2b017ce285
Define table_schema_version as a distinct tagged_uuid class, So it can be differentiated from other uuid-class types, in particular table_id. Added reversed(table_schema_version) for convenience and uniformity since the same logic is currently open coded in several places. Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
45 lines
1.3 KiB
C++
45 lines
1.3 KiB
C++
/*
|
|
* Copyright (C) 2019-present ScyllaDB
|
|
*/
|
|
|
|
/*
|
|
* SPDX-License-Identifier: AGPL-3.0-or-later
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <seastar/core/shared_ptr.hh>
|
|
|
|
#include "utils/UUID.hh"
|
|
#include "utils/UUID_gen.hh"
|
|
|
|
using column_count_type = uint32_t;
|
|
|
|
// Column ID, unique within column_kind
|
|
using column_id = column_count_type;
|
|
|
|
class schema;
|
|
class schema_extension;
|
|
|
|
using schema_ptr = seastar::lw_shared_ptr<const schema>;
|
|
|
|
using table_id = utils::tagged_uuid<struct table_id_tag>;
|
|
|
|
// Cluster-wide identifier of schema version of particular table.
|
|
//
|
|
// The version changes the value not only on structural changes but also
|
|
// temporal. For example, schemas with the same set of columns but created at
|
|
// different times should have different versions. This allows nodes to detect
|
|
// if the version they see was already synchronized with or not even if it has
|
|
// the same structure as the past versions.
|
|
//
|
|
// Schema changes merged in any order should result in the same final version.
|
|
//
|
|
// When table_schema_version changes, schema_tables::calculate_schema_digest() should
|
|
// also change when schema mutations are applied.
|
|
using table_schema_version = utils::tagged_uuid<struct table_schema_version_tag>;
|
|
|
|
inline table_schema_version reversed(table_schema_version v) noexcept {
|
|
return table_schema_version(utils::UUID_gen::negate(v.uuid()));
|
|
}
|