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182 lines
7.0 KiB
C++
182 lines
7.0 KiB
C++
#include "inplaceBlockConversions.h"
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#include <Core/Block.h>
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#include <Parsers/queryToString.h>
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#include <Interpreters/TreeRewriter.h>
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#include <Interpreters/ExpressionAnalyzer.h>
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#include <Interpreters/ExpressionActions.h>
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#include <Parsers/ASTExpressionList.h>
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#include <Parsers/ASTWithAlias.h>
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#include <Parsers/ASTIdentifier.h>
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#include <Parsers/ASTLiteral.h>
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#include <Parsers/ASTFunction.h>
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#include <utility>
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#include <DataTypes/DataTypesNumber.h>
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#include <Interpreters/RequiredSourceColumnsVisitor.h>
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#include <Common/checkStackSize.h>
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#include <Storages/ColumnsDescription.h>
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namespace DB
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{
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namespace
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{
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/// Add all required expressions for missing columns calculation
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void addDefaultRequiredExpressionsRecursively(
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const Block & block, const String & required_column_name, DataTypePtr required_column_type,
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const ColumnsDescription & columns, ASTPtr default_expr_list_accum, NameSet & added_columns, bool null_as_default)
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{
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checkStackSize();
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bool is_column_in_query = block.has(required_column_name);
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bool convert_null_to_default = false;
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if (is_column_in_query)
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convert_null_to_default = null_as_default && block.findByName(required_column_name)->type->isNullable() && !required_column_type->isNullable();
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if ((is_column_in_query && !convert_null_to_default) || added_columns.count(required_column_name))
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return;
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auto column_default = columns.getDefault(required_column_name);
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if (column_default)
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{
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/// expressions must be cloned to prevent modification by the ExpressionAnalyzer
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auto column_default_expr = column_default->expression->clone();
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/// Our default may depend on columns with default expr which not present in block
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/// we have to add them to block too
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RequiredSourceColumnsVisitor::Data columns_context;
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RequiredSourceColumnsVisitor(columns_context).visit(column_default_expr);
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NameSet required_columns_names = columns_context.requiredColumns();
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auto expr = makeASTFunction("_CAST", column_default_expr, std::make_shared<ASTLiteral>(columns.get(required_column_name).type->getName()));
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if (is_column_in_query && convert_null_to_default)
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expr = makeASTFunction("ifNull", std::make_shared<ASTIdentifier>(required_column_name), std::move(expr));
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default_expr_list_accum->children.emplace_back(setAlias(expr, required_column_name));
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added_columns.emplace(required_column_name);
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for (const auto & next_required_column_name : required_columns_names)
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{
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/// Required columns of the default expression should not be converted to NULL,
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/// since this map value to default and MATERIALIZED values will not work.
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///
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/// Consider the following structure:
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/// - A Nullable(Int64)
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/// - X Int64 materialized coalesce(A, -1)
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///
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/// With recursive_null_as_default=true you will get:
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///
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/// _CAST(coalesce(A, -1), 'Int64') AS X, NULL AS A
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///
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/// And this will ignore default expression.
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bool recursive_null_as_default = false;
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addDefaultRequiredExpressionsRecursively(block,
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next_required_column_name, required_column_type,
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columns, default_expr_list_accum, added_columns,
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recursive_null_as_default);
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}
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}
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else if (columns.has(required_column_name))
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{
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/// In case of dictGet function we allow to use it with identifier dictGet(identifier, 'column_name', key_expression)
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/// and this identifier will be in required columns. If such column is not in ColumnsDescription we ignore it.
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/// This column is required, but doesn't have default expression, so lets use "default default"
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auto column = columns.get(required_column_name);
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auto default_value = column.type->getDefault();
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auto default_ast = std::make_shared<ASTLiteral>(default_value);
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default_expr_list_accum->children.emplace_back(setAlias(default_ast, required_column_name));
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added_columns.emplace(required_column_name);
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}
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}
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ASTPtr defaultRequiredExpressions(const Block & block, const NamesAndTypesList & required_columns, const ColumnsDescription & columns, bool null_as_default)
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{
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ASTPtr default_expr_list = std::make_shared<ASTExpressionList>();
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NameSet added_columns;
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for (const auto & column : required_columns)
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addDefaultRequiredExpressionsRecursively(block, column.name, column.type, columns, default_expr_list, added_columns, null_as_default);
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if (default_expr_list->children.empty())
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return nullptr;
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return default_expr_list;
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}
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ASTPtr convertRequiredExpressions(Block & block, const NamesAndTypesList & required_columns)
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{
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ASTPtr conversion_expr_list = std::make_shared<ASTExpressionList>();
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for (const auto & required_column : required_columns)
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{
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if (!block.has(required_column.name))
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continue;
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auto column_in_block = block.getByName(required_column.name);
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if (column_in_block.type->equals(*required_column.type))
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continue;
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auto cast_func = makeASTFunction(
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"_CAST", std::make_shared<ASTIdentifier>(required_column.name), std::make_shared<ASTLiteral>(required_column.type->getName()));
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conversion_expr_list->children.emplace_back(setAlias(cast_func, required_column.name));
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}
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return conversion_expr_list;
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}
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ActionsDAGPtr createExpressions(
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const Block & header,
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ASTPtr expr_list,
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bool save_unneeded_columns,
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ContextPtr context)
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{
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if (!expr_list)
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return nullptr;
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auto syntax_result = TreeRewriter(context).analyze(expr_list, header.getNamesAndTypesList());
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auto expression_analyzer = ExpressionAnalyzer{expr_list, syntax_result, context};
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auto dag = std::make_shared<ActionsDAG>(header.getNamesAndTypesList());
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auto actions = expression_analyzer.getActionsDAG(true, !save_unneeded_columns);
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dag = ActionsDAG::merge(std::move(*dag), std::move(*actions));
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return dag;
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}
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}
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void performRequiredConversions(Block & block, const NamesAndTypesList & required_columns, ContextPtr context)
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{
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ASTPtr conversion_expr_list = convertRequiredExpressions(block, required_columns);
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if (conversion_expr_list->children.empty())
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return;
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if (auto dag = createExpressions(block, conversion_expr_list, true, context))
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{
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auto expression = std::make_shared<ExpressionActions>(std::move(dag), ExpressionActionsSettings::fromContext(context));
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expression->execute(block);
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}
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}
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ActionsDAGPtr evaluateMissingDefaults(
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const Block & header,
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const NamesAndTypesList & required_columns,
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const ColumnsDescription & columns,
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ContextPtr context,
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bool save_unneeded_columns,
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bool null_as_default)
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{
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if (!columns.hasDefaults())
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return nullptr;
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ASTPtr expr_list = defaultRequiredExpressions(header, required_columns, columns, null_as_default);
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return createExpressions(header, expr_list, save_unneeded_columns, context);
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}
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}
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