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https://github.com/ClickHouse/ClickHouse.git
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330212e0f4
The original motivation for this commit was that shared_ptr_helper used std::shared_ptr<>() which does two heap allocations instead of make_shared<>() which does a single allocation. Turned out that 1. the affected code (--> Storages/) is not on a hot path (rendering the performance argument moot ...) 2. yet copying Storage objects is potentially dangerous and was previously allowed. Hence, this change - removes shared_ptr_helper and as a result all inherited create() methods, - instead, Storage objects are now created using make_shared<>() by the caller (for that to work, many constructors had to be made public), and - all Storage classes were marked as noncopyable using boost::noncopyable. In sum, we are (likely) not making things faster but the code becomes cleaner and harder to misuse.
78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
#include <Storages/StorageNull.h>
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#include <Storages/StorageFactory.h>
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#include <Storages/AlterCommands.h>
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#include <Interpreters/InterpreterAlterQuery.h>
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#include <Interpreters/Context.h>
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#include <Databases/IDatabase.h>
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#include <IO/WriteHelpers.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 NOT_IMPLEMENTED;
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extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
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extern const int ALTER_OF_COLUMN_IS_FORBIDDEN;
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}
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void registerStorageNull(StorageFactory & factory)
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{
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factory.registerStorage("Null", [](const StorageFactory::Arguments & args)
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{
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if (!args.engine_args.empty())
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throw Exception(
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"Engine " + args.engine_name + " doesn't support any arguments (" + toString(args.engine_args.size()) + " given)",
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ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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return std::make_shared<StorageNull>(args.table_id, args.columns, args.constraints, args.comment);
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},
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{
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.supports_parallel_insert = true,
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});
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}
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void StorageNull::checkAlterIsPossible(const AlterCommands & commands, ContextPtr context) const
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{
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auto name_deps = getDependentViewsByColumn(context);
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for (const auto & command : commands)
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{
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if (command.type != AlterCommand::Type::ADD_COLUMN
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&& command.type != AlterCommand::Type::MODIFY_COLUMN
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&& command.type != AlterCommand::Type::DROP_COLUMN
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&& command.type != AlterCommand::Type::COMMENT_COLUMN
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&& command.type != AlterCommand::Type::COMMENT_TABLE)
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throw Exception(ErrorCodes::NOT_IMPLEMENTED, "Alter of type '{}' is not supported by storage {}",
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command.type, getName());
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if (command.type == AlterCommand::DROP_COLUMN && !command.clear)
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{
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const auto & deps_mv = name_deps[command.column_name];
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if (!deps_mv.empty())
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{
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throw Exception(
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"Trying to ALTER DROP column " + backQuoteIfNeed(command.column_name) + " which is referenced by materialized view "
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+ toString(deps_mv),
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ErrorCodes::ALTER_OF_COLUMN_IS_FORBIDDEN);
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}
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}
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}
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}
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void StorageNull::alter(const AlterCommands & params, ContextPtr context, AlterLockHolder &)
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{
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auto table_id = getStorageID();
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StorageInMemoryMetadata new_metadata = getInMemoryMetadata();
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params.apply(new_metadata, context);
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DatabaseCatalog::instance().getDatabase(table_id.database_name)->alterTable(context, table_id, new_metadata);
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setInMemoryMetadata(new_metadata);
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}
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}
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