How to Get True Size of MySQL Database?

问题:

I would like to know how much space does my MySQL database use, in order to select a web host. I found the command SHOW TABLE STATUS LIKE 'table_name' so when I do the query, I get something like this:

Name       | Rows | Avg. Row Length | Data_Length | Index Length
----------   ----   ---------------   -----------   ------------
table_name   400          55            362000        66560

• numbers are rounded.

So do I have 362000 or 400*362000 = 144800000 bytes of data for this table? And what does Index Length mean? Thanks !

回答1:

From S. Prakash, found at the MySQL forum:

SELECT table_schema "database name",
    sum( data_length + index_length ) / 1024 / 1024 "database size in MB",
    sum( data_free )/ 1024 / 1024 "free space in MB"
FROM information_schema.TABLES
GROUP BY table_schema; 

Or in a single line for easier copy-pasting:

SELECT table_schema "database name", sum( data_length + index_length ) / 1024 / 1024 "database size in MB", sum( data_free )/ 1024 / 1024 "free space in MB" FROM information_schema.TABLES GROUP BY table_schema; 

回答2:

You can get the size of your Mysql database by running the following command in Mysql client

SELECT  sum(round(((data_length + index_length) / 1024 / 1024 / 1024), 2))  as "Size in GB"
FROM information_schema.TABLES
WHERE table_schema = "<database_name>"

回答3:

If you use phpMyAdmin, it can tell you this information.

Just go to "Databases" (menu on top) and click "Enable Statistics".

You will see something like this:

This will probably lose some accuracy as the sizes go up, but it should be accurate enough for your purposes.

回答4:

if you want to find it in MB do this

SELECT table_schema                                        "DB Name", 
   Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

回答5:

Basically there are two ways: query DB (data length + index length) or check files size. Index length is related to data stored in indexes.

Everything is described here:

http://www.mkyong.com/mysql/how-to-calculate-the-mysql-database-size/

回答6:

None of the answers include the overhead size and the metadata sizes of tables.

Here is a more accurate estimation of the "disk space" allocated by a database.

SELECT ROUND((SUM(data_length+index_length+data_free) + (COUNT(*) * 300 * 1024))/1048576+150, 2) AS MegaBytes FROM information_schema.TABLES WHERE table_schema = 'DATABASE-NAME'

回答7:

SUM(Data_free) may or may not be valid. It depends on the history of innodb_file_per_table. More discussion is found here.

回答8:

MySQL Utilities by Oracle have a command called mysqldiskusage that displays the disk usage of every database: https://dev.mysql.com/doc/mysql-utilities/1.6/en/mysqldiskusage.html

回答9:

If you are using MySql Workbench, its very easy to get all details of Database size, each table size, index size etc.

1. Right Click on Schema

2. Select Schema Inspector option

   

3. It Shows all details of Schema size

4. Select Tables Tab to see size of each table.

   

5. Table size diplayed in Data Lenght column

回答10:

If you want to find the size of all MySQL databases, us this command, it will show their respective sizes in megabytes;

SELECT table_schema "database", sum(data_length + index_length)/1024/1024 "size in MB" FROM information_schema.TABLES GROUP BY table_schema;

If you have large databases, you can use the following command to show the result in gigabytes;

SELECT table_schema "database", sum(data_length + index_length)/1024/1024/1024 "size in GB" FROM information_schema.TABLES GROUP BY table_schema;

If you want to show the size of only a specific database, for example YOUR_DATABASE_NAME, you could use the following query;

SELECT table_schema "database", sum(data_length + index_length)/1024/1024/1024 "size in GB" FROM information_schema.TABLES WHERE table_schema='YOUR_DATABASE_NAME' GROUP BY table_schema;