在我的服务器上找到最大的数据库

Question

我在同一个 MySQL 服务器上运行了数百个数据库。如何获得按数据库大小排序的列表？

Answer 1

如果你想在 INFORMATION_SCHEMA 数据库中查询，我有以下内容：

按数据库划分的总存储量（以 MB 为单位）

SELECT DBName,CONCAT(LPAD(FORMAT(SDSize/POWER(1024,pw),3),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "DataSize",
CONCAT(LPAD(FORMAT(SXSize/POWER(1024,pw),3),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "IndexSize",
CONCAT(LPAD(FORMAT(STSize/POWER(1024,pw),3),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "Total Size"
FROM (SELECT IFNULL(DB,'All Databases') DBName,SUM(DSize) SDSize,
SUM(XSize) SXSize,SUM(TSize) STSize
FROM (SELECT table_schema DB,data_length DSize,index_length XSize, 
data_length+index_length TSize FROM information_schema.tables WHERE
table_schema NOT IN ('mysql','information_schema','performance_schema')) AAA
GROUP BY DB WITH ROLLUP) AA,(SELECT 2 pw) BB ORDER BY (SDSize+SXSize);

按存储引擎划分的总存储量

SELECT IFNULL(B.engine,'Total') "Storage Engine",
CONCAT(LPAD(REPLACE(FORMAT(B.DSize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "Data Size",
CONCAT(LPAD(REPLACE(FORMAT(B.ISize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "Index Size",
CONCAT(LPAD(REPLACE(FORMAT(B.TSize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "Table Size" FROM
(SELECT engine,SUM(data_length) DSize,SUM(index_length) ISize,
SUM(data_length+index_length) TSize FROM information_schema.tables
WHERE table_schema NOT IN ('mysql','information_schema','performance_schema')
AND engine IS NOT NULL GROUP BY engine WITH ROLLUP) B,(SELECT 2 pw) A ORDER BY TSize;

总存储数据库和存储引擎

SELECT IF(ISNULL(B.table_schema)+ISNULL(B.engine)=2,
"Storage for All Databases",IF(ISNULL(B.table_schema)+ISNULL(B.engine)=1,
CONCAT("Storage for ",B.table_schema),
CONCAT(B.engine," Tables for ",B.table_schema))) Statistic,
CONCAT(LPAD(REPLACE(FORMAT(B.DSize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "DataSize",
CONCAT(LPAD(REPLACE(FORMAT(B.ISize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "IndexSize",
CONCAT(LPAD(REPLACE(FORMAT(B.TSize/POWER(1024,pw),3),',',''),17,' '),' ',
SUBSTR(' KMGTP',pw+1,1),'B') "Table Size" FROM
(SELECT table_schema,engine,SUM(data_length) DSize,
SUM(index_length) ISize,SUM(data_length+index_length) TSize
FROM information_schema.tables WHERE table_schema NOT IN
('mysql','information_schema','performance_schema') AND
engine IS NOT NULL GROUP BY table_schema,engine WITH ROLLUP) B,
(SELECT 2 pw) A ORDER BY TSize;

请注意，在所有查询中，您看到的子查询如下所示： (SELECT 2 pw)

• (SELECT 0 pw) 以字节为单位显示数据库大小
• (SELECT 1 pw) 以千字节为单位显示数据库大小
• (SELECT 2 pw) 以兆字节为单位显示数据库大小
• (SELECT 3 pw) 以千兆字节为单位显示数据库大小
• (SELECT 4 pw) 以太字节为单位显示数据库大小
• (SELECT 5 pw) 以 PetaBytes 为单位显示数据库大小（如果你曾经运行过这个，请给我发电子邮件）

Answer 2

这应该可以让您获得数据的大小和数据库的索引（仅查看 MyISAM 或 InnoDB）：

SELECT table_schema 'database', 
 concat( round( sum( data_length + index_length ) / ( 1024 *1024 ) , 2 ) , 'M' ) size 
FROM information_schema.TABLES
WHERE ENGINE=('MyISAM' || 'InnoDB' ) 
GROUP BY table_schema 
ORDER BY size ASC;

请注意，这不一定是磁盘上的大小，尤其是在使用 InnoDB 时。您的 ibdata 文件（以及单个 *.idb 文件，如果使用innodb_file_per_table选项）会持续增长，但不会自动缩小。

要获取磁盘上的文件大小（如果使用 Linux）：

du -s /path/to/mysql/data/dir | sort -n