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[SPARK-56949][SQL] DecimalAggregates drops evalMode when rewriting Sum/Average #56009

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[SPARK-56949][SQL] DecimalAggregates drops evalMode when rewriting Sum/Average #56009

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36 changes: 20 additions & 16 deletions sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -2587,43 +2587,47 @@ object DecimalAggregates extends Rule[LogicalPlan] {
// Window arm: `ExtractWindowExpressions` hoists composite children
// (here the widening Cast) into a child Project, so widened-Cast
// peel is unreachable from this expression-level rule.
case Sum(e @ DecimalExpression(prec, scale), _) if prec + 10 <= MAX_LONG_DIGITS =>
MakeDecimal(we.copy(windowFunction = ae.copy(aggregateFunction = Sum(UnscaledValue(e)))),
case s @ Sum(e @ DecimalExpression(prec, scale), _) if prec + 10 <= MAX_LONG_DIGITS =>
MakeDecimal(we.copy(windowFunction =
ae.copy(aggregateFunction = s.copy(child = UnscaledValue(e)))),
prec + 10, scale)

case Average(e @ DecimalExpression(prec, scale), _) if prec + 4 <= MAX_DOUBLE_DIGITS =>
case a @ Average(e @ DecimalExpression(prec, scale), _)
if prec + 4 <= MAX_DOUBLE_DIGITS =>
val newAggExpr =
we.copy(windowFunction = ae.copy(aggregateFunction = Average(UnscaledValue(e))))
we.copy(windowFunction = ae.copy(aggregateFunction =
a.copy(child = UnscaledValue(e))))
Cast(
Divide(newAggExpr, Literal.create(math.pow(10.0, scale), DoubleType)),
DecimalType(prec + 4, scale + 4), Option(conf.sessionLocalTimeZone))

case _ => we
}
case ae @ AggregateExpression(af, _, _, _, _) => af match {
case Sum(WidenedDecimalChild(inner, p, pPrime, s), _)
case s @ Sum(WidenedDecimalChild(inner, p, pPrime, s_scale), _)
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@peter-toth peter-toth May 20, 2026

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Does this bug affect the above case Sum(e @ DecimalExpression(prec, scale), _) and case Average(e @ DecimalExpression(prec, scale), _) branches?

if p + 10 <= MAX_LONG_DIGITS =>
Cast(
MakeDecimal(
ae.copy(aggregateFunction = Sum(UnscaledValue(inner))),
p + 10, s),
DecimalType.bounded(pPrime + 10, s),
ae.copy(aggregateFunction = s.copy(child = UnscaledValue(inner))),
p + 10, s_scale),
DecimalType.bounded(pPrime + 10, s_scale),
Option(conf.sessionLocalTimeZone))

case Sum(e @ DecimalExpression(prec, scale), _) if prec + 10 <= MAX_LONG_DIGITS =>
MakeDecimal(ae.copy(aggregateFunction = Sum(UnscaledValue(e))), prec + 10, scale)
case s @ Sum(e @ DecimalExpression(prec, scale), _) if prec + 10 <= MAX_LONG_DIGITS =>
MakeDecimal(ae.copy(aggregateFunction = s.copy(child = UnscaledValue(e))),
prec + 10, scale)

// Ordered before the un-widened Average arm: when pPrime in [8, 11],
// the outer Cast's DecimalType would otherwise match that arm first.
case Average(WidenedDecimalChild(inner, p, pPrime, s), _)
case a @ Average(WidenedDecimalChild(inner, p, pPrime, s_scale), _)
if p <= AVG_PEEL_MAX_INNER_PRECISION =>
val newAggExpr = ae.copy(aggregateFunction = Average(UnscaledValue(inner)))
val newAggExpr = ae.copy(aggregateFunction = a.copy(child = UnscaledValue(inner)))
Cast(
Divide(newAggExpr, Literal.create(math.pow(10.0, s), DoubleType)),
DecimalType.bounded(pPrime + 4, s + 4), Option(conf.sessionLocalTimeZone))
Divide(newAggExpr, Literal.create(math.pow(10.0, s_scale), DoubleType)),
DecimalType.bounded(pPrime + 4, s_scale + 4), Option(conf.sessionLocalTimeZone))

case Average(e @ DecimalExpression(prec, scale), _) if prec + 4 <= MAX_DOUBLE_DIGITS =>
val newAggExpr = ae.copy(aggregateFunction = Average(UnscaledValue(e)))
case a @ Average(e @ DecimalExpression(prec, scale), _) if prec + 4 <= MAX_DOUBLE_DIGITS =>
val newAggExpr = ae.copy(aggregateFunction = a.copy(child = UnscaledValue(e)))
Cast(
Divide(newAggExpr, Literal.create(math.pow(10.0, scale), DoubleType)),
DecimalType(prec + 4, scale + 4), Option(conf.sessionLocalTimeZone))
Expand Down
95 changes: 94 additions & 1 deletion ...alyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/DecimalAggregatesSuite.scala
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Expand Up @@ -23,7 +23,7 @@ import org.scalatestplus.scalacheck.ScalaCheckDrivenPropertyChecks
import org.apache.spark.sql.catalyst.dsl.expressions._
import org.apache.spark.sql.catalyst.dsl.plans._
import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.expressions.aggregate.Sum
import org.apache.spark.sql.catalyst.expressions.aggregate.{Average, Sum}
import org.apache.spark.sql.catalyst.plans.PlanTest
import org.apache.spark.sql.catalyst.plans.logical.{LocalRelation, LogicalPlan}
import org.apache.spark.sql.catalyst.rules.RuleExecutor
Expand Down Expand Up @@ -582,4 +582,97 @@ class DecimalAggregatesSuite extends PlanTest with ScalaCheckDrivenPropertyCheck
val correctAnswer = q.analyze
comparePlans(optimized, correctAnswer)
}

