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102 lines
3.5 KiB
C++
102 lines
3.5 KiB
C++
#include "evaluateMissingDefaults.h"
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#include <Core/Block.h>
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#include <Storages/ColumnDefault.h>
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#include <Interpreters/SyntaxAnalyzer.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 <utility>
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#include <DataTypes/DataTypesNumber.h>
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namespace DB
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{
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static ASTPtr requiredExpressions(Block & block, const NamesAndTypesList & required_columns, const ColumnDefaults & column_defaults)
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{
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ASTPtr default_expr_list = std::make_shared<ASTExpressionList>();
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for (const auto & column : required_columns)
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{
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if (block.has(column.name))
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continue;
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const auto it = column_defaults.find(column.name);
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/// expressions must be cloned to prevent modification by the ExpressionAnalyzer
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if (it != column_defaults.end())
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default_expr_list->children.emplace_back(
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setAlias(it->second.expression->clone(), it->first));
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}
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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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void evaluateMissingDefaults(Block & block,
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const NamesAndTypesList & required_columns,
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const ColumnDefaults & column_defaults,
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const Context & context, bool save_unneeded_columns)
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{
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if (column_defaults.empty())
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return;
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ASTPtr default_expr_list = requiredExpressions(block, required_columns, column_defaults);
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if (!default_expr_list)
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return;
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if (!save_unneeded_columns)
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{
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auto syntax_result = SyntaxAnalyzer(context).analyze(default_expr_list, block.getNamesAndTypesList());
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ExpressionAnalyzer{default_expr_list, syntax_result, context}.getActions(true)->execute(block);
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return;
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}
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/** ExpressionAnalyzer eliminates "unused" columns, in order to ensure their safety
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* we are going to operate on a copy instead of the original block */
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Block copy_block{block};
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auto syntax_result = SyntaxAnalyzer(context).analyze(default_expr_list, block.getNamesAndTypesList());
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auto expression_analyzer = ExpressionAnalyzer{default_expr_list, syntax_result, context};
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auto required_source_columns = syntax_result->requiredSourceColumns();
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auto rows_was = copy_block.rows();
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// Delete all not needed columns in DEFAULT expression.
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// They can intersect with columns added in PREWHERE
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// test 00950_default_prewhere
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// CLICKHOUSE-4523
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for (const auto & delete_column : copy_block.getNamesAndTypesList())
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{
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if (std::find(required_source_columns.begin(), required_source_columns.end(), delete_column.name) == required_source_columns.end())
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{
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copy_block.erase(delete_column.name);
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}
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}
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if (copy_block.columns() == 0)
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{
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// Add column to indicate block size in execute()
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copy_block.insert({DataTypeUInt8().createColumnConst(rows_was, 0u), std::make_shared<DataTypeUInt8>(), "__dummy"});
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}
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expression_analyzer.getActions(true)->execute(copy_block);
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/// move evaluated columns to the original block, materializing them at the same time
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size_t pos = 0;
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for (auto col = required_columns.begin(); col != required_columns.end(); ++col, ++pos)
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{
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if (copy_block.has(col->name))
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{
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auto evaluated_col = copy_block.getByName(col->name);
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evaluated_col.column = evaluated_col.column->convertToFullColumnIfConst();
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block.insert(pos, std::move(evaluated_col));
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}
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}
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}
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}
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