waynexia commented on code in PR #8437: URL: https://github.com/apache/arrow-datafusion/pull/8437#discussion_r1428733555
########## datafusion/physical-expr/src/utils/guarantee.rs: ########## @@ -0,0 +1,709 @@ +// 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. + +//! [`LiteralGuarantee`] predicate analysis to determine if a column is a +//! constant. + +use crate::utils::split_disjunction; +use crate::{split_conjunction, PhysicalExpr}; +use datafusion_common::{Column, ScalarValue}; +use datafusion_expr::Operator; +use std::collections::{HashMap, HashSet}; +use std::sync::Arc; + +/// Represents a guarantee that must be true for a boolean expression to +/// evaluate to `true`. +/// +/// The guarantee takes the form of a column and a set of literal (constant) +/// [`ScalarValue`]s. For the expression to evaluate to `true`, the column *must +/// satisfy* the guarantee(s). +/// +/// To satisfy the guarantee, depending on [`Guarantee`], the values in the +/// column must either: +/// +/// 1. be ONLY one of that set +/// 2. NOT be ANY of that set +/// +/// # Uses `LiteralGuarantee`s +/// +/// `LiteralGuarantee`s can be used to simplify filter expressions and skip data +/// files (e.g. row groups in parquet files) by proving expressions can not +/// possibly evaluate to `true`. For example, if we have a guarantee that `a` +/// must be in (`1`) for a filter to evaluate to `true`, then we can skip any +/// partition where we know that `a` never has the value of `1`. +/// +/// **Important**: If a `LiteralGuarantee` is not satisfied, the relevant +/// expression is *guaranteed* to evaluate to `false` or `null`. **However**, +/// the opposite does not hold. Even if all `LiteralGurantee`s are satisfied, +/// that does does not guarantee that the predicate will actually evaluate to Review Comment: Nit: ```suggestion /// that does not guarantee that the predicate will actually evaluate to ``` ########## datafusion/physical-expr/src/utils/guarantee.rs: ########## @@ -0,0 +1,709 @@ +// 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. + +//! [`LiteralGuarantee`] predicate analysis to determine if a column is a +//! constant. + +use crate::utils::split_disjunction; +use crate::{split_conjunction, PhysicalExpr}; +use datafusion_common::{Column, ScalarValue}; +use datafusion_expr::Operator; +use std::collections::{HashMap, HashSet}; +use std::sync::Arc; + +/// Represents a guarantee that must be true for a boolean expression to +/// evaluate to `true`. +/// +/// The guarantee takes the form of a column and a set of literal (constant) +/// [`ScalarValue`]s. For the expression to evaluate to `true`, the column *must +/// satisfy* the guarantee(s). +/// +/// To satisfy the guarantee, depending on [`Guarantee`], the values in the +/// column must either: +/// +/// 1. be ONLY one of that set +/// 2. NOT be ANY of that set +/// +/// # Uses `LiteralGuarantee`s +/// +/// `LiteralGuarantee`s can be used to simplify filter expressions and skip data +/// files (e.g. row groups in parquet files) by proving expressions can not +/// possibly evaluate to `true`. For example, if we have a guarantee that `a` +/// must be in (`1`) for a filter to evaluate to `true`, then we can skip any +/// partition where we know that `a` never has the value of `1`. +/// +/// **Important**: If a `LiteralGuarantee` is not satisfied, the relevant +/// expression is *guaranteed* to evaluate to `false` or `null`. **However**, +/// the opposite does not hold. Even if all `LiteralGurantee`s are satisfied, +/// that does does not guarantee that the predicate will actually evaluate to +/// `true`: it may still evaluate to `true`, `false` or `null`. +/// +/// # Creating `LiteralGuarantee`s +/// +/// Use [`LiteralGuarantee::analyze`] to extract literal guarantees from a +/// filter predicate. +/// +/// # Details +/// A guarantee can be one of two forms: +/// +/// 1. The column must be one a particular set of values for the predicate Review Comment: ```suggestion /// 1. The column must be one of a particular set of values for the predicate ``` ########## datafusion/physical-expr/src/utils/guarantee.rs: ########## @@ -0,0 +1,699 @@ +// 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. + +//! [`LiteralGuarantee`] predicate analysis to determine if a column is a +//! constant. + +use crate::utils::split_disjunction; +use crate::{split_conjunction, PhysicalExpr}; +use datafusion_common::{Column, ScalarValue}; +use datafusion_expr::Operator; +use std::collections::{HashMap, HashSet}; +use std::sync::Arc; + +/// Represents a guarantee that must be true for a boolean expression to +/// evaluate to `true`. +/// +/// The guarantee takes the form of a column and a set of literal (constant) +/// [`ScalarValue`]s. For the expression to evaluate to `true`, the column *must +/// satisfy* the guarantee(s). +/// +/// To satisfy the guarantee, depending on [`Guarantee`], the values in the +/// column must either: +/// +/// 1. be ONLY one of that set +/// 2. NOT be ANY of that set +/// +/// # Uses `LiteralGuarantee`s +/// +/// `LiteralGuarantee`s can be used to simplify filter expressions and skip data +/// files (e.g. row groups in parquet files) by proving expressions can not +/// possibly evaluate to `true`. For example, if we have a guarantee that `a` +/// must be in (`1`) for a filter to evaluate to `true`, then we can skip any +/// partition where we know that `a` never has the value of `1`. +/// +/// **Important**: If a `LiteralGuarantee` is not satisfied, the relevant +/// expression is *guaranteed* to evaluate to `false` or `null`. **However**, +/// the opposite does not hold. Even if all `LiteralGurantee`s are satisfied, +/// that does does not guarantee that the predicate will actually evaluate to +/// `true`: it may still evaluate to `true`, `false` or `null`. +/// +/// # Creating `LiteralGuarantee`s +/// +/// Use [`LiteralGuarantee::analyze`] to extract literal guarantees from a +/// filter predicate. +/// +/// # Details +/// A guarantee can be one of two forms: +/// +/// 1. The column must be one a particular set of values for the predicate +/// to be `true`. If the column takes on any other value, the predicate can not +/// evaluate to `true`. For example, +/// `(a = 1)`, `(a = 1 OR a = 2) or `a IN (1, 2, 3)` +/// +/// 2. The column must NOT be one of a particular set of values for the predicate to +/// be `true`. If the column takes on any of the values, the predicate can not +/// evaluate to `true`. For example, +/// `(a != 1)`, `(a != 1 AND a != 2)` or `a NOT IN (1, 2, 3)` Review Comment: This helps a lot 👍 The guarantee is similar to bloom filter: it might be false-positive, but negative result is reliable. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
