Exporting data
Enterprise Edition
This command is supported by the Enterprise Edition only.
$ tt [crud] export URI FILE SPACE [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 ifcrud
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.
Примечание
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.csv customers
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.csv customers \
--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.csv customers \
--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.
-
--username
STRING
¶ A username for connecting to the instance.