Back up and Restore Data
It is crucial to back up your databases to ensure that you can recover your data and quickly resume operations in the event of problems such as system crashes, hardware failures, or accidental data deletion by users.
This document provides instructions on how to back up and restore data using the Greptime command line and the SQL COPY
command.
Back up and restore schemas
Before backing up and restoring data for tables or databases, it is necessary to back up and restore the schemas.
Back up schemas
The following example command line connects to the GreptimeDB server at 127.0.0.1:4000
and exports the CREATE TABLE
SQL statements to the folder /home/backup/schema/
:
greptime cli export --addr '127.0.0.1:4000' --output-dir /home/backup/schema/ --target create-table
Restore schemas
To restore the schema to a specified database, use the PostgreSQL client.
For example,
the following command line runs the CREATE TABLE
SQL statements in the file greptime-public.sql
and creates table to the public
database:
psql -h 127.0.0.1 -p 4003 -d public -f /home/backup/schema/greptime-public.sql
Back up and restore tables
Before restoring data, ensure that the table exists in the database. To avoid missing the table schema, you can also back up the table schemas when backing up the table data. Restore the schemas before restoring the data.
Back up tables
The following SQL command backs up the monitor
table in parquet
format to the file /home/backup/monitor/monitor.parquet
:
COPY monitor TO '/home/backup/monitor/monitor.parquet' WITH (FORMAT = 'parquet');
To back up the data within a specific time range, you can specify the START_TIME
and END_TIME
options.
For example, the following command exports the data for the date 2024-05-18
.
COPY monitor TO '/home/backup/monitor/monitor_20240518.parquet' WITH (FORMAT = 'parquet', START_TIME='2024-05-18 00:00:00', END_TIME='2024-05-19 00:00:00');
Restore tables
The following SQL command restores the monitor
table:
COPY monitor FROM '/home/backup/monitor/monitor.parquet' WITH (FORMAT = 'parquet');
If you have exported the data incrementally,
where each file has a different name but is located in the same folder,
you can restore them using the PATTERN
option:
COPY monitor FROM '/home/backup/monitor/' WITH (FORMAT = 'parquet', PATTERN = '.*parquet');
Back up and restore databases
Before restoring data, ensure that the database and tables exist in the database. If the database does not exist, create it first using the following SQL command:
CREATE DATABASE <dbname>;
To avoid missing the table schema, you can also back up the table schemas when backing up the database data. Restore the schemas before restoring the data.
Back up databases
The following SQL command backs up the public
database in parquet
format to the folder /home/backup/public/
:
COPY DATABASE public TO '/home/backup/public/' WITH (FORMAT='parquet');
When you look at the folder /home/backup/public/
, you will find that each table is exported as a separate file.
Restore a database
To restore the public
database from the folder /home/backup/public/
, use the following SQL command:
COPY DATABASE public FROM '/home/backup/public/' WITH (FORMAT='parquet');