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92 lines
3.1 KiB
C++
92 lines
3.1 KiB
C++
#include <DataStreams/AddingDefaultBlockOutputStream.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/evaluateMissingDefaults.h>
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#include <Core/Block.h>
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namespace DB
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{
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void AddingDefaultBlockOutputStream::write(const Block & block)
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{
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Block res = block;
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/// Adds not specified default values.
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size_t rows = res.rows();
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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, ColumnPtr> offset_columns;
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for (size_t i = 0, size = res.columns(); i < size; ++i)
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{
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const auto & elem = res.getByPosition(i);
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if (const ColumnArray * array = 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 & offsets_column = offset_columns[offsets_name];
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/// If for some reason there are different offset columns for one nested structure, then we take nonempty.
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if (!offsets_column || offsets_column->empty())
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offsets_column = array->getOffsetsPtr();
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}
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}
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for (const auto & requested_column : required_columns)
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{
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if (res.has(requested_column.name) || column_defaults.count(requested_column.name))
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continue;
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ColumnWithTypeAndName column_to_add;
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column_to_add.name = requested_column.name;
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column_to_add.type = requested_column.type;
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String offsets_name = Nested::extractTableName(column_to_add.name);
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if (offset_columns.count(offsets_name))
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{
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ColumnPtr offsets_column = offset_columns[offsets_name];
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DataTypePtr nested_type = typeid_cast<const DataTypeArray &>(*column_to_add.type).getNestedType();
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UInt64 nested_rows = rows ? get<UInt64>((*offsets_column)[rows - 1]) : 0;
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ColumnPtr nested_column = nested_type->createColumnConstWithDefaultValue(nested_rows)->convertToFullColumnIfConst();
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column_to_add.column = ColumnArray::create(nested_column, offsets_column);
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}
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else
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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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column_to_add.column = column_to_add.type->createColumnConstWithDefaultValue(rows)->convertToFullColumnIfConst();
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}
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res.insert(std::move(column_to_add));
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}
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/// Computes explicitly specified values (in column_defaults) by default.
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evaluateMissingDefaults(res, required_columns, column_defaults, context);
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output->write(res);
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}
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void AddingDefaultBlockOutputStream::flush()
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{
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output->flush();
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}
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void AddingDefaultBlockOutputStream::writePrefix()
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{
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output->writePrefix();
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}
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void AddingDefaultBlockOutputStream::writeSuffix()
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{
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output->writeSuffix();
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}
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}
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