From 326b78668c1a4489fa7204e184775241946c89a1 Mon Sep 17 00:00:00 2001
From: Yuya Ebihara <ebyhry@gmail.com>
Date: Fri, 7 Oct 2022 17:52:33 +0900
Subject: [PATCH] Hide Hive system schemas in Hudi

---
 .../src/main/java/io/trino/plugin/hudi/HudiMetadata.java   | 4 +++-
 .../java/io/trino/plugin/hudi/BaseHudiConnectorTest.java   | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/plugin/trino-hudi/src/main/java/io/trino/plugin/hudi/HudiMetadata.java b/plugin/trino-hudi/src/main/java/io/trino/plugin/hudi/HudiMetadata.java
index 7e191e7e0624..bd2d83fa762b 100644
--- a/plugin/trino-hudi/src/main/java/io/trino/plugin/hudi/HudiMetadata.java
+++ b/plugin/trino-hudi/src/main/java/io/trino/plugin/hudi/HudiMetadata.java
@@ -89,7 +89,9 @@ public HudiMetadata(HiveMetastore metastore, HdfsEnvironment hdfsEnvironment, Ty
     @Override
     public List<String> listSchemaNames(ConnectorSession session)
     {
-        return metastore.getAllDatabases();
+        return metastore.getAllDatabases().stream()
+                .filter(schemaName -> !isHiveSystemSchema(schemaName))
+                .collect(toImmutableList());
     }
 
     @Override
diff --git a/plugin/trino-hudi/src/test/java/io/trino/plugin/hudi/BaseHudiConnectorTest.java b/plugin/trino-hudi/src/test/java/io/trino/plugin/hudi/BaseHudiConnectorTest.java
index 34aea735cf2d..9d23bf6cdcf8 100644
--- a/plugin/trino-hudi/src/test/java/io/trino/plugin/hudi/BaseHudiConnectorTest.java
+++ b/plugin/trino-hudi/src/test/java/io/trino/plugin/hudi/BaseHudiConnectorTest.java
@@ -79,6 +79,13 @@ public void testShowCreateTable()
                         ")");
     }
 
+    @Test
+    public void testHideHiveSysSchema()
+    {
+        assertThat(computeActual("SHOW SCHEMAS").getOnlyColumnAsSet()).doesNotContain("sys");
+        assertQueryFails("SHOW TABLES IN hudi.sys", ".*Schema 'sys' does not exist");
+    }
+
     protected static String columnsToHide()
     {
         List<String> columns = new ArrayList<>(HOODIE_META_COLUMNS.size() + 1);