Merge pull request #33017 from stigsb/table-overrides-drop-add-column-support

Remove the possibility of adding columns with table overrides

docs/en/engines/database-engines/materialized-mysql.md

@@ -151,14 +151,32 @@ Table overrides can be used to customize the ClickHouse DDL queries, allowing yo
 application. This is especially useful for controlling partitioning, which is important for the overall performance of
 MaterializedMySQL.
 
+These are the schema conversion manipulations you can do with table overrides for MaterializedMySQL:
+
+ * Modify column type. Must be compatible with the original type, or replication will fail. For example,
+   you can modify a UInt32 column to UInt64, but you can not modify a String column to Array(String).
+ * Modify [column TTL](../table-engines/mergetree-family/mergetree/#mergetree-column-ttl).
+ * Modify [column compression codec](../../sql-reference/statements/create/table/#codecs).
+ * Add [ALIAS columns](../../sql-reference/statements/create/table/#alias).
+ * Add [skipping indexes](../table-engines/mergetree-family/mergetree/#table_engine-mergetree-data_skipping-indexes)
+ * Add [projections](../table-engines/mergetree-family/mergetree/#projections). Note that projection optimizations are
+   disabled when using `SELECT ... FINAL` (which MaterializedMySQL does by default), so their utility is limited here.
+   `INDEX ... TYPE hypothesis` as [described in the v21.12 blog post]](https://clickhouse.com/blog/en/2021/clickhouse-v21.12-released/)
+   may be more useful in this case.
+ * Modify [PARTITION BY](../table-engines/mergetree-family/custom-partitioning-key/)
+ * Modify [ORDER BY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Modify [PRIMARY KEY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Add [SAMPLE BY](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+ * Add [table TTL](../table-engines/mergetree-family/mergetree/#mergetree-query-clauses)
+
 ```sql
 CREATE DATABASE db_name ENGINE = MaterializedMySQL(...)
 [SETTINGS ...]
 [TABLE OVERRIDE table_name (
     [COLUMNS (
-        [name1 [type1] [DEFAULT|MATERIALIZED|ALIAS expr1] [TTL expr1], ...]
+        [col_name [datatype] [ALIAS expr] [CODEC(...)] [TTL expr], ...]
-        [INDEX index_name1 expr1 TYPE type1(...) GRANULARITY value1, ...]
+        [INDEX index_name expr TYPE indextype[(...)] GRANULARITY val, ...]
-        [PROJECTION projection_name_1 (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY]), ...]
+        [PROJECTION projection_name (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY]), ...]
     )]
     [ORDER BY expr]
     [PRIMARY KEY expr]
@@ -182,26 +200,26 @@ TABLE OVERRIDE table1 (
 ),
 TABLE OVERRIDE table2 (
     COLUMNS (
-	    ip_hash UInt32 MATERIALIZED xxHash32(client_ip),
         client_ip String TTL created + INTERVAL 72 HOUR
     )
     SAMPLE BY ip_hash
 )
 ```
 
-The `COLUMNS` list is sparse; it contains only modified or extra (MATERIALIZED or ALIAS) columns. Modified columns with
+The `COLUMNS` list is sparse; existing columns are modified as specified, extra ALIAS columns are added. It is not
-a different type must be assignable from the original type. There is currently no validation of this or similar issues
+possible to add ordinary or MATERIALIZED columns.  Modified columns with a different type must be assignable from the
-when the `CREATE DATABASE` query executes, so extra care needs to be taken.
+original type. There is currently no validation of this or similar issues when the `CREATE DATABASE` query executes, so
+extra care needs to be taken.
 
 You may specify overrides for tables that do not exist yet.
 
-!!! note "Warning"
+!!! warning "Warning"
-    It is easy to break replication with TABLE OVERRIDEs if not used with care. For example:
+    It is easy to break replication with table overrides if not used with care. For example:
     
-    * If a column is added with a table override, but then later added to the source MySQL table, the converted ALTER TABLE
+    * If an ALIAS column is added with a table override, and a column with the same name is later added to the source
-      query in ClickHouse will fail because the column already exists.
+	    MySQL table, the converted ALTER TABLE query in ClickHouse will fail and replication stops.
