From 9c900cb6d2bfe5d0a2c4d0e6cdfeb7a3caecf6f8 Mon Sep 17 00:00:00 2001
From: GoGoWen <82132356+GoGoWen@users.noreply.github.com>
Date: Mon, 10 Apr 2023 14:13:12 +0800
Subject: [PATCH] [fix](multi catalog) fix show catalogs after drop (#18481)

steps to repo:
1, create any catalog re; [OK]
2, switch re [OK]
3, show catalogs [OK]
4, drop catalog re [OK]
5, show catalogs [FAIL with "Current catalog is not exist, please switch catalog." ]

expect:
show catalogs should always be OK, not depends on current catalog.
---
 .../apache/doris/datasource/CatalogMgr.java   |  2 +-
 .../org/apache/doris/qe/ShowExecutor.java     |  6 ++--
 .../query_p0/show/test_show_catalogs.groovy   | 33 +++++++++++++++++++
 3 files changed, 36 insertions(+), 5 deletions(-)
 create mode 100644 regression-test/suites/query_p0/show/test_show_catalogs.groovy

diff --git a/fe/fe-core/src/main/java/org/apache/doris/datasource/CatalogMgr.java b/fe/fe-core/src/main/java/org/apache/doris/datasource/CatalogMgr.java
index 1d219da65f..9d8c3fe985 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/datasource/CatalogMgr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/datasource/CatalogMgr.java
@@ -368,7 +368,7 @@ public class CatalogMgr implements Writable, GsonPostProcessable {
                         row.add(String.valueOf(catalog.getId()));
                         row.add(name);
                         row.add(catalog.getType());
-                        if (name.equals(currentCtlg)) {
+                        if (currentCtlg != null && name.equals(currentCtlg)) {
                             row.add(YES);
                         } else {
                             row.add("");
diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/ShowExecutor.java b/fe/fe-core/src/main/java/org/apache/doris/qe/ShowExecutor.java
index aadc9129a0..709bea5b31 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/qe/ShowExecutor.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/qe/ShowExecutor.java
@@ -2434,10 +2434,8 @@ public class ShowExecutor {
 
     public void handleShowCatalogs() throws AnalysisException {
         ShowCatalogStmt showStmt = (ShowCatalogStmt) stmt;
-        if (ctx.getCurrentCatalog() == null) {
-            throw new AnalysisException("Current catalog is not exist, please switch catalog.");
-        }
-        resultSet = Env.getCurrentEnv().getCatalogMgr().showCatalogs(showStmt, ctx.getCurrentCatalog().getName());
+        resultSet = Env.getCurrentEnv().getCatalogMgr().showCatalogs(showStmt, ctx.getCurrentCatalog() != null
+            ? ctx.getCurrentCatalog().getName() : null);
     }
 
     // Show create catalog
diff --git a/regression-test/suites/query_p0/show/test_show_catalogs.groovy b/regression-test/suites/query_p0/show/test_show_catalogs.groovy
new file mode 100644
index 0000000000..85be7d0975
--- /dev/null
+++ b/regression-test/suites/query_p0/show/test_show_catalogs.groovy
@@ -0,0 +1,33 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+suite("test_show_catalogs") {
+    // define a catalog name
+    String catalog_name = "test_show_catalogs";
+
+    sql """drop catalog if exists ${catalog_name} """
+    sql """CREATE CATALOG ${catalog_name}  PROPERTIES (
+           "hive.metastore.uris" = "thrift://11.119.172.189:9083",
+           "type" = "hms"
+        );"""
+
+    sql """switch ${catalog_name};"""
+    sql """drop catalog ${catalog_name};"""
+
+    //should be OK to call show catalogs after drop current catalog
+    sql """show catalogs;"""
+}