Add String Column Support for Count Distinct Aggregation #1196
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atangwbd
added
the
safe to test
aabbasi-hbo
previously approved these changes
Jun 27, 2023
xiaoyongzhu
previously approved these changes
Jun 27, 2023
|
@atangwbd looks like there's a test failure? do you mind fixing it? Gradle suite > Gradle test > com.linkedin.feathr.offline.SlidingWindowAggIntegTest > testSWACountDistinct FAILED |
atangwbd
added
DO-NOT-MERGE
Fixed. |
atangwbd
removed
the
work-in-progress/do-not-merge
|
Thanks for the PR! The tests failed should be irrelevant to this change |
xiaoyongzhu
approved these changes
Jun 28, 2023
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Add String Support for Count Distinct Aggregation
Currently, feathr doesn't support the COUNT_DISTINCT aggregation on string column types, since it assumes the data type from the schema prior to the aggregation. When we try applying COUNT_DISTINCT on string columns, we get this error:
Caused by: Job aborted due to stage failure: Error while encoding: java.lang.RuntimeException: java.lang.Integer is not a valid external type for schema of stringThis PR converts each string into a unique 32 bit number using the built in spark hash function such that COUNT_DISTINCT aggregations can also work on string columns.
How was this PR tested?
I ran spark jobs locally and saw them fail before this change, and succeed after this change.
Does this PR introduce any user-facing changes?
COUNT_DISTINCT should now work on string columns.