     * It is currently possible to add overrides that reference nullable columns where not-nullable are required, such as in
-      `ORDER BY` or `PARTITION BY`.
+      `ORDER BY` or `PARTITION BY`. This will cause CREATE TABLE queries that will fail, also causing replication to stop.
 
 ## Examples of Use {#examples-of-use}
 
@@ -218,11 +236,9 @@ mysql> SELECT * FROM test;
 ```
 
 ```text
-+---+------+------+
+┌─a─┬───b─┬─c────┐
-| a |    b |    c |
+│ 2 │ 222 │ Wow! │
-+---+------+------+
+└───┴─────┴──────┘
-| 2 |  222 | Wow! |
-+---+------+------+
 ```
 
 Database in ClickHouse, exchanging data with the MySQL server:

src/Interpreters/MySQL/InterpretersMySQLDDLQuery.cpp

@@ -25,6 +25,7 @@
 #include <Interpreters/InterpreterCreateQuery.h>
 #include <Interpreters/ExpressionAnalyzer.h>
 #include <Interpreters/TreeRewriter.h>
+#include <Interpreters/applyTableOverride.h>
 #include <Storages/IStorage.h>
 
 namespace DB
@@ -520,10 +521,10 @@ ASTs InterpreterCreateImpl::getRewrittenQueries(
     rewritten_query->set(rewritten_query->storage, storage);
     rewritten_query->set(rewritten_query->columns_list, columns);
 
-    if (auto table_override = tryGetTableOverride(mapped_to_database, create_query.table))
+    if (auto override_ast = tryGetTableOverride(mapped_to_database, create_query.table))
     {
-        auto * override_ast = table_override->as<ASTTableOverride>();
+        const auto & override = override_ast->as<const ASTTableOverride &>();
-        override_ast->applyToCreateTableQuery(rewritten_query.get());
+        applyTableOverrideToCreateQuery(override, rewritten_query.get());
     }
 
     return ASTs{rewritten_query};

src/Interpreters/applyTableOverride.cpp

@@ -0,0 +1,125 @@
+#include <Interpreters/applyTableOverride.h>
+
+#include <Parsers/ASTCreateQuery.h>
+#include <Parsers/ASTTableOverrides.h>
+#include <Parsers/ASTColumnDeclaration.h>
+#include <Parsers/ASTIndexDeclaration.h>
+#include <Parsers/ASTConstraintDeclaration.h>
+#include <Parsers/ASTProjectionDeclaration.h>
+
+namespace DB
+{
+
+void applyTableOverrideToCreateQuery(const ASTTableOverride & override, ASTCreateQuery * create_query)
+{
+    if (auto * columns = override.columns)
+    {
+        if (!create_query->columns_list)
+            create_query->set(create_query->columns_list, std::make_shared<ASTColumns>());
+        if (columns->columns)
+        {
+            for (const auto & override_column_ast : columns->columns->children)
+            {
+                auto * override_column = override_column_ast->as<ASTColumnDeclaration>();
+                if (!override_column)
+                    continue;
+                if (!create_query->columns_list->columns)
+                    create_query->columns_list->set(create_query->columns_list->columns, std::make_shared<ASTExpressionList>());
+                auto & dest_children = create_query->columns_list->columns->children;
+                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
+                {
+                    return node->as<ASTColumnDeclaration>()->name == override_column->name;
+                });
+                /// For columns, only allow adding ALIAS (non-physical) for now.
+                /// TODO: This logic should instead be handled by validation that is
+                ///       executed from InterpreterCreateQuery / InterpreterAlterQuery.
