Changing AUS expiration policies

You can change AUS expiration policies to customize how often statistics are updated based on how old the statistics are, how much data has changed, or how large the table is.

You must be connected to the sysadmin database as user informix or another authorized user.

To change the value of an expiration policy, update the value column in the ph_threshold table in the sysadmin database.

For example, if you find that queries against small tables with 1000 rows or fewer run faster if their statistics are updated more frequently, you can change the expiration policy to ensure that their statistics are updated every week. The following example changes the value of the AUS_SMALL_TABLES threshold to 1000:

UPDATE ph_threshold
SET value = 1000
WHERE name = "AUS_SMALL_TABLES";

The new threshold takes effect the next time the Auto Update Statistics Evaluator task runs.