Function registerDatabaseBackup

src/Databases/DatabaseBackup.cpp:470–585

void registerDatabaseBackup(DatabaseFactory & factory);
void registerDatabaseBackup(DatabaseFactory & factory)
{
    auto create_fn = [](const DatabaseFactory::Arguments & args)
    {
        auto * engine_define = args.create_query.storage;
        const ASTFunction * engine = engine_define->engine;

        ASTs engine_args;
        if (engine->arguments)
            engine_args = engine->arguments->children;

        auto config = parseArguments(engine_args, args.context);
        return std::make_shared<DatabaseBackup>(args.database_name, args.metadata_path, config, args.context);
    };

    factory.registerDatabase("Backup", create_fn, {.supports_arguments = true, .is_external = true}, Documentation{
        .description = R"DOCS_MD(
Database backup allows to instantly attach table/database from [backups](/operations/backup/overview) in read-only mode.

Database backup works with both incremental and non-incremental backups.

## Creating a database {#creating-a-database}

```sql
CREATE DATABASE backup_database
ENGINE = Backup('database_name_inside_backup', Disk('disk_name', 'backup_name'))
```

The backup destination can be any valid backup [destination](/operations/backup/disk#configure-backup-destinations-for-disk), such as `Disk`, `S3`, or `File`. It is passed as a function, for example `Disk('disk_name', 'backup_name')`.

**Engine Parameters**

- `database_name_inside_backup` — Name of the database inside the backup.
- `backup_destination` — Backup destination.

## Usage example {#usage-example}

Let's make an example with a `Disk` backup destination. Let's first setup backups disk in `storage.xml`:

```xml
<storage_configuration>
    <disks>
        <backups>
            <type>local</type>
            <path>/home/ubuntu/ClickHouseWorkDir/backups/</path>
        </backups>
    </disks>
</storage_configuration>
<backups>
    <allowed_disk>backups</allowed_disk>
    <allowed_path>/home/ubuntu/ClickHouseWorkDir/backups/</allowed_path>
</backups>
```

Example of usage. Let's create test database, tables, insert some data and then create a backup:

```sql
CREATE DATABASE test_database;