Re: expertise with FCF or FAN

So I forgot to mention a minor drawback of this method: it requires UCP to be configured on the db host. If your already doing connection pooling on the app side, this can appear to be moving a resource consumer from the app to the DB, possibly chewing up more resources on the DB side. For large configurations this might impact the cpu count and Oracle licensing, so there is a debate as to the efficiency - do connection pooling on the app server side, or the DB side ? My real-world experience is that you continue to do the connecting pooling on the app side, but configure UCP on the db as well. This also means you have to be rigorous in the db side Java RU patches to go along with the DB and Grid patches, because now you are certainly using Java on the db side. So it first appears that this is can lead to a significant performance issue, but real-world experience shows it is rarely a problem. If you have the luxury of picking your java server, I would suggest Weblogic or Websphere for the best support of this feature, but it works ok with Tomcat at least for ver 8 and higher. The 19c doc versions of FCF, FAN etc are much improved for implementation details. The reason I mention this issue is that I had some RAC that went as high as 20 nodes, replicating to multiple DG targets, and it appeared that UCP was causing a performance issue that was later traced back to something unrelated.

On Wed, Feb 16, 2022 at 1:47 AM Jon Crisler <joncrisler_at_gmail.com> wrote:

> So the POC will be an Oracle Restart configuration, but will the final
> platform be a multinode RAC ? Most of the functionality for JDBC
> connectivity is part of the jdbc.jar, so if you have both the local and
> target DB in the connect strings, it will connect fine without any app
> changes. A common problem is the failure to open up ONS between the app
> and db, port 6200 by default. Metalink has a ONS java validation program
> somewhere that is good to check the network and db setup. Also check that
> ONS is responding properly on the db side, but this is pretty reliable in
> 12c and beyond. Also try to use a very recent ojdbc.jar- generally use the
> same or higher version on the client . versions 11 and early 12.1 had
> some nasty and difficult to find bugs dealing with Scan-IP, but I found
> that 19c has been pretty solid.
>
> On Tue, Feb 15, 2022 at 12:39 PM Tim Gorman <tim.evdbt_at_gmail.com> wrote:
>
>> Friends and colleagues,
>>
>> I have a customer interested in setting up FCF (fast connection failover)
>> and FAN (fast application notification) on their JDBC applications for a
>> POC using Oracle DataGuard.
>>
>> Does anyone have expertise and/or gotchas in setting FCF/FAN over a
>> single-instance Oracle Restart configuration?
>>
>> We've reviewed doc pages on About FCF
>> <https://docs.oracle.com/en/database/oracle/oracle-database/19/jjucp/fast-connection-failover.html#GUID-126F8C9B-C0B3-426B-B07D-4B127BBDD867>
>> and Automating FCF
>> <https://docs.oracle.com/database/121/HABPT/config_fcf.htm#HABPT4967>,
>> and we're hoping to chat with someone with practical expertise?
>>
>> Thanks!
>>
>> -Tim
>>
>

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