bloat_table.sql 3.21 KB
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-- Originally from: https://github.com/ioguix/pgsql-bloat-estimation/blob/master/table/table_bloat.sql
/* WARNING: executed with a non-superuser role, the query inspect only tables you are granted to read.
* This query is compatible with PostgreSQL 9.0 and more
*/
SELECT current_database(), schemaname, tblname AS object_name, bs*tblpages AS real_size,
  (tblpages-est_tblpages)*bs AS extra_size,
  CASE WHEN tblpages - est_tblpages > 0
    THEN 100 * (tblpages - est_tblpages)/tblpages::float
    ELSE 0
  END AS extra_ratio, fillfactor,
  CASE WHEN tblpages - est_tblpages_ff > 0
    THEN (tblpages-est_tblpages_ff)*bs
    ELSE 0
  END AS bloat_size,
  CASE WHEN tblpages - est_tblpages_ff > 0
    THEN 100 * (tblpages - est_tblpages_ff)/tblpages::float
    ELSE 0
  END AS bloat_ratio, is_na
  -- , (pst).free_percent + (pst).dead_tuple_percent AS real_frag
FROM (
  SELECT ceil( reltuples / ( (bs-page_hdr)/tpl_size ) ) + ceil( toasttuples / 4 ) AS est_tblpages,
    ceil( reltuples / ( (bs-page_hdr)*fillfactor/(tpl_size*100) ) ) + ceil( toasttuples / 4 ) AS est_tblpages_ff,
    tblpages, fillfactor, bs, tblid, schemaname, tblname, heappages, toastpages, is_na
    -- , stattuple.pgstattuple(tblid) AS pst
  FROM (
    SELECT
      ( 4 + tpl_hdr_size + tpl_data_size + (2*ma)
        - CASE WHEN tpl_hdr_size%ma = 0 THEN ma ELSE tpl_hdr_size%ma END
        - CASE WHEN ceil(tpl_data_size)::int%ma = 0 THEN ma ELSE ceil(tpl_data_size)::int%ma END
      ) AS tpl_size, bs - page_hdr AS size_per_block, (heappages + toastpages) AS tblpages, heappages,
      toastpages, reltuples, toasttuples, bs, page_hdr, tblid, schemaname, tblname, fillfactor, is_na
    FROM (
      SELECT
        tbl.oid AS tblid, ns.nspname AS schemaname, tbl.relname AS tblname, tbl.reltuples,
        tbl.relpages AS heappages, coalesce(toast.relpages, 0) AS toastpages,
        coalesce(toast.reltuples, 0) AS toasttuples,
        coalesce(substring(
          array_to_string(tbl.reloptions, ' ')
          FROM 'fillfactor=([0-9]+)')::smallint, 100) AS fillfactor,
        current_setting('block_size')::numeric AS bs,
        CASE WHEN version()~'mingw32' OR version()~'64-bit|x86_64|ppc64|ia64|amd64' THEN 8 ELSE 4 END AS ma,
        24 AS page_hdr,
        23 + CASE WHEN MAX(coalesce(null_frac,0)) > 0 THEN ( 7 + count(*) ) / 8 ELSE 0::int END
          + CASE WHEN tbl.relhasoids THEN 4 ELSE 0 END AS tpl_hdr_size,
        sum( (1-coalesce(s.null_frac, 0)) * coalesce(s.avg_width, 1024) ) AS tpl_data_size,
        bool_or(att.atttypid = 'pg_catalog.name'::regtype)
          OR count(att.attname) <> count(s.attname) AS is_na
      FROM pg_attribute AS att
        JOIN pg_class AS tbl ON att.attrelid = tbl.oid
        JOIN pg_namespace AS ns ON ns.oid = tbl.relnamespace
        LEFT JOIN pg_stats AS s ON s.schemaname=ns.nspname
          AND s.tablename = tbl.relname AND s.inherited=false AND s.attname=att.attname
        LEFT JOIN pg_class AS toast ON tbl.reltoastrelid = toast.oid
      WHERE att.attnum > 0 AND NOT att.attisdropped
        AND tbl.relkind = 'r'
      GROUP BY 1,2,3,4,5,6,7,8,9,10, tbl.relhasoids
      ORDER BY 2,3
    ) AS s
  ) AS s2
) AS s3
WHERE NOT is_na
--   AND tblpages*((pst).free_percent + (pst).dead_tuple_percent)::float4/100 >= 1
AND   schemaname= 'public';