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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2022/05/10 20:31:38 UTC
[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #2279: Add `CREATE VIEW`
alamb commented on code in PR #2279:
URL: https://github.com/apache/arrow-datafusion/pull/2279#discussion_r869654798
##########
datafusion/core/src/datasource/view.rs:
##########
@@ -121,11 +117,171 @@ mod tests {
"| column1 | column2 | column3 |",
"+---------+---------+---------+",
"| 1 | 2 | 3 |",
+ "| 4 | 5 | 6 |",
"+---------+---------+---------+",
];
assert_batches_eq!(expected, &results);
Ok(())
}
+
+ #[tokio::test]
+ async fn query_view_with_projection() -> Result<()> {
+ let session_ctx = SessionContext::with_config(
+ SessionConfig::new().with_information_schema(true),
+ );
+
+ session_ctx
+ .sql("CREATE TABLE abc AS VALUES (1,2,3), (4,5,6)")
+ .await?
+ .collect()
+ .await?;
+
+ let view_sql = "CREATE VIEW xyz AS SELECT column1, column2 FROM abc";
+ session_ctx.sql(view_sql).await?.collect().await?;
+
+ let results = session_ctx.sql("SELECT * FROM information_schema.tables WHERE table_type='VIEW' AND table_name = 'xyz'").await?.collect().await?;
+ assert_eq!(results[0].num_rows(), 1);
+
+ let results = session_ctx
+ .sql("SELECT column1 FROM xyz")
+ .await?
+ .collect()
+ .await?;
+
+ let expected = vec![
+ "+---------+",
+ "| column1 |",
+ "+---------+",
+ "| 1 |",
+ "| 4 |",
+ "+---------+",
+ ];
+
+ assert_batches_eq!(expected, &results);
+
+ Ok(())
+ }
+
+ #[tokio::test]
+ async fn query_view_plan() -> Result<()> {
+ let session_ctx = SessionContext::with_config(
+ SessionConfig::new().with_information_schema(true),
+ );
+
+ session_ctx
+ .sql("CREATE TABLE abc AS VALUES (1,2,3), (4,5,6)")
+ .await?
+ .collect()
+ .await?;
+
+ let view_sql = "CREATE VIEW xyz AS SELECT * FROM abc";
+ session_ctx.sql(view_sql).await?.collect().await?;
+
+ let results = session_ctx
+ .sql("EXPLAIN CREATE VIEW xyz AS SELECT * FROM abc")
+ .await?
+ .collect()
+ .await?;
+
+ let expected = vec![
+ "+---------------+--------------------------------------------------------+",
+ "| plan_type | plan |",
+ "+---------------+--------------------------------------------------------+",
+ "| logical_plan | CreateView: \"xyz\" |",
+ "| | Projection: #abc.column1, #abc.column2, #abc.column3 |",
+ "| | TableScan: abc projection=Some([0, 1, 2]) |",
+ "| physical_plan | EmptyExec: produce_one_row=false |",
+ "| | |",
+ "+---------------+--------------------------------------------------------+",
+ ];
+
+ assert_batches_eq!(expected, &results);
+
+ let results = session_ctx
Review Comment:
I think more interesting tests might be to create a view and then run queries against the view (also adding things like filters to on the view
For example
```sql
select coumn1, count(colum2) from xyz where column3 > 2
```
##########
datafusion/core/src/datasource/view.rs:
##########
@@ -0,0 +1,131 @@
+// 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.
+
+//! The table implementation.
+
+use std::{any::Any, sync::Arc};
+
+use arrow::datatypes::SchemaRef;
+use async_trait::async_trait;
+
+use crate::{
+ error::Result,
+ execution::context::SessionContext,
+ logical_plan::{Expr, LogicalPlan},
+ physical_plan::ExecutionPlan,
+};
+
+use crate::datasource::{
+ datasource::TableProviderFilterPushDown, TableProvider, TableType,
+};
+
+/// An implementation of `TableProvider` that uses the object store
+/// or file system listing capability to get the list of files.
+pub struct ViewTable {
+ /// To create ExecutionPlan
+ context: SessionContext,
+ /// LogicalPlan of the view
+ logical_plan: LogicalPlan,
+ /// File fields + partition columns
+ table_schema: SchemaRef,
+}
+
+impl ViewTable {
+ /// Create new view that is executed at query runtime.
+ /// Takes a `LogicalPlan` as input.
+ pub fn try_new(context: SessionContext, logical_plan: LogicalPlan) -> Result<Self> {
+ let table_schema = logical_plan.schema().as_ref().to_owned().into();
+
+ let view = Self {
+ context,
+ logical_plan,
+ table_schema,
+ };
+
+ Ok(view)
+ }
+}
+
+#[async_trait]
+impl TableProvider for ViewTable {
+ fn as_any(&self) -> &dyn Any {
+ self
+ }
+
+ fn schema(&self) -> SchemaRef {
+ Arc::clone(&self.table_schema)
+ }
+
+ fn table_type(&self) -> TableType {
+ TableType::View
+ }
+
+ async fn scan(
+ &self,
+ projection: &Option<Vec<usize>>,
+ filters: &[Expr],
+ limit: Option<usize>,
+ ) -> Result<Arc<dyn ExecutionPlan>> {
+ self.context.create_physical_plan(&self.logical_plan).await
Review Comment:
👍
##########
datafusion/core/src/datasource/view.rs:
##########
@@ -0,0 +1,131 @@
+// 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.
+
+//! The table implementation.
+
+use std::{any::Any, sync::Arc};
+
+use arrow::datatypes::SchemaRef;
+use async_trait::async_trait;
+
+use crate::{
+ error::Result,
+ execution::context::SessionContext,
+ logical_plan::{Expr, LogicalPlan},
+ physical_plan::ExecutionPlan,
+};
+
+use crate::datasource::{
+ datasource::TableProviderFilterPushDown, TableProvider, TableType,
+};
+
+/// An implementation of `TableProvider` that uses the object store
+/// or file system listing capability to get the list of files.
Review Comment:
The implementation uses another LogicalPlan
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