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System statistics table

The stats table is one of the system tables added in version 1.16 of RethinkDB. It provides statistics about server read/write throughput, client connections, and memory usage.

Querying the stats table

Note: as with other system tables, the jobs table can only be accessed by the admin user account.

The table’s primary key is the id field, and the keys are always arrays. The first element in the array is always a string indicating the object type being queried (i.e., "table", "server", etc.); for all objects but the cluster (which has only one document in the stats table), the second element is the UUID of the object being queried.

// get a dump of all current statistics
r.db("rethinkdb").table("stats").run(conn, callback);

// query about the cluster as a whole
r.db("rethinkdb").table("stats").get(["cluster"]).run(conn, callback);

// query about a specific server
r.db("rethinkdb").table("stats").get(["server", "de8b75d1-3184-48f0-b1ef-99a9c04e2be5"]).run(conn, callback);

// query about a specific table
r.db("rethinkdb").table("stats").get(["table", "31c92680-f70c-4a4b-a49e-b238eb12c023"]).run(conn, callback);

// query about a replica of a table on a specific server
// this requires *two* UUIDs: the table's, then the server's
r.db("rethinkdb").table("stats").get(["table_server", "31c92680-f70c-4a4b-a49e-b238eb12c023", "de8b75d1-3184-48f0-b1ef-99a9c04e2be5"]).run(conn, callback);

Document schema

Each object has its own document schema. The field names are, for the most part, self-explanatory. The fields server, db and table will be either UUIDs or strings depending on the value of the identifier_format optional argument to table.

cluster

{
  id: ["cluster"],
  query_engine: {
    queries_per_sec: <NUMBER>,
    read_docs_per_sec: <NUMBER>,
    written_docs_per_sec: <NUMBER>
  }
}

server

{
  id: ["server", <UUID>],
  server: <UUID> or <STRING>,
  query_engine: {
    queries_per_sec: <NUMBER>,
    queries_total: <NUMBER>,
    read_docs_per_sec: <NUMBER>,
    read_docs_total: <NUMBER>,
    written_docs_per_sec: <NUMBER>,
    written_docs_total: <NUMBER>,
    client_connections: <NUMBER>
  },
}

If a server has timed out, the returned document will contain no statistics, but will contain an error field.

{
  id: ["server", <UUID>],
  server: <UUID> or <STRING>,
  error: "Timed out. Unable to retrieve stats."
}

table

{
  id: ["table", <UUID>],
  table: <UUID> or <STRING>,
  db: <UUID> or <STRING>,
  query_engine: {
    read_docs_per_sec: <NUMBER>,
    written_docs_per_sec: <NUMBER>
  }
}

replica (table/server pair)

{
  id: ["table_server", <UUID>, <UUID>]  // table_id, server_id
  server: <UUID> or <STRING>,
  table: <UUID> or <STRING>,
  db: <UUID> or <STRING>,
  query_engine: {
    read_docs_per_sec: <NUMBER>,
    read_docs_total: <NUMBER>,
    written_docs_per_sec: <NUMBER>,
    written_docs_total: <NUMBER>
  },
  storage_engine: {
      cache: {
        in_use_bytes: <NUMBER>
      },
      disk: {
        read_bytes_per_sec: <NUMBER>,
        read_bytes_total: <NUMBER>,
        written_bytes_per_sec: <NUMBER>,
        written_bytes_total: <NUMBER>,
        space_usage: {
          metadata_bytes: <NUMBER>,
          data_bytes: <NUMBER>,
          garbage_bytes: <NUMBER>,
          preallocated_bytes: <NUMBER>
        }
      }
   }
}

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https://rethinkdb.com/docs/system-stats/