zhulipeng opened a new pull request, #12152:
URL: https://github.com/apache/gluten/pull/12152
## What changes are proposed in this pull request?
When offloading `Like` to Velox, omit the escape literal argument and emit
the 2-arg form (`like(input, pattern)`) when both:
1. the pattern is a constant `Literal`, and
2. the escape char is Spark's default `\` AND the pattern does not contain
`\`.
Otherwise we still emit the 3-arg form (`like(input, pattern, escape)`) as
before.
## Why are the changes needed?
Spark's `Like` node always carries an `escapeChar` (defaulting to `\`) even
when
the SQL did not specify `ESCAPE`. We previously always sent the 3-arg form to
Velox, which forces Velox's `makeLike` (`Re2Functions.cpp`) to take the
escape-aware path: `parsePattern` runs an extra unescape pass, and
`determinePatternKind` runs with `escapeChar.has_value() == true`, even when
no actual escaping is needed.
When the pattern literal contains no `\`, the 2-arg and 3-arg forms are
semantically identical, so we can safely send the cheaper 2-arg form. Velox
already registers both signatures via `likeSignatures()`.
## How was this patch tested?
- Existing `Like` query coverage in `VeloxStringFunctionsSuite` (`like` /
`rlike` / `ilike`) — query results unchanged.
- TPC-H Q13 end-to-end run at 6 TB scale — see Performance section.
- `./dev/format-scala-code.sh` clean.
## Performance
**TPC-H Q13 @ 6 TB scale: >6% end-to-end latency reduction.**
Q13's `l_comment NOT LIKE '%special%requests%'` filter scans every lineitem
row.
With the 3-arg form, the constant-pattern fast paths in
`determinePatternKind`
are bypassed and Velox falls back to the generic `LikeWithRe2` path, which
hot-loops in `re2::DFA::InlinedSearchLoop` — CPU profiling shows
`InlinedSearchLoop` accounts for **>8% of total cycles** on Q13.
Sending the 2-arg form lets `determinePatternKind` recognize this as the
`kSubstrings` shape and dispatch to the dedicated
`OptimizedLike<kSubstrings>`
kernel, eliminating the RE2 DFA cost. No regression observed on other
queries.
## Was this patch authored or co-authored using generative AI tooling?
Reviewed-by: Claude claude-opus-4-7
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