1 Introduction and Requirements

Patches are a small collection of files copied over an existing installation. They are associated to particular versions of Oracle Products. When applied to the correct version of an installed product, patches result in an upgraded version of the product.

The OPatch Java-based utility enables the application and rollback of interim patches to Oracle's software. OPatch is platform-independent and runs on all supported operating systems.

This chapter discusses the following introductory and advisory topics:

• OPatch Features

• Requirements for OPatch

• Environment Variables OPatch Uses

• Backup Recommendations

OPatch Features

The OPatch 10.2 utility has the following features:

• Scalability — OPatch is scalable to support a large number of patches.

• Reliability — OPatch is reliable and protects the Oracle home and inventory. It can return the Oracle home to a stable state from patch application failures. It can also easily detect patch conflicts.

• Portability — OPatch is compatible with all operating systems for which Oracle releases software.

• Robust — OPatch is very robust. It is very easy to apply a patch as well as remove it.

• Easy to maintain — OPatch is easy to maintain and is also extensible.

• Support for Silent Operation — OPatch supports silent operation. This mode enables you to run the software without any user interaction.

• Support for Real Application Clusters — OPatch supports Real Application Clusters and works well in that setup. It is easy to extend it to the Grid Control.

• Easy to debug — OPatch has various levels of logging and tracing mechanisms. It also has a debug option that helps to easily diagnose software problems.

OPatch supports the following capabilities:

• Applying an interim patch.

• Rolling back the application of an interim patch.

• Detecting conflict when applying an interim patch after previous interim patches have been applied. It also suggests the best options to resolve a conflict.

• Reporting on installed products and interim patch.

Requirements for OPatch

The OPatch utility requires the following items:

• The Oracle Universal Installer must be installed.

• The Oracle home environment variable (ORACLE_HOME) must point to a valid Oracle home directory and match the value used during installation of the Oracle home directory. See Chapter 3, "OPatch Prerequisite Checks" for more information.

• Java SDK 1.4 or higher must be available.

• Java commands for Windows must be available.

• ar, cp, fuser, and make commands for UNIX must be available.

• The library path must be set correctly for Oracle Real Application Clusters environments. OPatch uses some APIs to detect if the system is Real Application Clusters. Ensure that the library path is set correctly as follows:

  For Solaris
  LD_LIBRARY_PATH = $ORACLE_HOME/lib32:$ORACLE_HOME/lib
  For HP-UX - 
  SHLIB_PATH=$ORACLE_HOME/lib32:/usr/lib
  

  See Also:

  For the latest information about the OPatch utility, to check for updates, and to get latest versions, refer to My Oracle Support (formerly MetaLink) at:

  http://www.oracle.com/support/metalink/index.html

Environment Variables OPatch Uses

OPatch uses the following environment variables:

ORACLE_HOME — Oracle home location."Recovering from a Failed Patching Session Using OPatch"

OPATCH_DEBUG — Log level that specifies the amount of logging OPatch should perform.

OPATCH_PLATFORM_ID — Unique platform ID.

PATH — Path information.

Backup Recommendations

It is highly recommended that you back up the ORACLE_HOME before any patch operation. You can back up the ORACLE_HOME using your preferred method. You can use any method, such as zip, cp -r, tar, and cpio to compress the ORACLE_HOME.

For recovery information, see "Recovering from a Failed Patching Session Using OPatch" on page 7E2.