listTableSizes

Measure every table in a schema on disk: table size, index size and grand total per relation.

read-onlyany connectionsweeps instancesweeps group

Synopsis

listTableSizes(schema)

Description

Measure every table in a schema on disk: table size, index size and grand total per relation. COSTS MORE THAN IT LOOKS, and more here than in tableSize: one relation is opened per table, each taking AccessShareLock, so a single table held under AccessExclusiveLock by an ALTER TABLE blocks the whole call rather than one row of it, and on a large schema this is thousands of file-metadata calls. Prefer size_estimate from listTableStats, which is free, and call this when the estimates are too stale to act on.

Partitioned tables report their own storage, which is zero; listPartitions summarises them and partitionDetails names their partitions.

Parameters

schema requiredstring

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

Output

Keyed by table name; each value is that table's measured size, index size and total. An absent extension or a missing grant is reported as {error, hint} in place of the map.

Scope

A physical replica is byte-identical here, so asking each member of a replication group adds nothing.

Example mocked data

Request

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

Result

{
  "orders": {
    "kind": "table",
    "size": 192848896,
    "indexes_size": 60489728,
    "total_size": 253338624
  },
  "customers": {
    "kind": "table",
    "size": 14032896,
    "indexes_size": 5226496,
    "total_size": 19259392
  }
}

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.