Vendredi 21 mars 2025 à 15:15

Note de type #mémento pour calculer la taille des tables PostgreSQL.

Commande pour calculer la taille de la base de données entière :

postgres=# select pg_size_pretty(pg_database_size('postgres'));
 pg_size_pretty
----------------
 74 GB

Commande pour voir les détails table par table :

SELECT
  nspname                                               AS "schema",
  pg_class.relname                                      AS "table",
  pg_size_pretty(pg_total_relation_size(pg_class.oid))  AS "total_size",
  pg_size_pretty(pg_relation_size(pg_class.oid))        AS "data_size",
  pg_size_pretty(pg_indexes_size(pg_class.oid))         AS "index_size",
  pg_stat_user_tables.n_live_tup                        AS "rows",
  pg_size_pretty(
    pg_total_relation_size(pg_class.oid) /
    (pg_stat_user_tables.n_live_tup + 1)
  )                                                     AS "total_row_size",
  pg_size_pretty(
    pg_relation_size(pg_class.oid) /
    (pg_stat_user_tables.n_live_tup + 1)
  )                                                     AS "row_size"
FROM
  pg_stat_user_tables
JOIN
  pg_class
ON
  pg_stat_user_tables.relid = pg_class.oid
JOIN
  pg_catalog.pg_namespace AS ns
ON
  pg_class.relnamespace = ns.oid
ORDER BY
  pg_total_relation_size(pg_class.oid) DESC;

 schema |      table      | total_size | data_size  | index_size |  rows   | total_row_size |  row_size
--------+-----------------+------------+------------+------------+---------+----------------+------------
 public | table1          | 72 GB      | 1616 MB    | 1039 MB    | 7456403 | 10 kB          | 227 bytes
 public | table2          | 1153 MB    | 754 MB     | 399 MB     | 2747998 | 440 bytes      | 287 bytes
 public | table3          | 370 MB     | 8192 bytes | 47 MB      |       8 | 41 MB          | 910 bytes
 public | table4        | 232 kB     | 136 kB     | 56 kB      |     422 | 561 bytes      | 329 bytes
(7 rows)