ClickHouse/programs/odbc-bridge/ColumnInfoHandler.cpp

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#include "ColumnInfoHandler.h"
#if USE_ODBC
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#include <DataTypes/DataTypeFactory.h>
#include <DataTypes/DataTypeNullable.h>
#include <Server/HTTP/WriteBufferFromHTTPServerResponse.h>
#include <IO/ReadHelpers.h>
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#include <IO/WriteHelpers.h>
#include <Parsers/ParserQueryWithOutput.h>
#include <Server/HTTP/HTMLForm.h>
#include <Poco/Net/HTTPServerRequest.h>
#include <Poco/Net/HTTPServerResponse.h>
#include <Poco/NumberParser.h>
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#include <Interpreters/Context.h>
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#include <Common/logger_useful.h>
#include <Common/BridgeProtocolVersion.h>
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#include <Common/quoteString.h>
#include "getIdentifierQuote.h"
#include "validateODBCConnectionString.h"
#include "ODBCPooledConnectionFactory.h"
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#include <sql.h>
#include <sqlext.h>
namespace DB
{
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namespace ErrorCodes
{
extern const int UNKNOWN_TABLE;
extern const int BAD_ARGUMENTS;
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}
namespace
{
DataTypePtr getDataType(SQLSMALLINT type)
{
const auto & factory = DataTypeFactory::instance();
switch (type)
{
case SQL_TINYINT:
return factory.get("Int8");
case SQL_INTEGER:
return factory.get("Int32");
case SQL_SMALLINT:
return factory.get("Int16");
case SQL_BIGINT:
return factory.get("Int64");
case SQL_FLOAT:
return factory.get("Float64");
case SQL_REAL:
return factory.get("Float32");
case SQL_DOUBLE:
return factory.get("Float64");
case SQL_DATETIME:
return factory.get("DateTime");
case SQL_TYPE_TIMESTAMP:
return factory.get("DateTime");
case SQL_TYPE_DATE:
return factory.get("Date");
default:
return factory.get("String");
}
}
}
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void ODBCColumnsInfoHandler::handleRequest(HTTPServerRequest & request, HTTPServerResponse & response, const ProfileEvents::Event & /*write_event*/)
{
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HTMLForm params(getContext()->getSettingsRef(), request, request.getStream());
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LOG_TRACE(log, "Request URI: {}", request.getURI());
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auto process_error = [&response, this](const std::string & message)
{
response.setStatusAndReason(Poco::Net::HTTPResponse::HTTP_INTERNAL_SERVER_ERROR);
if (!response.sent())
*response.send() << message << '\n';
LOG_WARNING(log, fmt::runtime(message));
};
size_t version;
if (!params.has("version"))
version = 0; /// assumed version for too old servers which do not send a version
else
{
String version_str = params.get("version");
if (!tryParse(version, version_str))
{
process_error("Unable to parse 'version' string in request URL: '" + version_str + "' Check if the server and library-bridge have the same version.");
return;
}
}
if (version != XDBC_BRIDGE_PROTOCOL_VERSION)
{
/// backwards compatibility is considered unnecessary for now, just let the user know that the server and the bridge must be upgraded together
process_error("Server and library-bridge have different versions: '" + std::to_string(version) + "' vs. '" + std::to_string(LIBRARY_BRIDGE_PROTOCOL_VERSION) + "'");
return;
}
if (!params.has("table"))
{
process_error("No 'table' param in request URL");
return;
}
if (!params.has("connection_string"))
{
process_error("No 'connection_string' in request URL");
return;
}
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std::string schema_name;
std::string table_name = params.get("table");
std::string connection_string = params.get("connection_string");
if (params.has("schema"))
schema_name = params.get("schema");
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LOG_TRACE(log, "Got connection str '{}'", connection_string);
try
{
const bool external_table_functions_use_nulls = Poco::NumberParser::parseBool(params.get("external_table_functions_use_nulls", "false"));
auto connection_holder = ODBCPooledConnectionFactory::instance().get(
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validateODBCConnectionString(connection_string),
getContext()->getSettingsRef().odbc_bridge_connection_pool_size);
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/// In XDBC tables it is allowed to pass either database_name or schema_name in table definion, but not both of them.
