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[SPARK-52817][SQL] Fix Like Expression performance #51510

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[SPARK-52817][SQL] Fix Like Expression performance #51510

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b85f4c4
Fix Like Expression
zhixingheyi-tian Jul 16, 2025
1b2a46f
Add UTs
zhixingheyi-tian Jul 16, 2025
833c554
Fix Style
zhixingheyi-tian Jul 17, 2025
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8 changes: 4 additions & 4 deletions sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -743,10 +743,10 @@ object SupportedBinaryExpr {
object LikeSimplification extends Rule[LogicalPlan] with PredicateHelper {
// if guards below protect from escapes on trailing %.
// Cases like "something\%" are not optimized, but this does not affect correctness.
private val startsWith = "([^_%]+)%".r
private val endsWith = "%([^_%]+)".r
private val startsAndEndsWith = "([^_%]+)%([^_%]+)".r
private val contains = "%([^_%]+)%".r
private val startsWith = "([^_%]+)%+".r
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@cloud-fan cloud-fan Jul 17, 2025 •
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So a single % is the same as more than one %? Can we leave a code comment to explain this case?

private val endsWith = "%+([^_%]+)".r
private val startsAndEndsWith = "([^_%]+)%+([^_%]+)".r
private val contains = "%+([^_%]+)%+".r
private val equalTo = "([^_%]*)".r

private def simplifyLike(
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48 changes: 48 additions & 0 deletions ...lyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/LikeSimplificationSuite.scala
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Expand Up @@ -165,6 +165,54 @@ class LikeSimplificationSuite extends PlanTest {
comparePlans(optimized5, correctAnswer5)
}

test("SPARK-52817: Spark SQL LIKE expressions show poor performance when using multiple '%'") {
val originalQuery1 =
testRelation
.where($"a" like "abc%%")
val optimized1 = Optimize.execute(originalQuery1.analyze)
val correctAnswer1 = testRelation
.where(StartsWith($"a", "abc"))
.analyze
comparePlans(optimized1, correctAnswer1)

val originalQuery2 =
testRelation
.where($"a" like "%%xyz")
val optimized2 = Optimize.execute(originalQuery2.analyze)
val correctAnswer2 = testRelation
.where(EndsWith($"a", "xyz"))
.analyze
comparePlans(optimized2, correctAnswer2)

val originalQuery3 =
testRelation
.where($"a" like "abc%%def")
val optimized3 = Optimize.execute(originalQuery3.analyze)
val correctAnswer3 = testRelation
.where(
(Length($"a") >= 6 && (StartsWith($"a", "abc") && EndsWith($"a", "def"))))
.analyze
comparePlans(optimized3, correctAnswer3)

val originalQuery4 =
testRelation
.where(($"a" like "%%mn%%"))
val optimized4 = Optimize.execute(originalQuery4.analyze)
val correctAnswer4 = testRelation
.where(Contains($"a", "mn"))
.analyze
comparePlans(optimized4, correctAnswer4)

val originalQuery5 =
testRelation
.where(($"a" like "%%%mn%%%"))
val optimized5 = Optimize.execute(originalQuery5.analyze)
val correctAnswer5 = testRelation
.where(Contains($"a", "mn"))
.analyze
comparePlans(optimized5, correctAnswer5)
}

test("simplify LikeAll") {
val originalQuery =
testRelation
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