Once you have had history collecting for an interval of time, you may want to look at using summarization and pruning to control the quantity of data being retained, and to also take advantage of the ability to use summarized data for trending purposes.
Below is an example of the configuration options for summarization and pruning. As part of the earlier exercise we enabled TDW history collection for Common Storage. Now we are going to enable summarization and pruning for this data.
By specifying summarization and pruning, we can control the quantity of data being retained within the TDW. This can be very important, especially for high volume tables of data or tables being collected for a large number of managed systems.
Another consideration to be aware of is that when you specify summarization, the summarization agent will create another set of tables. In the above example, the agent will have DB2 to create a table for hourly data and another table to hold daily data.
This is an area of confusion for some uers. I have encountered some shops who thought they were going to save space right away by turning on summarization. However, when they enabled the function, the TDW database ended up requiring more space. Why? Because the summarization agent had to create the additional tables to store the summarized data.