@标签 PostgreSQL Database db SQL table size

参考文章：

• How to determine the size of PostgreSQL databases and tables

查看单个数据库的存储空间占用

注意把 mydb 替换成你实际要查看的数据库的名字

SELECT pg_size_pretty( pg_database_size('mydb') );

据我实测，300GB 的数据库查询一次耗时不到一秒：

+------------------+
| pg_size_pretty   |
|------------------|
| 325 GB           |
+------------------+
SELECT 1
Time: 0.798s

查看单张表的存储空间占用

注意把 mytable 替换成你实际要查看的数据表的名字

SELECT pg_size_pretty( pg_total_relation_size('mytable') );

输出示例：

+------------------+
| pg_size_pretty   |
|------------------|
| 1985 MB          |
+------------------+
SELECT 1
Time: 0.254s

高级技巧

用 Python 依次输出数据库和当前数据库中每张表的存储空间占用

cur = db.execute_sql("SELECT pg_size_pretty( pg_database_size('mydb') );")
print("## Total database size: {}".format(cur.fetchone()[0]))
cur = db.execute_sql("SELECT tablename FROM pg_tables WHERE schemaname = 'public';")
for res in cur.fetchall():
    tbl_name = res[0]
    tsize = db.execute_sql(
        "SELECT pg_size_pretty( pg_total_relation_size(%s));",
        [tbl_name]
    ).fetchone()[0]
    print("* {} size: {}".format(tbl_name, tsize))

输出示例：

## Total database size: 325 GB
* table_a size: 37 MB
* table_b size: 33 MB
* table_c size: 3928 kB
...