[SPARK-48441][SQL] Fix StringTrim behaviour for non-UTF8_BINARY collations#46762
Closed
uros-db wants to merge 21 commits into
Closed
[SPARK-48441][SQL] Fix StringTrim behaviour for non-UTF8_BINARY collations#46762uros-db wants to merge 21 commits into
uros-db wants to merge 21 commits into
Conversation
HyukjinKwon
reviewed
May 27, 2024
cloud-fan
pushed a commit
that referenced
this pull request
Jun 6, 2024
### What changes were proposed in this pull request? CollationFactory has been updated to no longer mark UNICODE as collation that supportsBinaryCollation. To reflect these changes, various tests have been updated. However, some tests have been (temporarily) removed because StringTrim no longer supports UNICODE collation given the new UNICODE definition in CollationFactory. At this time, StringTrim expression only supports UTF8_BINARY & UTF8_BINARY_LCASE, but not ICU collations. This work is in progress (#46762), so we'll ensure appropriate test coverage with those changes. ### Why are the changes needed? UNICODE collation should not support binary collation. Note: in the future, we may want to consider a collation such as UNICODE_BINARY, which will support binary equality, but also maintain UNICODE ordering. ### Does this PR introduce _any_ user-facing change? Yes, UNICODE is no longer treated as a binary collation. This affects how equality works for UNICODE, and also which codepath is taken for various collation-aware string expression given UNICODE collated string arguments. ### How was this patch tested? Updated existing unit and e2e sql test for UNICODE collation. ### Was this patch authored or co-authored using generative AI tooling? No. Closes #46772 from uros-db/fix-unicode. Authored-by: Uros Bojanic <157381213+uros-db@users.noreply.github.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com>
cloud-fan
pushed a commit
that referenced
this pull request
Jun 11, 2024
### What changes were proposed in this pull request? Renaming `UTF8_BINARY_LCASE` collation to `UTF8_LCASE`. ### Why are the changes needed? As part of the collation effort in Spark, we've moved away from byte-by-byte logic towards character-by-character logic, so what we used to call `UTF8_BINARY_LCASE` is now more precisely `UTF8_LCASE`. For example, string searching in UTF8_LCASE now works on character-level (rather than on byte-level), which is reflected in this PRs: #46511, #46589, #46682, #46761, #46762. In addition, string comparison also works on character-level now, as per the changes introduced in this PR: #46700. ### Does this PR introduce _any_ user-facing change? Yes, what was previously named `UTF8_BINARY_LCASE` collation, will from now on be named `UTF8_LCASE`. ### How was this patch tested? Existing tests. ### Was this patch authored or co-authored using generative AI tooling? No. Closes #46924 from uros-db/rename-lcase. Authored-by: Uros Bojanic <157381213+uros-db@users.noreply.github.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com>
mkaravel
reviewed
Jun 20, 2024
Contributor
|
@uros-db Can we please update the PR description to refer to the UTF8_LCASE collation as opposed to UTF8_BINARY_LCASE? |
Contributor
|
In the PR description it is stated:
I think it is worth adding that the changes refer to collated strings only. So something like: Yes, behaviour of trim* expressions for non-default collated strings is changed for edge cases with one-to-many case mapping. |
mkaravel
approved these changes
Jul 12, 2024
Contributor
mkaravel
left a comment
There was a problem hiding this comment.
PR looks good, nothing blocking.
My comments are about:
- Improving the code documentation.
- Potentially improving the performance for ICU collations (by de-duplicating the trimming characters).
- Coding style.
I am approving this PR (as none of these is a blocker), but please address them before merging.
Contributor
Author
|
@cloud-fan ready for review |
cloud-fan
approved these changes
Jul 15, 2024
Contributor
|
thanks, merging to master! |
jingz-db
pushed a commit
to jingz-db/spark
that referenced
this pull request
Jul 22, 2024
…tions
### What changes were proposed in this pull request?
String searching in UTF8_LCASE now works on character-level, rather than on byte-level. For example: `ltrim("İ", "i")` now returns `"İ"`, because there exist **no characters** in `"İ"`, starting from the left, such that lowercased version of those characters are equal to `"i"`. Note, however, that there is a byte subsequence of `"İ"` such that lowercased version of that UTF-8 byte sequence equals to `"i"` (so the new behaviour is different than the old behaviour).
Also, translation for ICU collations works by repeatedly trimming the longest possible substring that matches a character in the trim string, starting from the left side of the input string, until trimming is done.
### Why are the changes needed?
Fix functions that give unusable results due to one-to-many case mapping when performing string search under UTF8_LCASE (see example above).
### Does this PR introduce _any_ user-facing change?
Yes, behaviour of `trim*` expressions is changed for collated strings for edge cases with one-to-many case mapping.
### How was this patch tested?
New unit tests in `CollationSupportSuite` and new e2e sql tests in `CollationStringExpressionsSuite`.
### Was this patch authored or co-authored using generative AI tooling?
No.
Closes apache#46762 from uros-db/alter-trim.
Authored-by: Uros Bojanic <157381213+uros-db@users.noreply.github.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What changes were proposed in this pull request?
String searching in UTF8_LCASE now works on character-level, rather than on byte-level. For example:
ltrim("İ", "i")now returns"İ", because there exist no characters in"İ", starting from the left, such that lowercased version of those characters are equal to"i". Note, however, that there is a byte subsequence of"İ"such that lowercased version of that UTF-8 byte sequence equals to"i"(so the new behaviour is different than the old behaviour).Also, translation for ICU collations works by repeatedly trimming the longest possible substring that matches a character in the trim string, starting from the left side of the input string, until trimming is done.
Why are the changes needed?
Fix functions that give unusable results due to one-to-many case mapping when performing string search under UTF8_LCASE (see example above).
Does this PR introduce any user-facing change?
Yes, behaviour of
trim*expressions is changed for collated strings for edge cases with one-to-many case mapping.How was this patch tested?
New unit tests in
CollationSupportSuiteand new e2e sql tests inCollationStringExpressionsSuite.Was this patch authored or co-authored using generative AI tooling?
No.