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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');