Merge pull request #31062 from Enmk/Governance/view_comment

Views with comment

src/Parsers/ASTCreateQuery.cpp

@@ -427,8 +427,11 @@ void ASTCreateQuery::formatQueryImpl(const FormatSettings & settings, FormatStat
 
     if (select)
     {
-        settings.ostr << (settings.hilite ? hilite_keyword : "") << " AS" << settings.nl_or_ws << (settings.hilite ? hilite_none : "");
+        settings.ostr << (settings.hilite ? hilite_keyword : "") << " AS"
+                      << (comment ? "(" : "")
+                      << settings.nl_or_ws << (settings.hilite ? hilite_none : "");
         select->formatImpl(settings, state, frame);
+        settings.ostr << (comment ? ")" : "");
     }
 
     if (tables)

src/Parsers/ParserCreateQuery.cpp

@@ -747,6 +747,7 @@ bool ParserCreateLiveViewQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & e
     if (!select_p.parse(pos, select, expected))
         return false;
 
+    auto comment = parseComment(pos, expected);
 
     auto query = std::make_shared<ASTCreateQuery>();
     node = query;
@@ -781,6 +782,9 @@ bool ParserCreateLiveViewQuery::parseImpl(Pos & pos, ASTPtr & node, Expected & e
     if (live_view_periodic_refresh)
         query->live_view_periodic_refresh.emplace(live_view_periodic_refresh->as<ASTLiteral &>().value.safeGet<UInt64>());
 
+    if (comment)
+        query->set(query->comment, comment);
+
     return true;
 }
 

src/Storages/LiveView/StorageLiveView.cpp

@@ -280,7 +280,8 @@ StorageLiveView::StorageLiveView(
     const StorageID & table_id_,
     ContextPtr context_,
     const ASTCreateQuery & query,
-    const ColumnsDescription & columns_)
+    const ColumnsDescription & columns_,
+    const String & comment)
     : IStorage(table_id_)
     , WithContext(context_->getGlobalContext())
 {
@@ -291,6 +292,9 @@ StorageLiveView::StorageLiveView(
 
     StorageInMemoryMetadata storage_metadata;
     storage_metadata.setColumns(columns_);
+    if (!comment.empty())
+        storage_metadata.setComment(comment);
+
     setInMemoryMetadata(storage_metadata);
 
     if (!query.select)
@@ -621,7 +625,7 @@ void registerStorageLiveView(StorageFactory & factory)
                 "Experimental LIVE VIEW feature is not enabled (the setting 'allow_experimental_live_view')",
                 ErrorCodes::SUPPORT_IS_DISABLED);
 
-        return StorageLiveView::create(args.table_id, args.getLocalContext(), args.query, args.columns);
+        return StorageLiveView::create(args.table_id, args.getLocalContext(), args.query, args.columns, args.comment);
     });
 }
 

src/Storages/LiveView/StorageLiveView.h

@@ -233,7 +233,7 @@ private:
         ContextPtr context_,
         const ASTCreateQuery & query,
         const ColumnsDescription & columns
-    );
+    , const String & comment);
 };
 
 }

src/Storages/StorageFactory.cpp

@@ -156,9 +156,6 @@ StoragePtr StorageFactory::get(
                     throw Exception("Unknown table engine " + name, ErrorCodes::UNKNOWN_STORAGE);
             }
 
-            if (query.comment)
-                comment = query.comment->as<ASTLiteral &>().value.get<String>();
-
             auto check_feature = [&](String feature_description, FeatureMatcherFn feature_matcher_fn)
             {
                 if (!feature_matcher_fn(it->second.features))
@@ -204,6 +201,9 @@ StoragePtr StorageFactory::get(
         }
     }
 
+    if (query.comment)
+        comment = query.comment->as<ASTLiteral &>().value.get<String>();
+
     ASTs empty_engine_args;
     Arguments arguments{
         .engine_name = name,

src/Storages/StorageMaterializedView.cpp

@@ -60,7 +60,8 @@ StorageMaterializedView::StorageMaterializedView(
     ContextPtr local_context,
     const ASTCreateQuery & query,
     const ColumnsDescription & columns_,
-    bool attach_)
+    bool attach_,
+    const String & comment)
     : IStorage(table_id_), WithMutableContext(local_context->getGlobalContext())
 {
     StorageInMemoryMetadata storage_metadata;
@@ -81,6 +82,9 @@ StorageMaterializedView::StorageMaterializedView(
 
     auto select = SelectQueryDescription::getSelectQueryFromASTForMatView(query.select->clone(), local_context);
     storage_metadata.setSelectQuery(select);
+    if (!comment.empty())
+        storage_metadata.setComment(comment);
+
     setInMemoryMetadata(storage_metadata);
 
     bool point_to_itself_by_uuid = has_inner_table && query.to_inner_uuid != UUIDHelpers::Nil
@@ -432,7 +436,7 @@ void registerStorageMaterializedView(StorageFactory & factory)
         /// Pass local_context here to convey setting for inner table
         return StorageMaterializedView::create(
             args.table_id, args.getLocalContext(), args.query,
-            args.columns, args.attach);
+            args.columns, args.attach, args.comment);
     });
 }
 

src/Storages/StorageMaterializedView.h

@@ -108,7 +108,8 @@ protected:
         ContextPtr local_context,
         const ASTCreateQuery & query,
         const ColumnsDescription & columns_,
-        bool attach_);
+        bool attach_,
+        const String & comment);
 };
 
 }

tests/queries/0_stateless/02048_views_with_comment.reference

@@ -0,0 +1,3 @@
+live_view_comment_test	LiveView	live view
+materialized_view_comment_test	MaterializedView	materialized view
+view_comment_test	View	simple view

tests/queries/0_stateless/02048_views_with_comment.sql

@@ -0,0 +1,12 @@
+-- Make sure that any kind of `VIEW` can be created with a `COMMENT` clause
+-- and value of that clause is visible as `comment` column of `system.tables` table.
+
+CREATE VIEW view_comment_test AS (SELECT 1) COMMENT 'simple view';
+CREATE MATERIALIZED VIEW materialized_view_comment_test TO test1 (a UInt64) AS (SELECT 1) COMMENT 'materialized view';
+
+SET allow_experimental_live_view=1;
+CREATE LIVE VIEW live_view_comment_test AS (SELECT 1) COMMENT 'live view';
+
+SYSTEM FLUSH LOGS;
+
+SELECT name, engine, comment FROM system.tables WHERE database == currentDatabase() ORDER BY name;