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356 lines
14 KiB
C++
356 lines
14 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 <DataTypes/ObjectUtils.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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#include <DataTypes/NestedUtils.h>
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#include <Columns/ColumnArray.h>
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#include <DataTypes/DataTypeArray.h>
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#include <Storages/StorageInMemoryMetadata.h>
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#include <Storages/BlockNumberColumn.h>
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namespace DB
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{
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namespace ErrorCode
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{
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extern const int LOGICAL_ERROR;
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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 && isNullableOrLowCardinalityNullable(block.findByName(required_column_name)->type) && !isNullableOrLowCardinalityNullable(required_column_type);
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if ((is_column_in_query && !convert_null_to_default) || added_columns.contains(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 required_type = std::make_shared<ASTLiteral>(columns.get(required_column_name).type->getName());
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auto expr = makeASTFunction("_CAST", column_default_expr, required_type);
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if (is_column_in_query && convert_null_to_default)
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{
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expr = makeASTFunction("ifNull", std::make_shared<ASTIdentifier>(required_column_name), std::move(expr));
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/// ifNull does not respect LowCardinality.
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/// It may be fixed later or re-implemented properly for identical types.
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expr = makeASTFunction("_CAST", std::move(expr), required_type);
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}
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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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const auto & column = columns.get(required_column_name);
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auto default_value = column.type->getDefault();
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ASTPtr expr = std::make_shared<ASTLiteral>(default_value);
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if (is_column_in_query && convert_null_to_default)
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{
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/// We should CAST default value to required type, otherwise the result of ifNull function can be different type.
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auto cast_expr = makeASTFunction("_CAST", std::move(expr), std::make_shared<ASTLiteral>(columns.get(required_column_name).type->getName()));
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expr = makeASTFunction("ifNull", std::make_shared<ASTIdentifier>(required_column_name), std::move(cast_expr));
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}
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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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}
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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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bool needConvertAnyNullToDefault(const Block & header, const NamesAndTypesList & required_columns, const ColumnsDescription & columns)
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{
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for (const auto & required_column : required_columns)
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{
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if (columns.has(required_column.name) && isNullableOrLowCardinalityNullable(header.findByName(required_column.name)->type) && !isNullableOrLowCardinalityNullable(required_column.type))
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return true;
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}
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return false;
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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() && (!null_as_default || !needConvertAnyNullToDefault(header, required_columns, columns)))
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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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static std::unordered_map<String, ColumnPtr> collectOffsetsColumns(
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const NamesAndTypesList & available_columns, const Columns & res_columns)
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{
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std::unordered_map<String, ColumnPtr> offsets_columns;
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auto available_column = available_columns.begin();
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for (size_t i = 0; i < available_columns.size(); ++i, ++available_column)
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{
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if (res_columns[i] == nullptr || isColumnConst(*res_columns[i]))
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continue;
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auto serialization = IDataType::getSerialization(*available_column);
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serialization->enumerateStreams([&](const auto & subpath)
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{
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if (subpath.empty() || subpath.back().type != ISerialization::Substream::ArraySizes)
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return;
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auto stream_name = ISerialization::getFileNameForStream(*available_column, subpath);
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const auto & current_offsets_column = subpath.back().data.column;
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/// If for some reason multiple offsets columns are present
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/// for the same nested data structure, choose the one that is not empty.
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if (current_offsets_column && !current_offsets_column->empty())
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{
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auto & offsets_column = offsets_columns[stream_name];
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if (!offsets_column)
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offsets_column = current_offsets_column;
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#ifndef NDEBUG
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const auto & offsets_data = assert_cast<const ColumnUInt64 &>(*offsets_column).getData();
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const auto & current_offsets_data = assert_cast<const ColumnUInt64 &>(*current_offsets_column).getData();
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if (offsets_data != current_offsets_data)
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throw Exception(ErrorCodes::LOGICAL_ERROR,
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"Found non-equal columns with offsets (sizes: {} and {}) for stream {}",
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offsets_data.size(), current_offsets_data.size(), stream_name);
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#endif
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}
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}, available_column->type, res_columns[i]);
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}
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return offsets_columns;
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}
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void fillMissingColumns(
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Columns & res_columns,
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size_t num_rows,
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const NamesAndTypesList & requested_columns,
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const NamesAndTypesList & available_columns,
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const NameSet & partially_read_columns,
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StorageMetadataPtr metadata_snapshot, size_t block_number)
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{
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size_t num_columns = requested_columns.size();
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if (num_columns != res_columns.size())
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throw Exception(ErrorCodes::LOGICAL_ERROR,
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"Invalid number of columns passed to fillMissingColumns. Expected {}, got {}",
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num_columns, res_columns.size());
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/// For a missing column of a nested data structure
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/// we must create not a column of empty arrays,
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/// but a column of arrays of correct length.
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/// First, collect offset columns for all arrays in the block.
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auto offsets_columns = collectOffsetsColumns(available_columns, res_columns);
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/// Insert default values only for columns without default expressions.
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auto requested_column = requested_columns.begin();
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for (size_t i = 0; i < num_columns; ++i, ++requested_column)
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{
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const auto & [name, type] = *requested_column;
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if (res_columns[i] && partially_read_columns.contains(name))
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res_columns[i] = nullptr;
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if (res_columns[i])
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continue;
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if (metadata_snapshot && metadata_snapshot->getColumns().hasDefault(name))
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continue;
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std::vector<ColumnPtr> current_offsets;
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size_t num_dimensions = 0;
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const auto * array_type = typeid_cast<const DataTypeArray *>(type.get());
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if (array_type && !offsets_columns.empty())
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{
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num_dimensions = getNumberOfDimensions(*array_type);
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current_offsets.resize(num_dimensions);
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auto serialization = IDataType::getSerialization(*requested_column);
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serialization->enumerateStreams([&](const auto & subpath)
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{
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if (subpath.empty() || subpath.back().type != ISerialization::Substream::ArraySizes)
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return;
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size_t level = ISerialization::getArrayLevel(subpath);
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/// It can happen if element of Array is Map.
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if (level >= num_dimensions)
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return;
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auto stream_name = ISerialization::getFileNameForStream(*requested_column, subpath);
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auto it = offsets_columns.find(stream_name);
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if (it != offsets_columns.end())
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current_offsets[level] = it->second;
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});
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for (size_t j = 0; j < num_dimensions; ++j)
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{
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if (!current_offsets[j])
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{
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current_offsets.resize(j);
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break;
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}
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}
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}
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if (!current_offsets.empty())
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{
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size_t num_empty_dimensions = num_dimensions - current_offsets.size();
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auto scalar_type = createArrayOfType(getBaseTypeOfArray(type), num_empty_dimensions);
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size_t data_size = assert_cast<const ColumnUInt64 &>(*current_offsets.back()).getData().back();
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res_columns[i] = scalar_type->createColumnConstWithDefaultValue(data_size)->convertToFullColumnIfConst();
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for (auto it = current_offsets.rbegin(); it != current_offsets.rend(); ++it)
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res_columns[i] = ColumnArray::create(res_columns[i], *it);
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}
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else
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{
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if (requested_column->name == BlockNumberColumn::name)
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res_columns[i] = type->createColumnConst(num_rows, block_number)->convertToFullColumnIfConst();
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else
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/// We must turn a constant column into a full column because the interpreter could infer
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/// that it is constant everywhere but in some blocks (from other parts) it can be a full column.
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res_columns[i] = type->createColumnConstWithDefaultValue(num_rows)->convertToFullColumnIfConst();
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}
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}
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}
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}
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