From e8651ec0f4c3114c68a669d3785f621610b5c807 Mon Sep 17 00:00:00 2001
From: robot-clickhouse <robot-clickhouse@users.noreply.github.com>
Date: Tue, 1 Oct 2024 22:27:09 +0000
Subject: [PATCH] Backport #70144 to 24.8: Fix possible hung in ALTER COLUMN
 with Dynamic type

---
 src/Interpreters/MutationsInterpreter.cpp     | 21 +++++++++++++------
 .../03246_alter_update_dynamic_hung.reference |  0
 .../03246_alter_update_dynamic_hung.sql       |  7 +++++++
 3 files changed, 22 insertions(+), 6 deletions(-)
 create mode 100644 tests/queries/0_stateless/03246_alter_update_dynamic_hung.reference
 create mode 100644 tests/queries/0_stateless/03246_alter_update_dynamic_hung.sql

diff --git a/src/Interpreters/MutationsInterpreter.cpp b/src/Interpreters/MutationsInterpreter.cpp
index 0b93b5989b1..58e9c469568 100644
--- a/src/Interpreters/MutationsInterpreter.cpp
+++ b/src/Interpreters/MutationsInterpreter.cpp
@@ -500,12 +500,6 @@ static void validateUpdateColumns(
                 throw Exception(ErrorCodes::NO_SUCH_COLUMN_IN_TABLE, "There is no column {} in table", backQuote(column_name));
             }
         }
-        else if (storage_columns.getColumn(GetColumnsOptions::Ordinary, column_name).type->hasDynamicSubcolumns())
-        {
-            throw Exception(ErrorCodes::CANNOT_UPDATE_COLUMN,
-                            "Cannot update column {} with type {}: updates of columns with dynamic subcolumns are not supported",
-                            backQuote(column_name), storage_columns.getColumn(GetColumnsOptions::Ordinary, column_name).type->getName());
-        }
     }
 }
 
@@ -1340,6 +1334,21 @@ void MutationsInterpreter::validate()
         }
     }
 
+    const auto & storage_columns = source.getStorageSnapshot(metadata_snapshot, context)->metadata->getColumns();
+    for (const auto & command : commands)
+    {
+        for (const auto & [column_name, _] : command.column_to_update_expression)
+        {
+            auto column = storage_columns.tryGetColumn(GetColumnsOptions::Ordinary, column_name);
+            if (column && column->type->hasDynamicSubcolumns())
+            {
+                throw Exception(ErrorCodes::CANNOT_UPDATE_COLUMN,
+                                "Cannot update column {} with type {}: updates of columns with dynamic subcolumns are not supported",
+                                backQuote(column_name), storage_columns.getColumn(GetColumnsOptions::Ordinary, column_name).type->getName());
+            }
+        }
+    }
+
     QueryPlan plan;
 
     initQueryPlan(stages.front(), plan);
diff --git a/tests/queries/0_stateless/03246_alter_update_dynamic_hung.reference b/tests/queries/0_stateless/03246_alter_update_dynamic_hung.reference
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/queries/0_stateless/03246_alter_update_dynamic_hung.sql b/tests/queries/0_stateless/03246_alter_update_dynamic_hung.sql
new file mode 100644
index 00000000000..e3bf7bb5a37
--- /dev/null
+++ b/tests/queries/0_stateless/03246_alter_update_dynamic_hung.sql
@@ -0,0 +1,7 @@
+SET allow_experimental_dynamic_type = 1;
+DROP TABLE IF EXISTS t0;
+CREATE TABLE t0 (c0 Int) ENGINE = MergeTree() ORDER BY tuple();
+INSERT INTO t0 (c0) VALUES (1);
+ALTER TABLE t0 UPDATE c0 = EXISTS (SELECT 1 FROM t1 CROSS JOIN t0) WHERE 1;
+ALTER TABLE t0 MODIFY COLUMN c0 Dynamic; --{serverError UNFINISHED}
+DROP TABLE t0;