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95 lines
3.5 KiB
C++
95 lines
3.5 KiB
C++
#include <Interpreters/addMissingDefaults.h>
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#include <Common/typeid_cast.h>
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#include <DataTypes/NestedUtils.h>
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#include <DataTypes/DataTypeArray.h>
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#include <Columns/ColumnArray.h>
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#include <Interpreters/inplaceBlockConversions.h>
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#include <Core/Block.h>
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#include <Storages/ColumnsDescription.h>
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#include <Interpreters/ExpressionActions.h>
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#include <Functions/IFunctionAdaptors.h>
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#include <Functions/materialize.h>
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namespace DB
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{
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ActionsDAGPtr addMissingDefaults(
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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 null_as_default)
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{
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auto actions = std::make_shared<ActionsDAG>(header.getColumnsWithTypeAndName());
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auto & index = actions->getIndex();
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/// For missing columns of nested structure, you need to create not a column of empty arrays, but a column of arrays of correct lengths.
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/// First, remember the offset columns for all arrays in the block.
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std::map<String, ActionsDAG::NodeRawConstPtrs> nested_groups;
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for (size_t i = 0, size = header.columns(); i < size; ++i)
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{
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const auto & elem = header.getByPosition(i);
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if (typeid_cast<const ColumnArray *>(&*elem.column))
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{
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String offsets_name = Nested::extractTableName(elem.name);
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auto & group = nested_groups[offsets_name];
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if (group.empty())
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group.push_back(nullptr);
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group.push_back(actions->getInputs()[i]);
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}
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}
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FunctionOverloadResolverPtr func_builder_replicate = FunctionFactory::instance().get("replicate", context);
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/// We take given columns from input block and missed columns without default value
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/// (default and materialized will be computed later).
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for (const auto & column : required_columns)
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{
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if (header.has(column.name))
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continue;
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if (columns.hasDefault(column.name))
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continue;
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String offsets_name = Nested::extractTableName(column.name);
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if (nested_groups.count(offsets_name))
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{
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DataTypePtr nested_type = typeid_cast<const DataTypeArray &>(*column.type).getNestedType();
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ColumnPtr nested_column = nested_type->createColumnConstWithDefaultValue(0);
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const auto & constant = actions->addColumn({std::move(nested_column), nested_type, column.name});
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auto & group = nested_groups[offsets_name];
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group[0] = &constant;
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index.push_back(&actions->addFunction(func_builder_replicate, group, constant.result_name));
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continue;
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}
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/** It is necessary to turn a constant column into a full column, since in part of blocks (from other parts),
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* it can be full (or the interpreter may decide that it is constant everywhere).
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*/
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auto new_column = column.type->createColumnConstWithDefaultValue(0);
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const auto * col = &actions->addColumn({std::move(new_column), column.type, column.name});
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index.push_back(&actions->materializeNode(*col));
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}
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/// Computes explicitly specified values by default and materialized columns.
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if (auto dag = evaluateMissingDefaults(actions->getResultColumns(), required_columns, columns, context, true, null_as_default))
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actions = ActionsDAG::merge(std::move(*actions), std::move(*dag));
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else
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/// Removes unused columns and reorders result.
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/// The same is done in evaluateMissingDefaults if not empty dag is returned.
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actions->removeUnusedActions(required_columns.getNames());
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return actions;
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}
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}
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