Need to enable or disable certain bug fixes?

Yes, it is possible.

This is typically used in the optimizer area to allow specific fixes to be turned on or off as some fixes can have a significant  effect on execution plans.

_FIX_CONTROL is a special hidden dynamic parameter introduced in which accomplishes exactly this.

The syntax for using _FIX_CONTROL is:


To enable:
“_fix_control”=’Bugno:ON’    (OR)   “_fix_control”=”Bugno:1”

To disable:
“_fix_control”=’Bugno:OFF’  (OR)   “_fix_control”=”Bugno:0”

Source: MOS note 827984.1

Also check Tim Hall website for more info:


Oracle 12c – Transaction Guard and Application Continuity

São dois recursos novos disponíveis nas options Oracle Real Application Clusters (RAC), Oracle RAC One Node e Oracle Active Data Guard:

  1. Transaction Guard is a reliable protocol and tool available with the Oracle Database 12c that returns the outcome of the last in-flight transaction after outages that make the database session unavailable. It is used by Application Continuity to ensure that an in-flight transaction is committed successfully, no more than once.
  2. Application Continuity (AC) is a new feature available with the Oracle Real Application Clusters (RAC), Oracle RAC One Node and Oracle Active Data Guard options that masks outages from end users and applications by recovering the in-flight database sessions following recoverable outages. Application Continuity masks outages from end users and applications by recovering the in-flight work for impacted database sessions following outages. Application Continuity performs this recovery beneath the application so that the outage appears to the application as a slightly delayed execution. Application Continuity strengthens the fault tolerance of systems and applications that use an Oracle database.

Ou seja, com esse recurso a Oracle melhora a experiência do usuário quando ocorrem indisponibilidades planejadas ou não.

Quer ver na prática como funciona, acesse o link:

Dois white papers estão disponíveis com mais informações:

Click to access application-continuity-wp-12c-1966213.pdf

Click to access transaction-guard-wp-12c-1966209.pdf