partition/range.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
// Copyright 2023 Greptime Team
//
// Licensed 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.
use std::any::Any;
use datafusion_expr::Operator;
use datatypes::prelude::*;
use serde::{Deserialize, Serialize};
use snafu::OptionExt;
use store_api::storage::RegionNumber;
use crate::error::{self, Error};
use crate::partition::{PartitionExpr, PartitionRule};
/// [RangePartitionRule] manages the distribution of partitions partitioning by some column's value
/// range. It's generated from create table request, using MySQL's syntax:
///
/// ```SQL
/// CREATE TABLE table_name (
/// columns definition
/// )
/// PARTITION BY RANGE (column_name) (
/// PARTITION partition_name VALUES LESS THAN (value)[,
/// PARTITION partition_name VALUES LESS THAN (value)][,
/// ...]
/// )
/// ```
///
/// Please refer to MySQL's ["RANGE Partitioning"](https://dev.mysql.com/doc/refman/8.0/en/partitioning-range.html)
/// document for more details.
///
/// Some partition related validations like:
/// - the column used in partitioning must be defined in the create table request
/// - partition name must be unique
/// - range bounds(the "value"s) must be strictly increased
/// - the last partition range must be bounded by "MAXVALUE"
///
/// are all been done in the create table SQL parsing stage. So we can safely skip some checks on the
/// input arguments.
///
/// # Important Notes on Partition and Region
///
/// Technically, table "partition" is a concept of data sharding logically, i.e., how table's data are
/// distributed in logic. And "region" is of how data been placed physically. They should be used
/// in different ways.
///
/// However, currently we have only one region for each partition. For the sake of simplicity, the
/// terms "partition" and "region" are used interchangeably.
///
// TODO(LFC): Further clarify "partition" and "region".
// Could be creating an extra layer between partition and region.
#[derive(Debug, Serialize, Deserialize)]
pub struct RangePartitionRule {
column_name: String,
// Does not store the last "MAXVALUE" bound; because in this way our binary search in finding
// partitions are easier (besides, it's hard to represent "MAXVALUE" in our `Value`).
// Then the length of `bounds` is one less than `regions`.
bounds: Vec<Value>,
regions: Vec<RegionNumber>,
}
impl RangePartitionRule {
pub fn new(
column_name: impl Into<String>,
bounds: Vec<Value>,
regions: Vec<RegionNumber>,
) -> Self {
Self {
column_name: column_name.into(),
bounds,
regions,
}
}
pub fn column_name(&self) -> &String {
&self.column_name
}
pub fn all_regions(&self) -> &Vec<RegionNumber> {
&self.regions
}
pub fn bounds(&self) -> &Vec<Value> {
&self.bounds
}
}
impl PartitionRule for RangePartitionRule {
fn as_any(&self) -> &dyn Any {
self
}
fn partition_columns(&self) -> Vec<String> {
vec![self.column_name().to_string()]
}
fn find_region(&self, values: &[Value]) -> Result<RegionNumber, Error> {
debug_assert_eq!(
values.len(),
1,
"RangePartitionRule can only handle one partition value, actual {}",
values.len()
);
let value = &values[0];
Ok(match self.bounds.binary_search(value) {
Ok(i) => self.regions[i + 1],
Err(i) => self.regions[i],
})
}
fn find_regions_by_exprs(&self, exprs: &[PartitionExpr]) -> Result<Vec<RegionNumber>, Error> {
if exprs.is_empty() {
return Ok(self.regions.clone());
}
debug_assert_eq!(
exprs.len(),
1,
"RangePartitionRule can only handle one partition expr, actual {}",
exprs.len()
);
let PartitionExpr { column, op, value } =
