fix: PushDownFilter for GROUP BY on uppercase col names

[aditanase]

Which issue does this PR close?

PushDownFilter does not push a predicate when the table has columns that are not all lowercase. Tried with and without enable_ident_normalization - no change. The logic inside parse_identifiers_normalized does not seem to properly detect quotes and it will lowercase the column used in the group by expression.

Here's the query I used, just for illustration:

SELECT * FROM (
    SELECT
        fm.Timestamp,
        SUM(fm.ConsumedUnits)
    FROM fm
    WHERE
        fm.Timestamp BETWEEN to_timestamp('2025-04-10') AND to_timestamp('2025-04-20')
    GROUP BY fm.Timestamp
)
WHERE Timestamp = to_timestamp('2025-04-12')

Expected query plan:

Aggregate: groupBy=[[fm.Timestamp]], aggr=[[sum(fm.ConsumedUnits)]]
  TableScan: fm projection=[ConsumedUnits, Timestamp], full_filters=[fm.Timestamp = TimestampMicrosecond(1744416000000000, Some("UTC")), fm.Timestamp >= TimestampMicrosecond(1744243200000000, Some("UTC")), fm.Timestamp <= TimestampMicrosecond(1745107200000000, Some("UTC"))]

Actual query plan:

Filter: fm.Timestamp = TimestampMicrosecond(1744416000000000, Some("UTC"))
  Aggregate: groupBy=[[fm.Timestamp]], aggr=[[sum(fm.ConsumedUnits)]]
    TableScan: fm projection=[ConsumedUnits, Timestamp], full_filters=[fm.Timestamp >= TimestampMicrosecond(1744243200000000, Some("UTC")), fm.Timestamp <= TimestampMicrosecond(1745107200000000, Some("UTC"))]

An alterate fix could use expr_to_columns to extract the columns, as in Unnest above:

let mut group_expr_columns: HashSet<Column> = HashSet::new();
for p in &agg.group_expr {
    expr_to_columns(&p, &mut group_expr_columns)?;
}

Question: should we make the same change in the Window functions branch?

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Yes, from a client application.

I did not add any unit tests, none of the existing tests in this module use upper case columns. Tried to add another table/schema, but then the test was failing, I am unsure of how to control the lowercasing of column names.

Are there any user-facing changes?

[aditanase]

@adriangb Saw you recent commits in this area, would appreciate if you weighed in on this. Thank you! 🙌

[adriangb]

Hmm I've been doing a lot with the physical optimizer of the same name but haven't touched the logical optimizer. The recent changes may mean that the pushdown ends up happening regardless at the physical level but I think it's worth fixing the logical level anyway.

I don't fully understand the issue: does from_qualified_name_ignore_case do something different with quotes than from_qualified_name? I also don't see any quotes in your example.

[aditanase]

I don't fully understand the issue: does from_qualified_name_ignore_case do something different with quotes than from_qualified_name? I also don't see any quotes in your example.

Sorry for not being more clear. I was referring to these lines:

datafusion/datafusion/common/src/utils/mod.rs

Lines 297 to 298 in 923bfb7

	.map(|id| match id.quote_style {
	Some(_) => id.value,

Reading it made me think that if I used quotes I might convince it to remain unchanged, but it still converts to lowercase timestamp, no matter what I tried, so I didn't include it in the code sample.