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https://issues.apache.org/jira/browse/IMPALA-15106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mihaly Szjatinya resolved IMPALA-15106.
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Resolution: Later
Deferred: not needed for Puffin NDV stats after IMPALA-15459. The
implementation is kept on https://gerrit.cloudera.org/c/24889/ in case it is
needed later.
> Support missing types with theta sketches
> -----------------------------------------
>
> Key: IMPALA-15106
> URL: https://issues.apache.org/jira/browse/IMPALA-15106
> Project: IMPALA
> Issue Type: New Feature
> Components: Backend
> Reporter: Csaba Ringhofer
> Assignee: Mihaly Szjatinya
> Priority: Major
> Labels: datasketches, impala-iceberg
>
> Existing theta sketches functions don't work for all types, for example there
> is no support for TIMESTAMP. To use Iceberg's puffin files to store
> incremental NDV stats, we need to support all types currently handled by
> COMPUTE STATS. The Iceberg spec defines clearly how to do this for all types:
> https://iceberg.apache.org/puffin-spec/#apache-datasketches-theta-v1-blob-type
> https://iceberg.apache.org/spec/#appendix-d-single-value-serialization
> Note that we may be unable to use nanosecond timestamps, probably an error
> could be returned in that case.
> In the frontend theta functions are added here:
> https://github.com/apache/impala/blob/0b8294b1a5b0ad4a817dee13b7fbb2ee53f534e2/fe/src/main/java/org/apache/impala/catalog/BuiltinsDb.java#L1171
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