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feat: estimate Decimal filter selectivity with interval analysis #25790

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0900fc9
feat: estimate Decimal filter selectivity with interval analysis
shrivasshankar Sep 27, 2026
4870150
Merge branch 'main' into decimal-filter-selectivity
shrivasshankar Sep 29, 2026
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243 changes: 237 additions & 6 deletions datafusion/expr-common/src/interval_arithmetic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,10 @@ use crate::type_coercion::binary::{BinaryTypeCoercer, comparison_coercion};
use arrow::compute::{CastOptions, cast_with_options};
use arrow::datatypes::{
DataType, IntervalDayTime, IntervalMonthDayNano, IntervalUnit,
MAX_DECIMAL32_FOR_EACH_PRECISION, MAX_DECIMAL64_FOR_EACH_PRECISION,
MAX_DECIMAL128_FOR_EACH_PRECISION, MAX_DECIMAL256_FOR_EACH_PRECISION,
MIN_DECIMAL128_FOR_EACH_PRECISION, MIN_DECIMAL256_FOR_EACH_PRECISION, TimeUnit,
MIN_DECIMAL32_FOR_EACH_PRECISION, MIN_DECIMAL64_FOR_EACH_PRECISION,
MIN_DECIMAL128_FOR_EACH_PRECISION, MIN_DECIMAL256_FOR_EACH_PRECISION, TimeUnit, i256,
};
use datafusion_common::rounding::{alter_fp_rounding_mode, next_down, next_up};
use datafusion_common::{
Expand All @@ -37,7 +39,14 @@ use datafusion_common::{
};

macro_rules! get_extreme_value {
($extreme:ident, $DECIMAL128_ARRAY:ident, $DECIMAL256_ARRAY:ident, $value:expr) => {
(
$extreme:ident,
$DECIMAL32_ARRAY:ident,
$DECIMAL64_ARRAY:ident,
$DECIMAL128_ARRAY:ident,
$DECIMAL256_ARRAY:ident,
$value:expr
) => {
match $value {
DataType::UInt8 => ScalarValue::UInt8(Some(u8::$extreme)),
DataType::UInt16 => ScalarValue::UInt16(Some(u16::$extreme)),
Expand Down Expand Up @@ -84,6 +93,16 @@ macro_rules! get_extreme_value {
DataType::Interval(IntervalUnit::MonthDayNano) => {
ScalarValue::IntervalMonthDayNano(Some(IntervalMonthDayNano::$extreme))
}
DataType::Decimal32(precision, scale) => ScalarValue::Decimal32(
Some($DECIMAL32_ARRAY[*precision as usize]),
*precision,
*scale,
),
DataType::Decimal64(precision, scale) => ScalarValue::Decimal64(
Some($DECIMAL64_ARRAY[*precision as usize]),
*precision,
*scale,
),
DataType::Decimal128(precision, scale) => ScalarValue::Decimal128(
Some($DECIMAL128_ARRAY[*precision as usize]),
*precision,
Expand All @@ -100,7 +119,15 @@ macro_rules! get_extreme_value {
}

macro_rules! value_transition {
($bound:ident, $direction:expr, $value:expr) => {
(
$bound:ident,
$direction:expr,
$DECIMAL32_ARRAY:ident,
$DECIMAL64_ARRAY:ident,
$DECIMAL128_ARRAY:ident,
$DECIMAL256_ARRAY:ident,
$value:expr
) => {
match $value {
UInt8(Some(value)) if value == u8::$bound => UInt8(None),
UInt16(Some(value)) if value == u16::$bound => UInt16(None),
Expand Down Expand Up @@ -147,6 +174,28 @@ macro_rules! value_transition {
{
IntervalMonthDayNano(None)
}
// Decimals saturate at the extreme value of their precision, not of
// the underlying integer type:
Decimal32(Some(value), precision, scale)
if value == $DECIMAL32_ARRAY[precision as usize] =>
{
Decimal32(None, precision, scale)
}
Decimal64(Some(value), precision, scale)
if value == $DECIMAL64_ARRAY[precision as usize] =>
{
Decimal64(None, precision, scale)
}
Decimal128(Some(value), precision, scale)
if value == $DECIMAL128_ARRAY[precision as usize] =>
{
Decimal128(None, precision, scale)
}
Decimal256(Some(value), precision, scale)
if value == $DECIMAL256_ARRAY[precision as usize] =>
{
Decimal256(None, precision, scale)
}
_ => next_value_helper::<$direction>($value),
}
};
Expand Down Expand Up @@ -1203,6 +1252,8 @@ fn handle_overflow<const UPPER: bool>(
(true, false) => {
get_extreme_value!(
MIN,
MIN_DECIMAL32_FOR_EACH_PRECISION,
MIN_DECIMAL64_FOR_EACH_PRECISION,
MIN_DECIMAL128_FOR_EACH_PRECISION,
MIN_DECIMAL256_FOR_EACH_PRECISION,
dt
Expand All @@ -1211,6 +1262,8 @@ fn handle_overflow<const UPPER: bool>(
(false, true) => {
get_extreme_value!(
MAX,
MAX_DECIMAL32_FOR_EACH_PRECISION,
MAX_DECIMAL64_FOR_EACH_PRECISION,
MAX_DECIMAL128_FOR_EACH_PRECISION,
MAX_DECIMAL256_FOR_EACH_PRECISION,
dt
Expand All @@ -1223,14 +1276,30 @@ fn handle_overflow<const UPPER: bool>(
// used without caution.
fn next_value(value: ScalarValue) -> ScalarValue {
use ScalarValue::*;
value_transition!(MAX, true, value)
value_transition!(
MAX,
true,
MAX_DECIMAL32_FOR_EACH_PRECISION,
MAX_DECIMAL64_FOR_EACH_PRECISION,
MAX_DECIMAL128_FOR_EACH_PRECISION,
MAX_DECIMAL256_FOR_EACH_PRECISION,
value
)
}

