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96 lines
3.2 KiB
C++
96 lines
3.2 KiB
C++
#include <Common/OptimizedRegularExpression.h>
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#include <Common/typeid_cast.h>
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#include <Storages/StorageMerge.h>
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#include <Parsers/ASTLiteral.h>
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#include <Parsers/ASTFunction.h>
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#include <TableFunctions/ITableFunction.h>
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#include <Interpreters/evaluateConstantExpression.h>
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#include <Interpreters/Context.h>
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#include <TableFunctions/TableFunctionMerge.h>
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#include <TableFunctions/TableFunctionFactory.h>
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#include <TableFunctions/registerTableFunctions.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int UNKNOWN_TABLE;
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}
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static NamesAndTypesList chooseColumns(const String & source_database, const String & table_name_regexp_, const Context & context)
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{
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OptimizedRegularExpression table_name_regexp(table_name_regexp_);
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auto table_name_match = [&](const String & table_name) { return table_name_regexp.match(table_name); };
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StoragePtr any_table;
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{
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auto database = DatabaseCatalog::instance().getDatabase(source_database);
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auto iterator = database->getTablesIterator(context, table_name_match);
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if (iterator->isValid())
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if (const auto & table = iterator->table())
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any_table = table;
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}
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if (!any_table)
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throw Exception("Error while executing table function merge. In database " + source_database + " no one matches regular expression: "
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+ table_name_regexp_, ErrorCodes::UNKNOWN_TABLE);
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return any_table->getInMemoryMetadataPtr()->getColumns().getAllPhysical();
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}
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void TableFunctionMerge::parseArguments(const ASTPtr & ast_function, const Context & context)
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{
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ASTs & args_func = ast_function->children;
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if (args_func.size() != 1)
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throw Exception("Table function 'merge' requires exactly 2 arguments"
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" - name of source database and regexp for table names.",
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ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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ASTs & args = args_func.at(0)->children;
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if (args.size() != 2)
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throw Exception("Table function 'merge' requires exactly 2 arguments"
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" - name of source database and regexp for table names.",
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ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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args[0] = evaluateConstantExpressionForDatabaseName(args[0], context);
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args[1] = evaluateConstantExpressionAsLiteral(args[1], context);
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source_database = args[0]->as<ASTLiteral &>().value.safeGet<String>();
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table_name_regexp = args[1]->as<ASTLiteral &>().value.safeGet<String>();
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}
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ColumnsDescription TableFunctionMerge::getActualTableStructure(const Context & context) const
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{
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return ColumnsDescription{chooseColumns(source_database, table_name_regexp, context)};
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}
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StoragePtr TableFunctionMerge::executeImpl(const ASTPtr & /*ast_function*/, const Context & context, const std::string & table_name, ColumnsDescription /*cached_columns*/) const
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{
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auto res = StorageMerge::create(
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StorageID(getDatabaseName(), table_name),
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getActualTableStructure(context),
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source_database,
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table_name_regexp,
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context);
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res->startup();
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return res;
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}
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void registerTableFunctionMerge(TableFunctionFactory & factory)
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{
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factory.registerFunction<TableFunctionMerge>();
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}
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}
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