Autoextend

By default the autoextend property in Oracle tablespaces allows them to grow, as needed, until they exhaust all file system space. In this default, the only way to fail to extend the tablespace is by running out of disk/file system space.

The embedded MySQL database lets you define an initial size and an autoextend ceiling. This ceiling is a hard coded value in the MySQL config file. To change this, define the following in the my.ini/my.cnf files at creation time:

[Installation root]/oware3rd/mysql/ibdata/ibdata1:1024M:autoextend:max:2048M

What this says is to create a 1G data file at initiation and allow it to grow to a maximum of 2G, as needed. Once 2G is reached the server will start issuing errors (number 1114) for each insert attempted. If this occurs, you must add another data file to the system and revise Database Aging Policies accordingly.

The installer also lets you choose these MySQL values, defaulting to 1024M for initial and 8096M for the ceiling.

One example system would add a data file to the database to account for alarm/event history data:

[Installation root\/oware3rd/mysql/ibdata/ibdata1:2048M;c:/dorado/oware3rd/mysql/ibdata/ibdata2:2048M:autoextend:max:2048M

The autoextend property can only be found in the last data file specified. YOu must specify the size to which the first file grew when adding the second data file. See MySQL's documentation on the addition or removal of innoDB data files to determine the syntax. It is located at dev.mysql.com/doc/refman/4.1/en/adding-and-removing.html

The process essentially follows these steps:

1. Shutdown the application

2. Shutdown MySQL

3. Modify my.ini/my.cnf

4. Restart MySQL

5. Restart the application

If you store more historical data online (in your database) you must size it accordingly. This avoids databases filling before you are ready to manage the system.