JoinedTables related changes

dbms/src/Interpreters/DatabaseAndTableWithAlias.h

@@ -48,11 +48,11 @@ struct TableWithColumnNames
         , columns(columns_)
     {}
 
-    void addHiddenColumns(const NamesAndTypesList & addition)
-    {
-        for (auto & column : addition)
-            hidden_columns.push_back(column.name);
-    }
+    TableWithColumnNames(const DatabaseAndTableWithAlias table_, Names && columns_, Names && hidden_columns_)
+        : table(table_)
+        , columns(columns_)
+        , hidden_columns(hidden_columns_)
+    {}
 
     bool hasColumn(const String & name) const
     {
@@ -69,9 +69,42 @@ struct TableWithColumnNames
     mutable NameSet columns_set;
 };
 
+struct TableWithColumnNamesAndTypes
+{
+    DatabaseAndTableWithAlias table;
+    NamesAndTypesList columns;
+    NamesAndTypesList hidden_columns;
+
+    TableWithColumnNamesAndTypes(const DatabaseAndTableWithAlias & table_, const NamesAndTypesList & columns_)
+        : table(table_)
+        , columns(columns_)
+    {}
+
+    void addHiddenColumns(const NamesAndTypesList & addition)
+    {
+        hidden_columns.insert(hidden_columns.end(), addition.begin(), addition.end());
+    }
+
+    TableWithColumnNames removeTypes() const
+    {
+        Names out_columns;
+        out_columns.reserve(columns.size());
+        for (auto & col : columns)
+            out_columns.push_back(col.name);
+
+        Names out_hidden_columns;
+        out_hidden_columns.reserve(hidden_columns.size());
+        for (auto & col : hidden_columns)
+            out_hidden_columns.push_back(col.name);
+
+        return TableWithColumnNames(table, std::move(out_columns), std::move(out_hidden_columns));
+    }
+};
+
 std::vector<DatabaseAndTableWithAlias> getDatabaseAndTables(const ASTSelectQuery & select_query, const String & current_database);
 std::optional<DatabaseAndTableWithAlias> getDatabaseAndTable(const ASTSelectQuery & select, size_t table_number);
 
 using TablesWithColumnNames = std::vector<TableWithColumnNames>;
+using TablesWithColumnNamesAndTypes = std::vector<TableWithColumnNames>;
 
 }

dbms/src/Interpreters/InterpreterSelectQuery.cpp

@@ -56,7 +56,6 @@
 #include <Storages/MergeTree/MergeTreeData.h>
 #include <Storages/MergeTree/MergeTreeWhereOptimizer.h>
 #include <Storages/IStorage.h>
-#include <Storages/StorageValues.h>
 
 #include <TableFunctions/ITableFunction.h>
 #include <TableFunctions/TableFunctionFactory.h>
@@ -236,25 +235,22 @@ InterpreterSelectQuery::InterpreterSelectQuery(
         throw Exception("Too deep subqueries. Maximum: " + settings.max_subquery_depth.toString(),
             ErrorCodes::TOO_DEEP_SUBQUERIES);
 
-    CrossToInnerJoinVisitor::Data cross_to_inner;
-    CrossToInnerJoinVisitor(cross_to_inner).visit(query_ptr);
+    JoinedTables joined_tables(getSelectQuery());
+    if (joined_tables.hasJoins())
+    {
+        CrossToInnerJoinVisitor::Data cross_to_inner;
+        CrossToInnerJoinVisitor(cross_to_inner).visit(query_ptr);
 
-    JoinToSubqueryTransformVisitor::Data join_to_subs_data{*context};
-    JoinToSubqueryTransformVisitor(join_to_subs_data).visit(query_ptr);
+        JoinToSubqueryTransformVisitor::Data join_to_subs_data{*context};
+        JoinToSubqueryTransformVisitor(join_to_subs_data).visit(query_ptr);
 
-    max_streams = settings.max_threads;
-    auto & query = getSelectQuery();
+        joined_tables.reset(getSelectQuery());
+    }
 
