Exporting data | Tarantool

Exporting data

Enterprise Edition

This command is supported by the Enterprise Edition only.

$ tt [crud] export URI SPACE:FILE ... [EXPORT_OPTION ...]

tt [crud] export exports a space’s data to a file. The crud command is optional and can be used to export a cluster’s data by using the CRUD module. Without crud, data is exported using the box.space API.

tt [crud] export takes the following arguments:

  • URI: The URI of a router instance if crud is used. Otherwise, it should specify the URI of a storage.
  • FILE: The name of a file for storing exported data.
  • SPACE: The name of a space from which data is exported.

Note

Read access to the space is required to export its data.

Exporting isn’t supported for the interval field type.

The command below exports data of the customers space to the customers.csv file:

$ tt crud export localhost:3301 customers:customers.csv

If the customers space has five fields (id, bucket_id, firstname, lastname, and age), the file with exported data might look like this:

1,477,Andrew,Fuller,38
2,401,Michael,Suyama,46
3,2804,Robert,King,33
# ...

If a tuple contains a null value, for example, [1, 477, 'Andrew', null, 38], it is exported as an empty value:

1,477,Andrew,,38

To export data with a space’s field names in the first row, use the --header option:

$ tt crud export localhost:3301 customers:customers.csv  \
                 --header

In this case, field values start from the second row, for example:

id,bucket_id,firstname,lastname,age
1,477,Andrew,Fuller,38
2,401,Michael,Suyama,46
3,2804,Robert,King,33
# ...

By default, tt exports empty values for fields containing compound data such as arrays or maps. To export compound values in a specific format, use the --compound-value-format option. For example, the command below exports compound values serialized in JSON:

$ tt crud export localhost:3301 customers:customers.csv  \
                 --compound-value-format json

--batch-queue-size INT

The maximum number of tuple batches in a queue between a fetch and write threads (the default is 32).

tt exports data using two threads:

  • A fetch thread makes requests and receives data from a Tarantool instance.
  • A write thread encodes received data and writes it to the output.

The fetch thread uses a queue to pass received tuple batches to the write thread. If a queue is full, the fetch thread waits until the write thread takes a batch from the queue.

--batch-size INT

The number of tuples to transfer per request (the default is 10000).

--compound-value-format STRING

A format used to export compound values like arrays or maps. By default, tt exports empty values for fields containing such values.

Supported formats: json.

See also: Exporting compound data.

--header

Add field names in the first row.

See also: Exporting headers.

--password STRING

A password used to connect to the instance.

--readview

Export data using a read view.

--username STRING

A username for connecting to the instance.

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