i must determine if there's a mysql command to look for the presently used actual storage size a mysql area.
Maybe something similar to "show used_storage myfield FROM ... WHERE ..."
Oddly I couln'd find anything such as this.
(Exactly the same for postgresql could be interessting too)
For PostgreSQL you should use
Choose your_column, pg_column_size(your_column) Out of your_table
An entire listing of this type of functions is incorporated in the manual
If you work with a personality data area, the easiest could be
SELECT SUM(LENGTH(myField)) From MyTable
If you work with some statistical data type, you can just obtain a rely on the rows, and multiply it through the size, for example 4 for INTEGER, or 8 for DOUBLE.
It will not reflect the particular size taken on disk however. This really is most likely much more hard to discover. And even when it had been accurate, the particular size on the table might be a lot more compared to total size of all of the posts because of fragmentation along with other factors.
You will get the dimensions (and index size) of the entire table with:
SHOW TABLE STATUS LIKE 'MyTable';
Should you copy out only the column you need to a brand new temporary table, you might have the ability to obtain a more realistic look at just how much space your area is really taking on disk.