[Spark] Fix char/varchar to string column conversions #2731
Conversation
This file contains 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
dhruvarya-db
force-pushed
the
alter-column-fix-chrToStr
branch
from
9262713 to
17e78f5
Compare
prakharjain09
approved these changes
Mar 14, 2024
5 tasks
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
Which Delta project/connector is this regarding?
Description
Users are currently allowed to change the data type of their columns from char/varchar to string. Even though the command succeeds, the column metadata that indicates that the column is char/varchar is not removed during the process. As a result, Delta enforces the old char/varchar constraints on future inserts.
This PR fixes that by removing this metadata from any updated char/varchar column when the column is updated.
How was this patch tested?
Added a new test which was failing without the code fix.
Does this PR introduce any user-facing changes?
Yes,
ALTER COLUMN X TYPE STRING;will now work correctly when X is char/varchar.