } + } + } + + Ok(TableScan { + snapshot, + file_io: self.table.file_io().clone(), + table_metadata: self.table.metadata_ref(), + column_names: self.column_names, + schema, + }) + } +} + +/// Table scan. +#[derive(Debug)] +#[allow(dead_code)] +pub struct TableScan { + snapshot: SnapshotRef, + table_metadata: TableMetadataRef, + file_io: FileIO, + column_names: Vec<String>, + schema: SchemaRef, +} + +/// A stream of [`FileScanTask`]. +pub type FileScanTaskStream = BoxStream<'static, crate::Result<FileScanTask>>; + +impl TableScan { + /// Returns a stream of file scan tasks. + pub async fn plan_files(&self) -> crate::Result<FileScanTaskStream> { + let manifest_list = self + .snapshot + .load_manifest_list(&self.file_io, &self.table_metadata) + .await?; + + // Get minimum sequence number of data files. + let min_data_file_seq_num = manifest_list + .entries() + .iter() + .filter(|e| e.content == ManifestContentType::Data) + .map(|e| e.min_sequence_number) + .min() + .unwrap_or(INITIAL_SEQUENCE_NUMBER); + + // Collect deletion files first. + let mut position_delete_files = Vec::with_capacity(manifest_list.entries().len()); + let mut eq_delete_files = Vec::with_capacity(manifest_list.entries().len()); + + // TODO: We should introduce runtime api to enable parallel scan. + for manifest_list_entry in manifest_list.entries().iter().filter(|e| { + e.content == ManifestContentType::Deletes && e.sequence_number >= min_data_file_seq_num + }) { + let manifest_file = manifest_list_entry.load_manifest(&self.file_io).await?; + + for manifest_entry in manifest_file.entries().iter().filter(|e| e.is_alive()) { + match manifest_entry.content_type() { + DataContentType::PositionDeletes => { + position_delete_files.push(manifest_entry.clone()); + } + DataContentType::EqualityDeletes => { + eq_delete_files.push(manifest_entry.clone()); + } + DataContentType::Data => { + return Err(Error::new( + ErrorKind::DataInvalid, + format!( + "Data file entry({}) found in delete manifest file({})", + manifest_entry.file_path(), + manifest_list_entry.manifest_path + ), + )); + } + } + } + } + + // Sort delete files by sequence number. + position_delete_files + .sort_by_key(|f| f.sequence_number().unwrap_or(INITIAL_SEQUENCE_NUMBER)); + eq_delete_files.sort_by_key(|f| f.sequence_number().unwrap_or(INITIAL_SEQUENCE_NUMBER)); + + // Generate data file stream + let mut file_scan_tasks = Vec::with_capacity(manifest_list.entries().len()); + for manifest_list_entry in manifest_list + .entries() + .iter() + .filter(|e| e.content == ManifestContentType::Data) + { + // Data file + let manifest = manifest_list_entry.load_manifest(&self.file_io).await?; + + for manifest_entry in manifest.entries() { + if manifest_entry.is_alive() { + file_scan_tasks.push(Ok(FileScanTask { + data_file: manifest_entry.clone(), + position_delete_files: TableScan::filter_position_delete_files( + manifest_entry, + &position_delete_files, + ), + eq_delete_files: TableScan::filter_eq_delete_files( + manifest_entry, + &eq_delete_files, + ), + start: 0, + length: manifest_entry.file_size_in_bytes(), + })); + } + } + } + + Ok(iter(file_scan_tasks).boxed()) + } + + /// Return the position delete files that should be applied to the data file. + /// + /// Here we assume that the position delete files are sorted by sequence number in ascending order. + fn filter_position_delete_files( + data_file: &ManifestEntry, + position_deletes: &[ManifestEntryRef], + ) -> Vec<ManifestEntryRef> { + let data_seq_num = data_file + .sequence_number() + .unwrap_or(INITIAL_SEQUENCE_NUMBER); + + // Find the first position delete file whose sequence number is greater than or equal to the data file. + let first_entry = position_deletes.partition_point(|e| { + e.sequence_number().unwrap_or(INITIAL_SEQUENCE_NUMBER) < data_seq_num Review Comment: Not exists after removing deletion files support. -- This is an automated message from the Apache Git Service. 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