Exporting data to the file system

The tools dump command dumps the database data and objects schema to the client file system, in the format described in the File system:

ydb [connection options] tools dump [options]

where [connection options] are database connection options

[options]: Command parameters:

-p PATH or --path PATH: Path to the database directory with objects or a path to the table to be dumped. The root database directory is used by default. The dump includes all subdirectories whose names don't begin with a dot and the tables in them whose names don't begin with a dot. To dump such tables or the contents of such directories, you can specify their names explicitly in this parameter.

-o PATH or --output PATH: Path to the directory in the client file system to dump the data to. If such a directory doesn't exist, it will be created. The entire path to it must already exist, however. If the specified directory exists, it must be empty. If the parameter is omitted, a directory with the name backup_YYYYDDMMTHHMMSS will be created in the current directory, with YYYYDDMM being the date and HHMMSS: the time when the dump began.

--exclude STRING: Template (PCRE) to exclude paths from export. Specify this parameter multiple times for different templates.

--scheme-only: Dump only the details about the database schema objects, without dumping their data

--consistency-level VAL: The consistency level. Possible options:

• database: A fully consistent dump, with one snapshot taken before starting dumping. Applied by default.
• table: Consistency within each dumped table, taking individual independent snapshots for each table dumped. Might run faster and have a smaller effect on the current workload processing in the database.

--avoid-copy: Do not create a snapshot before dumping. The consistency snapshot taken by default might be inapplicable in some cases (for example, for tables with external blobs).

--save-partial-result: Don't delete the result of partial dumping. Without this option, the dumps that terminated with an error are deleted.

--preserve-pool-kinds: If this option is enabled, the tools dump command saves storage device types specified for column groups of the tables to the dump (see the DATA parameter in Column groups for the reference). To import such a dump, the same storage pools must be present in the database. If at least one storage pool is missing, the import procedure will end with an error. By default this option is disabled, and the import procedure will use the default storage pool that was specified at the moment of database creation (see Creating a database for the reference).

--ordered: Rows in the exported tables will be sorted by the primary key.

Examples

Exporting a database

With automatic creation of the backup_... directory In the current directory:

ydb --profile quickstart tools dump

To a specific directory:

ydb --profile quickstart tools dump -o ~/backup_quickstart

Dumping the table structure within a specified database directory (including subdirectories)

ydb --profile quickstart tools dump -p dir1 --scheme-only