I create a lot of small databases to do testing on. The trouble is that I often need to change the size of redo log files when I'm testing large transaction workloads or loading a lot of data. Now there are lots of better ways to do whats shown in the code below but this approach gave me the chance to keep brushing up my python skills and use the might cx_oracle driver. The following should never be considered anything but a nasty hack but it does save me a little bit of time i.e. don't use this on anything but a test database… Clearly the sensible way to do this is to write my own scripts to build databases.

The following code works it's way through the redo log files drops one thats inactive and then simply recreates it. It finished when it's set all of the redo to the right size.

Running the script is simply a case of running it with the parameters shown below

python ChangeRedoSize -u sys -p welcome1 -cs myserver/orclcdb --size 300

Note : the user is the sysdba of the container database if you are using the multitenant arhcitecture and the size is in Mega Bytes.

You should then see something similar to the following

Current Redo Log configuration
+-----------+------------+--------------+-----------+---------------+----------+
| Group No. | Thread No. | Sequence No. | Size (MB) | No of Members |  Status  |
+-----------+------------+--------------+-----------+---------------+----------+
|     1     |     1      |     446      | 524288000 |       1       | INACTIVE |
|     2     |     1      |     448      | 524288000 |       1       | CURRENT  |
|     3     |     1      |     447      | 524288000 |       1       |  ACTIVE  |
+-----------+------------+--------------+-----------+---------------+----------+
alter system switch logfile
alter system switch logfile
alter database drop logfile group 2
alter database add logfile group 2 size 314572800
alter system switch logfile
alter database drop logfile group 1
alter database add logfile group 1 size 314572800
alter system switch logfile
alter system switch logfile
alter system switch logfile
alter system switch logfile
alter database drop logfile group 3
alter database add logfile group 3 size 314572800
alter system switch logfile
All logs correctly sized. Finishing...
New Redo Log configuration
+-----------+------------+--------------+-----------+---------------+----------+
| Group No. | Thread No. | Sequence No. | Size (MB) | No of Members |  Status  |
+-----------+------------+--------------+-----------+---------------+----------+
|     1     |     1      |     455      | 314572800 |       1       |  ACTIVE  |
|     2     |     1      |     454      | 314572800 |       1       | INACTIVE |
|     3     |     1      |     456      | 314572800 |       1       | CURRENT  |
+-----------+------------+--------------+-----------+---------------+----------+