Useful PostgreSQL utilities
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\prompt 'This utility will read tables with given mask using pgstattuple extension and return top 20 bloated tables.\nWARNING: without table mask query will read all available tables which could cause I/O spikes.\nPlease enter mask for table name (check all tables if nothing is specified): ' tablename
--faster version of table_bloat.sql which returns approximate results and doesn't read whole table (but reads toast tables)
--pgstattuple v1.3+ extension required (available since postgresql 9.5)
--WARNING: without table name/mask query will read all available tables which could cause I/O spikes
select table_name,
pg_size_pretty(relation_size + toast_relation_size) as total_size,
pg_size_pretty(toast_relation_size) as toast_size,
round(greatest(((relation_size * fillfactor/100)::numeric - tuple_len) / greatest((relation_size * fillfactor/100)::numeric, 1) * 100, 0)::numeric, 1) AS table_waste_percent,
pg_size_pretty((relation_size * fillfactor/100 - tuple_len)::bigint) AS table_waste,
round((((relation_size * fillfactor/100) + toast_relation_size - (tuple_len + toast_tuple_len))::numeric / greatest((relation_size * fillfactor/100) + toast_relation_size, 1)::numeric) * 100, 1) AS total_waste_percent,
pg_size_pretty(((relation_size * fillfactor/100) + toast_relation_size - (tuple_len + toast_tuple_len))::bigint) AS total_waste
from (
select
(case when n.nspname = 'public' then format('%I', c.relname) else format('%I.%I', n.nspname, c.relname) end) as table_name,
(select approx_tuple_len from pgstattuple_approx(c.oid)) as tuple_len,
pg_relation_size(c.oid) as relation_size,
(case when reltoastrelid = 0 then 0 else (select approx_tuple_len from pgstattuple_approx(c.reltoastrelid)) end) as toast_tuple_len,
coalesce(pg_relation_size(c.reltoastrelid), 0) as toast_relation_size,
coalesce((SELECT (regexp_matches(reloptions::text, E'.*fillfactor=(\\d+).*'))[1]),'100')::real AS fillfactor
from pg_class c
left join pg_namespace n on (n.oid = c.relnamespace)
where nspname not in ('pg_catalog', 'information_schema')
and nspname !~ '^pg_toast' and nspname !~ '^pg_temp' and relkind in ('r', 'm') and (relpersistence = 'p' or not pg_is_in_recovery())
--put your table name/mask here
and relname ~ :'tablename'
) t
order by total_waste_percent desc
limit 20;