-    ASTPtr table_expression = extractTableExpression(query, 0);
-    String database_name, table_name;
+    max_streams = settings.max_threads;
+    ASTSelectQuery & query = getSelectQuery();
 
-    bool is_table_func = false;
-    bool is_subquery = false;
-    if (table_expression)
-    {
-        is_table_func = table_expression->as<ASTFunction>();
-        is_subquery = table_expression->as<ASTSelectWithUnionQuery>();
-    }
+    const ASTPtr & left_table_expression = joined_tables.leftTableExpression();
 
     if (input)
     {
@@ -266,55 +262,35 @@ InterpreterSelectQuery::InterpreterSelectQuery(
         /// Read from prepared input.
         source_header = input_pipe->getHeader();
     }
-    else if (is_subquery)
+    else if (joined_tables.isLeftTableSubquery())
     {
         /// Read from subquery.
         interpreter_subquery = std::make_unique<InterpreterSelectWithUnionQuery>(
-            table_expression, getSubqueryContext(*context), options.subquery(), required_columns);
+            left_table_expression, getSubqueryContext(*context), options.subquery(), required_columns);
 
         source_header = interpreter_subquery->getSampleBlock();
     }
     else if (!storage)
     {
-        if (is_table_func)
+        if (joined_tables.isLeftTableFunction())
         {
             /// Read from table function. propagate all settings from initSettings(),
             /// alternative is to call on current `context`, but that can potentially pollute it.
-            storage = getSubqueryContext(*context).executeTableFunction(table_expression);
+            storage = getSubqueryContext(*context).executeTableFunction(left_table_expression);
         }
         else
-        {
-            getDatabaseAndTableNames(query, database_name, table_name, *context);
-
-            if (auto view_source = context->getViewSource())
-            {
-                auto & storage_values = static_cast<const StorageValues &>(*view_source);
-                auto tmp_table_id = storage_values.getStorageID();
-                if (tmp_table_id.database_name == database_name && tmp_table_id.table_name == table_name)
-                {
-                    /// Read from view source.
-                    storage = context->getViewSource();
-                }
-            }
-
-            if (!storage)
-            {
-                /// Read from table. Even without table expression (implicit SELECT ... FROM system.one).
-                storage = context->getTable(database_name, table_name);
-            }
-        }
+            storage = joined_tables.getLeftTableStorage(*context);
     }
 
     if (storage)
     {
         table_lock = storage->lockStructureForShare(false, context->getInitialQueryId());
         table_id = storage->getStorageID();
-    }
 
-    /// Extract joined tables colunms if any.
-    /// It could get storage from context without lockStructureForShare(). TODO: add lock there or rewrite this logic.
-    JoinedTables joined_tables;
-    joined_tables.resolveTables(*query_ptr->as<ASTSelectQuery>(), storage, *context, source_header.getNamesAndTypesList());
+        joined_tables.resolveTables(getSubqueryContext(*context), storage);
+    }
+    else
+        joined_tables.resolveTables(getSubqueryContext(*context), source_header.getNamesAndTypesList());
 
     auto analyze = [&] (bool try_move_to_prewhere = true)
     {
@@ -353,9 +329,9 @@ InterpreterSelectQuery::InterpreterSelectQuery(
             if (syntax_analyzer_result->rewrite_subqueries)
             {
                 /// remake interpreter_subquery when PredicateOptimizer rewrites subqueries and main table is subquery
-                if (is_subquery)
+                if (joined_tables.isLeftTableSubquery())
                     interpreter_subquery = std::make_unique<InterpreterSelectWithUnionQuery>(
-                            table_expression,
+                            left_table_expression,
                             getSubqueryContext(*context),
                             options.subquery(),
                             required_columns);
@@ -430,6 +406,9 @@ InterpreterSelectQuery::InterpreterSelectQuery(
     if (query.prewhere() && !query.where())
         analysis_result.prewhere_info->need_filter = true;
 
