1. pg_class表
postgres=# \d pg_class
Table "pg_catalog.pg_class"
Column | Type | Collation | Nullable | Default
---------------------+--------------+-----------+----------+---------
oid | oid | | not null | 行标识符号
relname | name | | not null | 表，索引、视图等名字
relnamespace | oid | | not null | 包含该关系的名字空间oid
reltype | oid | | not null |
reloftype | oid | | not null |
relowner | oid | | not null |
relam | oid | | not null |
relfilenode | oid | | not null |
reltablespace | oid | | not null |
relpages | integer | | not null |
reltuples | real | | not null |
relallvisible | integer | | not null |
reltoastrelid | oid | | not null |
relhasindex | boolean | | not null |
relisshared | boolean | | not null |
relpersistence | "char" | | not null |
relkind | "char" | | not null |
relnatts | smallint | | not null |
relchecks | smallint | | not null |
relhasrules | boolean | | not null |
relhastriggers | boolean | | not null |
relhassubclass | boolean | | not null |
relrowsecurity | boolean | | not null |
relforcerowsecurity | boolean | | not null |
relispopulated | boolean | | not null |
relreplident | "char" | | not null |
relispartition | boolean | | not null |
relrewrite | oid | | not null |
relfrozenxid | xid | | not null |
relminmxid | xid | | not null |
relacl | aclitem[] | | |
reloptions | text[] | C | |
relpartbound | pg_node_tree | C | |
Indexes:
"pg_class_oid_index" PRIMARY KEY, btree (oid)
"pg_class_relname_nsp_index" UNIQUE CONSTRAINT, btree (relname, relnamespace)
"pg_class_tblspc_relfilenode_index" btree (reltablespace, relfilenode)
2.pg_stats
postgres=# \d pg_stats
View "pg_catalog.pg_stats"
Column | Type | Collation | Nullable | Default
------------------------+----------+-----------+----------+---------
schemaname | name | | | 表的模式名
tablename | name | | | 表的名称
attname | name | | | 列名
inherited | boolean | | | 如果为真，表示此行包括继承子列，不仅仅是指定表中的值
null_frac | real | | | 为空的比例
avg_width | integer | | | 列的条目的平均字节宽度
n_distinct | real | | | -1表示该列中无重复值，小于1，表示有重复值
most_common_vals | anyarray | | | 列中最常用值的一个列表(如果没有任何一个值看起来比其它更常用，此列为空)
most_common_freqs | real[] | | | 最常用值的频率列表，即每一个常用值的出现次数除以总数(如果most_common_vals为空，则此列为空)
histogram_bounds | anyarray | | |
correlation | real | | |
most_common_elems | anyarray | | |
most_common_elem_freqs | real[] | | |
elem_count_histogram | real[] | | |
标签：11,real,stats,oid,boolean,pg,null,class From： https://www.cnblogs.com/zmc60/p/17924486.html