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// 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 simplified [`TableProvider`] for streaming partitioned datasets
use std::any::Any;
use std::sync::Arc;
use arrow::datatypes::SchemaRef;
use async_trait::async_trait;
use datafusion_common::{DataFusionError, Result};
use datafusion_expr::{Expr, TableType};
use log::debug;
use crate::datasource::TableProvider;
use crate::execution::context::SessionState;
use crate::physical_plan::streaming::{PartitionStream, StreamingTableExec};
use crate::physical_plan::ExecutionPlan;
/// A [`TableProvider`] that streams a set of [`PartitionStream`]
pub struct StreamingTable {
schema: SchemaRef,
partitions: Vec<Arc<dyn PartitionStream>>,
infinite: bool,
}
impl StreamingTable {
/// Try to create a new [`StreamingTable`] returning an error if the schema is incorrect
pub fn try_new(
schema: SchemaRef,
partitions: Vec<Arc<dyn PartitionStream>>,
) -> Result<Self> {
for x in partitions.iter() {
let partition_schema = x.schema();
if !schema.contains(partition_schema) {
debug!(
"target schema does not contain partition schema. \
Target_schema: {schema:?}. Partiton Schema: {partition_schema:?}"
);
return Err(DataFusionError::Plan(
"Mismatch between schema and batches".to_string(),
));
}
}
Ok(Self {
schema,
partitions,
infinite: false,
})
}
/// Sets streaming table can be infinite.
pub fn with_infinite_table(mut self, infinite: bool) -> Self {
self.infinite = infinite;
self
}
}
#[async_trait]
impl TableProvider for StreamingTable {
fn as_any(&self) -> &dyn Any {
self
}
fn schema(&self) -> SchemaRef {
self.schema.clone()
}
fn table_type(&self) -> TableType {
TableType::View
}
async fn scan(
&self,
_state: &SessionState,
projection: Option<&Vec<usize>>,
_filters: &[Expr],
_limit: Option<usize>,
) -> Result<Arc<dyn ExecutionPlan>> {
// TODO: push limit down
Ok(Arc::new(StreamingTableExec::try_new(
self.schema.clone(),
self.partitions.clone(),
projection,
None,
self.infinite,
)?))
}
}