sagib1 commented on code in PR #16061:
URL: https://github.com/apache/iceberg/pull/16061#discussion_r3110646571
##########
core/src/main/java/org/apache/iceberg/jdbc/JdbcCatalog.java:
##########
@@ -550,6 +550,13 @@ public boolean dropNamespace(Namespace namespace) throws
NamespaceNotEmptyExcept
}
}
+ List<Namespace> childNamespaces = listNamespaces(namespace);
+ if (childNamespaces != null && !childNamespaces.isEmpty()) {
+ throw new NamespaceNotEmptyException(
+ "Namespace %s is not empty. Contains %d child namespace(s).",
+ namespace, childNamespaces.size());
+ }
Review Comment:
Yes, I reviewed the other _SupportsNamespaces_ implementations. This issue
is unique to JdbcCatalog because it must manually emulate hierarchical path
validation over a flat SQL table.
Other catalogs avoid this because they defer the drop operation to backends
that enforce these constraints natively, or they structurally cannot support
nested namespaces:
**HadoopCatalog**: In its
[dropNamespace](https://github.com/apache/iceberg/blob/main/core/src/main/java/org/apache/iceberg/hadoop/HadoopCatalog.java#L335)
implementation, it calls `fs.delete(dir, false)`. By passing false for the
recursive flag, it relies on the native Hadoop FileSystem to throw an
`IOException` if any child directories (which represent sub-namespaces or
tables) exist.
**HiveCatalog**: Its
[dropNamespace](https://github.com/apache/iceberg/blob/main/hive-metastore/src/main/java/org/apache/iceberg/hive/HiveCatalog.java#L543)
method delegates to HMS via `client.dropDatabase(name, false, false, false)`
(where the final flag is cascade=false). The Hive Metastore natively throws an
exception if the database is not empty. Furthermore, HMS structurally does not
support nested namespaces.
**GlueCatalog**: AWS Glue only supports top-level databases. Iceberg's
[IcebergToGlueConverter.toDatabaseName](https://github.com/apache/iceberg/blob/main/aws/src/main/java/org/apache/iceberg/aws/glue/IcebergToGlueConverter.java#L123)
enforces this by throwing a `ValidationException` if the namespace has more
than 1 level, making this specific nested-drop edge case impossible.
**NessieCatalog**: Defers entirely to the Nessie API via
[api.deleteNamespace()](https://github.com/apache/iceberg/blob/main/nessie/src/main/java/org/apache/iceberg/nessie/NessieIcebergClient.java#L321).
the logic simply sends a delete() request to the remote Nessie Server. Because
Nessie is essentially "Git for Data," the Nessie server itself maintains the
entire hierarchical tree of commits and references. When the server receives
the delete request, its internal engine traverses the commit tree. If it finds
any active keys (whether they are tables, views, or child namespaces) under
that path, the server rejects the request and throws a
`NessieNamespaceNotEmptyException` back over the wire.
##########
core/src/test/java/org/apache/iceberg/jdbc/TestJdbcCatalog.java:
##########
@@ -859,6 +859,25 @@ public void testDropNamespace() {
.hasMessage("Namespace db is not empty. Contains 1 table(s).");
}
+ @Test
+ public void testDropNamespaceWithChildNamespace() {
+ Namespace parent = Namespace.of("parent_ns");
+ Namespace child = Namespace.of("parent_ns", "child_ns");
+
+ // 1. Create the parent and child namespaces
+ catalog.createNamespace(parent);
+ catalog.createNamespace(child);
+
+ // 2. Assert that dropping the parent fails because the child exists
+ assertThatThrownBy(() -> catalog.dropNamespace(parent))
+ .isInstanceOf(NamespaceNotEmptyException.class)
+ .hasMessageStartingWith("Namespace parent_ns is not empty. Contains 1
child namespace(s).");
+
+ // 3. Verify the namespaces still safely exist in the catalog
Review Comment:
agreed, removed
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