+                if (exists == dest_children.end())
+                {
+                    if (override_column->default_specifier == "ALIAS")
+                        dest_children.emplace_back(override_column_ast);
+                }
+                else
+                    dest_children[exists - dest_children.begin()] = override_column_ast;
+            }
+        }
+        if (columns->indices)
+        {
+            for (const auto & override_index_ast : columns->indices->children)
+            {
+                auto * override_index = override_index_ast->as<ASTIndexDeclaration>();
+                if (!override_index)
+                    continue;
+                if (!create_query->columns_list->indices)
+                    create_query->columns_list->set(create_query->columns_list->indices, std::make_shared<ASTExpressionList>());
+                auto & dest_children = create_query->columns_list->indices->children;
+                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
+                {
+                    return node->as<ASTIndexDeclaration>()->name == override_index->name;
+                });
+                if (exists == dest_children.end())
+                    dest_children.emplace_back(override_index_ast);
+                else
+                    dest_children[exists - dest_children.begin()] = override_index_ast;
+            }
+        }
+        if (columns->constraints)
+        {
+            for (const auto & override_constraint_ast : columns->constraints->children)
+            {
+                auto * override_constraint = override_constraint_ast->as<ASTConstraintDeclaration>();
+                if (!override_constraint)
+                    continue;
+                if (!create_query->columns_list->constraints)
+                    create_query->columns_list->set(create_query->columns_list->constraints, std::make_shared<ASTExpressionList>());
+                auto & dest_children = create_query->columns_list->constraints->children;
+                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
+                {
+                    return node->as<ASTConstraintDeclaration>()->name == override_constraint->name;
+                });
+                if (exists == dest_children.end())
+                    dest_children.emplace_back(override_constraint_ast);
+                else
+                    dest_children[exists - dest_children.begin()] = override_constraint_ast;
+            }
+        }
+        if (columns->projections)
+        {
+            for (const auto & override_projection_ast : columns->projections->children)
+            {
+                auto * override_projection = override_projection_ast->as<ASTProjectionDeclaration>();
+                if (!override_projection)
+                    continue;
+                if (!create_query->columns_list->projections)
+                    create_query->columns_list->set(create_query->columns_list->projections, std::make_shared<ASTExpressionList>());
+                auto & dest_children = create_query->columns_list->projections->children;
+                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
+                {
+                    return node->as<ASTProjectionDeclaration>()->name == override_projection->name;
+                });
+                if (exists == dest_children.end())
+                    dest_children.emplace_back(override_projection_ast);
+                else
+                    dest_children[exists - dest_children.begin()] = override_projection_ast;
+            }
+        }
+    }
+    if (auto * storage = override.storage)
+    {
+        if (!create_query->storage)
+            create_query->set(create_query->storage, std::make_shared<ASTStorage>());
+        if (storage->partition_by)
+            create_query->storage->set(create_query->storage->partition_by, storage->partition_by->clone());
+        if (storage->primary_key)
+            create_query->storage->set(create_query->storage->primary_key, storage->primary_key->clone());
+        if (storage->order_by)
+            create_query->storage->set(create_query->storage->order_by, storage->order_by->clone());
