konstantinb opened a new pull request, #6494:
URL: https://github.com/apache/hive/pull/6494
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### What changes were proposed in this pull request?
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HIVE-29618: fix multiline string matches for vectorization too (follows up
on HIVE-22008)
Add the `Pattern.DOTALL` flag to the vectorized `LIKE` operator's
`ComplexChecker` regex compile
(`AbstractFilterStringColLikeStringScalar.java:422`), restoring parity with the
non-vectorized
`UDFLike` (`UDFLike.java:194`, fixed by HIVE-22008 in 2019). Extend
`udf_like.q` with a regression test for the `COMPLEX`/regex path and run every
statement once more with
`hive.vectorized.execution.enabled=false` to lock in cross-mode parity.
Add a focused Java unit test in `TestVectorStringExpressions`.
### Why are the changes needed?
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HIVE-22008 fixed non-vectorized LIKE to match multi-line input but missed
the parallel vectorized implementation. Patterns containing an unescaped `_`
route through `ComplexChecker`, which compiled
its regex without `DOTALL`; the resulting `.` (from `_`) and `.*?` (from
`%`) cannot cross newlines, so vectorized LIKE silently drops rows whose values
contain `\n`. The result is silently wrong
query output — the same `LIKE` query returns different row counts in
vectorized vs non-vectorized mode.
### Does this PR introduce _any_ user-facing change?
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Yes, as a bug fix. Vectorized `LIKE` patterns containing `_` now match
multi-line strings consistently with non-vectorized execution and with SQL
semantics. Queries that previously dropped rows now
return them. No syntax, API, or config changes.
### How was this patch tested?
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- New unit test
`TestVectorStringExpressions#testStringLikeComplexCheckerMultiLine` — fails
before the fix, passes after.
- `udf_like.q` extended; the regenerated `udf_like.q.out` differs from the
pre-fix snapshot by a single character (`0` → `2`) at the new test's
vectorized-mode result line — every other expected
output is unchanged.
- `mvn checkstyle:check -pl ql` clean.
- Manually verified the diff produced no other behavior changes in the
`udf_like` golden.
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