From 4c33457b198b4b9824b333fd9023543f2f59cd44 Mon Sep 17 00:00:00 2001
From: Ning Sun <sunng@protonmail.com>
Date: Mon, 8 Jul 2024 18:05:54 +0800
Subject: [PATCH] fix: error on show databases in non-default catalog

---
 .../src/information_schema/schemata.rs        | 13 +++----
 tests-integration/src/tests/instance_test.rs  | 39 ++++++++++++++++++-
 2 files changed, 43 insertions(+), 9 deletions(-)

diff --git a/src/catalog/src/information_schema/schemata.rs b/src/catalog/src/information_schema/schemata.rs
index d4151e827916..e33efea89dc6 100644
--- a/src/catalog/src/information_schema/schemata.rs
+++ b/src/catalog/src/information_schema/schemata.rs
@@ -33,7 +33,7 @@ use store_api::storage::{ScanRequest, TableId};
 
 use super::SCHEMATA;
 use crate::error::{
-    CreateRecordBatchSnafu, InternalSnafu, Result, SchemaNotFoundSnafu, TableMetadataManagerSnafu,
+    CreateRecordBatchSnafu, InternalSnafu, Result, TableMetadataManagerSnafu,
     UpgradeWeakCatalogManagerRefSnafu,
 };
 use crate::information_schema::{utils, InformationTable, Predicates};
@@ -172,17 +172,14 @@ impl InformationSchemaSchemataBuilder {
 
         for schema_name in catalog_manager.schema_names(&catalog_name).await? {
             let opts = if let Some(table_metadata_manager) = &table_metadata_manager {
-                let schema_opts = table_metadata_manager
+                table_metadata_manager
                     .schema_manager()
                     .get(SchemaNameKey::new(&catalog_name, &schema_name))
                     .await
                     .context(TableMetadataManagerSnafu)?
-                    .context(SchemaNotFoundSnafu {
-                        catalog: &catalog_name,
-                        schema: &schema_name,
-                    })?;
-
-                Some(format!("{schema_opts}"))
+                    // information_schema is not available from this
+                    // table_metadata_manager and we return None
+                    .map(|schema_opts| format!("{schema_opts}"))
             } else {
                 None
             };
diff --git a/tests-integration/src/tests/instance_test.rs b/tests-integration/src/tests/instance_test.rs
index b40ed6113b06..b0bc7f4c881f 100644
--- a/tests-integration/src/tests/instance_test.rs
+++ b/tests-integration/src/tests/instance_test.rs
@@ -16,7 +16,7 @@ use std::assert_matches::assert_matches;
 use std::env;
 use std::sync::Arc;
 
-use client::OutputData;
+use client::{OutputData, DEFAULT_SCHEMA_NAME};
 use common_catalog::consts::DEFAULT_CATALOG_NAME;
 use common_query::Output;
 use common_recordbatch::util;
@@ -1879,6 +1879,43 @@ async fn test_information_schema_dot_tables(instance: Arc<dyn MockInstance>) {
     check_output_stream(output, expected).await;
 }
 
+#[apply(both_instances_cases)]
+async fn test_show_databases(instance: Arc<dyn MockInstance>) {
+    common_telemetry::init_default_ut_logging();
+    let instance = instance.frontend();
+
+    let sql = "show databases";
+
+    let query_ctx = Arc::new(QueryContext::with(
+        DEFAULT_CATALOG_NAME,
+        DEFAULT_SCHEMA_NAME,
+    ));
+    let output = execute_sql_with(&instance, sql, query_ctx.clone())
+        .await
+        .data;
+    let expected = "\
++--------------------+
+| Database           |
++--------------------+
+| greptime_private   |
+| information_schema |
+| public             |
++--------------------+";
+    check_output_stream(output, expected).await;
+
+    let query_ctx = Arc::new(QueryContext::with("random_catalog", DEFAULT_SCHEMA_NAME));
+    let output = execute_sql_with(&instance, sql, query_ctx.clone())
+        .await
+        .data;
+    let expected = "\
++--------------------+
+| Database           |
++--------------------+
+| information_schema |
++--------------------+";
+    check_output_stream(output, expected).await;
+}
+
 #[apply(both_instances_cases)]
 async fn test_information_schema_dot_columns(instance: Arc<dyn MockInstance>) {
     common_telemetry::init_default_ut_logging();