PG_AUTOCTL_SHOW_STATE(1)

📦
version 2.1 · 2 versions
, in fedora 43, fedora 44

🌸 PG_AUTOCTL SHOW STATE(1) 🌸

okay bestie, welcome to pg_autoctl show state — the pg_autoctl show state of all time. It's giving "let me tell you exactly what's happening in your failover formation" energy, and honestly? iconic. 💖

✨ NAME ✨

pg_autoctl show state — pg_autoctl show state

pg_autoctl show state — Prints monitor's state of nodes in a given formation and group

✨ SYNOPSIS ✨

So like, this command outputs the current state of the formation and groups registered to the pg_auto_failover monitor:

usage: pg_autoctl show state  [ --pgdata --formation --group ]

--pgdata      path to data directory
--monitor     pg_auto_failover Monitor Postgres URL
--formation   formation to query, defaults to 'default'
--group       group to query formation, defaults to all
--local       show local data, do not connect to the monitor
--watch       display an auto-updating dashboard
--json        output data in the JSON format

Quick lil vibe check on those flags, bestie:

  • --pgdata — path to data directory
  • --monitor — pg_auto_failover Monitor Postgres URL
  • --formation — formation to query, defaults to 'default'
  • --group — group to query formation, defaults to all
  • --local — show local data, do not connect to the monitor
  • --watch — display an auto-updating dashboard
  • --json — output data in the JSON format

✨ OPTIONS ✨

  • --pgdata — Location of the Postgres node being managed locally. Defaults to the environment variable PGDATA. Use --monitor to connect to a monitor from anywhere, rather than the monitor URI used by a local Postgres node managed with pg_autoctl. 🗂️
  • --monitor — Postgres URI used to connect to the monitor. Must use the autoctl_node username and target the pg_auto_failover database name. It is possible to show the Postgres URI from the monitor node using the command pg_autoctl show uri. 🔗
  • --formation — List the events recorded for nodes in the given formation. Defaults to default. 🌈
  • --group — Limit output to a single group in the formation. Default to including all groups registered in the target formation. 🎀
  • --local — Print the local state information without connecting to the monitor. 🙈
  • --watch — Take control of the terminal and display the current state of the system and the last events from the monitor. The display is updated automatically every 500 milliseconds (half a second) and reacts properly to window size change. 👑

Depending on the terminal window size, a different set of columns is visible in the state part of the output. See pg_autoctl watch.

  • --json — Output a JSON formatted data instead of a table formatted list. 🤖

✨ ENVIRONMENT ✨

PGDATA

Postgres directory location. Can be used instead of the --pgdata option.

PG_AUTOCTL_MONITOR

Postgres URI to connect to the monitor node, can be used instead of the --monitor option.

XDG_CONFIG_HOME

The pg_autoctl command stores its configuration files in the standard place XDG_CONFIG_HOME. See the XDG Base Directory Specification. 📁

XDG_DATA_HOME

The pg_autoctl command stores its internal states files in the standard place XDG_DATA_HOME, which defaults to ~/.local/share. See the XDG Base Directory Specification. 📁

✨ DESCRIPTION ✨

The pg_autoctl show state output includes the following columns, bestie — let's go one by one because each one is lowkey important:

  • Name — Name of the node.
  • Node — Node information. When the formation has a single group (group zero), then this column only contains the nodeId.

Only Citus formations allow several groups. When using a Citus formation the Node column contains the groupId and the nodeId, separated by a colon, such as 0:1 for the first coordinator node.

  • Host:Port — Hostname and port number used to connect to the node.
  • TLI: LSN — Timeline identifier (TLI) and Postgres Log Sequence Number (LSN).

The LSN is the current position in the Postgres WAL stream. This is a hexadecimal number. See pg_lsn for more information.

The current timeline is incremented each time a failover happens, or when doing Point In Time Recovery. A node can only reach the secondary state when it is on the same timeline as its primary node.

  • Connection — This output field contains two bits of information. First, the Postgres connection type that the node provides, either read-write or read-only. Then the mark ! is added when the monitor has failed to connect to this node, and ? when the monitor didn't connect to the node yet.
  • Reported State — The latest reported FSM state, as reported to the monitor by the pg_autoctl process running on the Postgres node.
  • Assigned State — The assigned FSM state on the monitor. When the assigned state is not the same as the reported start, then the pg_autoctl process running on the Postgres node might have not retrieved the assigned state yet, or might still be implementing the FSM transition from the current state to the assigned state.

✨ EXAMPLES ✨

okay so here's the whole table moment, look at her:

$ pg_autoctl show state
 Name |  Node |      Host:Port |       TLI: LSN |   Connection |      Reported State |      Assigned State
------+-------+----------------+----------------+--------------+---------------------+--------------------
node1 |     1 | localhost:5501 |   1: 0/4000678 |   read-write |             primary |             primary
node2 |     2 | localhost:5502 |   1: 0/4000678 |    read-only |           secondary |           secondary
node3 |     3 | localhost:5503 |   1: 0/4000678 |    read-only |           secondary |           secondary

and then the --local serve, no monitor needed, she's self-sufficient:

$ pg_autoctl show state --local
 Name |  Node |      Host:Port |       TLI: LSN |   Connection |      Reported State |      Assigned State
------+-------+----------------+----------------+--------------+---------------------+--------------------
node1 |     1 | localhost:5501 |   1: 0/4000678 | read-write ? |             primary |             primary

and for my data girlies, the --json version:

$ pg_autoctl show state --json
[
    {
        "health": 1,
        "node_id": 1,
        "group_id": 0,
        "nodehost": "localhost",
        "nodename": "node1",
        "nodeport": 5501,
        "reported_lsn": "0/4000678",
        "reported_tli": 1,
        "formation_kind": "pgsql",
        "candidate_priority": 50,
        "replication_quorum": true,
        "current_group_state": "primary",
        "assigned_group_state": "primary"
    },
    {
        "health": 1,
        "node_id": 2,
        "group_id": 0,
        "nodehost": "localhost",
        "nodename": "node2",
        "nodeport": 5502,
        "reported_lsn": "0/4000678",
        "reported_tli": 1,
        "formation_kind": "pgsql",
        "candidate_priority": 50,
        "replication_quorum": true,
        "current_group_state": "secondary",
        "assigned_group_state": "secondary"
    },
    {
        "health": 1,
        "node_id": 3,
        "group_id": 0,
        "nodehost": "localhost",
        "nodename": "node3",
        "nodeport": 5503,
        "reported_lsn": "0/4000678",
        "reported_tli": 1,
        "formation_kind": "pgsql",
        "candidate_priority": 50,
        "replication_quorum": true,
        "current_group_state": "secondary",
        "assigned_group_state": "secondary"
    }
]

✨ AUTHOR ✨

Microsoft 👑

Copyright (c) Microsoft Corporation. All rights reserved.

and that's the whole page, bestie 🫶 this was pg_auto_failover version 2.1, dated Jan 18, 2025, and honestly? she ate. go forth and show state responsibly 💅✨

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