+        if (storage->sample_by)
+            create_query->storage->set(create_query->storage->sample_by, storage->sample_by->clone());
+        if (storage->ttl_table)
+            create_query->storage->set(create_query->storage->ttl_table, storage->ttl_table->clone());
+        // No support for overriding ENGINE and SETTINGS
+    }
+
+}
+
+}

src/Interpreters/applyTableOverride.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <Parsers/ASTCreateQuery.h>
+#include <Parsers/ASTIdentifier.h>
+#include <Parsers/ASTTableOverrides.h>
+
+namespace DB
+{
+
+class ASTTableOverride;
+class ASTCreateQuery;
+class ASTIndentifier;
+
+void applyTableOverrideToCreateQuery(const ASTTableOverride & override, ASTCreateQuery * create_query);
+
+}

src/Interpreters/tests/gtest_table_overrides.cpp

@@ -0,0 +1,88 @@
+#include <Interpreters/applyTableOverride.h>
+#include <Parsers/ParserCreateQuery.h>
+#include <Parsers/parseQuery.h>
+#include <Parsers/formatAST.h>
+
+#include <iostream>
+#include <gtest/gtest.h>
+
+namespace
+{
+using namespace DB;
+using namespace std::literals;
+}
+
+
+struct TableOverrideTestCase
+{
+    String create_database_query;
+    String create_table_query;
+    String expected_create_table_query;
+};
+
+std::ostream & operator<<(std::ostream & ostr, const TableOverrideTestCase & test_case)
+{
+    return ostr << "database: " << test_case.create_database_query << ", table: " << test_case.create_table_query
+                << ", expected: " << test_case.expected_create_table_query;
+}
+
+class TableOverrideTest : public ::testing::TestWithParam<TableOverrideTestCase>
+{};
+
+TEST_P(TableOverrideTest, applyOverrides)
+{
+    const auto & [database_query, table_query, expected_query] = GetParam();
+    ParserCreateQuery parser;
+    ASTPtr database_ast;
+    ASSERT_NO_THROW(database_ast = parseQuery(parser, database_query, 0, 0));
+    auto * database = database_ast->as<ASTCreateQuery>();
+    ASSERT_NE(nullptr, database);
+    ASTPtr table_ast;
+    ASSERT_NO_THROW(table_ast = parseQuery(parser, table_query, 0, 0));
+    auto * table = table_ast->as<ASTCreateQuery>();
+    ASSERT_NE(nullptr, table);
+    auto table_name = table->table->as<ASTIdentifier>()->name();
+    if (database->table_overrides)
+    {
+        auto override_ast = database->table_overrides->tryGetTableOverride(table_name);
+        ASSERT_NE(nullptr, override_ast);
+        auto * override_table_ast = override_ast->as<ASTTableOverride>();
+        ASSERT_NE(nullptr, override_table_ast);
+        applyTableOverrideToCreateQuery(*override_table_ast, table);
+    }
+    EXPECT_EQ(expected_query, serializeAST(*table));
+}
+
+INSTANTIATE_TEST_SUITE_P(ApplyTableOverrides, TableOverrideTest,
+    ::testing::ValuesIn(std::initializer_list<TableOverrideTestCase>{
+    {
+        "CREATE DATABASE db",
+        "CREATE TABLE db.t (id Int64) ENGINE=Log",
+        "CREATE TABLE db.t (`id` Int64) ENGINE = Log"
+    },
+    {
+        "CREATE DATABASE db TABLE OVERRIDE t (PARTITION BY tuple())",
+        "CREATE TABLE db.t (id Int64) ENGINE=MergeTree",
+        "CREATE TABLE db.t (`id` Int64) ENGINE = MergeTree PARTITION BY tuple()"
+    },
+    {
+        "CREATE DATABASE db TABLE OVERRIDE t (COLUMNS (id UInt64 CODEC(Delta), shard UInt8 ALIAS modulo(id, 16)) PARTITION BY shard)",
+        "CREATE TABLE db.t (id Int64) ENGINE=MergeTree",
+        "CREATE TABLE db.t (`id` UInt64 CODEC(Delta), `shard` UInt8 ALIAS id % 16) ENGINE = MergeTree PARTITION BY shard"
+    },
+    {
+        "CREATE DATABASE db TABLE OVERRIDE a (PARTITION BY modulo(id, 3)), TABLE OVERRIDE b (PARTITION BY modulo(id, 5))",
+        "CREATE TABLE db.a (id Int64) ENGINE=MergeTree",
+        "CREATE TABLE db.a (`id` Int64) ENGINE = MergeTree PARTITION BY id % 3"
+    },
+    {
+        "CREATE DATABASE db TABLE OVERRIDE a (PARTITION BY modulo(id, 3)), TABLE OVERRIDE b (PARTITION BY modulo(id, 5))",
+        "CREATE TABLE db.b (id Int64) ENGINE=MergeTree",
+        "CREATE TABLE db.b (`id` Int64) ENGINE = MergeTree PARTITION BY id % 5"
+    },
+    {
+        "CREATE DATABASE db TABLE OVERRIDE `tbl` (PARTITION BY toYYYYMM(created))",
+        "CREATE TABLE db.tbl (id Int64, created DateTime) ENGINE=Foo",
