ClickHouse/src/Databases/DatabaseLazy.cpp
Alexander Tokmakov 6e77155dc8 fix
2022-07-20 23:11:35 +02:00

350 lines
12 KiB
C++

#include <Core/Settings.h>
#include <Databases/DatabaseLazy.h>
#include <Databases/DatabaseOnDisk.h>
#include <Databases/DatabasesCommon.h>
#include <Interpreters/Context.h>
#include <IO/ReadHelpers.h>
#include <IO/WriteBufferFromFile.h>
#include <IO/WriteHelpers.h>
#include <Parsers/ASTCreateQuery.h>
#include <Storages/IStorage.h>
#include <Common/escapeForFileName.h>
#include <Common/logger_useful.h>
#include <Common/scope_guard_safe.h>
#include <base/sort.h>
#include <iomanip>
#include <filesystem>
namespace fs = std::filesystem;
namespace DB
{
namespace ErrorCodes
{
extern const int TABLE_ALREADY_EXISTS;
extern const int UNKNOWN_TABLE;
extern const int UNSUPPORTED_METHOD;
extern const int LOGICAL_ERROR;
}
DatabaseLazy::DatabaseLazy(const String & name_, const String & metadata_path_, time_t expiration_time_, ContextPtr context_)
: DatabaseOnDisk(name_, metadata_path_, "data/" + escapeForFileName(name_) + "/", "DatabaseLazy (" + name_ + ")", context_)
, expiration_time(expiration_time_)
{
}
void DatabaseLazy::loadStoredObjects(
ContextMutablePtr local_context, LoadingStrictnessLevel /*mode*/, bool /* skip_startup_tables */)
{
iterateMetadataFiles(local_context, [this, &local_context](const String & file_name)
{
const std::string table_name = unescapeForFileName(file_name.substr(0, file_name.size() - 4));
fs::path detached_permanently_flag = fs::path(getMetadataPath()) / (file_name + detached_suffix);
if (fs::exists(detached_permanently_flag))
{
LOG_DEBUG(log, "Skipping permanently detached table {}.", backQuote(table_name));
return;
}
attachTable(local_context, table_name, nullptr, {});
});
}
void DatabaseLazy::createTable(
ContextPtr local_context,
const String & table_name,
const StoragePtr & table,
const ASTPtr & query)
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
if (!endsWith(table->getName(), "Log"))
throw Exception("Lazy engine can be used only with *Log tables.", ErrorCodes::UNSUPPORTED_METHOD);
DatabaseOnDisk::createTable(local_context, table_name, table, query);
/// DatabaseOnDisk::createTable renames file, so we need to get new metadata_modification_time.
std::lock_guard lock(mutex);
auto it = tables_cache.find(table_name);
if (it != tables_cache.end())
it->second.metadata_modification_time = DatabaseOnDisk::getObjectMetadataModificationTime(table_name);
}
void DatabaseLazy::dropTable(
ContextPtr local_context,
const String & table_name,
bool sync)
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
DatabaseOnDisk::dropTable(local_context, table_name, sync);
}
void DatabaseLazy::renameTable(
ContextPtr local_context,
const String & table_name,
IDatabase & to_database,
const String & to_table_name,
bool exchange,
bool dictionary)
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
DatabaseOnDisk::renameTable(local_context, table_name, to_database, to_table_name, exchange, dictionary);
}
time_t DatabaseLazy::getObjectMetadataModificationTime(const String & table_name) const
{
std::lock_guard lock(mutex);
auto it = tables_cache.find(table_name);
if (it != tables_cache.end())
return it->second.metadata_modification_time;
throw Exception("Table " + backQuote(database_name) + "." + backQuote(table_name) + " doesn't exist.", ErrorCodes::UNKNOWN_TABLE);
}
void DatabaseLazy::alterTable(
ContextPtr /* context */,
const StorageID & /*table_id*/,
const StorageInMemoryMetadata & /* metadata */)
{
clearExpiredTables();
throw Exception("ALTER query is not supported for Lazy database.", ErrorCodes::UNSUPPORTED_METHOD);
}
bool DatabaseLazy::isTableExist(const String & table_name) const
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
std::lock_guard lock(mutex);
return tables_cache.find(table_name) != tables_cache.end();
}
StoragePtr DatabaseLazy::tryGetTable(const String & table_name) const
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
{
std::lock_guard lock(mutex);
auto it = tables_cache.find(table_name);
if (it == tables_cache.end())
return {};
if (it->second.table)
{
cache_expiration_queue.erase(it->second.expiration_iterator);
it->second.last_touched = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
it->second.expiration_iterator = cache_expiration_queue.emplace(cache_expiration_queue.end(), it->second.last_touched, table_name);
return it->second.table;
}
}
return loadTable(table_name);
}
DatabaseTablesIteratorPtr DatabaseLazy::getTablesIterator(ContextPtr, const FilterByNameFunction & filter_by_table_name) const
{
std::lock_guard lock(mutex);
Strings filtered_tables;
for (const auto & [table_name, cached_table] : tables_cache)
{
if (!filter_by_table_name || filter_by_table_name(table_name))
filtered_tables.push_back(table_name);
}
::sort(filtered_tables.begin(), filtered_tables.end());
return std::make_unique<DatabaseLazyIterator>(*this, std::move(filtered_tables));
}
bool DatabaseLazy::empty() const
{
std::lock_guard lock(mutex);
return tables_cache.empty();
}
void DatabaseLazy::attachTable(ContextPtr /* context_ */, const String & table_name, const StoragePtr & table, const String &)
{
LOG_DEBUG(log, "Attach table {}.", backQuote(table_name));
std::lock_guard lock(mutex);
