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//! Query planning — `plan_query()` without executing against the database.
use super::super::{Executor, QueryType};
use crate::{
db::traits::DatabaseAdapter,
error::{FraiseQLError, Result},
runtime::{ExplainPlan, suggest_similar},
};
impl<A: DatabaseAdapter> Executor<A> {
/// Generate an explain plan for a query without executing it.
///
/// Returns the SQL that would be generated, parameters, cost estimate,
/// and views that would be accessed.
///
/// # Errors
///
/// Returns error if the query cannot be parsed or matched against the schema.
pub fn plan_query(
&self,
query: &str,
variables: Option<&serde_json::Value>,
) -> Result<ExplainPlan> {
let query_type = self.classify_query(query)?;
match query_type {
QueryType::Regular => {
let query_match = self.ctx.matcher.match_query(query, variables)?;
let view = query_match
.query_def
.sql_source
.clone()
.unwrap_or_else(|| "unknown".to_string());
let plan = self.ctx.planner.plan(&query_match)?;
Ok(ExplainPlan {
sql: plan.sql,
parameters: plan.parameters,
estimated_cost: plan.estimated_cost,
views_accessed: vec![view],
query_type: "regular".to_string(),
})
},
QueryType::Mutation { ref name, .. } => {
let mutation_def =
self.ctx.schema.mutations.iter().find(|m| m.name == *name).ok_or_else(
|| {
let display_names: Vec<String> = self
.ctx
.schema
.mutations
.iter()
.map(|m| self.ctx.schema.display_name(&m.name))
.collect();
let candidate_refs: Vec<&str> =
display_names.iter().map(String::as_str).collect();
let suggestion = suggest_similar(name, &candidate_refs);
let message = match suggestion.as_slice() {
[s] => format!(
"Mutation '{name}' not found in schema. Did you mean '{s}'?"
),
_ => format!("Mutation '{name}' not found in schema"),
};
FraiseQLError::Validation {
message,
path: None,
}
},
)?;
let fn_name =
mutation_def.sql_source.clone().unwrap_or_else(|| format!("fn_{name}"));
Ok(ExplainPlan {
sql: format!("SELECT * FROM {fn_name}(...)"),
parameters: Vec::new(),
estimated_cost: 100,
views_accessed: vec![fn_name],
query_type: "mutation".to_string(),
})
},
QueryType::Aggregate(ref name) => {
let sql_source = self
.ctx
.schema
.queries
.iter()
.find(|q| q.name == *name)
.and_then(|q| q.sql_source.clone())
.unwrap_or_else(|| "unknown".to_string());
Ok(ExplainPlan {
sql: format!("SELECT ... FROM {sql_source} -- aggregate"),
parameters: Vec::new(),
estimated_cost: 200,
views_accessed: vec![sql_source],
query_type: "aggregate".to_string(),
})
},
QueryType::Window(ref name) => {
let sql_source = self
.ctx
.schema
.queries
.iter()
.find(|q| q.name == *name)
.and_then(|q| q.sql_source.clone())
.unwrap_or_else(|| "unknown".to_string());
Ok(ExplainPlan {
sql: format!("SELECT ... FROM {sql_source} -- window"),
parameters: Vec::new(),
estimated_cost: 250,
views_accessed: vec![sql_source],
query_type: "window".to_string(),
})
},
QueryType::IntrospectionSchema | QueryType::IntrospectionType(_) => Ok(ExplainPlan {
sql: String::new(),
parameters: Vec::new(),
estimated_cost: 0,
views_accessed: Vec::new(),
query_type: "introspection".to_string(),
}),
QueryType::Federation(_) => Ok(ExplainPlan {
sql: String::new(),
parameters: Vec::new(),
estimated_cost: 0,
views_accessed: Vec::new(),
query_type: "federation".to_string(),
}),
QueryType::NodeQuery { .. } => Ok(ExplainPlan {
sql: String::new(),
parameters: Vec::new(),
estimated_cost: 50,
views_accessed: Vec::new(),
query_type: "node".to_string(),
}),
}
}
}