ClickHouse/dbms/Interpreters/loadMetadata.cpp
2020-04-03 03:19:11 +03:00

153 lines
4.7 KiB
C++

#include <Common/ThreadPool.h>
#include <Poco/DirectoryIterator.h>
#include <Parsers/ParserCreateQuery.h>
#include <Parsers/ASTCreateQuery.h>
#include <Parsers/parseQuery.h>
#include <Interpreters/InterpreterCreateQuery.h>
#include <Interpreters/Context.h>
#include <Interpreters/loadMetadata.h>
#include <Databases/DatabaseOrdinary.h>
#include <IO/ReadBufferFromFile.h>
#include <IO/ReadHelpers.h>
#include <Common/escapeForFileName.h>
#include <Common/typeid_cast.h>
namespace DB
{
static void executeCreateQuery(
const String & query,
Context & context,
const String & database,
const String & file_name,
bool has_force_restore_data_flag)
{
ParserCreateQuery parser;
ASTPtr ast = parseQuery(parser, query.data(), query.data() + query.size(), "in file " + file_name, 0);
auto & ast_create_query = ast->as<ASTCreateQuery &>();
ast_create_query.database = database;
InterpreterCreateQuery interpreter(ast, context);
interpreter.setInternal(true);
interpreter.setForceRestoreData(has_force_restore_data_flag);
interpreter.execute();
}
static void loadDatabase(
Context & context,
const String & database,
const String & database_path,
bool force_restore_data)
{
String database_attach_query;
String database_metadata_file = database_path + ".sql";
if (Poco::File(database_metadata_file).exists())
{
/// There is .sql file with database creation statement.
ReadBufferFromFile in(database_metadata_file, 1024);
readStringUntilEOF(database_attach_query, in);
}
else if (Poco::File(database_path).exists())
{
/// Database exists, but .sql file is absent. It's old-style Ordinary database (e.g. system or default)
database_attach_query = "ATTACH DATABASE " + backQuoteIfNeed(database) + " ENGINE = Ordinary";
}
else
{
/// It's first server run and we need create default and system databases.
/// .sql file with database engine will be written for CREATE query.
database_attach_query = "CREATE DATABASE " + backQuoteIfNeed(database);
}
executeCreateQuery(database_attach_query, context, database,
database_metadata_file, force_restore_data);
}
#define SYSTEM_DATABASE "system"
void loadMetadata(Context & context, const String & default_database_name)
{
String path = context.getPath() + "metadata";
/** There may exist 'force_restore_data' file, that means,
* skip safety threshold on difference of data parts while initializing tables.
* This file is deleted after successful loading of tables.
* (flag is "one-shot")
*/
Poco::File force_restore_data_flag_file(context.getFlagsPath() + "force_restore_data");
bool has_force_restore_data_flag = force_restore_data_flag_file.exists();
/// Loop over databases.
std::map<String, String> databases;
Poco::DirectoryIterator dir_end;
for (Poco::DirectoryIterator it(path); it != dir_end; ++it)
{
if (!it->isDirectory())
continue;
/// For '.svn', '.gitignore' directory and similar.
if (it.name().at(0) == '.')
continue;
if (it.name() == SYSTEM_DATABASE)
continue;
databases.emplace(unescapeForFileName(it.name()), it.path().toString());
}
if (!default_database_name.empty() && !databases.count(default_database_name))
databases.emplace(default_database_name, path + "/" + escapeForFileName(default_database_name));
for (const auto & [name, db_path] : databases)
loadDatabase(context, name, db_path, has_force_restore_data_flag);
if (has_force_restore_data_flag)
{
try
{
force_restore_data_flag_file.remove();
}
catch (...)
{
tryLogCurrentException("Load metadata", "Can't remove force restore file to enable data sanity checks");
}
}
}
void loadMetadataSystem(Context & context)
{
String path = context.getPath() + "metadata/" SYSTEM_DATABASE;
if (Poco::File(path).exists())
{
/// 'has_force_restore_data_flag' is true, to not fail on loading query_log table, if it is corrupted.
loadDatabase(context, SYSTEM_DATABASE, path, true);
}
else
{
/// Initialize system database manually
String global_path = context.getPath();
Poco::File(global_path + "data/" SYSTEM_DATABASE).createDirectories();
Poco::File(global_path + "metadata/" SYSTEM_DATABASE).createDirectories();
auto system_database = std::make_shared<DatabaseOrdinary>(SYSTEM_DATABASE, global_path + "metadata/" SYSTEM_DATABASE "/", context);
DatabaseCatalog::instance().attachDatabase(SYSTEM_DATABASE, system_database);
}
}
}