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https://issues.apache.org/jira/browse/SPARK-58876?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-58876:
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Labels: pull-request-available (was: )
> Oracle: Read DATE and TIMESTAMP as TimestampNTZType
> ---------------------------------------------------
>
> Key: SPARK-58876
> URL: https://issues.apache.org/jira/browse/SPARK-58876
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 4.4.0
> Reporter: Aleksandar Trajković
> Priority: Major
> Labels: pull-request-available
>
> Oracle {{DATE}} and plain {{TIMESTAMP}} are zoneless, and both arrive from the
> Oracle JDBC driver under JDBC type code {{Types.TIMESTAMP}}. Today
> {{OracleDialect}}
> has no mapping for {{Types.TIMESTAMP}}, so they fall through to the shared
> default
> and are read as {{TimestampType}} (or {{TimestampNTZType}} only when the JDBC
> read
> option {{preferTimestampNTZ}} is set).
> Mapping a zoneless source type to {{TimestampType}} -- an instant rendered in
> the
> session time zone -- is not faithful: the same wall-clock value is
> reinterpreted as
> an instant and shifts under a non-UTC {{spark.sql.session.timeZone}}.
> {{TimestampNTZType}} (timestamp without time zone) represents these Oracle
> types
> correctly.
> This maps Oracle {{DATE}} and plain {{TIMESTAMP}} to {{TimestampNTZType}} by
> default,
> independent of {{preferTimestampNTZ}}. Oracle {{TIMESTAMP WITH TIME ZONE}} and
> {{TIMESTAMP WITH LOCAL TIME ZONE}} carry an instant, arrive under their own
> JDBC
> codes, and are unaffected.
> This mirrors the sibling JDBC dialect timestamp-mapping corrections in Spark
> 4.0:
> SPARK-47871 (Oracle, write side), SPARK-48387 (Postgres), SPARK-47515 (MySQL).
> As a behavior change it is gated by a legacy config
> {{spark.sql.legacy.oracle.timestampNTZMapping.enabled}} (default false) that
> restores
> the previous behavior, and is documented in the SQL migration guide.
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