sql文1：

SELECT relname,reltuples,(relpages / 128) as mbytes,(relpages * 8192.0 / (reltuples + 1e-10)) as average_row_size FROM pg_class ORDER BY mbytes DESC;

sql文2：

SELECT pgn.nspname,relname,pg_size_pretty(relpages::bigint * 8 * 1024) AS size,CASE WHEN relkind = 
't' THEN (SELECT pgd.relname FROM pg_class pgd WHERE pgd.reltoastrelid = pg.oid) WHEN nspname = 
'pg_toast' AND relkind = 'i' THEN (SELECT pgt.relname FROM pg_class pgt WHERE SUBSTRING(pgt.relname 
FROM 10) = REPLACE(SUBSTRING(pg.relname FROM 10),'_index','')) ELSE (SELECT pgc.relname FROM 
pg_class pgc WHERE pg.reltoastrelid = pgc.oid) END::varchar AS refrelname,CASE WHEN nspname = 
'pg_toast' AND relkind = 'i' THEN (SELECT pgts.relname FROM pg_class pgts WHERE pgts.reltoastrelid = 
(SELECT pgt.oid FROM pg_class pgt WHERE SUBSTRING(pgt.relname FROM 10) = REPLACE(SUBSTRING(pg.relname 
FROM 10),''))) END AS relidxrefrelname,relfilenode,relkind,reltuples::bigint,relpages 
FROM pg_class pg,pg_namespace pgn WHERE pg.relnamespace = pgn.oid AND pgn.nspname NOT IN 
('information_schema','pg_catalog') ORDER BY relpages DESC;