+        "CREATE TABLE db.tbl (`id` Int64, `created` DateTime) ENGINE = Foo PARTITION BY toYYYYMM(created)",
+    }
+}));

src/Parsers/ASTTableOverrides.cpp

@@ -71,111 +71,6 @@ void ASTTableOverride::formatImpl(const FormatSettings & settings_, FormatState
     settings.ostr << nl_or_nothing << ')';
 }
 
-void ASTTableOverride::applyToCreateTableQuery(ASTCreateQuery * create_query) const
-{
-    if (columns)
-    {
-        if (!create_query->columns_list)
-            create_query->set(create_query->columns_list, std::make_shared<ASTColumns>());
-        if (columns->columns)
-        {
-            for (const auto & override_column_ast : columns->columns->children)
-            {
-                auto * override_column = override_column_ast->as<ASTColumnDeclaration>();
-                if (!override_column)
-                    continue;
-                if (!create_query->columns_list->columns)
-                    create_query->columns_list->set(create_query->columns_list->columns, std::make_shared<ASTExpressionList>());
-                auto & dest_children = create_query->columns_list->columns->children;
-                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
-                {
-                    return node->as<ASTColumnDeclaration>()->name == override_column->name;
-                });
-                if (exists == dest_children.end())
-                    dest_children.emplace_back(override_column_ast);
-                else
-                    dest_children[exists - dest_children.begin()] = override_column_ast;
-            }
-        }
-        if (columns->indices)
-        {
-            for (const auto & override_index_ast : columns->indices->children)
-            {
-                auto * override_index = override_index_ast->as<ASTIndexDeclaration>();
-                if (!override_index)
-                    continue;
-                if (!create_query->columns_list->indices)
-                    create_query->columns_list->set(create_query->columns_list->indices, std::make_shared<ASTExpressionList>());
-                auto & dest_children = create_query->columns_list->indices->children;
-                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
-                {
-                    return node->as<ASTIndexDeclaration>()->name == override_index->name;
-                });
-                if (exists == dest_children.end())
-                    dest_children.emplace_back(override_index_ast);
-                else
-                    dest_children[exists - dest_children.begin()] = override_index_ast;
-            }
-        }
-        if (columns->constraints)
-        {
-            for (const auto & override_constraint_ast : columns->constraints->children)
-            {
-                auto * override_constraint = override_constraint_ast->as<ASTConstraintDeclaration>();
-                if (!override_constraint)
-                    continue;
-                if (!create_query->columns_list->constraints)
-                    create_query->columns_list->set(create_query->columns_list->constraints, std::make_shared<ASTExpressionList>());
-                auto & dest_children = create_query->columns_list->constraints->children;
-                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
-                {
-                    return node->as<ASTConstraintDeclaration>()->name == override_constraint->name;
-                });
-                if (exists == dest_children.end())
-                    dest_children.emplace_back(override_constraint_ast);
-                else
-                    dest_children[exists - dest_children.begin()] = override_constraint_ast;
-            }
-        }
-        if (columns->projections)
-        {
-            for (const auto & override_projection_ast : columns->projections->children)
-            {
-                auto * override_projection = override_projection_ast->as<ASTProjectionDeclaration>();
-                if (!override_projection)
-                    continue;
-                if (!create_query->columns_list->projections)
-                    create_query->columns_list->set(create_query->columns_list->projections, std::make_shared<ASTExpressionList>());
