STATCHANGE configuration parameter

Use the STATCHANGE configuration parameter to specify a positive integer for a global percentage of a change threshold for the server to use to determine if distribution statistics qualify for an update when the automatic mode for UPDATE STATISTICS operations is enabled.

onconfig.std value
STATCHANGE 10
values
0 - 100
units
percentage of a change threshold
takes effect
After you edit your onconfig file and restart the database server.
When you reset the value dynamically in your onconfig file by running the onmode -wf command.
When you reset the value in memory by running the onmode -wm command.

Usage

The database server uses the value of the STATCHANGE configuration parameter when the AUTO_STAT_MODE configuration parameter, the AUTO_STAT_MODE session environment variable, or the AUTO keyword of the UPDATE STATISTICS statement has enabled the automatic mode for UPDATE STATISTICS operations.

The STATCHANGE setting specifies a change threshold for the database server to use to determine if distribution statistics qualify for an update when the automatic mode for UPDATE STATISTICS operations is enabled. When this mode is enabled, the UPDATE STATISTICS statement compares the STATCHANGE setting with the percentage of rows that have changed in each table or fragment since the current data distributions were calculated, and selectively updates only the missing or stale distribution statistics for each table or fragment within the scope of the UPDATE STATISTICS statement.


Copyright© 2019 HCL Technologies Limited