// This function should remain private since it may corrupt the an interval if
// used without caution.
fn prev_value(value: ScalarValue) -> ScalarValue {
use ScalarValue::*;
value_transition!(MIN, false, value)
value_transition!(
MIN,
false,
MIN_DECIMAL32_FOR_EACH_PRECISION,
MIN_DECIMAL64_FOR_EACH_PRECISION,
MIN_DECIMAL128_FOR_EACH_PRECISION,
MIN_DECIMAL256_FOR_EACH_PRECISION,
value
)
}

trait OneTrait: Sized + std::ops::Add + std::ops::Sub {
Expand All @@ -1241,6 +1310,12 @@ macro_rules! impl_OneTrait{
}
impl_OneTrait! {u8, u16, u32, u64, i8, i16, i32, i64, i128}

impl OneTrait for i256 {
fn one() -> Self {
i256::ONE
}
}

impl OneTrait for IntervalDayTime {
fn one() -> Self {
IntervalDayTime {
Expand Down Expand Up @@ -1295,6 +1370,23 @@ fn next_value_helper<const INC: bool>(value: ScalarValue) -> ScalarValue {
UInt16(Some(val)) => UInt16(Some(increment_decrement::<INC, u16>(val))),
UInt32(Some(val)) => UInt32(Some(increment_decrement::<INC, u32>(val))),
UInt64(Some(val)) => UInt64(Some(increment_decrement::<INC, u64>(val))),
// Decimals step by one unit in the last place, keeping precision and scale:
Decimal32(Some(val), precision, scale) => {
Decimal32(Some(increment_decrement::<INC, i32>(val)), precision, scale)
}
Decimal64(Some(val), precision, scale) => {
Decimal64(Some(increment_decrement::<INC, i64>(val)), precision, scale)
}
Decimal128(Some(val), precision, scale) => Decimal128(
Some(increment_decrement::<INC, i128>(val)),
precision,
scale,
),
Decimal256(Some(val), precision, scale) => Decimal256(
Some(increment_decrement::<INC, i256>(val)),
precision,
scale,
),
DurationSecond(Some(val)) => {
DurationSecond(Some(increment_decrement::<INC, i64>(val)))
}
Expand Down Expand Up @@ -2274,7 +2366,10 @@ mod tests {
};

use crate::interval_arithmetic::NullableInterval;
use arrow::datatypes::DataType;
use arrow::datatypes::{
DataType, MAX_DECIMAL128_FOR_EACH_PRECISION, MIN_DECIMAL128_FOR_EACH_PRECISION,
i256,
};
use datafusion_common::rounding::{next_down, next_up};
use datafusion_common::{Result, ScalarValue};

Expand Down Expand Up @@ -2365,6 +2460,124 @@ mod tests {
Ok(())
}

#[test]
fn test_next_prev_value_decimal() {
use ScalarValue::*;

// Decimals step by one unit in the last place, keeping precision and scale:
let cases = vec![
(Decimal32(Some(2400), 9, 2), Decimal32(Some(2401), 9, 2)),
(Decimal64(Some(2400), 18, 2), Decimal64(Some(2401), 18, 2)),
(Decimal128(Some(2400), 15, 2), Decimal128(Some(2401), 15, 2)),
(
Decimal256(Some(i256::from(2400)), 40, 2),
Decimal256(Some(i256::from(2401)), 40, 2),
),
(Decimal128(Some(-1), 3, 2), Decimal128(Some(0), 3, 2)),
];
for (value, next) in cases {
assert_eq!(next_value(value.clone()), next);
assert_eq!(prev_value(next), value);
}

