Considerable size difference between mysql versions

Question

We usually employ different MySQL versions for different scenarios. And I realized that similar databases, whith the same amount of tables and data, just because of different mysql versions differs in size from 43M to 223M. (~5x more)

My goal is understand why of that 5x more disk space required..

Some version 5.5.46 have this size:

du -hs /var/lib/mysql/
43M

And some 5.7.11 habe this size:

du -hs /var/lib/mysql/
223M

Inside of it, we use to have those default datafiles like: ib_logfile0, ib_logfile1, ibdata1, mysql..

Within 5.5.46 thay usually have this sizes respectively:

5.1M   ib_logfile0
5.1M   ib_logfile1
26M   ibdata1
6.5M   mysql

..but within 5.7.11 are waaay bigger:

48M   ib_logfile0
48M   ib_logfile1
76M   ibdata1
12M   have also this ibtmp1
25M   mysql

In order to understand all that difference, I took a look to release notes where Oracle writes down what they're changing: https://dev.mysql.com/doc/relnotes/mysql/5.5/en/

But could not find something conclusive. I appreciate your help on that.

Answer 1

I suggest looking at the 5.6/5.7 release notes to see what changed from 5.5.

ib_logfile file size are because the innodb_log_file_size changed from the outrageously small value of 5M to something that actually performs when people update any modest amount of data.

The ibdata1 increase in size might be a result of utf8_mb4 being the default.

System tables support more features and have some bigger fields.

Overall, its not that much. Are you really running on an embedded processor?

Answer 2

48M   ib_logfile0   -- new default is much better for most applications
48M   ib_logfile1
76M   ibdata1       -- did innodb_file_per_table change?
12M   have also this ibtmp1  -- new feature
25M   mysql         -- lots of features feed into this change

If the size is a big concern, you could lower innodb_log_file_size, but I would not go back to the old 5M. And it is a bit tricky to change that particular setting.

"concern about using minimum storaging space as possible" -- There are a lot of settings that affect RAM that could be lowered. The 5.7 defaults are better for the majority of systems than the pre 5.7 settings.