Fix remove TTL for column

src/Storages/AlterCommands.cpp

@@ -793,6 +793,7 @@ void AlterCommands::apply(StorageInMemoryMetadata & metadata, const Context & co
         throw DB::Exception("Alter commands is not prepared. Cannot apply. It's a bug", ErrorCodes::LOGICAL_ERROR);
 
     auto metadata_copy = metadata;
+
     for (const AlterCommand & command : *this)
         if (!command.ignore)
             command.apply(metadata_copy, context);
@@ -823,6 +824,7 @@ void AlterCommands::apply(StorageInMemoryMetadata & metadata, const Context & co
 
     /// Changes in columns may lead to changes in TTL expressions.
     auto column_ttl_asts = metadata_copy.columns.getColumnTTLs();
+    metadata_copy.column_ttls_by_name.clear();
     for (const auto & [name, ast] : column_ttl_asts)
     {
         auto new_ttl_entry = TTLDescription::getTTLFromAST(ast, metadata_copy.columns, context, metadata_copy.primary_key);
@@ -830,7 +832,7 @@ void AlterCommands::apply(StorageInMemoryMetadata & metadata, const Context & co
     }
 
     if (metadata_copy.table_ttl.definition_ast != nullptr)
-        metadata.table_ttl = TTLTableDescription::getTTLForTableFromAST(
+        metadata_copy.table_ttl = TTLTableDescription::getTTLForTableFromAST(
             metadata_copy.table_ttl.definition_ast, metadata_copy.columns, context, metadata_copy.primary_key);
 
     metadata = std::move(metadata_copy);

tests/queries/0_stateless/01603_remove_column_ttl.reference

+1	32
+2	0
+CREATE TABLE default.table_with_column_ttl\n(\n    `EventTime` DateTime,\n    `UserID` UInt64,\n    `Age` UInt8\n)\nENGINE = MergeTree\nORDER BY tuple()\nSETTINGS index_granularity = 8192
+1	32
+2	0
+3	27

tests/queries/0_stateless/01603_remove_column_ttl.sql

+DROP TABLE IF EXISTS table_with_column_ttl;
+CREATE TABLE table_with_column_ttl
+(
+    EventTime DateTime,
+    UserID UInt64,
+    Age UInt8 TTL EventTime + INTERVAL 3 MONTH
+)
+ENGINE MergeTree()
+ORDER BY tuple();
+
+INSERT INTO table_with_column_ttl VALUES (now(), 1, 32);
+
+INSERT INTO table_with_column_ttl VALUES (now() - INTERVAL 4 MONTH, 2, 45);
+
+OPTIMIZE TABLE table_with_column_ttl FINAL;
+
+SELECT UserID, Age FROM table_with_column_ttl ORDER BY UserID;
+
+ALTER TABLE table_with_column_ttl MODIFY COLUMN Age REMOVE TTL;
+
+SHOW CREATE TABLE table_with_column_ttl;
+
+INSERT INTO table_with_column_ttl VALUES (now() - INTERVAL 10 MONTH, 3, 27);
+
+OPTIMIZE TABLE table_with_column_ttl FINAL;
+
+SELECT UserID, Age FROM table_with_column_ttl ORDER BY UserID;
+
+DROP TABLE table_with_column_ttl;