From b53fc06947ffbf1f4e78ff2a506392df5c475da7 Mon Sep 17 00:00:00 2001
From: Anton Ivashkin <ianton@live.com>
Date: Mon, 10 Nov 2025 09:12:42 +0100
Subject: [PATCH 1/3] Fix SYSTEM DROP FILESYSTEM CACHE 'cache' ON CLUSTER
 'cluster'

---
 src/Parsers/ASTSystemQuery.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/Parsers/ASTSystemQuery.cpp b/src/Parsers/ASTSystemQuery.cpp
index 992971dd1ac8..00925e561219 100644
--- a/src/Parsers/ASTSystemQuery.cpp
+++ b/src/Parsers/ASTSystemQuery.cpp
@@ -163,7 +163,13 @@ void ASTSystemQuery::formatImpl(WriteBuffer & ostr, const FormatSettings & setti
 
     print_keyword("SYSTEM") << " ";
     print_keyword(typeToString(type));
-    if (!cluster.empty())
+
+    std::unordered_set<Type> queries_with_on_cluster_at_end = {
+        Type::DROP_FILESYSTEM_CACHE,
+        Type::SYNC_FILESYSTEM_CACHE,
+    };
+
+    if (!queries_with_on_cluster_at_end.contains(type) && !cluster.empty())
         formatOnCluster(ostr, settings);
 
     switch (type)
@@ -519,6 +525,9 @@ void ASTSystemQuery::formatImpl(WriteBuffer & ostr, const FormatSettings & setti
         case Type::END:
             throw Exception(ErrorCodes::LOGICAL_ERROR, "Unknown SYSTEM command");
     }
+
+    if (queries_with_on_cluster_at_end.contains(type) && !cluster.empty())
+        formatOnCluster(ostr, settings);
 }
 
 

From 7061fbc3c0938ab8a69b57cc39a7f20e41939793 Mon Sep 17 00:00:00 2001
From: Anton Ivashkin <ianton@live.com>
Date: Mon, 10 Nov 2025 09:32:33 +0100
Subject: [PATCH 2/3] Add test

---
 ...drop_filesystem_cache_on_cluster.reference |  0
 ...system_drop_filesystem_cache_on_cluster.sh | 31 +++++++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference
 create mode 100755 tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.sh

diff --git a/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference b/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.sh b/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.sh
new file mode 100755
index 000000000000..8f40316ac5d1
--- /dev/null
+++ b/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.sh
@@ -0,0 +1,31 @@
+#!/usr/bin/env bash
+# Tags: no-fasttest, no-parallel, no-object-storage, no-random-settings
+
+# set -x
+
+CUR_DIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
+# shellcheck source=../shell_config.sh
+. "$CUR_DIR"/../shell_config.sh
+
+
+disk_name="${CLICKHOUSE_TEST_UNIQUE_NAME}"
+$CLICKHOUSE_CLIENT -m --query """
+DROP TABLE IF EXISTS test;
+CREATE TABLE test (a Int32, b String)
+ENGINE = MergeTree() ORDER BY tuple()
+SETTINGS disk = disk(name = '$disk_name', type = cache, max_size = '100Ki', path = ${CLICKHOUSE_TEST_UNIQUE_NAME}, disk = s3_disk);
+
+INSERT INTO test SELECT 1, 'test';
+"""
+
+$CLICKHOUSE_CLIENT --query """
+SYSTEM SYNC FILESYSTEM CACHE '$disk_name' ON CLUSTER 'test_shard_localhost';
+"""
+
+$CLICKHOUSE_CLIENT --query """
+SYSTEM DROP FILESYSTEM CACHE '$disk_name' ON CLUSTER 'test_shard_localhost';
+"""
+
+$CLICKHOUSE_CLIENT --query """
+DROP TABLE IF EXISTS test;
+"""

From aebebf500c5c00a00a8ab81ab43ea8aac03b715f Mon Sep 17 00:00:00 2001
From: Anton Ivashkin <ianton@live.com>
Date: Tue, 11 Nov 2025 09:44:31 +0100
Subject: [PATCH 3/3] Fix test

---
 .../03643_system_drop_filesystem_cache_on_cluster.reference     | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference b/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference
index e69de29bb2d1..1444d39d9578 100644
--- a/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference
+++ b/tests/queries/0_stateless/03643_system_drop_filesystem_cache_on_cluster.reference
@@ -0,0 +1,2 @@
+localhost	9000	0		0	0
+localhost	9000	0		0	0