数据库查看表大小

SELECT
  TABLE_NAME AS `Table`,
  ROUND((DATA_LENGTH + INDEX_LENGTH) / 1024 / 1024) AS `Size (MB)`
FROM
  information_schema.TABLES
WHERE
    TABLE_SCHEMA = "$DB_NAME"
  AND
    TABLE_NAME = "$TABLE_NAME"
ORDER BY
  (DATA_LENGTH + INDEX_LENGTH)
DESC;

select table_schema as database_name, table_name, round( (data_length + index_length) / 1024 / 1024, 2) as total_size, round( (data_length) / 1024 / 1024, 2) as data_size, round( (index_length) / 1024 / 1024, 2) as index_size from information_schema.tables where table_schema not in ('information_schema', 'mysql', 'performance_schema' ,'sys') and table_type = 'BASE TABLE' order by total_size desc limit 10;

// 查看表数据占用空间
SELECT pg_size_pretty(pg_relation_size('sms_push_log'));
// 查看表索引占用空间
SELECT pg_size_pretty(pg_indexes_size('sms_push_log'));
// 查看表的总占用空间
SELECT pg_size_pretty(pg_total_relation_size('sms_push_log'));

SELECT 
  relname, 
  100 * idx_scan / (seq_scan + idx_scan) percent_of_times_index_used, 
  n_live_tup rows_in_table
FROM 
  pg_stat_user_tables
WHERE 
    seq_scan + idx_scan > 0 
ORDER BY 
  n_live_tup DESC;