databaseStats

Return per-database statistics (pg_stat_database) for every database in the cluster: connections, commits/rollbacks, block hit ratio inputs, tuple counts, conflicts, deadlocks, temp file usage, and checksum failures.

read-onlyany connectionsweeps replication groupsweeps group

Synopsis

databaseStats()

Description

Parameters

None of its own.

Also accepts connection, replication_group, group, role, described once under arguments every tool takes.

Output

Keyed by database name; each value is that database's pg_stat_database counters. An absent extension or a missing grant is reported as {error, hint} in place of the map.

Scope

This reading is instance-wide -- every database on the same postmaster returns it identically, so asking each of them in turn repeats one answer. The counters here are each server's own, so members of a replication group legitimately disagree and the answer is their sum, not the primary's copy.

Example mocked data

Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "databaseStats",
    "arguments": {}
  }
}

Result

{
  "shop": {
    "numbackends": 84,
    "xact_commit": 902211408,
    "xact_rollback": 120442,
    "blks_read": 81220331,
    "blks_hit": 99201844221,
    "temp_files": 211,
    "temp_bytes": 90211332096,
    "deadlocks": 3,
    "checksum_failures": null,
    "stats_reset": "2026-08-01T00:00:00Z"
  }
}

Invented values on a fictional shop database, shaped by and checked against this tool's output schema. Real output is returned as structuredContent to clients that negotiate MCP 2025-06-18 or later.