alamb commented on code in PR #11796:
URL: https://github.com/apache/datafusion/pull/11796#discussion_r1704612803
##########
datafusion/sqllogictest/test_files/string_view.slt:
##########
@@ -379,3 +379,56 @@ select t.dt from dates t where arrow_cast('2024-01-01',
'Utf8View') < t.dt;
statement ok
drop table dates;
+
+statement ok
+create table temp as values
+('value1', arrow_cast('rust', 'Utf8View'), arrow_cast('fast', 'Utf8View')),
+('value2', arrow_cast('datafusion', 'Utf8View'), arrow_cast('cool',
'Utf8View'));
+
+query T
+select column2||' is fast' from temp;
+----
+rust is fast
+datafusion is fast
+
+
+query T
+select column2 || ' is ' || column3 from temp;
+----
+rust is fast
+datafusion is cool
+
+query TT
+explain select column2 || 'is' || column3 from temp;
+----
+logical_plan
+01)Projection: CAST(temp.column2 AS Utf8) || Utf8("is") || CAST(temp.column3
AS Utf8)
+02)--TableScan: temp projection=[column2, column3]
+
+
+query TT
+explain select column2||' is fast' from temp;
+----
+logical_plan
+01)Projection: CAST(temp.column2 AS Utf8) || Utf8(" is fast")
Review Comment:
likewise here it would be better to use Utf8View
##########
datafusion/expr/src/type_coercion/binary.rs:
##########
@@ -890,15 +890,22 @@ fn dictionary_coercion(
/// 2. Data type of the other side should be able to cast to string type
fn string_concat_coercion(lhs_type: &DataType, rhs_type: &DataType) ->
Option<DataType> {
use arrow::datatypes::DataType::*;
- string_coercion(lhs_type, rhs_type).or(match (lhs_type, rhs_type) {
- (Utf8, from_type) | (from_type, Utf8) => {
- string_concat_internal_coercion(from_type, &Utf8)
- }
- (LargeUtf8, from_type) | (from_type, LargeUtf8) => {
- string_concat_internal_coercion(from_type, &LargeUtf8)
+ match (lhs_type, rhs_type) {
+ // If Utf8View is in any side, we coerce to Utf8.
Review Comment:
I think it would be better to coerce to `Utf8View` as that coercsion will
often be faster (it is faster to cast Utf8 -> Utf8View than the other way
around)
Is that possible?
##########
datafusion/sqllogictest/test_files/string_view.slt:
##########
@@ -379,3 +379,56 @@ select t.dt from dates t where arrow_cast('2024-01-01',
'Utf8View') < t.dt;
statement ok
drop table dates;
+
+statement ok
+create table temp as values
+('value1', arrow_cast('rust', 'Utf8View'), arrow_cast('fast', 'Utf8View')),
+('value2', arrow_cast('datafusion', 'Utf8View'), arrow_cast('cool',
'Utf8View'));
+
+query T
+select column2||' is fast' from temp;
+----
+rust is fast
+datafusion is fast
+
+
+query T
+select column2 || ' is ' || column3 from temp;
+----
+rust is fast
+datafusion is cool
+
+query TT
+explain select column2 || 'is' || column3 from temp;
+----
+logical_plan
+01)Projection: CAST(temp.column2 AS Utf8) || Utf8("is") || CAST(temp.column3
AS Utf8)
Review Comment:
This would be a better plan (likely faster) if the casting was to `Utf8View`
rather than `Utf8`
##########
datafusion/sqllogictest/test_files/string_view.slt:
##########
@@ -379,3 +379,56 @@ select t.dt from dates t where arrow_cast('2024-01-01',
'Utf8View') < t.dt;
statement ok
drop table dates;
+
+statement ok
+create table temp as values
+('value1', arrow_cast('rust', 'Utf8View'), arrow_cast('fast', 'Utf8View')),
+('value2', arrow_cast('datafusion', 'Utf8View'), arrow_cast('cool',
'Utf8View'));
+
+query T
+select column2||' is fast' from temp;
+----
+rust is fast
+datafusion is fast
Review Comment:
❤️
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