uros-b commented on code in PR #58362:
URL: https://github.com/apache/spark/pull/58362#discussion_r3890866686
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sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala:
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@@ -830,11 +830,13 @@ object LikeSimplification extends Rule[LogicalPlan] with
PredicateHelper {
case endsWith(postfix) =>
Some(EndsWith(input, Literal.create(postfix, input.dataType)))
// 'a%a' pattern is basically same with 'a%' && '%a'.
- // However, the additional `Length` condition is required to prevent
'a' match 'a%a'.
+ // However, the additional length condition is required to prevent 'a'
match 'a%a'.
+ // Since StartsWith/EndsWith already pin the prefix and suffix at
code-point boundaries,
+ // a byte-length guard (OctetLength, O(1)) is equivalent to a
char-length guard and cheaper.
case startsAndEndsWith(prefix, postfix) =>
- Some(And(GreaterThanOrEqual(Length(input),
- Literal.create(prefix.codePointCount(0, prefix.length)
- + postfix.codePointCount(0, postfix.length))),
+ Some(And(GreaterThanOrEqual(OctetLength(input),
Review Comment:
The main thing to be aware of here is that collation-aware anchors can match
code points with different UTF-8 lengths.
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