time_t current_time = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
auto [it, inserted] = tables_cache.emplace(std::piecewise_construct,
std::forward_as_tuple(table_name),
std::forward_as_tuple(table, current_time, DatabaseOnDisk::getObjectMetadataModificationTime(table_name)));
if (!inserted)
throw Exception("Table " + backQuote(database_name) + "." + backQuote(table_name) + " already exists.", ErrorCodes::TABLE_ALREADY_EXISTS);
it->second.expiration_iterator = cache_expiration_queue.emplace(cache_expiration_queue.end(), current_time, table_name);
}
StoragePtr DatabaseLazy::detachTable(ContextPtr /* context */, const String & table_name)
{
StoragePtr res;
{
LOG_DEBUG(log, "Detach table {}.", backQuote(table_name));
std::lock_guard lock(mutex);
auto it = tables_cache.find(table_name);
if (it == tables_cache.end())
throw Exception("Table " + backQuote(database_name) + "." + backQuote(table_name) + " doesn't exist.", ErrorCodes::UNKNOWN_TABLE);
res = it->second.table;
if (it->second.expiration_iterator != cache_expiration_queue.end())
cache_expiration_queue.erase(it->second.expiration_iterator);
tables_cache.erase(it);
}
return res;
}
void DatabaseLazy::shutdown()
{
TablesCache tables_snapshot;
{
std::lock_guard lock(mutex);
tables_snapshot = tables_cache;
}
for (const auto & kv : tables_snapshot)
{
if (kv.second.table)
kv.second.table->flushAndShutdown();
}
std::lock_guard lock(mutex);
tables_cache.clear();
}
DatabaseLazy::~DatabaseLazy()
{
try
{
shutdown();
}
catch (...)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
}
}
StoragePtr DatabaseLazy::loadTable(const String & table_name) const
{
SCOPE_EXIT_MEMORY_SAFE({ clearExpiredTables(); });
LOG_DEBUG(log, "Load table {} to cache.", backQuote(table_name));
const String table_metadata_path = fs::path(getMetadataPath()) / (escapeForFileName(table_name) + ".sql");
try
{
StoragePtr table;
auto context_copy = Context::createCopy(context); /// some tables can change context, but not LogTables
auto ast = parseQueryFromMetadata(log, getContext(), table_metadata_path, /*throw_on_error*/ true, /*remove_empty*/false);
if (ast)
{
const auto & ast_create = ast->as<const ASTCreateQuery &>();
String table_data_path_relative = getTableDataPath(ast_create);
table = createTableFromAST(ast_create, getDatabaseName(), table_data_path_relative, context_copy, false).second;
}
if (!ast || !endsWith(table->getName(), "Log"))
throw Exception("Only *Log tables can be used with Lazy database engine.", ErrorCodes::LOGICAL_ERROR);
table->startup();
{
std::lock_guard lock(mutex);
auto it = tables_cache.find(table_name);
if (it == tables_cache.end())
throw Exception("Table " + backQuote(database_name) + "." + backQuote(table_name) + " doesn't exist.", ErrorCodes::UNKNOWN_TABLE);
if (it->second.expiration_iterator != cache_expiration_queue.end())
cache_expiration_queue.erase(it->second.expiration_iterator);
it->second.last_touched = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
it->second.expiration_iterator = cache_expiration_queue.emplace(cache_expiration_queue.end(), it->second.last_touched, table_name);
return it->second.table = table;
}
}
catch (Exception & e)
{
e.addMessage("Cannot create table from metadata file " + table_metadata_path);
throw;
}
}
void DatabaseLazy::clearExpiredTables() const
try
{
std::lock_guard lock(mutex);
auto time_now = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
CacheExpirationQueue expired_tables;
auto expired_it = cache_expiration_queue.begin();
while (expired_it != cache_expiration_queue.end() && (time_now - expired_it->last_touched) >= expiration_time)
++expired_it;
expired_tables.splice(expired_tables.end(), cache_expiration_queue, cache_expiration_queue.begin(), expired_it);
CacheExpirationQueue busy_tables;
while (!expired_tables.empty())
{
String table_name = expired_tables.front().table_name;
auto it = tables_cache.find(table_name);
if (!it->second.table || it->second.table.unique())
{
LOG_DEBUG(log, "Drop table {} from cache.", backQuote(it->first));
it->second.table.reset();
expired_tables.erase(it->second.expiration_iterator);
it->second.expiration_iterator = cache_expiration_queue.end();
}
else
{
LOG_DEBUG(log, "Table {} is busy.", backQuote(it->first));
busy_tables.splice(busy_tables.end(), expired_tables, it->second.expiration_iterator);
}
}
cache_expiration_queue.splice(cache_expiration_queue.begin(), busy_tables, busy_tables.begin(), busy_tables.end());
}
catch (...)
{
tryLogCurrentException(log, __PRETTY_FUNCTION__);
}
DatabaseLazyIterator::DatabaseLazyIterator(const DatabaseLazy & database_, Strings && table_names_)
: IDatabaseTablesIterator(database_.database_name)
, database(database_)
, table_names(std::move(table_names_))
, iterator(table_names.begin())
, current_storage(nullptr)
{
}
void DatabaseLazyIterator::next()
{
current_storage.reset();
++iterator;
while (isValid() && !database.isTableExist(*iterator))
++iterator;
}
bool DatabaseLazyIterator::isValid() const
{
return iterator != table_names.end();
}
const String & DatabaseLazyIterator::name() const
{
return *iterator;
}
const StoragePtr & DatabaseLazyIterator::table() const
{
if (!current_storage)
current_storage = database.tryGetTable(*iterator);
return current_storage;
}
}