// ---------------------------------------------------------------------------
// SPARK-56949: DecimalAggregates must preserve evalMode / evalContext when
// rewriting Sum / Average through the fast-path. The pre-fix rule called the
// single-arg helper ctor `Sum(child)` / `Average(child)`, which re-reads
// EvalMode from SQLConf and silently drops EvalMode.TRY from try_sum /
// try_avg, breaking their "return NULL on overflow" semantics.
//
// Vanilla 3.5.3 ground-truth (rule OFF vs ON) recorded in todos repo:
// features/spark-decimal-aggregate-evalmode-preserve/docs/0001-idea.md (section 3)
// ---------------------------------------------------------------------------

private def findSum(plan: LogicalPlan): Seq[Sum] =
plan.collect { case n => n.expressions }.flatten
.flatMap(_.collect { case s: Sum => s })
private def findAverage(plan: LogicalPlan): Seq[Average] =
plan.collect { case n => n.expressions }.flatten
.flatMap(_.collect { case a: Average => a })

test("SPARK-56949: DecimalAggregates preserves Sum.evalContext for try_sum") {
val trySum = Sum($"a", NumericEvalContext(EvalMode.TRY))
val q = testRelation.select(trySum.toAggregateExpression().as("ts"))
val optimized = Optimize.execute(q.analyze)
val sums = findSum(optimized)
assert(sums.nonEmpty, "DecimalAggregates fast path should fire for dec(2,1)")
assert(sums.forall(_.evalContext.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
sums.map(_.evalContext.evalMode).mkString(","))
}

test("SPARK-56949: DecimalAggregates preserves Average.evalMode for try_avg") {
val tryAvg = Average($"a", EvalMode.TRY)
val q = testRelation.select(tryAvg.toAggregateExpression().as("ta"))
val optimized = Optimize.execute(q.analyze)
val avgs = findAverage(optimized)
assert(avgs.nonEmpty, "DecimalAggregates fast path should fire for dec(2,1)")
assert(avgs.forall(_.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
avgs.map(_.evalMode).mkString(","))
}

test("SPARK-56949: DecimalAggregates preserves Sum.evalContext " +
"for try_sum on widened-cast peel arm") {
val trySum = Sum($"d7_2".cast(DecimalType(12, 2)),
NumericEvalContext(EvalMode.TRY))
val q = widenRel.select(trySum.toAggregateExpression().as("ts"))
val optimized = Optimize.execute(q.analyze)
val sums = findSum(optimized)
assert(sums.nonEmpty, "widened-cast SUM peel should fire for dec(7,2)->dec(12,2)")
assert(sums.forall(_.evalContext.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
sums.map(_.evalContext.evalMode).mkString(","))
}

test("SPARK-56949: DecimalAggregates preserves Average.evalMode " +
"for try_avg on widened-cast peel arm") {
val tryAvg = Average($"d7_2".cast(DecimalType(12, 2)), EvalMode.TRY)
val q = widenRel.select(tryAvg.toAggregateExpression().as("ta"))
val optimized = Optimize.execute(q.analyze)
val avgs = findAverage(optimized)
assert(avgs.nonEmpty, "widened-cast AVG peel should fire for dec(7,2)->dec(12,2)")
assert(avgs.forall(_.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
avgs.map(_.evalMode).mkString(","))
}

test("SPARK-56949: DecimalAggregates preserves Sum.evalContext " +
"for try_sum over Window (un-widened arm)") {
val spec = windowSpec(Seq($"a"), Nil, UnspecifiedFrame)
val trySum = Sum($"a", NumericEvalContext(EvalMode.TRY))
val q = testRelation.select(
windowExpr(trySum.toAggregateExpression(), spec).as("ts"))
val optimized = Optimize.execute(q.analyze)
val sums = findSum(optimized)
assert(sums.nonEmpty, "Window-arm SUM peel should fire for dec(2,1)")
assert(sums.forall(_.evalContext.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
sums.map(_.evalContext.evalMode).mkString(","))
}

test("SPARK-56949: DecimalAggregates preserves Average.evalMode " +
"for try_avg over Window (un-widened arm)") {
val spec = windowSpec(Seq($"a"), Nil, UnspecifiedFrame)
val tryAvg = Average($"a", EvalMode.TRY)
val q = testRelation.select(
windowExpr(tryAvg.toAggregateExpression(), spec).as("ta"))
val optimized = Optimize.execute(q.analyze)
val avgs = findAverage(optimized)
assert(avgs.nonEmpty, "Window-arm AVG peel should fire for dec(2,1)")
assert(avgs.forall(_.evalMode == EvalMode.TRY),
s"evalMode should be preserved as TRY after rewrite, got " +
avgs.map(_.evalMode).mkString(","))
}
}