// Values at the extremes of their precision (e.g. -9.99 and 9.99 for
// precision 3, scale 2) become unbounded:
let d128_max = MAX_DECIMAL128_FOR_EACH_PRECISION[38];
let d128_min = MIN_DECIMAL128_FOR_EACH_PRECISION[38];
let cases = vec![
(
Decimal32(Some(-999), 3, 2),
Decimal32(Some(999), 3, 2),
Decimal32(Some(-998), 3, 2),
Decimal32(Some(998), 3, 2),
Decimal32(None, 3, 2),
),
(
Decimal64(Some(-999), 3, 2),
Decimal64(Some(999), 3, 2),
Decimal64(Some(-998), 3, 2),
Decimal64(Some(998), 3, 2),
Decimal64(None, 3, 2),
),
(
Decimal128(Some(-999), 3, 2),
Decimal128(Some(999), 3, 2),
Decimal128(Some(-998), 3, 2),
Decimal128(Some(998), 3, 2),
Decimal128(None, 3, 2),
),
(
Decimal256(Some(i256::from(-999)), 3, 2),
Decimal256(Some(i256::from(999)), 3, 2),
Decimal256(Some(i256::from(-998)), 3, 2),
Decimal256(Some(i256::from(998)), 3, 2),
Decimal256(None, 3, 2),
),
(
Decimal128(Some(d128_min), 38, 0),
Decimal128(Some(d128_max), 38, 0),
Decimal128(Some(d128_min + 1), 38, 0),
Decimal128(Some(d128_max - 1), 38, 0),
Decimal128(None, 38, 0),
),
];
for (min, max, after_min, before_max, inf) in cases {
assert_eq!(next_value(max.clone()), inf);
assert_eq!(prev_value(max), before_max);

assert_eq!(prev_value(min.clone()), inf);
assert_eq!(next_value(min), after_min);

assert_eq!(next_value(inf.clone()), inf);
assert_eq!(prev_value(inf.clone()), inf);
}
}

#[test]
fn test_satisfy_strict_comparison_decimal() -> Result<()> {
use ScalarValue::*;

// x in [0.00, 50.00], constraint 24.00 > x tightens x to [0.00, 23.99]:
let x =
Interval::try_new(Decimal128(Some(0), 15, 2), Decimal128(Some(5000), 15, 2))?;
let literal = Interval::try_new(
Decimal128(Some(2400), 15, 2),
Decimal128(Some(2400), 15, 2),
)?;
let (_, x_lt) = satisfy_greater(&literal, &x, true)?.unwrap();
assert_eq!(
x_lt,
Interval::try_new(Decimal128(Some(0), 15, 2), Decimal128(Some(2399), 15, 2))?
);

// Constraint x > 24.00 tightens x to [24.01, 50.00]:
let (x_gt, _) = satisfy_greater(&x, &literal, true)?.unwrap();
assert_eq!(
x_gt,
Interval::try_new(
Decimal128(Some(2401), 15, 2),
Decimal128(Some(5000), 15, 2),
)?
);

// Non-strict comparisons keep the closed bound:
let (_, x_le) = satisfy_greater(&literal, &x, false)?.unwrap();
assert_eq!(
x_le,
Interval::try_new(Decimal128(Some(0), 15, 2), Decimal128(Some(2400), 15, 2))?
);

// A strict bound at the precision's extreme conservatively becomes
// unbounded instead of stepping past it (x > 9.99 for Decimal128(3, 2)):
let x = Interval::make_unbounded(&DataType::Decimal128(3, 2))?;
let max =
Interval::try_new(Decimal128(Some(999), 3, 2), Decimal128(Some(999), 3, 2))?;
let (x_gt, _) = satisfy_greater(&x, &max, true)?.unwrap();
assert_eq!(x_gt, Interval::make_unbounded(&DataType::Decimal128(3, 2))?);

Ok(())
}

#[test]
fn test_new_interval() -> Result<()> {
use ScalarValue::*;
Expand Down Expand Up @@ -4064,6 +4277,24 @@ mod tests {
ScalarValue::Decimal128(Some(99999999999999999999999999999999999999), 38, 35)
);

// Test Decimal32/Decimal64 underflow handling:
let op = Operator::Minus;
let dt = DataType::Decimal32(3, 2);
let lhs = ScalarValue::Decimal32(Some(-999), 3, 2);
let rhs = ScalarValue::Decimal32(Some(1), 3, 2);
let result = handle_overflow::<true>(&dt, op, &lhs, &rhs);
assert_eq!(result, ScalarValue::Decimal32(Some(-999), 3, 2));
let result = handle_overflow::<false>(&dt, op, &lhs, &rhs);
assert_eq!(result, ScalarValue::Decimal32(None, 3, 2));

let dt = DataType::Decimal64(3, 2);
let lhs = ScalarValue::Decimal64(Some(-999), 3, 2);
let rhs = ScalarValue::Decimal64(Some(1), 3, 2);
let result = handle_overflow::<true>(&dt, op, &lhs, &rhs);
assert_eq!(result, ScalarValue::Decimal64(Some(-999), 3, 2));
let result = handle_overflow::<false>(&dt, op, &lhs, &rhs);
assert_eq!(result, ScalarValue::Decimal64(None, 3, 2));

Ok(())
}

Expand Down
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