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| 1 | +// Licensed to the Apache Software Foundation (ASF) under one |
| 2 | +// or more contributor license agreements. See the NOTICE file |
| 3 | +// distributed with this work for additional information |
| 4 | +// regarding copyright ownership. The ASF licenses this file |
| 5 | +// to you under the Apache License, Version 2.0 (the |
| 6 | +// "License"); you may not use this file except in compliance |
| 7 | +// with the License. You may obtain a copy of the License at |
| 8 | +// |
| 9 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | +// |
| 11 | +// Unless required by applicable law or agreed to in writing, |
| 12 | +// software distributed under the License is distributed on an |
| 13 | +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| 14 | +// KIND, either express or implied. See the License for the |
| 15 | +// specific language governing permissions and limitations |
| 16 | +// under the License. |
| 17 | + |
| 18 | +//! View data source which uses a LogicalPlan as it's input. |
| 19 | +
|
| 20 | +use std::{any::Any, borrow::Cow, sync::Arc}; |
| 21 | + |
| 22 | +use crate::Session; |
| 23 | +use crate::TableProvider; |
| 24 | + |
| 25 | +use arrow::datatypes::SchemaRef; |
| 26 | +use async_trait::async_trait; |
| 27 | +use datafusion_common::error::Result; |
| 28 | +use datafusion_common::Column; |
| 29 | +use datafusion_expr::TableType; |
| 30 | +use datafusion_expr::{Expr, LogicalPlan}; |
| 31 | +use datafusion_expr::{LogicalPlanBuilder, TableProviderFilterPushDown}; |
| 32 | +use datafusion_physical_plan::ExecutionPlan; |
| 33 | + |
| 34 | +/// An implementation of `TableProvider` that uses another logical plan. |
| 35 | +#[derive(Debug)] |
| 36 | +pub struct ViewTable { |
| 37 | + /// LogicalPlan of the view |
| 38 | + logical_plan: LogicalPlan, |
| 39 | + /// File fields + partition columns |
| 40 | + table_schema: SchemaRef, |
| 41 | + /// SQL used to create the view, if available |
| 42 | + definition: Option<String>, |
| 43 | +} |
| 44 | + |
| 45 | +impl ViewTable { |
| 46 | + /// Create new view that is executed at query runtime. |
| 47 | + /// |
| 48 | + /// Takes a `LogicalPlan` and optionally the SQL text of the `CREATE` |
| 49 | + /// statement. |
| 50 | + /// |
| 51 | + /// Notes: the `LogicalPlan` is not validated or type coerced. If this is |
| 52 | + /// needed it should be done after calling this function. |
| 53 | + pub fn new(logical_plan: LogicalPlan, definition: Option<String>) -> Self { |
| 54 | + let table_schema = logical_plan.schema().as_ref().to_owned().into(); |
| 55 | + Self { |
| 56 | + logical_plan, |
| 57 | + table_schema, |
| 58 | + definition, |
| 59 | + } |
| 60 | + } |
| 61 | + |
| 62 | + #[deprecated( |
| 63 | + since = "47.0.0", |
| 64 | + note = "Use `ViewTable::new` instead and apply TypeCoercion to the logical plan if needed" |
| 65 | + )] |
| 66 | + pub fn try_new( |
| 67 | + logical_plan: LogicalPlan, |
| 68 | + definition: Option<String>, |
| 69 | + ) -> Result<Self> { |
| 70 | + Ok(Self::new(logical_plan, definition)) |
| 71 | + } |
| 72 | + |
| 73 | + /// Get definition ref |
| 74 | + pub fn definition(&self) -> Option<&String> { |
| 75 | + self.definition.as_ref() |
| 76 | + } |
| 77 | + |
| 78 | + /// Get logical_plan ref |
| 79 | + pub fn logical_plan(&self) -> &LogicalPlan { |
| 80 | + &self.logical_plan |
| 81 | + } |
| 82 | +} |
| 83 | + |
| 84 | +#[async_trait] |
| 85 | +impl TableProvider for ViewTable { |
| 86 | + fn as_any(&self) -> &dyn Any { |
| 87 | + self |
| 88 | + } |
| 89 | + |
| 90 | + fn get_logical_plan(&self) -> Option<Cow<LogicalPlan>> { |
| 91 | + Some(Cow::Borrowed(&self.logical_plan)) |
| 92 | + } |
| 93 | + |
| 94 | + fn schema(&self) -> SchemaRef { |
| 95 | + Arc::clone(&self.table_schema) |
| 96 | + } |
| 97 | + |
| 98 | + fn table_type(&self) -> TableType { |
| 99 | + TableType::View |
| 100 | + } |
| 101 | + |
| 102 | + fn get_table_definition(&self) -> Option<&str> { |
| 103 | + self.definition.as_deref() |
| 104 | + } |
| 105 | + fn supports_filters_pushdown( |
| 106 | + &self, |
| 107 | + filters: &[&Expr], |
| 108 | + ) -> Result<Vec<TableProviderFilterPushDown>> { |
| 109 | + // A filter is added on the View when given |
| 110 | + Ok(vec![TableProviderFilterPushDown::Exact; filters.len()]) |
| 111 | + } |
| 112 | + |
| 113 | + async fn scan( |
| 114 | + &self, |
| 115 | + state: &dyn Session, |
| 116 | + projection: Option<&Vec<usize>>, |
| 117 | + filters: &[Expr], |
| 118 | + limit: Option<usize>, |
| 119 | + ) -> Result<Arc<dyn ExecutionPlan>> { |
| 120 | + let filter = filters.iter().cloned().reduce(|acc, new| acc.and(new)); |
| 121 | + let plan = self.logical_plan().clone(); |
| 122 | + let mut plan = LogicalPlanBuilder::from(plan); |
| 123 | + |
| 124 | + if let Some(filter) = filter { |
| 125 | + plan = plan.filter(filter)?; |
| 126 | + } |
| 127 | + |
| 128 | + let mut plan = if let Some(projection) = projection { |
| 129 | + // avoiding adding a redundant projection (e.g. SELECT * FROM view) |
| 130 | + let current_projection = |
| 131 | + (0..plan.schema().fields().len()).collect::<Vec<usize>>(); |
| 132 | + if projection == ¤t_projection { |
| 133 | + plan |
| 134 | + } else { |
| 135 | + let fields: Vec<Expr> = projection |
| 136 | + .iter() |
| 137 | + .map(|i| { |
| 138 | + Expr::Column(Column::from( |
| 139 | + self.logical_plan.schema().qualified_field(*i), |
| 140 | + )) |
| 141 | + }) |
| 142 | + .collect(); |
| 143 | + plan.project(fields)? |
| 144 | + } |
| 145 | + } else { |
| 146 | + plan |
| 147 | + }; |
| 148 | + |
| 149 | + if let Some(limit) = limit { |
| 150 | + plan = plan.limit(0, Some(limit))?; |
| 151 | + } |
| 152 | + |
| 153 | + state.create_physical_plan(&plan.build()?).await |
| 154 | + } |
| 155 | +} |
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