我在Postgres weekly上遇到了此查询,该查询以字节为单位显示表,表的大小,toast大小和索引大小:
SELECT
relname AS table_name,
pg_size_pretty(pg_total_relation_size(relid)) AS total,
pg_size_pretty(pg_relation_size(relid)) AS internal,
pg_size_pretty(pg_table_size(relid) - pg_relation_size(relid)) AS external,
pg_size_pretty(pg_indexes_size(relid)) AS indexes
FROM pg_catalog.pg_statio_user_tables
ORDER BY pg_total_relation_size(relid) DESC;
我知道Postgres正在为每个分区创建一个表,所以我要分别为每个分区获取条目,但是有没有一种方法可以使每个表获得一行,而不管该表是否已分区?
答案 0 :(得分:1)
当然可以,但是您必须与其他目录表结合使用GROUP BY
。
目录relkind
中的属性pg_class
将告诉您关系是否已分区(p
)(r
)。
目录pg_inherits
将告诉您哪个分区(inhrelid
)属于哪个分区表(inhparent
)。
由于可以再次对分区进行分区,因此,如果要覆盖所有基础,则必须编写一个递归公用表表达式。
答案 1 :(得分:1)
按照@Laurenz Albe的指示,我创建了一个满足我需要的查询。这将从特定数据库中获取所有分区表的总内存。
SELECT
pi.inhparent::regclass AS parent_table_name,
pg_size_pretty(sum(pg_total_relation_size(psu.relid))) AS total,
pg_size_pretty(sum(pg_relation_size(psu.relid))) AS internal,
pg_size_pretty(sum(pg_table_size(psu.relid) - pg_relation_size(psu.relid))) AS external, -- toast
pg_size_pretty(sum(pg_indexes_size(psu.relid))) AS indexes
FROM pg_catalog.pg_statio_user_tables psu
JOIN pg_class pc ON psu.relname = pc.relname
JOIN pg_database pd ON pc.relowner = pd.datdba
JOIN pg_inherits pi ON pi.inhrelid = pc.oid
WHERE pd.datname = :database_name
GROUP BY pi.inhparent
ORDER BY sum(pg_total_relation_size(psu.relid)) DESC;
请注意,在有分区分区的情况下,根表不会有一行,但是每个父表都会有自己的行
答案 2 :(得分:0)
即使我们有多个分区级别,这也会给出每个父表的表大小:
WITH RECURSIVE tables AS (
SELECT
c.oid AS parent,
c.oid AS relid,
1 AS level
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_inherits AS i ON c.oid = i.inhrelid
-- p = partitioned table, r = normal table
WHERE c.relkind IN ('p', 'r')
-- not having a parent table -> we only get the partition heads
AND i.inhrelid IS NULL
UNION ALL
SELECT
p.parent AS parent,
c.oid AS relid,
p.level + 1 AS level
FROM tables AS p
LEFT JOIN pg_catalog.pg_inherits AS i ON p.relid = i.inhparent
LEFT JOIN pg_catalog.pg_class AS c ON c.oid = i.inhrelid AND c.relispartition
WHERE c.oid IS NOT NULL
)
SELECT
parent ::REGCLASS AS table_name,
array_agg(relid :: REGCLASS) AS all_partitions,
pg_size_pretty(sum(pg_total_relation_size(relid))) AS pretty_total_size,
sum(pg_total_relation_size(relid)) AS total_size
FROM tables
GROUP BY parent
ORDER BY sum(pg_total_relation_size(relid)) DESC