簡化用於列表表和索引大小的Postgres SQL查詢？

以下Postgres SQL查詢將列出所有模式及其大小和索引大小的所有表。如果表只是一個索引表，它將顯示爲100％的索引。簡化用於列表表和索引大小的Postgres SQL查詢？

SELECT schema, 
     name, 
     pg_size_pretty(CASE WHEN is_index THEN 0 ELSE s  END) AS size, 
     pg_size_pretty(CASE WHEN is_index THEN s ELSE st - s END) AS index, 
     CASE WHEN st = 0 THEN 0 
      WHEN is_index THEN 100 
          ELSE 100 - ((s*100)/st) END || '%' as ratio, 
     pg_size_pretty(st) as total 
    FROM (SELECT *, 
       st = s AS is_index 
      FROM (SELECT nspname as schema, 
         relname as name, 
         pg_relation_size(nspname || '.' || relname) as s, 
         pg_total_relation_size(nspname || '.' || relname) as st 
        FROM pg_class 
      JOIN pg_namespace ON (relnamespace = pg_namespace.oid)) AS p)               
    AS pp                 
ORDER BY st DESC LIMIT 30;

它會給結果如下：

schema   |   name   | size | index | ratio | total 
----------------+------------------------+---------+---------+-------+--------- 
public   | conf     | 4072 kB | 4360 kB | 52% | 8432 kB 
archive  | product_param   | 4048 kB | 3968 kB | 50% | 8016 kB             
public   | conf_pkey    | 0 bytes | 4320 kB | 100% | 4320 kB 
archive  | product_value   | 1568 kB | 1136 kB | 43% | 2704 kB 
public   | param_mapping   | 1472 kB | 832 kB | 37% | 2304 kB 
archive  | supplie_price   | 944 kB | 896 kB | 49% | 1840 kB 
public   | product_param_param_id | 0 bytes | 1552 kB | 100% | 1552 kB 
archive  | product_param_id  | 0 bytes | 1536 kB | 100% | 1536 kB

我來到一個地步，我可以不見森林的所有樹木，它開始變得有點笨拙。

我想知道是否有什麼可以簡化或冗餘嗎？如果查詢可以變得更簡單，那麼列不一定保持不變。

來源

2012-04-04 Adam Lindberg

另請參見http://stackoverflow.com/questions/2596624/how-do-you-find-the-disk-size-of-a-postgres-postgresql-表和它的索引。 – Vadzim 2014-04-03 09:40:12

我得到類似的結果（用不同的格式），與此查詢：

select 
    nspname as schema, 
    relname as name, 
    pg_relation_size(pg_class.oid) as size, 
    pg_indexes_size(pg_class.oid) as index, 
    pg_total_relation_size(pg_class.oid) as total, 
    100 * case when relkind = 'i' then pg_relation_size(pg_class.oid) 
            else pg_indexes_size(pg_class.oid) end 
     /pg_total_relation_size(pg_class.oid) as i_ratio 
from 
    pg_class 
    join pg_namespace on relnamespace = pg_namespace.oid 
order by 5 desc

來源

2012-04-05 16:21:46

雖然沒有漂亮的打印。 :-( – 2012-04-15 14:05:08

@AdamLindberg）你可以很容易地爲查詢添加漂亮的打印，我的關鍵研究點是簡化連接和子查詢 – 2012-04-15 20:39:02

唯一的問題是在'pg_size_pretty（...）'命令之後排序基於漂亮大小的字符串值，因此96 Kb> 960 Kb。 – 2012-04-17 14:47:12

首先爲什麼不使用CTE他們會讓你的代碼更具可讀性。然後你不回is_index所以它似乎是redundunt

with p as (
SELECT nspname as schema, 
     relname as name, 
     pg_relation_size(nspname || '.' || relname) as s, 
     pg_total_relation_size(nspname || '.' || relname) as st 
    FROM pg_class 
     JOIN pg_namespace 
      ON (relnamespace = pg_namespace.oid) 
), 
pp as (
SELECT *, 
     case when st = s then 0 else s end as size, 
     case when st = s then s else st-s end as index 

    FROM p 
) 
select schema, 
     name, 
     pg_size_pretty(size) as size,   
     pg_size_pretty(index) as index, 
     (case st 
      when 0 then 0 
      else index*100/st 
     end) || '%' ratio, 
     st total 
from pp 
order by st desc limit 30;

來源

2012-04-04 07:24:23 quzary

這不是簡單或更短，海事組織。 – 2012-04-05 06:58:03

也許你是對的，但它似乎更容易理解它。我已經改變了一點。 – quzary 2012-04-05 11:07:26

我真正想要做的是指出， quzary的迴應應該使用oid，而不是創建將無法解析回oid的字符串。

現在我必須寫合適的崗位（也許這是從評論停止新手的地步呢？）這裏是另一種清潔和美化了一番版本：

WITH p AS (
    SELECT n.nspname AS schema, 
     c.relname AS name, 
     pg_relation_size(c.oid) AS s, 
     pg_total_relation_size(c.oid) AS st 
    FROM pg_class c, pg_namespace n 
    WHERE c.relnamespace = n.oid 
) 
SELECT schema, name, 
    pg_size_pretty(s) AS size,   
    pg_size_pretty(st - s) AS index, 
    (100.0 * s/NULLIF(st, 0))::numeric(10,1) AS "% data of total", 
    st AS total 
FROM p 
ORDER BY st DESC 
LIMIT 30;

注意，它可能是添加有用在下面的行：

AND c.relkind = 'r'

的p的WHERE子句。這將僅限於關係/表格，並使代碼對於表格大小的總體摘要很有用。

來源

2012-06-26 15:24:56

並且不要忘記pg_relation_size和pg_total_relation_size不區分大小寫！

pg_relation_size(nspname || '.' || relname)

實際上應該是：

pg_relation_size('"' || nspname || '.' || relname || '"')

所以它與上情況下工作過。（花了我一會兒來找出這一個）

來源

2012-07-19 09:35:48 estani

簡化用於列表表和索引大小的Postgres SQL查詢？

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