use anyhow::{Context, Result};
use ordered_float::OrderedFloat;
use crate::sql::{
AggregateKind, ArithmeticOp, CompareOp, Filter, Projection, ProjectionExpr, ScalarExpr,
};
use crate::storage::ColumnData;
use crate::types::{Schema, Value};
#[derive(Debug)]
pub(super) struct CompiledFilter {
pub(super) column_index: usize,
pub(super) op: CompareOp,
pub(super) value: Value,
}
#[derive(Debug, Clone)]
pub(super) struct CompiledProjection {
pub(super) alias: String,
pub(super) expr: CompiledProjectionExpr,
}
#[derive(Debug, Clone)]
pub(super) enum CompiledScalarExpr {
Literal(Value),
ColumnRef(usize),
BinaryOp {
left: Box<CompiledScalarExpr>,
op: ArithmeticOp,
right: Box<CompiledScalarExpr>,
},
UnaryMinus(Box<CompiledScalarExpr>),
}
#[derive(Debug, Clone)]
pub(super) enum CompiledProjectionExpr {
Column {
column_index: usize,
group_key_index: Option<usize>,
},
Scalar(CompiledScalarExpr),
Aggregate {
kind: AggregateKind,
column_index: Option<usize>,
},
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub(super) enum LocalKeyPart {
Int64(i64),
Float64(OrderedFloat<f64>),
Bool(bool),
String(String),
StringCode(u32),
}
impl LocalKeyPart {
pub(super) fn from_column(column: &ColumnData, row: usize) -> Result<Self> {
match column {
ColumnData::Int64(values) => Ok(Self::Int64(values[row])),
ColumnData::Float64(values) => Ok(Self::Float64(values[row])),
ColumnData::Bool(values) => Ok(Self::Bool(values[row])),
ColumnData::StringPlain(values) => Ok(Self::String(values[row].clone())),
ColumnData::StringDict { codes, .. } => Ok(Self::StringCode(codes[row])),
}
}
}
pub(super) fn compile_filters(schema: &Schema, filters: &[Filter]) -> Result<Vec<CompiledFilter>> {
let mut compiled = filters
.iter()
.map(|filter| {
let column_index = column_index(schema, &filter.column)?;
let data_type = schema.columns[column_index].data_type;
let value = match filter.value.clone() {
Some(v) => Value::cast_for(data_type, v)?,
None => Value::Null,
};
Ok(CompiledFilter {
column_index,
op: filter.op,
value,
})
})
.collect::<Result<Vec<_>>>()?;
compiled.sort_by_key(filter_priority);
Ok(compiled)
}
fn filter_priority(filter: &CompiledFilter) -> (u8, u8) {
let op_priority = match filter.op {
CompareOp::IsNull | CompareOp::IsNotNull => 0,
CompareOp::Eq => 1,
CompareOp::Gt | CompareOp::Gte | CompareOp::Lt | CompareOp::Lte => 2,
CompareOp::NotEq => 3,
};
let value_priority = match filter.value {
Value::Bool(_) => 0,
Value::Int64(_) | Value::Float64(_) => 1,
Value::String(_) => 2,
Value::Null => 0,
};
(op_priority, value_priority)
}
pub(super) fn compile_projections(
schema: &Schema,
group_by: &[String],
projections: &[Projection],
) -> Result<Vec<CompiledProjection>> {
projections
.iter()
.map(|projection| {
let expr = match &projection.expr {
ProjectionExpr::Column(name) => CompiledProjectionExpr::Column {
column_index: column_index(schema, name)?,
group_key_index: group_by
.iter()
.position(|group_column| group_column == name),
},
ProjectionExpr::Scalar(scalar) => {
CompiledProjectionExpr::Scalar(compile_scalar_expr(schema, scalar)?)
}
ProjectionExpr::Aggregate { kind, column } => CompiledProjectionExpr::Aggregate {
kind: *kind,
column_index: column
.as_ref()
.map(|name| column_index(schema, name))
.transpose()?,
},
};
Ok(CompiledProjection {
alias: projection.alias.clone(),
expr,
})
})
.collect()
}
pub(super) fn column_index(schema: &Schema, column_name: &str) -> Result<usize> {
schema
.columns
.iter()
.position(|column| column.name == column_name)
.with_context(|| format!("unknown column {column_name}"))
}
pub(super) fn required_column_indexes(
schema_len: usize,
filters: &[CompiledFilter],
projections: &[CompiledProjection],
extra_indexes: &[usize],
) -> Vec<usize> {
let mut required = vec![false; schema_len];
for filter in filters {
required[filter.column_index] = true;
}
for projection in projections {
match &projection.expr {
CompiledProjectionExpr::Column { column_index, .. } => required[*column_index] = true,
CompiledProjectionExpr::Scalar(scalar) => collect_scalar_columns(scalar, &mut required),
CompiledProjectionExpr::Aggregate {
column_index: Some(index),
..
} => required[*index] = true,
CompiledProjectionExpr::Aggregate {
column_index: None, ..
} => {}
}
}
for &index in extra_indexes {
required[index] = true;
}
required
.into_iter()
.enumerate()
.filter_map(|(index, include)| include.then_some(index))
.collect()
}
fn compile_scalar_expr(schema: &Schema, expr: &ScalarExpr) -> Result<CompiledScalarExpr> {
match expr {
ScalarExpr::Literal(value) => Ok(CompiledScalarExpr::Literal(value.clone())),
ScalarExpr::ColumnRef(name) => {
Ok(CompiledScalarExpr::ColumnRef(column_index(schema, name)?))
}
ScalarExpr::BinaryOp { left, op, right } => Ok(CompiledScalarExpr::BinaryOp {
left: Box::new(compile_scalar_expr(schema, left)?),
op: *op,
right: Box::new(compile_scalar_expr(schema, right)?),
}),
ScalarExpr::UnaryMinus(inner) => Ok(CompiledScalarExpr::UnaryMinus(Box::new(
compile_scalar_expr(schema, inner)?,
))),
}
}
fn collect_scalar_columns(expr: &CompiledScalarExpr, required: &mut [bool]) {
match expr {
CompiledScalarExpr::Literal(_) => {}
CompiledScalarExpr::ColumnRef(index) => required[*index] = true,
CompiledScalarExpr::BinaryOp { left, right, .. } => {
collect_scalar_columns(left, required);
collect_scalar_columns(right, required);
}
CompiledScalarExpr::UnaryMinus(inner) => collect_scalar_columns(inner, required),
}
}