For bug fixes or diagnostic patches on Oracle instances, hot fixesyou can perform the following actions:? Installation? Enable? Disable Hot patches: Overview Use hot fixes to install, enable, and disableis runningOfActive Oracle InstancesBug fixes or diagnostic patches on theprogram. using a hot patch is a recommended solution to avoid downtime when applying a hot patch. Oracle provides the use ofThe opatch command-line utility is capable of hot patching of any Oracle database. If the code changes scope andIf the complexity is small (for example, a diagnostic patch or minor bug fix), a hot fix is available.
? Applying hot patches does not require shutting down instances, re-linking OracleBinary file or restart the instance. ? Opatch can be used to install or uninstall hot fixes. Opatch can detect between two hot patches and a hot patch programconflicts with regular patches. Installing a hot patch differs from the usual patching mechanism, and applying a hot patch does not require you to close or restart the instance. Similar to regular patches, you can use Opatch to install hot patches. You can use the following command to determine if a patch is a hot fix: Opatch query-is_online_patch <patch location> oropatch Query <patchlocation>- All Note: The patched code will be provided as a dynamic/shared library, which will then be mapped to memory by each Oracle processthe.
- Advantages of hot Patches
? No downtime, no disruption of business? Extremely fast installation and uninstallation? Integration with Opatch: – Detect conflicts – listed in patch list – working in a RAC environment? Although the Oracle binaries on disk are not changed, hot patchesremains in effect when the instance is closed and started. The advantages of hot patches do not need to close the DB instance when applying a hot patch. Unlike regular patches, the installation and unloading speed of hot patches is extremelycome on. Because hot patches use opatch, you can get all the advantages of a regular patch that uses Opatch. NoHow many times the database is shut down, regardless of how long it takes to close the database, when the hot patch is closed and startedremain in effect at all times.
- General patches and hot fixes
Regular patches and hot patch general patches basically require the shutdown of the DB instance. Hot patches do not require any downtime. The application can continue to run when a hot patch is installed. Again, no need to stop.installed hot patches can be uninstalled by the machine.
? There may not be a hot fix on all platforms. Currently on the following platformsThere are hot patches on it:–linux x86–linux x86-64–solaris SPARC64? To consume some extra memory. – The exact amount of memory depends on:-Patch size-Number of Oracle processes currently running – Minimum memory: Each Oracle process accounts for approximately one OS page hot patch note an operating system (OS) page is typically 4 KB on Linux x86, and the Solaris SPAR 8 KB on C64. In the case of an average of approximately 1000 Oracle processes running concurrently, this means that a small hot patchadditional 4 MB of memory is used.
? Before each Oracle process installs or uninstalls a hot fix, there may bea very short delay (a few seconds). ? Not all bug fixes and diagnostic patches are available as hot fixes. You cannot use hot patches during downtime. If there is a possibility of downtime, you should install all of them in a regular patchrelated bug fixes. Hot Patch considerations (continued) A large portion of the diagnostic patches are available as hot patches. For bug fixes, it depends on their nature. Andnon-each bug fix or diagnostic patch can be used as a hot fix program. But the long-term goal of the hot patch tool is to be criticalPatch updates provide hot-fix functionality.
Source: http://blog.csdn.net/rlhua/article/details/16574625
