Exporting a Database

You can use gs_dump to export data and all object definitions of a database from openGauss. You can specify the information to export as follows:

• Export full information of a database, including its data and all object definitions.

  You can use the exported information to create a database containing the same data as the current one.

• Export all object definitions of a database, including the definitions of the database, functions, schemas, tables, indexes, and stored procedures.

  You can use the exported object definitions to quickly create a database that is the same as the current one, except that the new database does not have data.

• Export data of a database.

Procedure

1. Log in as the OS user omm to the primary node of the database.

2. Use gs_dump to export data of the postgres database.

   gs_dump -W Bigdata@123 -U jack -f /home/omm/backup/postgres_backup.tar -p 8000 postgres -F t 
   

   Table 1 Common parameters

   Parameter	Description	Example Value
   -U	Username for database connection. NOTE: If the username is not specified, the initial system administrator created during installation is used for connection by default.	-U jack
   -W	User password for database connection. This parameter is not required for database administrators if the trust policy is used for authentication. If you connect to the database without specifying this parameter and you are not a database administrator, you will be prompted to enter the password.	-W Bigdata@123
   -f	Folder to store exported files. If this parameter is not specified, the exported files are stored in the standard output.	-f /home/omm/backup/postgres_backup.tar
   -p	TCP port or local Unix-domain socket file extension on which the server is listening for connections.	-p 8000
   dbname	Name of the database to export.	postgres
   -F	Select the format of file to export. The values of -F are as follows: p: plaintext c: custom d: directory t: .tar	-F t

   For details about other parameters, see “Server Tools > gs_dump” in the Tool Reference.

Examples

Example 1: Run gs_dump to export full information of the postgres database and compress the exported files in .sql format.

gs_dump -W Bigdata@123 -f /home/omm/backup/postgres_backup.sql -p 8000 postgres -Z 8 -F p
gs_dump[port='8000'][postgres][2017-07-21 15:36:13]: dump database postgres successfully
gs_dump[port='8000'][postgres][2017-07-21 15:36:13]: total time: 3793  ms

Example 2: Run gs_dump to export data of the postgres database, excluding object definitions. The exported files are in a custom format.

gs_dump -W Bigdata@123 -f /home/omm/backup/postgres_data_backup.dmp -p 8000 postgres -a -F c
gs_dump[port='8000'][postgres][2017-07-21 15:36:13]: dump database postgres successfully
gs_dump[port='8000'][postgres][2017-07-21 15:36:13]: total time: 3793  ms

Example 3: Run gs_dump to export object definitions of the postgres database. The exported files are in .sql format.

--Before the export, the nation table contains data.
postgres=# select n_nationkey,n_name,n_regionkey from nation limit 3;
 n_nationkey |          n_name           | n_regionkey 
-------------+---------------------------+-------------
           0 | ALGERIA                   |           0
           3 | CANADA                    |           1
          11 | IRAQ                      |           4
(3 rows)

gs_dump -W Bigdata@123 -f /home/omm/backup/postgres_def_backup.sql -p 8000 postgres -s -F p
gs_dump[port='8000'][postgres][2017-07-20 15:04:14]: dump database postgres successfully
gs_dump[port='8000'][postgres][2017-07-20 15:04:14]: total time: 472 ms

Example 4: Run gs_dump to export object definitions of the postgres database. The exported files are in text format and are encrypted.

gs_dump -W Bigdata@123 -f /home/omm/backup/postgres_def_backup.sql -p 8000 postgres --with-encryption AES128 --with-key 1234567812345678 -s -F p
gs_dump[port='8000'][postgres][2018-11-14 11:25:18]: dump database postgres successfully
gs_dump[port='8000'][postgres][2018-11-14 11:25:18]: total time: 1161  ms