/// They both are passed as 'schema' parameter in request URL, so it is not clear whether it is database_name or schema_name passed.
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/// If it is schema_name then we know that database is added in odbc.ini. But if we have database_name as 'schema',
/// it is not guaranteed. For nanodbc database_name must be either in odbc.ini or passed as catalog_name.
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auto get_columns = [&](nanodbc::connection & connection)
{
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nanodbc::catalog catalog(connection);
std::string catalog_name;
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nanodbc::catalog::tables tables = catalog.find_tables(table_name, /* type = */ "", /* schema = */ "", /* catalog = */ schema_name);
if (tables.next())
{
catalog_name = tables.table_catalog();
/// `tables.next()` call is mandatory to drain the iterator before next operation and avoid "Invalid cursor state"
if (tables.next())
throw Exception(ErrorCodes::UNKNOWN_TABLE, "Driver returned more than one table for '{}': '{}' and '{}'",
table_name, catalog_name, tables.table_schema());
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LOG_TRACE(log, "Will fetch info for table '{}.{}'", catalog_name, table_name);
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return catalog.find_columns(/* column = */ "", table_name, /* schema = */ "", catalog_name);
}
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tables = catalog.find_tables(table_name, /* type = */ "", /* schema = */ schema_name);
if (tables.next())
{
catalog_name = tables.table_catalog();
/// `tables.next()` call is mandatory to drain the iterator before next operation and avoid "Invalid cursor state"
if (tables.next())
throw Exception(ErrorCodes::UNKNOWN_TABLE, "Driver returned more than one table for '{}': '{}' and '{}'",
table_name, catalog_name, tables.table_schema());
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LOG_TRACE(log, "Will fetch info for table '{}.{}.{}'", catalog_name, schema_name, table_name);
return catalog.find_columns(/* column = */ "", table_name, schema_name, catalog_name);
}
throw Exception(ErrorCodes::BAD_ARGUMENTS, "Table {} not found", schema_name.empty() ? table_name : schema_name + '.' + table_name);
};
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nanodbc::catalog::columns columns_definition = execute<nanodbc::catalog::columns>(
std::move(connection_holder),
[&](nanodbc::connection & connection) { return get_columns(connection); });
NamesAndTypesList columns;
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while (columns_definition.next())
{
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SQLSMALLINT type = columns_definition.sql_data_type();
std::string column_name = columns_definition.column_name();
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bool is_nullable = columns_definition.nullable() == SQL_NULLABLE;
auto column_type = getDataType(type);
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if (external_table_functions_use_nulls && is_nullable == SQL_NULLABLE)
column_type = std::make_shared<DataTypeNullable>(column_type);
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columns.emplace_back(column_name, std::move(column_type));
}
/// Usually this should not happen, since in case of table does not
/// exists, the call should be succeeded.
/// However it is possible sometimes because internally there are two
/// queries in ClickHouse ODBC bridge:
/// - system.tables
/// - system.columns
/// And if between this two queries the table will be removed, them
/// there will be no columns
///
/// Also sometimes system.columns can return empty result because of
/// the cached value of total tables to scan.
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if (columns.empty())
throw Exception(ErrorCodes::UNKNOWN_TABLE, "Columns definition was not returned");
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WriteBufferFromHTTPServerResponse out(
response,
request.getMethod() == Poco::Net::HTTPRequest::HTTP_HEAD,
keep_alive_timeout);
try
{
writeStringBinary(columns.toString(), out);
out.finalize();
}
catch (...)
{
out.finalize();
}
}
catch (...)
{
process_error("Error getting columns from ODBC '" + getCurrentExceptionMessage(false) + "'");
tryLogCurrentException(log);
}
}
}
#endif