Github user dongjoon-hyun commented on a diff in the pull request:
https://github.com/apache/spark/pull/20057#discussion_r168927868
--- Diff: docs/sql-programming-guide.md ---
@@ -1372,6 +1372,13 @@ 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 care. This option applies only to writing.
It defaults to the default cascading truncate behaviour of the JDBC database in
question, specified in the <code>isCascadeTruncate</code> in each JDBCDialect.
--- End diff --
Ur, for PostgreSQL, we are generating `TRUNCATE TABLE ONLY $table CASCADE`.
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