+    const String & database_name = joined_tables.leftTableDatabase();
+    const String & table_name = joined_tables.leftTableName();
+
     if (!table_name.empty() && !database_name.empty() /* always allow access to temporary tables */)
         context->checkAccess(AccessType::SELECT, database_name, table_name, required_columns);
 
@@ -447,25 +426,6 @@ InterpreterSelectQuery::InterpreterSelectQuery(
 }
 
 
-void InterpreterSelectQuery::getDatabaseAndTableNames(const ASTSelectQuery & query, String & database_name, String & table_name, const Context & context)
-{
-    if (auto db_and_table = getDatabaseAndTable(query, 0))
-    {
-        table_name = db_and_table->table;
-        database_name = db_and_table->database;
-
-        /// If the database is not specified - use the current database.
-        if (database_name.empty() && !context.isExternalTableExist(table_name))
-            database_name = context.getCurrentDatabase();
-    }
-    else /// If the table is not specified - use the table `system.one`.
-    {
-        database_name = "system";
-        table_name = "one";
-    }
-}
-
-
 Block InterpreterSelectQuery::getSampleBlock()
 {
     return result_header;

dbms/src/Interpreters/InterpreterSelectQuery.h

@@ -152,10 +152,6 @@ class InterpreterSelectQuery : public IInterpreter
     template <typename TPipeline>
     void executeImpl(TPipeline & pipeline, const BlockInputStreamPtr & prepared_input, std::optional<Pipe> prepared_pipe, QueryPipeline & save_context_and_storage);
 
-    /** From which table to read. With JOIN, the "left" table is returned.
-     */
-    static void getDatabaseAndTableNames(const ASTSelectQuery & query, String & database_name, String & table_name, const Context & context);
-
     /// Different stages of query execution.
 
     /// dry_run - don't read from table, use empty header block instead.

dbms/src/Interpreters/JoinedTables.cpp

@@ -3,6 +3,9 @@
 #include <Interpreters/getTableExpressions.h>
 #include <Storages/IStorage.h>
 #include <Storages/ColumnsDescription.h>
+#include <Storages/StorageValues.h>
+#include <Parsers/ASTFunction.h>
+#include <Parsers/ASTSelectWithUnionQuery.h>
 
 namespace DB
 {
@@ -15,61 +18,107 @@ namespace ErrorCodes
 namespace
 {
 
-std::vector<TableWithColumnNames> getTablesWithColumns(const std::vector<const ASTTableExpression * > & table_expressions,
-                                                const Context & context)
+template <typename T>
+void checkTablesWithColumns(const std::vector<T> & tables_with_columns, const Context & context)
 {
-    std::vector<TableWithColumnNames> tables_with_columns = getDatabaseAndTablesWithColumnNames(table_expressions, context);
-
     auto & settings = context.getSettingsRef();
     if (settings.joined_subquery_requires_alias && tables_with_columns.size() > 1)
     {
-        for (auto & pr : tables_with_columns)
-            if (pr.table.table.empty() && pr.table.alias.empty())
+        for (auto & t : tables_with_columns)
+            if (t.table.table.empty() && t.table.alias.empty())
                 throw Exception("No alias for subquery or table function in JOIN (set joined_subquery_requires_alias=0 to disable restriction).",
                                 ErrorCodes::ALIAS_REQUIRED);
     }
+}
 
-    return tables_with_columns;
 }
 
+JoinedTables::JoinedTables(const ASTSelectQuery & select_query)
+    : table_expressions(getTableExpressions(select_query))
+    , left_table_expression(extractTableExpression(select_query, 0))
+    , left_db_and_table(getDatabaseAndTable(select_query, 0))
+{}
+
+bool JoinedTables::isLeftTableSubquery() const
+{
+    return left_table_expression && left_table_expression->as<ASTSelectWithUnionQuery>();
 }
 
+bool JoinedTables::isLeftTableFunction() const
+{
+    return left_table_expression && left_table_expression->as<ASTFunction>();
+}
 
