【openGauss】运维常用的SQL

一、查模式

SELECT pn.oid AS schema_oid, iss.catalog_name, iss.schema_owner, iss.schema_name

FROM information_schema.schemata iss

INNER JOIN pg_namespace pn ON pn.nspname = iss.schema_name;

二、查对象

1. 查看某模式下的表名
   
   select tablename from pg_tables where schemaname = 'hsjc_bi';

select schemaname,tablename

from pg_tables

where schemaname = 'xxx' and tablename like 'fact_%';

select 'truncate table ' || schemaname || '.' || tablename || ';'

from pg_tables

where schemaname = 'xxx' and tablename like 'fact_%';

1. 查看某表的字段

SELECT

A.attname AS NAME,

format_type(A.atttypid, A.atttypmod) AS TYPE,

A.attnotnull AS NOTNULL,

col_description(A.attrelid, A.attnum) AS COMMENT

FROM

pg_class AS C,

pg_attribute AS A

WHERE

C.relname = 'tableName'

AND A.attnum > 0

AND A.attrelid = C.oid

1. 查询数据表名称及中文备注、每个表的记录数

SELECT a.relname AS name,

b.description AS comment,

a.reltuples

FROM pg_class a

LEFT OUTER JOIN pg_description b ON b.objsubid=0 AND a.oid = b.objoid

WHERE a.relnamespace = (SELECT oid FROM pg_namespace WHERE nspname='public') AND a.relkind='r'

ORDER BY a.relname;

1. 查某表的索引

二、查大小

1. 查看所有表的表大小

select table_schema,

TABLE_NAME,

reltuples,

pg_size_pretty(pg_total_relation_size('"'||table_schema||'"."'||table_name||'"'))

from pg_class, information_schema.tables

where relname = TABLE_NAME

ORDER BY reltuples desc

limit 20;

查看某表的索引