Mysql版
1、查看所有数据库容量大小
-- 查看所有数据库容量大小
SELECT
table_schema AS '数据库',
sum( table_rows ) AS '记录数',
sum(
TRUNCATE ( data_length / 1024 / 1024, 2 )) AS '数据容量(MB)',
sum(
TRUNCATE ( index_length / 1024 / 1024, 2 )) AS '索引容量(MB)'
FROM
information_schema.TABLES
GROUP BY
table_schema
ORDER BY
sum( data_length ) DESC,
sum( index_length ) DESC;
2、查看所有数据库各表容量大小
SELECT
table_schema AS '数据库',
table_name AS '表名',
table_rows AS '记录数',
TRUNCATE ( data_length / 1024 / 1024, 2 ) AS '数据容量(MB)',
TRUNCATE ( index_length / 1024 / 1024, 2 ) AS '索引容量(MB)'
FROM
information_schema.TABLES
ORDER BY
data_length DESC,
index_length DESC;
3、查看指定数据库容量大小
SELECT
table_schema AS '数据库',
sum( table_rows ) AS '记录数',
sum(
TRUNCATE ( data_length / 1024 / 1024, 2 )) AS '数据容量(MB)',
sum(
TRUNCATE ( index_length / 1024 / 1024, 2 )) AS '索引容量(MB)'
FROM
information_schema.TABLES
WHERE
table_schema = '数据库名';4.查看指定数据库各表容量大小
SELECT
table_schema AS '数据库',
table_name AS '表名',
table_rows AS '记录数',
TRUNCATE ( data_length / 1024 / 1024, 2 ) AS '数据容量(MB)',
TRUNCATE ( index_length / 1024 / 1024, 2 ) AS '索引容量(MB)'
FROM
information_schema.TABLES
WHERE
table_schema = '数据库名'
ORDER BY
data_length DESC,
index_length DESC;5.查看指定数据库各表信息
SHOW TABLE STATUS;
oracle版
-
查看表所占的空间大小
-- 不需要DBA权限
SELECT SEGMENT_NAME TABLENAME,(BYTES/1024/1024) MB
,RANK() OVER (PARTITION BY NULL ORDER BY BYTES DESC) RANK_ID //根据表大小进行排序
FROM USER_SEGMENTS
WHERE SEGMENT_TYPE='TABLE'
-- 需要DBA权限,一般情况下很少会给这么高的权限,可以说这个权限基本没有,所以一般工作中不是DBA的人不会常用到这个命令
SELECT t.tablespace_name, round(SUM(bytes / (1024 * 1024)), 0) ts_size
FROM dba_tablespaces t, dba_data_files d
WHERE t.tablespace_name = d.tablespace_name
GROUP BY t.tablespace_name; -
查看表空间的使用情况
SELECT a.tablespace_name "表空间名称",
total / (1024 * 1024) "表空间大小(M)",
free / (1024 * 1024) "表空间剩余大小(M)",
(total - free) / (1024 * 1024 ) "表空间使用大小(M)",
total / (1024 * 1024 * 1024) "表空间大小(G)",
free / (1024 * 1024 * 1024) "表空间剩余大小(G)",
(total - free) / (1024 * 1024 * 1024) "表空间使用大小(G)",
round((total - free) / total, 4) * 100 "使用率 %"
FROM (SELECT tablespace_name, SUM(bytes) free
FROM dba_free_space
GROUP BY tablespace_name) a,
(SELECT tablespace_name, SUM(bytes) total
FROM dba_data_files
GROUP BY tablespace_name) b
WHERE a.tablespace_name = b.tablespace_name-
查看回滚段名称及大小
SELECT segment_name,
tablespace_name,
r.status,
(initial_extent / 1024) initialextent,
(next_extent / 1024) nextextent,
max_extents,
v.curext curextent
FROM dba_rollback_segs r, v$rollstat v
WHERE r.segment_id = v.usn(+)
ORDER BY segment_name; 4、查看控制文件
SELECT NAME FROM v$controlfile; 5、查看日志文件
SELECT MEMBER FROM v$logfile; 6、查看数据库对象
SELECT owner, object_type, status, COUNT(*) count#
FROM all_objects
GROUP BY owner, object_type, status; 7、查看数据库版本
SELECT version
FROM product_component_version
WHERE substr(product, 1, 6) = 'Oracle'; 8、查看数据库的创建日期和归档方式
SELECT created, log_mode, log_mode FROM v$database;
注:在日常工作中经常查看数据库所占用的容量、每张表所占用的空间等十分重要。经历血的教训后才彻底明白的。
原文始发于微信公众号（Itbestboy）：常用查看数据库信息
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