-                auto & dest_children = create_query->columns_list->projections->children;
-                auto exists = std::find_if(dest_children.begin(), dest_children.end(), [&](ASTPtr node) -> bool
-                {
-                    return node->as<ASTProjectionDeclaration>()->name == override_projection->name;
-                });
-                if (exists == dest_children.end())
-                    dest_children.emplace_back(override_projection_ast);
-                else
-                    dest_children[exists - dest_children.begin()] = override_projection_ast;
-            }
-        }
-    }
-    if (storage)
-    {
-        if (!create_query->storage)
-            create_query->set(create_query->storage, std::make_shared<ASTStorage>());
-        if (storage->partition_by)
-            create_query->storage->set(create_query->storage->partition_by, storage->partition_by->clone());
-        if (storage->primary_key)
-            create_query->storage->set(create_query->storage->primary_key, storage->primary_key->clone());
-        if (storage->order_by)
-            create_query->storage->set(create_query->storage->order_by, storage->order_by->clone());
-        if (storage->sample_by)
-            create_query->storage->set(create_query->storage->sample_by, storage->sample_by->clone());
-        if (storage->ttl_table)
-            create_query->storage->set(create_query->storage->ttl_table, storage->ttl_table->clone());
-        // not supporting overriding ENGINE
-    }
-}
-
 ASTPtr ASTTableOverrideList::clone() const
 {
     auto res = std::make_shared<ASTTableOverrideList>(*this);

src/Parsers/ASTTableOverrides.h

@@ -26,7 +26,6 @@ public:
     String getID(char) const override { return "TableOverride " + table_name; }
     ASTPtr clone() const override;
     void formatImpl(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
-    void applyToCreateTableQuery(ASTCreateQuery * create_query) const;
 };
 
 /// List of table overrides, for example:

src/Parsers/tests/gtest_Parser.cpp

@@ -1,4 +1,5 @@
 #include <IO/WriteBufferFromOStream.h>
+#include <Interpreters/applyTableOverride.h>
 #include <Parsers/ASTCreateQuery.h>
 #include <Parsers/ASTFunction.h>
 #include <Parsers/ASTIdentifier.h>
@@ -57,46 +58,6 @@ TEST_P(ParserTest, parseQuery)
     }
 }
 
-struct TableOverrideTestCase
-{
-    DB::String create_database_query;
-    DB::String create_table_query;
-    DB::String expected_create_table_query;
-};
-
-std::ostream & operator<<(std::ostream & ostr, const TableOverrideTestCase & test_case)
-{
-    return ostr << "database: " << test_case.create_database_query << ", table: " << test_case.create_table_query
-                << ", expected: " << test_case.expected_create_table_query;
-}
-
-class TableOverrideTest : public ::testing::TestWithParam<TableOverrideTestCase>
-{};
-
-TEST_P(TableOverrideTest, applyOverrides)
-{
-    const auto & [database_query, table_query, expected_query] = GetParam();
-    ParserCreateQuery parser;
-    ASTPtr database_ast;
-    ASSERT_NO_THROW(database_ast = parseQuery(parser, database_query, 0, 0));
-    auto * database = database_ast->as<ASTCreateQuery>();
-    ASSERT_NE(nullptr, database);
-    ASTPtr table_ast;
-    ASSERT_NO_THROW(table_ast = parseQuery(parser, table_query, 0, 0));
-    auto * table = table_ast->as<ASTCreateQuery>();
-    ASSERT_NE(nullptr, table);
-    auto table_name = table->table->as<ASTIdentifier>()->name();
-    if (database->table_overrides)
-    {
-        auto override_ast = database->table_overrides->tryGetTableOverride(table_name);
-        ASSERT_NE(nullptr, override_ast);
-        auto * override_table_ast = override_ast->as<ASTTableOverride>();
-        ASSERT_NE(nullptr, override_table_ast);
-        override_table_ast->applyToCreateTableQuery(table);
-    }
-    EXPECT_EQ(expected_query, serializeAST(*table));
-}
-
 INSTANTIATE_TEST_SUITE_P(ParserOptimizeQuery, ParserTest,
     ::testing::Combine(
         ::testing::Values(std::make_shared<ParserOptimizeQuery>()),
@@ -265,37 +226,3 @@ INSTANTIATE_TEST_SUITE_P(ParserCreateDatabaseQuery, ParserTest,
