CREATE FUNCTION database_size (name) RETURNS bigint
    AS 'MODULE_PATHNAME', 'database_size'
    LANGUAGE C STRICT;

CREATE FUNCTION relation_size (text) RETURNS bigint
    AS 'MODULE_PATHNAME', 'relation_size'
    LANGUAGE C STRICT;

CREATE FUNCTION pg_tablespace_size(oid) RETURNS bigint
    AS 'MODULE_PATHNAME', 'pg_tablespace_size'
    LANGUAGE C STRICT;

CREATE FUNCTION pg_database_size(oid) RETURNS bigint
    AS 'MODULE_PATHNAME', 'pg_database_size'
    LANGUAGE C STRICT;

CREATE FUNCTION pg_relation_size(oid) RETURNS bigint
    AS 'MODULE_PATHNAME', 'pg_relation_size'
    LANGUAGE C STRICT;

CREATE FUNCTION pg_size_pretty(bigint) RETURNS text
    AS 'MODULE_PATHNAME', 'pg_size_pretty'
    LANGUAGE C STRICT;

CREATE FUNCTION total_relation_size (text) RETURNS bigint AS '
SELECT pg_relation_size(r.oid)
     + COALESCE(pg_relation_size(t.oid), 0)::bigint
     + COALESCE(pg_relation_size(ti.oid), 0)::bigint
     + COALESCE(SUM(pg_relation_size(i.indexrelid)), 0)::bigint
     + COALESCE(SUM(pg_relation_size(it.oid)), 0)::bigint
     + COALESCE(SUM(pg_relation_size(iti.oid)), 0)::bigint AS bytes
FROM pg_class r 
     LEFT JOIN pg_class t   ON (r.reltoastrelid = t.oid) 
     LEFT JOIN pg_class ti  ON (t.reltoastidxid = ti.oid) 
     LEFT JOIN pg_index i   ON (r.oid = i.indrelid) 
     LEFT JOIN pg_class ir  ON (ir.oid = i.indexrelid) 
     LEFT JOIN pg_class it  ON (ir.reltoastrelid = it.oid) 
     LEFT JOIN pg_class iti ON (it.reltoastidxid = iti.oid) 
WHERE r.relname = \$1 
GROUP BY r.oid, t.oid, ti.oid
' LANGUAGE SQL;

CREATE FUNCTION indexes_size (text) RETURNS bigint 
    AS '
SELECT COALESCE(SUM(pg_relation_size(ir.oid)), 0)::bigint
     + COALESCE(SUM(pg_relation_size(it.oid)), 0)::bigint
     + COALESCE(SUM(pg_relation_size(iti.oid)), 0)::bigint AS bytes
FROM pg_class r 
     LEFT JOIN pg_index i   ON (r.oid = i.indrelid) 
     LEFT JOIN pg_class ir  ON (ir.oid = i.indexrelid) 
     LEFT JOIN pg_class it  ON (ir.reltoastrelid = it.oid) 
     LEFT JOIN pg_class iti ON (it.reltoastidxid = iti.oid) 
WHERE r.relname = \$1 
' LANGUAGE SQL;

CREATE FUNCTION relation_size_components (text) RETURNS SETOF RECORD
    AS '
-- relation size
SELECT indexes_size(r.relname) AS indexes_size, 
       relation_size(r.relname) AS data_size, 
       total_relation_size(r.relname) AS total_size, 
       r.relname, r.relkind, r.oid AS relid, r.relfilenode 
FROM pg_class r 
WHERE r.relname = \$1 

UNION ALL 

-- relation toast size
SELECT indexes_size(toast.relname) AS indexes_size, 
       relation_size(''pg_toast.''||toast.relname) AS data_size, 
       total_relation_size(toast.relname) AS total_size, 
       toast.relname, toast.relkind, toast.oid AS relid, toast.relfilenode 
FROM pg_class r, pg_class toast
WHERE r.reltoastrelid = toast.oid 
  AND r.relname = \$1 

UNION ALL 

-- relation toast index size
SELECT indexes_size(toastidxr.relname) AS indexes_size, 
       relation_size(''pg_toast.''||toastidxr.relname) AS data_size, 
       total_relation_size(toastidxr.relname) AS total_size, 
       toastidxr.relname, toastidxr.relkind, 
       toastidxr.oid AS relid, toastidxr.relfilenode 
FROM pg_class r, pg_index toastidx, pg_class toastidxr
WHERE r.relname = \$1
  AND r.reltoastrelid = toastidx.indrelid 
  AND toastidx.indexrelid = toastidxr.oid 

UNION ALL 

-- relation indices size
SELECT indexes_size(idxr.relname) AS indexes_size, 
       relation_size(idxr.relname) AS data_size, 
       total_relation_size(idxr.relname) AS total_size, 
       idxr.relname, idxr.relkind, idxr.oid AS relid, idxr.relfilenode 
FROM pg_class r, pg_class idxr, pg_index idx 
WHERE r.relname = \$1
  AND r.oid = idx.indrelid
  AND idx.indexrelid = idxr.oid 

UNION ALL 

-- relation indices toast size
SELECT indexes_size(idxtoastr.relname) AS indexes_size, 
       relation_size(''pg_toast.''||idxtoastr.relname) AS data_size, 
       total_relation_size(idxtoastr.relname) AS total_size, 
       idxtoastr.relname, idxtoastr.relkind, idxtoastr.oid AS relid, 
       idxtoastr.relfilenode 
FROM pg_class r, pg_class idxr, pg_index idx, pg_class idxtoastr
WHERE r.relname = \$1
  AND r.oid = idx.indrelid
  AND idx.indexrelid = idxr.oid 
  AND idxr.reltoastrelid = idxtoastr.oid 

UNION ALL 

-- relation indices toast index size
SELECT indexes_size(idxtoastidxr.relname) AS indexes_size, 
       relation_size(''pg_toast.''||idxtoastidxr.relname) AS data_size, 
       total_relation_size(idxtoastidxr.relname) AS total_size, 
       idxtoastidxr.relname, idxtoastidxr.relkind, 
       idxtoastidxr.oid AS relid, idxtoastidxr.relfilenode 
FROM pg_class r, pg_class idxr, pg_index idx, pg_class idxtoast, 
     pg_class idxtoastidxr
WHERE r.relname = \$1
  AND r.oid = idx.indrelid
  AND idx.indexrelid = idxr.oid 
  AND idxr.reltoastrelid = idxtoast.oid 
  AND idxtoast.reltoastrelid = idxtoastidxr.oid 
' LANGUAGE SQL;