Fokko commented on code in PR #129: URL: https://github.com/apache/iceberg-rust/pull/129#discussion_r1446153732
########## crates/iceberg/src/scan.rs: ########## @@ -0,0 +1,448 @@ +// 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, ManifestEntryRef, SchemaRef, SnapshotRef, TableMetadataRef}; +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?; + + // 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() { + // Data file + let manifest = manifest_list_entry.load_manifest(&self.file_io).await?; + + for manifest_entry in manifest.entries().iter().filter(|e| e.is_alive()) { + match manifest_entry.content_type() { + DataContentType::EqualityDeletes | DataContentType::PositionDeletes => { + return Err(Error::new( + ErrorKind::FeatureUnsupported, + "Delete files are not supported yet.", Review Comment: ```suggestion "Delete files are not yet supported.", ``` ########## crates/iceberg/src/spec/snapshot.rs: ########## @@ -124,6 +150,70 @@ impl Snapshot { Utc.timestamp_millis_opt(self.timestamp_ms).unwrap() } + /// Get the schema id of this snapshot. + #[inline] + pub fn schema_id(&self) -> Option<SchemaId> { + self.schema_id + } + + /// Get the schema of this snapshot. + pub fn schema(&self, table_metadata: &TableMetadata) -> Result<SchemaRef> { + Ok(match self.schema_id() { + Some(schema_id) => table_metadata + .schema_by_id(schema_id) + .ok_or_else(|| { + Error::new( + ErrorKind::DataInvalid, + format!("Schema with id {} not found", schema_id), + ) + })? + .clone(), + None => table_metadata.current_schema().clone(), + }) + } Review Comment: In Python we just fixed it here: https://github.com/apache/iceberg-python/pull/247 The thing is that the `current-schema` can be pointing to a newer snapshot than the snapshot-id. This is because schema and data are tracked independently in Iceberg. However, if you just want to see the latest version of the table, you want to use the `current-snapshot`. When you want to see the table at a certain snapshot, then you want to use the schema-id from the snapshot. I think we can also do this in a separate PR. ########## crates/iceberg/src/scan.rs: ########## @@ -0,0 +1,448 @@ +// 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, ManifestEntryRef, SchemaRef, SnapshotRef, TableMetadataRef}; +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?; + + // 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() { + // Data file Review Comment: ```suggestion ``` -- This is an automated message from the Apache Git Service. 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