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73 lines
2.7 KiB
Markdown
73 lines
2.7 KiB
Markdown
---
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sidebar_position: 20
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sidebar_label: PostgreSQL Interface
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---
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# PostgreSQL Interface
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ClickHouse supports the PostgreSQL wire protocol, which allows you to use Postgres clients to connect to ClickHouse. In a sense, ClickHouse can pretend to be a PostgreSQL instance - allowing you to connect a PostgreSQL client application to ClickHouse that is not already directly supported by ClickHouse (for example, Amazon Redshift).
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To enable the PostgreSQL wire protocol, add the [postgresql_port](../operations/server-configuration-parameters/settings#server_configuration_parameters-postgresql_port) setting to your server's configuration file. For example, you could define the port in a new XML file in your `config.d` folder:
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```xml
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<clickhouse>
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<postgresql_port>9005</postgresql_port>
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</clickhouse>
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```
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Startup your ClickHouse server and look for a log message similar to the following that mentions **Listening for PostgreSQL compatibility protocol**:
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```response
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{} <Information> Application: Listening for PostgreSQL compatibility protocol: 127.0.0.1:9005
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```
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## Connect psql to ClickHouse
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The following command demonstrates how to connect the PostgreSQL client `psql` to ClickHouse:
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```bash
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psql -p [port] -h [hostname] -U [username] [database_name]
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```
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For example:
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```bash
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psql -p 9005 -h 127.0.0.1 -U alice default
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```
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:::note
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The `psql` client requires a login with a password, so you will not be able connect using the `default` user with no password. Either assign a password to the `default` user, or login as a different user.
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:::
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The `psql` client prompts for the password:
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```response
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Password for user alice:
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psql (14.2, server 22.3.1.1)
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WARNING: psql major version 14, server major version 22.
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Some psql features might not work.
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Type "help" for help.
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default=>
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```
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And that's it! You now have a PostgreSQL client connected to ClickHouse, and all commands and queries are executed on ClickHouse.
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:::caution
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The PostgreSQL protocol currently only supports plain-text passwords.
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:::
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## Using SSL
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If you have SSL/TLS configured on your ClickHouse instance, then `postgresql_port` will use the same settings (the port is shared for both secure and insecure clients).
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Each client has their own method of how to connect using SSL. The following command demonstrates how to pass in the certificates and key to securely connect `psql` to ClickHouse:
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```bash
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psql "port=9005 host=127.0.0.1 user=alice dbname=default sslcert=/path/to/certificate.pem sslkey=/path/to/key.pem sslrootcert=/path/to/rootcert.pem sslmode=verify-ca"
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```
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View the [PostgreSQL docs](https://jdbc.postgresql.org/documentation/head/ssl-client.html) for more details on their SSL settings.
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[Original article](https://clickhouse.com/docs/en/interfaces/postgresql)
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