DB2LUW 9.7 and below the database config section_actuals should be disabled once data collection is done

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Though this is applicable to Db2LUW V9.7and below it's important to share this details as it can save lot of time for the users using those older versions still.

There is a  database configuration parameter  section_actuals. This parameter enables measurement of section actuals (runtime statistics measured during section execution)

The details is documented in Knowledge Center,

https://www.ibm.com/support/knowledgecenter/SSEPGG_9.7.0/com.ibm.db2.luw.admin.config.doc/doc/r0056714.html

This database configuration is usually suggested by Db2 Support team to obtain deeper optimizer data.

Once the data collection is done it's  recommended to turn the config back to it's default value of "NONE"

There is a possible situation when due to this parameter in place Db2 queries can face significant performance impact due to an internal floating point alignment issue with higher TRP wait time at the system level  (prstat output)

This is observed in the Solaris environment.

In summary  if the db config parameter section_actuals  is used to collect specific data it's  needed to be set back to NONE  after collection.

The issue is not there from GA level Db2 V10.1  and above.