             "CREATE DATABASE db\nENGINE = Foo\nSETTINGS a = 1, b = 2\nTABLE OVERRIDE `a`\n(\n    ORDER BY (`id`, `version`)\n)\nCOMMENT 'db comment'"
         }
 })));
-
-INSTANTIATE_TEST_SUITE_P(ApplyTableOverrides, TableOverrideTest,
-    ::testing::ValuesIn(std::initializer_list<TableOverrideTestCase>{
-    {
-        "CREATE DATABASE db",
-        "CREATE TABLE db.t (id Int64) ENGINE=Log",
-        "CREATE TABLE db.t (`id` Int64) ENGINE = Log"
-    },
-    {
-        "CREATE DATABASE db TABLE OVERRIDE t (PARTITION BY tuple())",
-        "CREATE TABLE db.t (id Int64) ENGINE=MergeTree",
-        "CREATE TABLE db.t (`id` Int64) ENGINE = MergeTree PARTITION BY tuple()"
-    },
-    {
-        "CREATE DATABASE db TABLE OVERRIDE t (COLUMNS (id UInt64, shard UInt8 MATERIALIZED modulo(id, 16)) PARTITION BY shard)",
-        "CREATE TABLE db.t (id Int64) ENGINE=MergeTree",
-        "CREATE TABLE db.t (`id` UInt64, `shard` UInt8 MATERIALIZED id % 16) ENGINE = MergeTree PARTITION BY shard"
-    },
-    {
-        "CREATE DATABASE db TABLE OVERRIDE a (PARTITION BY modulo(id, 3)), TABLE OVERRIDE b (PARTITION BY modulo(id, 5))",
-        "CREATE TABLE db.a (id Int64) ENGINE=MergeTree",
-        "CREATE TABLE db.a (`id` Int64) ENGINE = MergeTree PARTITION BY id % 3"
-    },
-    {
-        "CREATE DATABASE db TABLE OVERRIDE a (PARTITION BY modulo(id, 3)), TABLE OVERRIDE b (PARTITION BY modulo(id, 5))",
-        "CREATE TABLE db.b (id Int64) ENGINE=MergeTree",
-        "CREATE TABLE db.b (`id` Int64) ENGINE = MergeTree PARTITION BY id % 5"
-    },
-    {
-        "CREATE DATABASE db ENGINE=MaterializeMySQL('addr:port', 'db', 'user', 'pw') TABLE OVERRIDE `tbl` (PARTITION BY toYYYYMM(created))",
-        "CREATE TABLE db.tbl (id Int64, created DateTime) ENGINE=Foo",
-        "CREATE TABLE db.tbl (`id` Int64, `created` DateTime) ENGINE = Foo PARTITION BY toYYYYMM(created)",
-    }
-}));

src/Storages/PostgreSQL/StorageMaterializedPostgreSQL.cpp

@@ -24,6 +24,7 @@
 #include <Parsers/ASTIdentifier.h>
 #include <Parsers/ASTTablesInSelectQuery.h>
 
+#include <Interpreters/applyTableOverride.h>
 #include <Interpreters/executeQuery.h>
 #include <Interpreters/InterpreterSelectQuery.h>
 #include <Interpreters/InterpreterDropQuery.h>
@@ -395,7 +396,7 @@ ASTPtr StorageMaterializedPostgreSQL::getCreateNestedTableQuery(
 {
     auto create_table_query = std::make_shared<ASTCreateQuery>();
     if (table_override)
-        table_override->applyToCreateTableQuery(create_table_query.get());
+        applyTableOverrideToCreateQuery(*table_override, create_table_query.get());
 
     auto table_id = getStorageID();
     create_table_query->setTable(getNestedTableName());

tests/integration/test_materialized_mysql_database/materialize_with_ddl.py

@@ -1066,10 +1066,19 @@ def table_overrides(clickhouse_node, mysql_node, service_name):
         mysql_node.query("COMMIT")
     clickhouse_node.query(f"""
         CREATE DATABASE table_overrides ENGINE=MaterializeMySQL('{service_name}:3306', 'table_overrides', 'root', 'clickhouse')
-        TABLE OVERRIDE t1 (COLUMNS (sensor_id UInt64))
+        TABLE OVERRIDE t1 (COLUMNS (sensor_id UInt64, temp_f Nullable(Float32) ALIAS if(isNull(temperature), NULL, (temperature * 9 / 5) + 32)))
     """)
+    check_query(
+        clickhouse_node,
+        "SELECT type FROM system.columns WHERE database = 'table_overrides' AND table = 't1' AND name = 'sensor_id'",
+        "UInt64\n")
+    check_query(
+        clickhouse_node,
+        "SELECT type, default_kind FROM system.columns WHERE database = 'table_overrides' AND table = 't1' AND name = 'temp_f'",
+        "Nullable(Float32)\tALIAS\n")
     check_query(clickhouse_node, "SELECT count() FROM table_overrides.t1", "1000\n")
-    check_query(clickhouse_node, "SELECT type FROM system.columns WHERE database = 'table_overrides' AND table = 't1' AND name = 'sensor_id'", "UInt64\n")
+    mysql_node.query("INSERT INTO table_overrides.t1 VALUES(1001, '2021-10-01 00:00:00', 42.0)")
+    check_query(clickhouse_node, "SELECT count() FROM table_overrides.t1", "1001\n")
     clickhouse_node.query("DROP DATABASE IF EXISTS table_overrides")
     mysql_node.query("DROP DATABASE IF EXISTS table_overrides")