exprs.first().context(error::FindRegionSnafu {
reason: "no partition expr is provided",
})?;
let regions = if column == self.column_name() {
// an example of bounds and regions:
// SQL:
// PARTITION p1 VALUES LESS THAN (10),
// PARTITION p2 VALUES LESS THAN (20),
// PARTITION p3 VALUES LESS THAN (50),
// PARTITION p4 VALUES LESS THAN (MAXVALUE),
// bounds: [10, 20, 50]
// regions: [1, 2, 3, 4]
match self.bounds.binary_search(value) {
Ok(i) => match op {
Operator::Lt => &self.regions[..=i],
Operator::LtEq => &self.regions[..=(i + 1)],
Operator::Eq => &self.regions[(i + 1)..=(i + 1)],
Operator::Gt | Operator::GtEq => &self.regions[(i + 1)..],
Operator::NotEq => &self.regions[..],
_ => unimplemented!(),
},
Err(i) => match op {
Operator::Lt | Operator::LtEq => &self.regions[..=i],
Operator::Eq => &self.regions[i..=i],
Operator::Gt | Operator::GtEq => &self.regions[i..],
Operator::NotEq => &self.regions[..],
_ => unimplemented!(),
},
}
.to_vec()
} else {
self.all_regions().clone()
};
Ok(regions)
}
}
#[cfg(test)]
mod test {
use datafusion_expr::Operator;
use super::*;
use crate::partition::PartitionExpr;
#[test]
fn test_find_regions() {
// PARTITION BY RANGE (a) (
// PARTITION p1 VALUES LESS THAN ('hz'),
// PARTITION p2 VALUES LESS THAN ('sh'),
// PARTITION p3 VALUES LESS THAN ('sz'),
// PARTITION p4 VALUES LESS THAN (MAXVALUE),
// )
let rule = RangePartitionRule {
column_name: "a".to_string(),
bounds: vec!["hz".into(), "sh".into(), "sz".into()],
regions: vec![1, 2, 3, 4],
};
let test =
|column: &str, op: Operator, value: &str, expected_regions: Vec<RegionNumber>| {
let expr = PartitionExpr {
column: column.to_string(),
op,
value: value.into(),
};
let regions = rule.find_regions_by_exprs(&[expr]).unwrap();
assert_eq!(
regions,
expected_regions.into_iter().collect::<Vec<RegionNumber>>()
);
};
test("a", Operator::NotEq, "hz", vec![1, 2, 3, 4]);
test("a", Operator::NotEq, "what", vec![1, 2, 3, 4]);
test("a", Operator::GtEq, "ab", vec![1, 2, 3, 4]);
test("a", Operator::GtEq, "hz", vec![2, 3, 4]);
test("a", Operator::GtEq, "ijk", vec![2, 3, 4]);
test("a", Operator::GtEq, "sh", vec![3, 4]);
test("a", Operator::GtEq, "ssh", vec![3, 4]);
test("a", Operator::GtEq, "sz", vec![4]);
test("a", Operator::GtEq, "zz", vec![4]);
test("a", Operator::Gt, "ab", vec![1, 2, 3, 4]);
test("a", Operator::Gt, "hz", vec![2, 3, 4]);
test("a", Operator::Gt, "ijk", vec![2, 3, 4]);
test("a", Operator::Gt, "sh", vec![3, 4]);
test("a", Operator::Gt, "ssh", vec![3, 4]);
test("a", Operator::Gt, "sz", vec![4]);
test("a", Operator::Gt, "zz", vec![4]);
test("a", Operator::Eq, "ab", vec![1]);
test("a", Operator::Eq, "hz", vec![2]);
test("a", Operator::Eq, "ijk", vec![2]);
test("a", Operator::Eq, "sh", vec![3]);
test("a", Operator::Eq, "ssh", vec![3]);
test("a", Operator::Eq, "sz", vec![4]);
test("a", Operator::Eq, "zz", vec![4]);
test("a", Operator::Lt, "ab", vec![1]);
test("a", Operator::Lt, "hz", vec![1]);
test("a", Operator::Lt, "ijk", vec![1, 2]);
test("a", Operator::Lt, "sh", vec![1, 2]);
test("a", Operator::Lt, "ssh", vec![1, 2, 3]);
test("a", Operator::Lt, "sz", vec![1, 2, 3]);
test("a", Operator::Lt, "zz", vec![1, 2, 3, 4]);
test("a", Operator::LtEq, "ab", vec![1]);
test("a", Operator::LtEq, "hz", vec![1, 2]);
test("a", Operator::LtEq, "ijk", vec![1, 2]);
test("a", Operator::LtEq, "sh", vec![1, 2, 3]);
test("a", Operator::LtEq, "ssh", vec![1, 2, 3]);
test("a", Operator::LtEq, "sz", vec![1, 2, 3, 4]);
test("a", Operator::LtEq, "zz", vec![1, 2, 3, 4]);
test("b", Operator::Lt, "1", vec![1, 2, 3, 4]);
}
}