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//! # Query Plan Explanation Formatting
//!
//! This module provides functionality for formatting query plans in different formats.
use super::core::{ExplainOptions, PlanNode};
impl PlanNode {
/// Explains the plan in text format
pub(crate) fn explain_text(&self, options: &ExplainOptions, indent: usize) -> String {
let indent_str = " ".repeat(indent * 2);
let node_str = match self {
Self::Scan {
table,
columns,
statistics,
} => {
let mut result = format!("{}Scan: {}", indent_str, table);
if !columns.is_empty() {
result.push_str(&format!(" [{}]", columns.join(", ")));
}
if options.with_statistics {
if let Some(stats) = statistics {
result.push_str(&format!(
" (rows: {}, size: {} bytes)",
stats.row_count, stats.size_bytes
));
}
}
result
}
Self::Project { columns, input } => {
let mut result = format!("{}Project: [{}]", indent_str, columns.join(", "));
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Filter {
predicate,
input,
selectivity,
} => {
let mut result = format!("{}Filter: {}", indent_str, predicate);
if options.with_statistics {
if let Some(sel) = selectivity {
result.push_str(&format!(" (selectivity: {:.2})", sel));
}
}
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Join {
join_type,
left,
right,
keys,
} => {
let keys_str = keys
.iter()
.map(|(l, r)| format!("{} = {}", l, r))
.collect::<Vec<_>>()
.join(" AND ");
let mut result = format!("{}Join: {} ON {}", indent_str, join_type, keys_str);
result.push('\n');
result.push_str(&left.explain_text(options, indent + 1));
result.push('\n');
result.push_str(&right.explain_text(options, indent + 1));
result
}
Self::Aggregate {
keys,
aggregates,
input,
} => {
let mut result = format!(
"{}Aggregate: group by [{}], agg [{}]",
indent_str,
keys.join(", "),
aggregates.join(", ")
);
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Sort { sort_exprs, input } => {
let mut result = format!("{}Sort: [{}]", indent_str, sort_exprs.join(", "));
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Limit { limit, input } => {
let mut result = format!("{}Limit: {}", indent_str, limit);
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Window {
window_functions,
input,
} => {
let mut result = format!("{}Window: [{}]", indent_str, window_functions.join(", "));
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
Self::Custom {
name,
params,
input,
} => {
let params_str = params
.iter()
.map(|(k, v)| format!("{}: {}", k, v))
.collect::<Vec<_>>()
.join(", ");
let mut result = format!("{}Custom: {} [{}]", indent_str, name, params_str);
result.push('\n');
result.push_str(&input.explain_text(options, indent + 1));
result
}
};
node_str
}
/// Explains the plan in JSON format
pub(crate) fn explain_json(&self, options: &ExplainOptions) -> String {
// Simplified JSON serialization
match self {
Self::Scan {
table,
columns,
statistics,
} => {
let stats_str = if options.with_statistics {
if let Some(stats) = statistics {
format!(
", \"rows\": {}, \"size\": {}",
stats.row_count, stats.size_bytes
)
} else {
String::new()
}
} else {
String::new()
};
format!(
"{{\"type\": \"Scan\", \"table\": \"{}\", \"columns\": [{}]{}}}",
table,
columns
.iter()
.map(|c| format!("\"{}\"", c))
.collect::<Vec<_>>()
.join(", "),
stats_str
)
}
Self::Project { columns, input } => {
format!(
"{{\"type\": \"Project\", \"columns\": [{}], \"input\": {}}}",
columns
.iter()
.map(|c| format!("\"{}\"", c))
.collect::<Vec<_>>()
.join(", "),
input.explain_json(options)
)
}
Self::Filter {
predicate,
input,
selectivity,
} => {
let selectivity_str = if options.with_statistics {
if let Some(sel) = selectivity {
format!(", \"selectivity\": {:.2}", sel)
} else {
String::new()
}
} else {
String::new()
};
format!(
"{{\"type\": \"Filter\", \"predicate\": \"{}\"{}, \"input\": {}}}",
escape_json(predicate),
selectivity_str,
input.explain_json(options)
)
}
Self::Join {
join_type,
left,
right,
keys,
} => {
let keys_json = keys
.iter()
.map(|(l, r)| format!("{{\"left\": \"{}\", \"right\": \"{}\"}}", l, r))
.collect::<Vec<_>>()
.join(", ");
format!(
"{{\"type\": \"Join\", \"join_type\": \"{}\", \"keys\": [{}], \"left\": {}, \"right\": {}}}",
join_type,
keys_json,
left.explain_json(options),
right.explain_json(options)
)
}
Self::Aggregate {
keys,
aggregates,
input,
} => {
format!(
"{{\"type\": \"Aggregate\", \"keys\": [{}], \"aggregates\": [{}], \"input\": {}}}",
keys.iter().map(|k| format!("\"{}\"", k)).collect::<Vec<_>>().join(", "),
aggregates.iter().map(|a| format!("\"{}\"", a)).collect::<Vec<_>>().join(", "),
input.explain_json(options)
)
}
Self::Sort { sort_exprs, input } => {
format!(
"{{\"type\": \"Sort\", \"sort_exprs\": [{}], \"input\": {}}}",
sort_exprs
.iter()
.map(|e| format!("\"{}\"", e))
.collect::<Vec<_>>()
.join(", "),
input.explain_json(options)
)
}
Self::Limit { limit, input } => {
format!(
"{{\"type\": \"Limit\", \"limit\": {}, \"input\": {}}}",
limit,
input.explain_json(options)
)
}
Self::Window {
window_functions,
input,
} => {
format!(
"{{\"type\": \"Window\", \"window_functions\": [{}], \"input\": {}}}",
window_functions
.iter()
.map(|w| format!("\"{}\"", w))
.collect::<Vec<_>>()
.join(", "),
input.explain_json(options)
)
}
Self::Custom {
name,
params,
input,
} => {
let params_json = params
.iter()
.map(|(k, v)| format!("\"{}\"\"{}\"", k, v))
.collect::<Vec<_>>()
.join(", ");
format!(
"{{\"type\": \"Custom\", \"name\": \"{}\", \"params\": {{{}}}, \"input\": {}}}",
name,
params_json,
input.explain_json(options)
)
}
}
}
}
/// Escapes a string for JSON
pub(crate) fn escape_json(s: &str) -> String {
s.replace('\\', "\\\\")
.replace('"', "\\\"")
.replace('\n', "\\n")
.replace('\r', "\\r")
.replace('\t', "\\t")
}