[jira] [Assigned] (SPARK-57555) Support the TIME data type in the built-in JDBC data source

["Uroš Bojanić (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-57555?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Uroš Bojanić reassigned SPARK-57555:
------------------------------------

    Assignee: Shrirang Mhalgi

> Support the TIME data type in the built-in JDBC data source
> -----------------------------------------------------------
>
>                 Key: SPARK-57555
>                 URL: https://issues.apache.org/jira/browse/SPARK-57555
>             Project: Spark
>          Issue Type: Sub-task
>          Components: SQL
>    Affects Versions: 4.3.0
>            Reporter: Max Gekk
>            Assignee: Shrirang Mhalgi
>            Priority: Major
>              Labels: pull-request-available
>
> h2. What
> Add native {{TIME}} support to the built-in JDBC data source so that SQL {{TIME}} columns
> in external databases map to Spark's {{TimeType}} on read, and {{TimeType}} columns map to
> SQL {{TIME}} on write.
> h2. Why
> This is the core motivation of the SPIP (SPARK-51162, Q5): simplify migration from
> PostgreSQL, Snowflake, Redshift, Teradata, DB2, etc. Today JDBC cannot represent TIME:
> * On read, {{JdbcUtils.getCatalystType}} maps {{java.sql.Types.TIME}} to a *timestamp*
>   type, not {{TimeType}}.
> * On write, {{JdbcUtils.getJdbcType}} has no {{case TimeType}}.
> * No dialect maps TIME.
> h2. Scope
> * {{JdbcUtils.getCatalystType}}: map {{java.sql.Types.TIME}} to {{TimeType}} (gated by the
>   TIME feature flag and a JDBC option for back-compat).
> * {{JdbcUtils.getJdbcType}}: add {{case TimeType => JdbcType("TIME", java.sql.Types.TIME)}}.
> * Value conversion in {{JdbcUtils}} (read {{ResultSet.getTime}}/getObject -> nanos-of-day;
>   write nanos-of-day -> {{java.sql.Time}}/{{LocalTime}}), preserving sub-second precision
>   where the driver allows.
> * Per-dialect overrides where the SQL type name/precision differs
>   (PostgreSQL, MySQL, MS SQL Server, Oracle, DB2, H2) in {{JdbcDialects}} and dialect
>   classes. Consider splitting per-dialect work into sub-tasks.
> h2. Compatibility
> * A back-compat switch so existing pipelines that read TIME-as-timestamp do not break;
>   document the new behavior.
> h2. Acceptance criteria
> * Read/write round-trip of TIME columns against the JDBC integration-test databases
>   (Postgres/MySQL/MS SQL/Oracle/DB2) preserves values.
> * Schema inference reports {{TimeType}} for TIME columns.



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