-void JoinedTables::resolveTables(const ASTSelectQuery & select_query, StoragePtr storage, const Context & context,
-                                 const NamesAndTypesList & source_columns)
+StoragePtr JoinedTables::getLeftTableStorage(Context & context)
 {
+    StoragePtr storage;
+
+    if (left_db_and_table)
+    {
+        database_name = left_db_and_table->database;
+        table_name = left_db_and_table->table;
+
+        /// If the database is not specified - use the current database.
+        if (database_name.empty() && !context.isExternalTableExist(table_name))
+            database_name = context.getCurrentDatabase();
+    }
+    else /// If the table is not specified - use the table `system.one`.
+    {
+        database_name = "system";
+        table_name = "one";
+    }
+
+    if (auto view_source = context.getViewSource())
+    {
+        auto & storage_values = static_cast<const StorageValues &>(*view_source);
+        auto tmp_table_id = storage_values.getStorageID();
+        if (tmp_table_id.database_name == database_name && tmp_table_id.table_name == table_name)
+        {
+            /// Read from view source.
+            storage = context.getViewSource();
+        }
+    }
+
     if (!storage)
     {
-        if (auto db_and_table = getDatabaseAndTable(select_query, 0))
-            storage = context.tryGetTable(db_and_table->database, db_and_table->table);
+        /// Read from table. Even without table expression (implicit SELECT ... FROM system.one).
+        storage = context.getTable(database_name, table_name);
     }
 
-    std::vector<const ASTTableExpression *> table_expressions = getTableExpressions(select_query);
-    tables_with_columns = getTablesWithColumns(table_expressions, context);
+    return storage;
+}
+
+const NamesAndTypesList & JoinedTables::secondTableColumns() const
+{
+    static const NamesAndTypesList empty;
+    if (tables_with_columns.size() > 1)
+        return tables_with_columns[1].columns;
+    return empty;
+}
+
+void JoinedTables::resolveTables(const Context & context, StoragePtr storage)
+{
+    tables_with_columns = getDatabaseAndTablesWithColumns(table_expressions, context);
+    checkTablesWithColumns(tables_with_columns, context);
 
     if (tables_with_columns.empty())
     {
-        if (storage)
-        {
-            const ColumnsDescription & storage_columns = storage->getColumns();
-            tables_with_columns.emplace_back(DatabaseAndTableWithAlias{}, storage_columns.getOrdinary().getNames());
-            auto & table = tables_with_columns.back();
-            table.addHiddenColumns(storage_columns.getMaterialized());
-            table.addHiddenColumns(storage_columns.getAliases());
-            table.addHiddenColumns(storage_columns.getVirtuals());
-        }
-        else
-        {
-            Names columns;
-            columns.reserve(source_columns.size());
-            for (const auto & column : source_columns)
-                columns.push_back(column.name);
-            tables_with_columns.emplace_back(DatabaseAndTableWithAlias{}, columns);
-        }
+        const ColumnsDescription & storage_columns = storage->getColumns();
+        tables_with_columns.emplace_back(DatabaseAndTableWithAlias{}, storage_columns.getOrdinary());
+        auto & table = tables_with_columns.back();
+        table.addHiddenColumns(storage_columns.getMaterialized());
+        table.addHiddenColumns(storage_columns.getAliases());
+        table.addHiddenColumns(storage_columns.getVirtuals());
     }
+}
+
+void JoinedTables::resolveTables(const Context & context, const NamesAndTypesList & source_columns)
+{
+    tables_with_columns = getDatabaseAndTablesWithColumns(table_expressions, context);
+    checkTablesWithColumns(tables_with_columns, context);
 
-    if (table_expressions.size() > 1)
-        columns_from_joined_table = getColumnsFromTableExpression(*table_expressions[1], context);
+    if (tables_with_columns.empty())
+        tables_with_columns.emplace_back(DatabaseAndTableWithAlias{}, source_columns);
 }
 
 }