Github user gatorsmile commented on a diff in the pull request:
https://github.com/apache/spark/pull/20057#discussion_r159118000
--- Diff: docs/sql-programming-guide.md ---
@@ -1339,6 +1339,13 @@ the following case-insensitive options:
This is a JDBC writer related option. When
<code>SaveMode.Overwrite</code> is enabled, this option causes Spark to
truncate an existing table instead of dropping and recreating it. This can be
more efficient, and prevents the table metadata (e.g., indices) from being
removed. However, it will not work in some cases, such as when the new data has
a different schema. It defaults to <code>false</code>. This option applies only
to writing.
</td>
</tr>
+
+ <tr>
+ <td><code>cascadeTruncate</code></td>
+ <td>
+ This is a JDBC writer related option. If enabled and supported by
the JDBC database (PostgreSQL and Oracle at the moment), this options allows
execution of a <code>TRUNCATE TABLE t CASCADE</code>. This will affect other
tables, and thus should be used with case. This option applies only to writing.
--- End diff --
This conf only takes an effect when `SaveMode.Overwrite` is enabled and
`truncate` is set to true. My doubt is the usage scenario of this extra conf
does not benefit most users. Could we hold this PR? When the other users have
similar requests, we can revisit it?
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