Oracle internals, debugging and undocumented features
This is also undocumented feature.As name suggest this utility is used to install patches or to be more precise online patches without shooting down instance ( as you know Oracle now offers online patching ).
This patch utility can be invoked by running oradebug command:
Here is list of all available options which are self descriptive:
[list|install|remove|disable|enable] <file> <temp>
temp = (disabled at restart
file = (in $ORACLE_HOME/hpatch/)
$ORACLE_HOME/hpatch directory contains shared libraries used by online patching.
$ORACLE_HOME/hpatch/orapatch@.cfg ( configuration file )
Oracle has dummy patch 6198642 which can be used to test online patching.You can see it on Laurent’s blog:
and more on online patching: