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117 lines
4.0 KiB
C++
117 lines
4.0 KiB
C++
#include "getStructureOfRemoteTable.h"
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#include <Interpreters/Cluster.h>
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#include <Interpreters/Context.h>
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#include <Interpreters/ClusterProxy/executeQuery.h>
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#include <Interpreters/InterpreterDescribeQuery.h>
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#include <DataStreams/RemoteBlockInputStream.h>
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#include <DataTypes/DataTypeFactory.h>
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#include <DataTypes/DataTypeString.h>
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#include <Columns/ColumnString.h>
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#include <Storages/IStorage.h>
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#include <Parsers/ExpressionListParsers.h>
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#include <Parsers/parseQuery.h>
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#include <Parsers/ASTFunction.h>
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#include <TableFunctions/TableFunctionFactory.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 NO_REMOTE_SHARD_FOUND;
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}
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ColumnsDescription getStructureOfRemoteTable(
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const Cluster & cluster,
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const std::string & database,
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const std::string & table,
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const Context & context,
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const ASTPtr & table_func_ptr)
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{
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/// Send to the first any remote shard.
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const auto & shard_info = cluster.getAnyShardInfo();
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String query;
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if (table_func_ptr)
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{
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if (shard_info.isLocal())
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{
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const auto * table_function = table_func_ptr->as<ASTFunction>();
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TableFunctionPtr table_function_ptr = TableFunctionFactory::instance().get(table_function->name, context);
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return table_function_ptr->execute(table_func_ptr, context, table_function_ptr->getName())->getColumns();
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}
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auto table_func_name = queryToString(table_func_ptr);
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query = "DESC TABLE " + table_func_name;
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}
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else
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{
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if (shard_info.isLocal())
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return context.getTable(database, table)->getColumns();
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/// Request for a table description
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query = "DESC TABLE " + backQuoteIfNeed(database) + "." + backQuoteIfNeed(table);
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}
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ColumnsDescription res;
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auto new_context = ClusterProxy::removeUserRestrictionsFromSettings(context, context.getSettingsRef());
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/// Expect only needed columns from the result of DESC TABLE. NOTE 'comment' column is ignored for compatibility reasons.
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Block sample_block
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{
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{ ColumnString::create(), std::make_shared<DataTypeString>(), "name" },
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{ ColumnString::create(), std::make_shared<DataTypeString>(), "type" },
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{ ColumnString::create(), std::make_shared<DataTypeString>(), "default_type" },
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{ ColumnString::create(), std::make_shared<DataTypeString>(), "default_expression" },
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};
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/// Execute remote query without restrictions (because it's not real user query, but part of implementation)
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auto input = std::make_shared<RemoteBlockInputStream>(shard_info.pool, query, sample_block, new_context);
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input->setPoolMode(PoolMode::GET_ONE);
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if (!table_func_ptr)
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input->setMainTable(QualifiedTableName{database, table});
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input->readPrefix();
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const DataTypeFactory & data_type_factory = DataTypeFactory::instance();
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ParserExpression expr_parser;
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while (Block current = input->read())
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{
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ColumnPtr name = current.getByName("name").column;
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ColumnPtr type = current.getByName("type").column;
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ColumnPtr default_kind = current.getByName("default_type").column;
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ColumnPtr default_expr = current.getByName("default_expression").column;
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size_t size = name->size();
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for (size_t i = 0; i < size; ++i)
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{
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ColumnDescription column;
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column.name = (*name)[i].get<const String &>();
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String data_type_name = (*type)[i].get<const String &>();
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column.type = data_type_factory.get(data_type_name);
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String kind_name = (*default_kind)[i].get<const String &>();
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if (!kind_name.empty())
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{
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column.default_desc.kind = columnDefaultKindFromString(kind_name);
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String expr_str = (*default_expr)[i].get<const String &>();
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column.default_desc.expression = parseQuery(
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expr_parser, expr_str.data(), expr_str.data() + expr_str.size(), "default expression", 0);
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}
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res.add(column);
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}
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}
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return res;
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}
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}
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