reifydb_engine/vm/volcano/join/
natural.rs

1// SPDX-License-Identifier: Apache-2.0
2// Copyright (c) 2026 ReifyDB
3
4use std::collections::{HashMap, HashSet};
5
6use reifydb_core::{
7	common::JoinType,
8	value::column::{columns::Columns, headers::ColumnHeaders},
9};
10use reifydb_runtime::hash::Hash128;
11use reifydb_transaction::transaction::Transaction;
12use reifydb_value::{
13	fragment::Fragment,
14	reifydb_assertions,
15	value::{Value, row_number::RowNumber},
16};
17use tracing::instrument;
18
19use super::common::{JoinContext, compute_join_hash, load_and_merge_all, resolve_column_names};
20use crate::{
21	Result,
22	vm::volcano::query::{QueryContext, QueryNode},
23};
24
25pub struct NaturalJoinNode {
26	left: Box<dyn QueryNode>,
27	right: Box<dyn QueryNode>,
28	join_type: JoinType,
29	alias: Option<Fragment>,
30	headers: Option<ColumnHeaders>,
31	context: JoinContext,
32}
33
34impl NaturalJoinNode {
35	pub(crate) fn new(
36		left: Box<dyn QueryNode>,
37		right: Box<dyn QueryNode>,
38		join_type: JoinType,
39		alias: Option<Fragment>,
40	) -> Self {
41		Self {
42			left,
43			right,
44			join_type,
45			alias,
46			headers: None,
47			context: JoinContext::new(),
48		}
49	}
50
51	fn find_common_columns(left_columns: &Columns, right_columns: &Columns) -> Vec<(String, usize, usize)> {
52		let mut common_columns = Vec::new();
53
54		for (left_idx, left_col) in left_columns.iter().enumerate() {
55			for (right_idx, right_col) in right_columns.iter().enumerate() {
56				if left_col.name() == right_col.name() {
57					common_columns.push((left_col.name().text().to_string(), left_idx, right_idx));
58				}
59			}
60		}
61
62		common_columns
63	}
64}
65
66impl QueryNode for NaturalJoinNode {
67	#[instrument(name = "volcano::join::natural::initialize", level = "trace", skip_all)]
68	fn initialize<'a>(&mut self, rx: &mut Transaction<'a>, ctx: &QueryContext) -> Result<()> {
69		self.context.set(ctx);
70		self.left.initialize(rx, ctx)?;
71		self.right.initialize(rx, ctx)?;
72		Ok(())
73	}
74
75	#[instrument(name = "volcano::join::natural::next", level = "trace", skip_all)]
76	fn next<'a>(&mut self, rx: &mut Transaction<'a>, ctx: &mut QueryContext) -> Result<Option<Columns>> {
77		reifydb_assertions! {
78			assert!(self.context.is_initialized(), "NaturalJoinNode::next() called before initialize()");
79		}
80
81		if self.headers.is_some() {
82			return Ok(None);
83		}
84
85		let left_columns = load_and_merge_all(&mut self.left, rx, ctx)?;
86		let right_columns = load_and_merge_all(&mut self.right, rx, ctx)?;
87
88		let left_rows = left_columns.row_count();
89		let left_row_numbers = left_columns.row_numbers.to_vec();
90
91		let common_columns = Self::find_common_columns(&left_columns, &right_columns);
92
93		if common_columns.is_empty() {
94			return Ok(None);
95		}
96
97		let excluded_right_cols: HashSet<usize> =
98			common_columns.iter().map(|(_, _, right_idx)| *right_idx).collect();
99
100		let excluded_indices: Vec<usize> = excluded_right_cols.iter().copied().collect();
101
102		let resolved =
103			resolve_column_names(&left_columns, &right_columns, &self.alias, Some(&excluded_indices));
104
105		let mut result_rows = Vec::new();
106		let mut result_row_numbers: Vec<RowNumber> = Vec::new();
107
108		let right_col_indices: Vec<usize> = common_columns.iter().map(|(_, _, ri)| *ri).collect();
109		let mut hash_buf = Vec::with_capacity(256);
110		let mut hash_table: HashMap<Hash128, Vec<usize>> = HashMap::new();
111		let right_rows = right_columns.row_count();
112		for j in 0..right_rows {
113			if let Some(h) = compute_join_hash(&right_columns, &right_col_indices, j, &mut hash_buf) {
114				hash_table.entry(h).or_default().push(j);
115			}
116		}
117
118		let left_col_indices: Vec<usize> = common_columns.iter().map(|(_, li, _)| *li).collect();
119
120		for i in 0..left_rows {
121			let left_row = left_columns.get_row(i);
122			let mut matched = false;
123
124			let candidates = compute_join_hash(&left_columns, &left_col_indices, i, &mut hash_buf)
125				.and_then(|h| hash_table.get(&h));
126
127			if let Some(indices) = candidates {
128				for &j in indices {
129					let right_row = right_columns.get_row(j);
130
131					let all_match = common_columns.iter().all(|(_, left_idx, right_idx)| {
132						left_row[*left_idx] == right_row[*right_idx]
133					});
134
135					if all_match {
136						let mut combined = left_row.clone();
137						for (idx, value) in right_row.iter().enumerate() {
138							if !excluded_right_cols.contains(&idx) {
139								combined.push(value.clone());
140							}
141						}
142						result_rows.push(combined);
143						matched = true;
144						if !left_row_numbers.is_empty() {
145							result_row_numbers.push(left_row_numbers[i]);
146						}
147					}
148				}
149			}
150
151			if !matched && matches!(self.join_type, JoinType::Left) {
152				let mut combined = left_row.clone();
153
154				let undefined_count = right_columns.len() - excluded_right_cols.len();
155				combined.extend(vec![Value::none(); undefined_count]);
156				result_rows.push(combined);
157				if !left_row_numbers.is_empty() {
158					result_row_numbers.push(left_row_numbers[i]);
159				}
160			}
161		}
162
163		let names_refs: Vec<&str> = resolved.qualified_names.iter().map(|s| s.as_str()).collect();
164		let columns = if result_row_numbers.is_empty() {
165			Columns::from_rows(&names_refs, &result_rows)
166		} else {
167			Columns::from_rows(&names_refs, &result_rows).with_row_numbers(result_row_numbers)
168		};
169
170		self.headers = Some(ColumnHeaders::from_columns(&columns));
171		Ok(Some(columns))
172	}
173
174	fn headers(&self) -> Option<ColumnHeaders> {
175		self.headers.clone()
176	}
177}
reifydb_engine/vm/volcano/join/natural.rs

reifydb_engine/vm/volcano/join/
natural.rs
