# postgresql_set – Change a PostgreSQL server configuration parameter

New in version 2.8.

- Synopsis
- Requirements
- Parameters
- Notes
- See Also
- Examples
- Return Values
- Status

## Synopsis

- Allows to change a PostgreSQL server configuration parameter.
- The module uses ALTER SYSTEM command and applies changes by reload server configuration.
- ALTER SYSTEM is used for changing server configuration parameters across the entire database cluster.
- It can be more convenient and safe than the traditional method of manually editing the postgresql.conf file.
- ALTER SYSTEM writes the given parameter setting to the $PGDATA/postgresql.auto.conf file, which is read in addition to postgresql.conf.
- The module allows to reset parameter to boot_val (cluster initial value) by reset=yes or remove parameter string from postgresql.auto.conf and reload value=default (for settings with postmaster context restart is required).
- After change you can see in the ansible output the previous and the new parameter value and other information using returned values and debug module.

## Requirements

The below requirements are needed on the host that executes this module.

- psycopg2

## Parameters

Parameter | Choices/Defaults | Comments
--- | --- | ---
ca_cert string |  | Specifies the name of a file containing SSL certificate authority (CA) certificate(s). If the file exists, the server's certificate will be verified to be signed by one of these authorities. aliases: ssl_rootcert
db string |  | Name of database to connect. aliases: login_db
login_host string |  | Host running the database.
login_password string |  | The password used to authenticate with.
login_unix_socket string |  | Path to a Unix domain socket for local connections.
login_user string | Default: "postgres" | The username used to authenticate with.
name string / required |  | Name of PostgreSQL server parameter.
port integer | Default: 5432 | Database port to connect to. aliases: login_port

reset
boolean

Choices:
- no ←
- yes

Restore parameter to initial state (boot_val). Mutually exclusive with value.

session_role string |  | Switch to session_role after connecting. The specified session_role must be a role that the current login_user is a member of. Permissions checking for SQL commands is carried out as though the session_role were the one that had logged in originally.

ssl_mode
string

Choices:
- allow
- disable
- prefer ←
- require
- verify-ca
- verify-full

Determines whether or with what priority a secure SSL TCP/IP connection will be negotiated with the server.
See https://www.postgresql.org/docs/current/static/libpq-ssl.html for more information on the modes.
Default of `prefer` matches libpq default.

value string / required |  | Parameter value to set. To remove parameter string from postgresql.auto.conf and reload the server configuration you must pass value=default. With value=default the playbook always returns changed is true.

## Notes

Note

- Supported version of PostgreSQL is 9.4 and later.
- Pay attention, change setting with ‘postmaster’ context can return changed is true when actually nothing changes because the same value may be presented in several different form, for example, 1024MB, 1GB, etc. However in pg_settings system view it can be defined like 131072 number of 8kB pages. The final check of the parameter value cannot compare it because the server was not restarted and the value in pg_settings is not updated yet.
- For some parameters restart of PostgreSQL server is required. See official documentation https://www.postgresql.org/docs/current/view-pg-settings.html.
- The default authentication assumes that you are either logging in as or sudo’ing to the `postgres` account on the host.
- To avoid “Peer authentication failed for user postgres” error, use postgres user as a become_user.
- This module uses psycopg2, a Python PostgreSQL database adapter. You must ensure that psycopg2 is installed on the host before using this module.
- If the remote host is the PostgreSQL server (which is the default case), then PostgreSQL must also be installed on the remote host.
- For Ubuntu-based systems, install the postgresql, libpq-dev, and python-psycopg2 packages on the remote host before using this module.
- The ca_cert parameter requires at least Postgres version 8.4 and psycopg2 version 2.4.3.

## See Also

See also

postgresql_info – Gather information about PostgreSQL servers
  The official documentation on the postgresql_info module.
PostgreSQL server configuration
  General information about PostgreSQL server configuration.
PostgreSQL view pg_settings reference
  Complete reference of the pg_settings view documentation.
PostgreSQL ALTER SYSTEM command reference
  Complete reference of the ALTER SYSTEM command documentation.

## Examples

    - name: Restore wal_keep_segments parameter to initial state
      postgresql_set:
        name: wal_keep_segments
        reset: yes

    # Set work_mem parameter to 32MB and show what's been changed and restart is required or not
    # (output example: "msg": "work_mem 4MB >> 64MB restart_req: False")
    - name: Set work mem parameter
      postgresql_set:
        name: work_mem
        value: 32mb
      register: set

    - debug:
        msg: "{{ set.name }} {{ set.prev_val_pretty }} >> {{ set.value_pretty }} restart_req: {{ set.restart_required }}"
      when: set.changed
    # Ensure that the restart of PostgreSQL server must be required for some parameters.
    # In this situation you see the same parameter in prev_val and value_prettyue, but 'changed=True'
    # (If you passed the value that was different from the current server setting).

    - name: Set log_min_duration_statement parameter to 1 second
      postgresql_set:
        name: log_min_duration_statement
        value: 1s

    - name: Set wal_log_hints parameter to default value (remove parameter from postgresql.auto.conf)
      postgresql_set:
        name: wal_log_hints
        value: default

## Return Values

Common return values are documented here, the following are the fields unique to this module:

Key | Returned | Description
--- | --- | ---
context string | always | PostgreSQL setting context. Sample: user
name string | always | Name of PostgreSQL server parameter. Sample: shared_buffers
prev_val_pretty string | always | Information about previous state of the parameter. Sample: 4MB
restart_required boolean | always | Information about parameter current state. Sample: True
value dictionary | always | Dictionary that contains the current parameter value (at the time of playbook finish). Pay attention that for real change some parameters restart of PostgreSQL server is required. Returns the current value in the check mode. Sample: {'value': 67108864, 'unit': 'b'}
value_pretty string | always | Information about current state of the parameter. Sample: 64MB

## Status

- This module is not guaranteed to have a backwards compatible interface. [preview]
- This module is maintained by the Ansible Community. [community]

### Authors

- Andrew Klychkov (@Andersson007)

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